python-3.6.zip added from Github

README.cosmo contains the necessary links.

third_party/python/Lib/asyncio/__init__.py

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+"""The asyncio package, tracking PEP 3156."""
+
+import sys
+
+# The selectors module is in the stdlib in Python 3.4 but not in 3.3.
+# Do this first, so the other submodules can use "from . import selectors".
+# Prefer asyncio/selectors.py over the stdlib one, as ours may be newer.
+try:
+    from . import selectors
+except ImportError:
+    import selectors  # Will also be exported.
+
+if sys.platform == 'win32':
+    # Similar thing for _overlapped.
+    try:
+        from . import _overlapped
+    except ImportError:
+        import _overlapped  # Will also be exported.
+
+# This relies on each of the submodules having an __all__ variable.
+from .base_events import *
+from .coroutines import *
+from .events import *
+from .futures import *
+from .locks import *
+from .protocols import *
+from .queues import *
+from .streams import *
+from .subprocess import *
+from .tasks import *
+from .transports import *
+
+__all__ = (base_events.__all__ +
+           coroutines.__all__ +
+           events.__all__ +
+           futures.__all__ +
+           locks.__all__ +
+           protocols.__all__ +
+           queues.__all__ +
+           streams.__all__ +
+           subprocess.__all__ +
+           tasks.__all__ +
+           transports.__all__)
+
+if sys.platform == 'win32':  # pragma: no cover
+    from .windows_events import *
+    __all__ += windows_events.__all__
+else:
+    from .unix_events import *  # pragma: no cover
+    __all__ += unix_events.__all__

third_party/python/Lib/asyncio/base_futures.py

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+__all__ = []
+
+import concurrent.futures._base
+import reprlib
+
+from . import events
+
+Error = concurrent.futures._base.Error
+CancelledError = concurrent.futures.CancelledError
+TimeoutError = concurrent.futures.TimeoutError
+
+
+class InvalidStateError(Error):
+    """The operation is not allowed in this state."""
+
+
+# States for Future.
+_PENDING = 'PENDING'
+_CANCELLED = 'CANCELLED'
+_FINISHED = 'FINISHED'
+
+
+def isfuture(obj):
+    """Check for a Future.
+
+    This returns True when obj is a Future instance or is advertising
+    itself as duck-type compatible by setting _asyncio_future_blocking.
+    See comment in Future for more details.
+    """
+    return (hasattr(obj.__class__, '_asyncio_future_blocking') and
+            obj._asyncio_future_blocking is not None)
+
+
+def _format_callbacks(cb):
+    """helper function for Future.__repr__"""
+    size = len(cb)
+    if not size:
+        cb = ''
+
+    def format_cb(callback):
+        return events._format_callback_source(callback, ())
+
+    if size == 1:
+        cb = format_cb(cb[0])
+    elif size == 2:
+        cb = '{}, {}'.format(format_cb(cb[0]), format_cb(cb[1]))
+    elif size > 2:
+        cb = '{}, <{} more>, {}'.format(format_cb(cb[0]),
+                                        size - 2,
+                                        format_cb(cb[-1]))
+    return 'cb=[%s]' % cb
+
+
+def _future_repr_info(future):
+    # (Future) -> str
+    """helper function for Future.__repr__"""
+    info = [future._state.lower()]
+    if future._state == _FINISHED:
+        if future._exception is not None:
+            info.append('exception={!r}'.format(future._exception))
+        else:
+            # use reprlib to limit the length of the output, especially
+            # for very long strings
+            result = reprlib.repr(future._result)
+            info.append('result={}'.format(result))
+    if future._callbacks:
+        info.append(_format_callbacks(future._callbacks))
+    if future._source_traceback:
+        frame = future._source_traceback[-1]
+        info.append('created at %s:%s' % (frame[0], frame[1]))
+    return info

third_party/python/Lib/asyncio/base_subprocess.py

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+import collections
+import subprocess
+import warnings
+
+from . import compat
+from . import protocols
+from . import transports
+from .coroutines import coroutine
+from .log import logger
+
+
+class BaseSubprocessTransport(transports.SubprocessTransport):
+
+    def __init__(self, loop, protocol, args, shell,
+                 stdin, stdout, stderr, bufsize,
+                 waiter=None, extra=None, **kwargs):
+        super().__init__(extra)
+        self._closed = False
+        self._protocol = protocol
+        self._loop = loop
+        self._proc = None
+        self._pid = None
+        self._returncode = None
+        self._exit_waiters = []
+        self._pending_calls = collections.deque()
+        self._pipes = {}
+        self._finished = False
+
+        if stdin == subprocess.PIPE:
+            self._pipes[0] = None
+        if stdout == subprocess.PIPE:
+            self._pipes[1] = None
+        if stderr == subprocess.PIPE:
+            self._pipes[2] = None
+
+        # Create the child process: set the _proc attribute
+        try:
+            self._start(args=args, shell=shell, stdin=stdin, stdout=stdout,
+                        stderr=stderr, bufsize=bufsize, **kwargs)
+        except:
+            self.close()
+            raise
+
+        self._pid = self._proc.pid
+        self._extra['subprocess'] = self._proc
+
+        if self._loop.get_debug():
+            if isinstance(args, (bytes, str)):
+                program = args
+            else:
+                program = args[0]
+            logger.debug('process %r created: pid %s',
+                         program, self._pid)
+
+        self._loop.create_task(self._connect_pipes(waiter))
+
+    def __repr__(self):
+        info = [self.__class__.__name__]
+        if self._closed:
+            info.append('closed')
+        if self._pid is not None:
+            info.append('pid=%s' % self._pid)
+        if self._returncode is not None:
+            info.append('returncode=%s' % self._returncode)
+        elif self._pid is not None:
+            info.append('running')
+        else:
+            info.append('not started')
+
+        stdin = self._pipes.get(0)
+        if stdin is not None:
+            info.append('stdin=%s' % stdin.pipe)
+
+        stdout = self._pipes.get(1)
+        stderr = self._pipes.get(2)
+        if stdout is not None and stderr is stdout:
+            info.append('stdout=stderr=%s' % stdout.pipe)
+        else:
+            if stdout is not None:
+                info.append('stdout=%s' % stdout.pipe)
+            if stderr is not None:
+                info.append('stderr=%s' % stderr.pipe)
+
+        return '<%s>' % ' '.join(info)
+
+    def _start(self, args, shell, stdin, stdout, stderr, bufsize, **kwargs):
+        raise NotImplementedError
+
+    def set_protocol(self, protocol):
+        self._protocol = protocol
+
+    def get_protocol(self):
+        return self._protocol
+
+    def is_closing(self):
+        return self._closed
+
+    def close(self):
+        if self._closed:
+            return
+        self._closed = True
+
+        for proto in self._pipes.values():
+            if proto is None:
+                continue
+            proto.pipe.close()
+
+        if (self._proc is not None
+        # the child process finished?
+        and self._returncode is None
+        # the child process finished but the transport was not notified yet?
+        and self._proc.poll() is None
+        ):
+            if self._loop.get_debug():
+                logger.warning('Close running child process: kill %r', self)
+
+            try:
+                self._proc.kill()
+            except ProcessLookupError:
+                pass
+
+            # Don't clear the _proc reference yet: _post_init() may still run
+
+    # On Python 3.3 and older, objects with a destructor part of a reference
+    # cycle are never destroyed. It's not more the case on Python 3.4 thanks
+    # to the PEP 442.
+    if compat.PY34:
+        def __del__(self):
+            if not self._closed:
+                warnings.warn("unclosed transport %r" % self, ResourceWarning,
+                              source=self)
+                self.close()
+
+    def get_pid(self):
+        return self._pid
+
+    def get_returncode(self):
+        return self._returncode
+
+    def get_pipe_transport(self, fd):
+        if fd in self._pipes:
+            return self._pipes[fd].pipe
+        else:
+            return None
+
+    def _check_proc(self):
+        if self._proc is None:
+            raise ProcessLookupError()
+
+    def send_signal(self, signal):
+        self._check_proc()
+        self._proc.send_signal(signal)
+
+    def terminate(self):
+        self._check_proc()
+        self._proc.terminate()
+
+    def kill(self):
+        self._check_proc()
+        self._proc.kill()
+
+    @coroutine
+    def _connect_pipes(self, waiter):
+        try:
+            proc = self._proc
+            loop = self._loop
+
+            if proc.stdin is not None:
+                _, pipe = yield from loop.connect_write_pipe(
+                    lambda: WriteSubprocessPipeProto(self, 0),
+                    proc.stdin)
+                self._pipes[0] = pipe
+
+            if proc.stdout is not None:
+                _, pipe = yield from loop.connect_read_pipe(
+                    lambda: ReadSubprocessPipeProto(self, 1),
+                    proc.stdout)
+                self._pipes[1] = pipe
+
+            if proc.stderr is not None:
+                _, pipe = yield from loop.connect_read_pipe(
+                    lambda: ReadSubprocessPipeProto(self, 2),
+                    proc.stderr)
+                self._pipes[2] = pipe
+
+            assert self._pending_calls is not None
+
+            loop.call_soon(self._protocol.connection_made, self)
+            for callback, data in self._pending_calls:
+                loop.call_soon(callback, *data)
+            self._pending_calls = None
+        except Exception as exc:
+            if waiter is not None and not waiter.cancelled():
+                waiter.set_exception(exc)
+        else:
+            if waiter is not None and not waiter.cancelled():
+                waiter.set_result(None)
+
+    def _call(self, cb, *data):
+        if self._pending_calls is not None:
+            self._pending_calls.append((cb, data))
+        else:
+            self._loop.call_soon(cb, *data)
+
+    def _pipe_connection_lost(self, fd, exc):
+        self._call(self._protocol.pipe_connection_lost, fd, exc)
+        self._try_finish()
+
+    def _pipe_data_received(self, fd, data):
+        self._call(self._protocol.pipe_data_received, fd, data)
+
+    def _process_exited(self, returncode):
+        assert returncode is not None, returncode
+        assert self._returncode is None, self._returncode
+        if self._loop.get_debug():
+            logger.info('%r exited with return code %r',
+                        self, returncode)
+        self._returncode = returncode
+        if self._proc.returncode is None:
+            # asyncio uses a child watcher: copy the status into the Popen
+            # object. On Python 3.6, it is required to avoid a ResourceWarning.
+            self._proc.returncode = returncode
+        self._call(self._protocol.process_exited)
+        self._try_finish()
+
+        # wake up futures waiting for wait()
+        for waiter in self._exit_waiters:
+            if not waiter.cancelled():
+                waiter.set_result(returncode)
+        self._exit_waiters = None
+
+    @coroutine
+    def _wait(self):
+        """Wait until the process exit and return the process return code.
+
+        This method is a coroutine."""
+        if self._returncode is not None:
+            return self._returncode
+
+        waiter = self._loop.create_future()
+        self._exit_waiters.append(waiter)
+        return (yield from waiter)
+
+    def _try_finish(self):
+        assert not self._finished
+        if self._returncode is None:
+            return
+        if all(p is not None and p.disconnected
+               for p in self._pipes.values()):
+            self._finished = True
+            self._call(self._call_connection_lost, None)
+
+    def _call_connection_lost(self, exc):
+        try:
+            self._protocol.connection_lost(exc)
+        finally:
+            self._loop = None
+            self._proc = None
+            self._protocol = None
+
+
+class WriteSubprocessPipeProto(protocols.BaseProtocol):
+
+    def __init__(self, proc, fd):
+        self.proc = proc
+        self.fd = fd
+        self.pipe = None
+        self.disconnected = False
+
+    def connection_made(self, transport):
+        self.pipe = transport
+
+    def __repr__(self):
+        return ('<%s fd=%s pipe=%r>'
+                % (self.__class__.__name__, self.fd, self.pipe))
+
+    def connection_lost(self, exc):
+        self.disconnected = True
+        self.proc._pipe_connection_lost(self.fd, exc)
+        self.proc = None
+
+    def pause_writing(self):
+        self.proc._protocol.pause_writing()
+
+    def resume_writing(self):
+        self.proc._protocol.resume_writing()
+
+
+class ReadSubprocessPipeProto(WriteSubprocessPipeProto,
+                              protocols.Protocol):
+
+    def data_received(self, data):
+        self.proc._pipe_data_received(self.fd, data)

third_party/python/Lib/asyncio/base_tasks.py

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+import linecache
+import traceback
+
+from . import base_futures
+from . import coroutines
+
+
+def _task_repr_info(task):
+    info = base_futures._future_repr_info(task)
+
+    if task._must_cancel:
+        # replace status
+        info[0] = 'cancelling'
+
+    coro = coroutines._format_coroutine(task._coro)
+    info.insert(1, 'coro=<%s>' % coro)
+
+    if task._fut_waiter is not None:
+        info.insert(2, 'wait_for=%r' % task._fut_waiter)
+    return info
+
+
+def _task_get_stack(task, limit):
+    frames = []
+    try:
+        # 'async def' coroutines
+        f = task._coro.cr_frame
+    except AttributeError:
+        f = task._coro.gi_frame
+    if f is not None:
+        while f is not None:
+            if limit is not None:
+                if limit <= 0:
+                    break
+                limit -= 1
+            frames.append(f)
+            f = f.f_back
+        frames.reverse()
+    elif task._exception is not None:
+        tb = task._exception.__traceback__
+        while tb is not None:
+            if limit is not None:
+                if limit <= 0:
+                    break
+                limit -= 1
+            frames.append(tb.tb_frame)
+            tb = tb.tb_next
+    return frames
+
+
+def _task_print_stack(task, limit, file):
+    extracted_list = []
+    checked = set()
+    for f in task.get_stack(limit=limit):
+        lineno = f.f_lineno
+        co = f.f_code
+        filename = co.co_filename
+        name = co.co_name
+        if filename not in checked:
+            checked.add(filename)
+            linecache.checkcache(filename)
+        line = linecache.getline(filename, lineno, f.f_globals)
+        extracted_list.append((filename, lineno, name, line))
+    exc = task._exception
+    if not extracted_list:
+        print('No stack for %r' % task, file=file)
+    elif exc is not None:
+        print('Traceback for %r (most recent call last):' % task,
+              file=file)
+    else:
+        print('Stack for %r (most recent call last):' % task,
+              file=file)
+    traceback.print_list(extracted_list, file=file)
+    if exc is not None:
+        for line in traceback.format_exception_only(exc.__class__, exc):
+            print(line, file=file, end='')

third_party/python/Lib/asyncio/compat.py

@@ -0,0 +1,18 @@
+"""Compatibility helpers for the different Python versions."""
+
+import sys
+
+PY34 = sys.version_info >= (3, 4)
+PY35 = sys.version_info >= (3, 5)
+PY352 = sys.version_info >= (3, 5, 2)
+
+
+def flatten_list_bytes(list_of_data):
+    """Concatenate a sequence of bytes-like objects."""
+    if not PY34:
+        # On Python 3.3 and older, bytes.join() doesn't handle
+        # memoryview.
+        list_of_data = (
+            bytes(data) if isinstance(data, memoryview) else data
+            for data in list_of_data)
+    return b''.join(list_of_data)

third_party/python/Lib/asyncio/constants.py

@@ -0,0 +1,12 @@
+"""Constants."""
+
+# After the connection is lost, log warnings after this many write()s.
+LOG_THRESHOLD_FOR_CONNLOST_WRITES = 5
+
+# Seconds to wait before retrying accept().
+ACCEPT_RETRY_DELAY = 1
+
+# Number of stack entries to capture in debug mode.
+# The large the number, the slower the operation in debug mode
+# (see extract_stack() in events.py)
+DEBUG_STACK_DEPTH = 10

third_party/python/Lib/asyncio/coroutines.py

@@ -0,0 +1,353 @@
+__all__ = ['coroutine',
+           'iscoroutinefunction', 'iscoroutine']
+
+import functools
+import inspect
+import opcode
+import os
+import sys
+import traceback
+import types
+
+from . import compat
+from . import constants
+from . import events
+from . import base_futures
+from .log import logger
+
+
+# Opcode of "yield from" instruction
+_YIELD_FROM = opcode.opmap['YIELD_FROM']
+
+# If you set _DEBUG to true, @coroutine will wrap the resulting
+# generator objects in a CoroWrapper instance (defined below).  That
+# instance will log a message when the generator is never iterated
+# over, which may happen when you forget to use "yield from" with a
+# coroutine call.  Note that the value of the _DEBUG flag is taken
+# when the decorator is used, so to be of any use it must be set
+# before you define your coroutines.  A downside of using this feature
+# is that tracebacks show entries for the CoroWrapper.__next__ method
+# when _DEBUG is true.
+_DEBUG = (not sys.flags.ignore_environment and
+          bool(os.environ.get('PYTHONASYNCIODEBUG')))
+
+
+try:
+    _types_coroutine = types.coroutine
+    _types_CoroutineType = types.CoroutineType
+except AttributeError:
+    # Python 3.4
+    _types_coroutine = None
+    _types_CoroutineType = None
+
+try:
+    _inspect_iscoroutinefunction = inspect.iscoroutinefunction
+except AttributeError:
+    # Python 3.4
+    _inspect_iscoroutinefunction = lambda func: False
+
+try:
+    from collections.abc import Coroutine as _CoroutineABC, \
+                                Awaitable as _AwaitableABC
+except ImportError:
+    _CoroutineABC = _AwaitableABC = None
+
+
+# Check for CPython issue #21209
+def has_yield_from_bug():
+    class MyGen:
+        def __init__(self):
+            self.send_args = None
+        def __iter__(self):
+            return self
+        def __next__(self):
+            return 42
+        def send(self, *what):
+            self.send_args = what
+            return None
+    def yield_from_gen(gen):
+        yield from gen
+    value = (1, 2, 3)
+    gen = MyGen()
+    coro = yield_from_gen(gen)
+    next(coro)
+    coro.send(value)
+    return gen.send_args != (value,)
+_YIELD_FROM_BUG = has_yield_from_bug()
+del has_yield_from_bug
+
+
+def debug_wrapper(gen):
+    # This function is called from 'sys.set_coroutine_wrapper'.
+    # We only wrap here coroutines defined via 'async def' syntax.
+    # Generator-based coroutines are wrapped in @coroutine
+    # decorator.
+    return CoroWrapper(gen, None)
+
+
+class CoroWrapper:
+    # Wrapper for coroutine object in _DEBUG mode.
+
+    def __init__(self, gen, func=None):
+        assert inspect.isgenerator(gen) or inspect.iscoroutine(gen), gen
+        self.gen = gen
+        self.func = func  # Used to unwrap @coroutine decorator
+        self._source_traceback = events.extract_stack(sys._getframe(1))
+        self.__name__ = getattr(gen, '__name__', None)
+        self.__qualname__ = getattr(gen, '__qualname__', None)
+
+    def __repr__(self):
+        coro_repr = _format_coroutine(self)
+        if self._source_traceback:
+            frame = self._source_traceback[-1]
+            coro_repr += ', created at %s:%s' % (frame[0], frame[1])
+        return '<%s %s>' % (self.__class__.__name__, coro_repr)
+
+    def __iter__(self):
+        return self
+
+    def __next__(self):
+        return self.gen.send(None)
+
+    if _YIELD_FROM_BUG:
+        # For for CPython issue #21209: using "yield from" and a custom
+        # generator, generator.send(tuple) unpacks the tuple instead of passing
+        # the tuple unchanged. Check if the caller is a generator using "yield
+        # from" to decide if the parameter should be unpacked or not.
+        def send(self, *value):
+            frame = sys._getframe()
+            caller = frame.f_back
+            assert caller.f_lasti >= 0
+            if caller.f_code.co_code[caller.f_lasti] != _YIELD_FROM:
+                value = value[0]
+            return self.gen.send(value)
+    else:
+        def send(self, value):
+            return self.gen.send(value)
+
+    def throw(self, type, value=None, traceback=None):
+        return self.gen.throw(type, value, traceback)
+
+    def close(self):
+        return self.gen.close()
+
+    @property
+    def gi_frame(self):
+        return self.gen.gi_frame
+
+    @property
+    def gi_running(self):
+        return self.gen.gi_running
+
+    @property
+    def gi_code(self):
+        return self.gen.gi_code
+
+    if compat.PY35:
+
+        def __await__(self):
+            cr_await = getattr(self.gen, 'cr_await', None)
+            if cr_await is not None:
+                raise RuntimeError(
+                    "Cannot await on coroutine {!r} while it's "
+                    "awaiting for {!r}".format(self.gen, cr_await))
+            return self
+
+        @property
+        def gi_yieldfrom(self):
+            return self.gen.gi_yieldfrom
+
+        @property
+        def cr_await(self):
+            return self.gen.cr_await
+
+        @property
+        def cr_running(self):
+            return self.gen.cr_running
+
+        @property
+        def cr_code(self):
+            return self.gen.cr_code
+
+        @property
+        def cr_frame(self):
+            return self.gen.cr_frame
+
+    def __del__(self):
+        # Be careful accessing self.gen.frame -- self.gen might not exist.
+        gen = getattr(self, 'gen', None)
+        frame = getattr(gen, 'gi_frame', None)
+        if frame is None:
+            frame = getattr(gen, 'cr_frame', None)
+        if frame is not None and frame.f_lasti == -1:
+            msg = '%r was never yielded from' % self
+            tb = getattr(self, '_source_traceback', ())
+            if tb:
+                tb = ''.join(traceback.format_list(tb))
+                msg += (f'\nCoroutine object created at '
+                        f'(most recent call last, truncated to '
+                        f'{constants.DEBUG_STACK_DEPTH} last lines):\n')
+                msg += tb.rstrip()
+            logger.error(msg)
+
+
+def coroutine(func):
+    """Decorator to mark coroutines.
+
+    If the coroutine is not yielded from before it is destroyed,
+    an error message is logged.
+    """
+    if _inspect_iscoroutinefunction(func):
+        # In Python 3.5 that's all we need to do for coroutines
+        # defined with "async def".
+        # Wrapping in CoroWrapper will happen via
+        # 'sys.set_coroutine_wrapper' function.
+        return func
+
+    if inspect.isgeneratorfunction(func):
+        coro = func
+    else:
+        @functools.wraps(func)
+        def coro(*args, **kw):
+            res = func(*args, **kw)
+            if (base_futures.isfuture(res) or inspect.isgenerator(res) or
+                isinstance(res, CoroWrapper)):
+                res = yield from res
+            elif _AwaitableABC is not None:
+                # If 'func' returns an Awaitable (new in 3.5) we
+                # want to run it.
+                try:
+                    await_meth = res.__await__
+                except AttributeError:
+                    pass
+                else:
+                    if isinstance(res, _AwaitableABC):
+                        res = yield from await_meth()
+            return res
+
+    if not _DEBUG:
+        if _types_coroutine is None:
+            wrapper = coro
+        else:
+            wrapper = _types_coroutine(coro)
+    else:
+        @functools.wraps(func)
+        def wrapper(*args, **kwds):
+            w = CoroWrapper(coro(*args, **kwds), func=func)
+            if w._source_traceback:
+                del w._source_traceback[-1]
+            # Python < 3.5 does not implement __qualname__
+            # on generator objects, so we set it manually.
+            # We use getattr as some callables (such as
+            # functools.partial may lack __qualname__).
+            w.__name__ = getattr(func, '__name__', None)
+            w.__qualname__ = getattr(func, '__qualname__', None)
+            return w
+
+    wrapper._is_coroutine = _is_coroutine  # For iscoroutinefunction().
+    return wrapper
+
+
+# A marker for iscoroutinefunction.
+_is_coroutine = object()
+
+
+def iscoroutinefunction(func):
+    """Return True if func is a decorated coroutine function."""
+    return (getattr(func, '_is_coroutine', None) is _is_coroutine or
+            _inspect_iscoroutinefunction(func))
+
+
+_COROUTINE_TYPES = (types.GeneratorType, CoroWrapper)
+if _CoroutineABC is not None:
+    _COROUTINE_TYPES += (_CoroutineABC,)
+if _types_CoroutineType is not None:
+    # Prioritize native coroutine check to speed-up
+    # asyncio.iscoroutine.
+    _COROUTINE_TYPES = (_types_CoroutineType,) + _COROUTINE_TYPES
+
+
+def iscoroutine(obj):
+    """Return True if obj is a coroutine object."""
+    return isinstance(obj, _COROUTINE_TYPES)
+
+
+def _format_coroutine(coro):
+    assert iscoroutine(coro)
+
+    if not hasattr(coro, 'cr_code') and not hasattr(coro, 'gi_code'):
+        # Most likely a built-in type or a Cython coroutine.
+
+        # Built-in types might not have __qualname__ or __name__.
+        coro_name = getattr(
+            coro, '__qualname__',
+            getattr(coro, '__name__', type(coro).__name__))
+        coro_name = '{}()'.format(coro_name)
+
+        running = False
+        try:
+            running = coro.cr_running
+        except AttributeError:
+            try:
+                running = coro.gi_running
+            except AttributeError:
+                pass
+
+        if running:
+            return '{} running'.format(coro_name)
+        else:
+            return coro_name
+
+    coro_name = None
+    if isinstance(coro, CoroWrapper):
+        func = coro.func
+        coro_name = coro.__qualname__
+        if coro_name is not None:
+            coro_name = '{}()'.format(coro_name)
+    else:
+        func = coro
+
+    if coro_name is None:
+        coro_name = events._format_callback(func, (), {})
+
+    coro_code = None
+    if hasattr(coro, 'cr_code') and coro.cr_code:
+        coro_code = coro.cr_code
+    elif hasattr(coro, 'gi_code') and coro.gi_code:
+        coro_code = coro.gi_code
+
+    coro_frame = None
+    if hasattr(coro, 'cr_frame') and coro.cr_frame:
+        coro_frame = coro.cr_frame
+    elif hasattr(coro, 'gi_frame') and coro.gi_frame:
+        coro_frame = coro.gi_frame
+
+    filename = '<empty co_filename>'
+    if coro_code and coro_code.co_filename:
+        filename = coro_code.co_filename
+
+    lineno = 0
+    coro_repr = coro_name
+
+    if (isinstance(coro, CoroWrapper) and
+            not inspect.isgeneratorfunction(coro.func) and
+            coro.func is not None):
+        source = events._get_function_source(coro.func)
+        if source is not None:
+            filename, lineno = source
+        if coro_frame is None:
+            coro_repr = ('%s done, defined at %s:%s'
+                         % (coro_name, filename, lineno))
+        else:
+            coro_repr = ('%s running, defined at %s:%s'
+                         % (coro_name, filename, lineno))
+    elif coro_frame is not None:
+        lineno = coro_frame.f_lineno
+        coro_repr = ('%s running at %s:%s'
+                     % (coro_name, filename, lineno))
+    elif coro_code:
+        lineno = coro_code.co_firstlineno
+        coro_repr = ('%s done, defined at %s:%s'
+                     % (coro_name, filename, lineno))
+
+    return coro_repr

third_party/python/Lib/asyncio/events.py

@@ -0,0 +1,715 @@
+"""Event loop and event loop policy."""
+
+__all__ = ['AbstractEventLoopPolicy',
+           'AbstractEventLoop', 'AbstractServer',
+           'Handle', 'TimerHandle',
+           'get_event_loop_policy', 'set_event_loop_policy',
+           'get_event_loop', 'set_event_loop', 'new_event_loop',
+           'get_child_watcher', 'set_child_watcher',
+           '_set_running_loop', '_get_running_loop',
+           ]
+
+import functools
+import inspect
+import os
+import reprlib
+import socket
+import subprocess
+import sys
+import threading
+import traceback
+
+from . import compat
+from . import constants
+
+
+def _get_function_source(func):
+    if compat.PY34:
+        func = inspect.unwrap(func)
+    elif hasattr(func, '__wrapped__'):
+        func = func.__wrapped__
+    if inspect.isfunction(func):
+        code = func.__code__
+        return (code.co_filename, code.co_firstlineno)
+    if isinstance(func, functools.partial):
+        return _get_function_source(func.func)
+    if compat.PY34 and isinstance(func, functools.partialmethod):
+        return _get_function_source(func.func)
+    return None
+
+
+def _format_args_and_kwargs(args, kwargs):
+    """Format function arguments and keyword arguments.
+
+    Special case for a single parameter: ('hello',) is formatted as ('hello').
+    """
+    # use reprlib to limit the length of the output
+    items = []
+    if args:
+        items.extend(reprlib.repr(arg) for arg in args)
+    if kwargs:
+        items.extend('{}={}'.format(k, reprlib.repr(v))
+                     for k, v in kwargs.items())
+    return '(' + ', '.join(items) + ')'
+
+
+def _format_callback(func, args, kwargs, suffix=''):
+    if isinstance(func, functools.partial):
+        suffix = _format_args_and_kwargs(args, kwargs) + suffix
+        return _format_callback(func.func, func.args, func.keywords, suffix)
+
+    if hasattr(func, '__qualname__') and func.__qualname__:
+        func_repr = func.__qualname__
+    elif hasattr(func, '__name__') and func.__name__:
+        func_repr = func.__name__
+    else:
+        func_repr = repr(func)
+
+    func_repr += _format_args_and_kwargs(args, kwargs)
+    if suffix:
+        func_repr += suffix
+    return func_repr
+
+def _format_callback_source(func, args):
+    func_repr = _format_callback(func, args, None)
+    source = _get_function_source(func)
+    if source:
+        func_repr += ' at %s:%s' % source
+    return func_repr
+
+
+def extract_stack(f=None, limit=None):
+    """Replacement for traceback.extract_stack() that only does the
+    necessary work for asyncio debug mode.
+    """
+    if f is None:
+        f = sys._getframe().f_back
+    if limit is None:
+        # Limit the amount of work to a reasonable amount, as extract_stack()
+        # can be called for each coroutine and future in debug mode.
+        limit = constants.DEBUG_STACK_DEPTH
+    stack = traceback.StackSummary.extract(traceback.walk_stack(f),
+                                           limit=limit,
+                                           lookup_lines=False)
+    stack.reverse()
+    return stack
+
+
+class Handle:
+    """Object returned by callback registration methods."""
+
+    __slots__ = ('_callback', '_args', '_cancelled', '_loop',
+                 '_source_traceback', '_repr', '__weakref__')
+
+    def __init__(self, callback, args, loop):
+        self._loop = loop
+        self._callback = callback
+        self._args = args
+        self._cancelled = False
+        self._repr = None
+        if self._loop.get_debug():
+            self._source_traceback = extract_stack(sys._getframe(1))
+        else:
+            self._source_traceback = None
+
+    def _repr_info(self):
+        info = [self.__class__.__name__]
+        if self._cancelled:
+            info.append('cancelled')
+        if self._callback is not None:
+            info.append(_format_callback_source(self._callback, self._args))
+        if self._source_traceback:
+            frame = self._source_traceback[-1]
+            info.append('created at %s:%s' % (frame[0], frame[1]))
+        return info
+
+    def __repr__(self):
+        if self._repr is not None:
+            return self._repr
+        info = self._repr_info()
+        return '<%s>' % ' '.join(info)
+
+    def cancel(self):
+        if not self._cancelled:
+            self._cancelled = True
+            if self._loop.get_debug():
+                # Keep a representation in debug mode to keep callback and
+                # parameters. For example, to log the warning
+                # "Executing <Handle...> took 2.5 second"
+                self._repr = repr(self)
+            self._callback = None
+            self._args = None
+
+    def _run(self):
+        try:
+            self._callback(*self._args)
+        except Exception as exc:
+            cb = _format_callback_source(self._callback, self._args)
+            msg = 'Exception in callback {}'.format(cb)
+            context = {
+                'message': msg,
+                'exception': exc,
+                'handle': self,
+            }
+            if self._source_traceback:
+                context['source_traceback'] = self._source_traceback
+            self._loop.call_exception_handler(context)
+        self = None  # Needed to break cycles when an exception occurs.
+
+
+class TimerHandle(Handle):
+    """Object returned by timed callback registration methods."""
+
+    __slots__ = ['_scheduled', '_when']
+
+    def __init__(self, when, callback, args, loop):
+        assert when is not None
+        super().__init__(callback, args, loop)
+        if self._source_traceback:
+            del self._source_traceback[-1]
+        self._when = when
+        self._scheduled = False
+
+    def _repr_info(self):
+        info = super()._repr_info()
+        pos = 2 if self._cancelled else 1
+        info.insert(pos, 'when=%s' % self._when)
+        return info
+
+    def __hash__(self):
+        return hash(self._when)
+
+    def __lt__(self, other):
+        return self._when < other._when
+
+    def __le__(self, other):
+        if self._when < other._when:
+            return True
+        return self.__eq__(other)
+
+    def __gt__(self, other):
+        return self._when > other._when
+
+    def __ge__(self, other):
+        if self._when > other._when:
+            return True
+        return self.__eq__(other)
+
+    def __eq__(self, other):
+        if isinstance(other, TimerHandle):
+            return (self._when == other._when and
+                    self._callback == other._callback and
+                    self._args == other._args and
+                    self._cancelled == other._cancelled)
+        return NotImplemented
+
+    def __ne__(self, other):
+        equal = self.__eq__(other)
+        return NotImplemented if equal is NotImplemented else not equal
+
+    def cancel(self):
+        if not self._cancelled:
+            self._loop._timer_handle_cancelled(self)
+        super().cancel()
+
+
+class AbstractServer:
+    """Abstract server returned by create_server()."""
+
+    def close(self):
+        """Stop serving.  This leaves existing connections open."""
+        return NotImplemented
+
+    def wait_closed(self):
+        """Coroutine to wait until service is closed."""
+        return NotImplemented
+
+
+class AbstractEventLoop:
+    """Abstract event loop."""
+
+    # Running and stopping the event loop.
+
+    def run_forever(self):
+        """Run the event loop until stop() is called."""
+        raise NotImplementedError
+
+    def run_until_complete(self, future):
+        """Run the event loop until a Future is done.
+
+        Return the Future's result, or raise its exception.
+        """
+        raise NotImplementedError
+
+    def stop(self):
+        """Stop the event loop as soon as reasonable.
+
+        Exactly how soon that is may depend on the implementation, but
+        no more I/O callbacks should be scheduled.
+        """
+        raise NotImplementedError
+
+    def is_running(self):
+        """Return whether the event loop is currently running."""
+        raise NotImplementedError
+
+    def is_closed(self):
+        """Returns True if the event loop was closed."""
+        raise NotImplementedError
+
+    def close(self):
+        """Close the loop.
+
+        The loop should not be running.
+
+        This is idempotent and irreversible.
+
+        No other methods should be called after this one.
+        """
+        raise NotImplementedError
+
+    def shutdown_asyncgens(self):
+        """Shutdown all active asynchronous generators."""
+        raise NotImplementedError
+
+    # Methods scheduling callbacks.  All these return Handles.
+
+    def _timer_handle_cancelled(self, handle):
+        """Notification that a TimerHandle has been cancelled."""
+        raise NotImplementedError
+
+    def call_soon(self, callback, *args):
+        return self.call_later(0, callback, *args)
+
+    def call_later(self, delay, callback, *args):
+        raise NotImplementedError
+
+    def call_at(self, when, callback, *args):
+        raise NotImplementedError
+
+    def time(self):
+        raise NotImplementedError
+
+    def create_future(self):
+        raise NotImplementedError
+
+    # Method scheduling a coroutine object: create a task.
+
+    def create_task(self, coro):
+        raise NotImplementedError
+
+    # Methods for interacting with threads.
+
+    def call_soon_threadsafe(self, callback, *args):
+        raise NotImplementedError
+
+    def run_in_executor(self, executor, func, *args):
+        raise NotImplementedError
+
+    def set_default_executor(self, executor):
+        raise NotImplementedError
+
+    # Network I/O methods returning Futures.
+
+    def getaddrinfo(self, host, port, *, family=0, type=0, proto=0, flags=0):
+        raise NotImplementedError
+
+    def getnameinfo(self, sockaddr, flags=0):
+        raise NotImplementedError
+
+    def create_connection(self, protocol_factory, host=None, port=None, *,
+                          ssl=None, family=0, proto=0, flags=0, sock=None,
+                          local_addr=None, server_hostname=None):
+        raise NotImplementedError
+
+    def create_server(self, protocol_factory, host=None, port=None, *,
+                      family=socket.AF_UNSPEC, flags=socket.AI_PASSIVE,
+                      sock=None, backlog=100, ssl=None, reuse_address=None,
+                      reuse_port=None):
+        """A coroutine which creates a TCP server bound to host and port.
+
+        The return value is a Server object which can be used to stop
+        the service.
+
+        If host is an empty string or None all interfaces are assumed
+        and a list of multiple sockets will be returned (most likely
+        one for IPv4 and another one for IPv6). The host parameter can also be a
+        sequence (e.g. list) of hosts to bind to.
+
+        family can be set to either AF_INET or AF_INET6 to force the
+        socket to use IPv4 or IPv6. If not set it will be determined
+        from host (defaults to AF_UNSPEC).
+
+        flags is a bitmask for getaddrinfo().
+
+        sock can optionally be specified in order to use a preexisting
+        socket object.
+
+        backlog is the maximum number of queued connections passed to
+        listen() (defaults to 100).
+
+        ssl can be set to an SSLContext to enable SSL over the
+        accepted connections.
+
+        reuse_address tells the kernel to reuse a local socket in
+        TIME_WAIT state, without waiting for its natural timeout to
+        expire. If not specified will automatically be set to True on
+        UNIX.
+
+        reuse_port tells the kernel to allow this endpoint to be bound to
+        the same port as other existing endpoints are bound to, so long as
+        they all set this flag when being created. This option is not
+        supported on Windows.
+        """
+        raise NotImplementedError
+
+    def create_unix_connection(self, protocol_factory, path, *,
+                               ssl=None, sock=None,
+                               server_hostname=None):
+        raise NotImplementedError
+
+    def create_unix_server(self, protocol_factory, path, *,
+                           sock=None, backlog=100, ssl=None):
+        """A coroutine which creates a UNIX Domain Socket server.
+
+        The return value is a Server object, which can be used to stop
+        the service.
+
+        path is a str, representing a file systsem path to bind the
+        server socket to.
+
+        sock can optionally be specified in order to use a preexisting
+        socket object.
+
+        backlog is the maximum number of queued connections passed to
+        listen() (defaults to 100).
+
+        ssl can be set to an SSLContext to enable SSL over the
+        accepted connections.
+        """
+        raise NotImplementedError
+
+    def create_datagram_endpoint(self, protocol_factory,
+                                 local_addr=None, remote_addr=None, *,
+                                 family=0, proto=0, flags=0,
+                                 reuse_address=None, reuse_port=None,
+                                 allow_broadcast=None, sock=None):
+        """A coroutine which creates a datagram endpoint.
+
+        This method will try to establish the endpoint in the background.
+        When successful, the coroutine returns a (transport, protocol) pair.
+
+        protocol_factory must be a callable returning a protocol instance.
+
+        socket family AF_INET or socket.AF_INET6 depending on host (or
+        family if specified), socket type SOCK_DGRAM.
+
+        reuse_address tells the kernel to reuse a local socket in
+        TIME_WAIT state, without waiting for its natural timeout to
+        expire. If not specified it will automatically be set to True on
+        UNIX.
+
+        reuse_port tells the kernel to allow this endpoint to be bound to
+        the same port as other existing endpoints are bound to, so long as
+        they all set this flag when being created. This option is not
+        supported on Windows and some UNIX's. If the
+        :py:data:`~socket.SO_REUSEPORT` constant is not defined then this
+        capability is unsupported.
+
+        allow_broadcast tells the kernel to allow this endpoint to send
+        messages to the broadcast address.
+
+        sock can optionally be specified in order to use a preexisting
+        socket object.
+        """
+        raise NotImplementedError
+
+    # Pipes and subprocesses.
+
+    def connect_read_pipe(self, protocol_factory, pipe):
+        """Register read pipe in event loop. Set the pipe to non-blocking mode.
+
+        protocol_factory should instantiate object with Protocol interface.
+        pipe is a file-like object.
+        Return pair (transport, protocol), where transport supports the
+        ReadTransport interface."""
+        # The reason to accept file-like object instead of just file descriptor
+        # is: we need to own pipe and close it at transport finishing
+        # Can got complicated errors if pass f.fileno(),
+        # close fd in pipe transport then close f and vise versa.
+        raise NotImplementedError
+
+    def connect_write_pipe(self, protocol_factory, pipe):
+        """Register write pipe in event loop.
+
+        protocol_factory should instantiate object with BaseProtocol interface.
+        Pipe is file-like object already switched to nonblocking.
+        Return pair (transport, protocol), where transport support
+        WriteTransport interface."""
+        # The reason to accept file-like object instead of just file descriptor
+        # is: we need to own pipe and close it at transport finishing
+        # Can got complicated errors if pass f.fileno(),
+        # close fd in pipe transport then close f and vise versa.
+        raise NotImplementedError
+
+    def subprocess_shell(self, protocol_factory, cmd, *, stdin=subprocess.PIPE,
+                         stdout=subprocess.PIPE, stderr=subprocess.PIPE,
+                         **kwargs):
+        raise NotImplementedError
+
+    def subprocess_exec(self, protocol_factory, *args, stdin=subprocess.PIPE,
+                        stdout=subprocess.PIPE, stderr=subprocess.PIPE,
+                        **kwargs):
+        raise NotImplementedError
+
+    # Ready-based callback registration methods.
+    # The add_*() methods return None.
+    # The remove_*() methods return True if something was removed,
+    # False if there was nothing to delete.
+
+    def add_reader(self, fd, callback, *args):
+        raise NotImplementedError
+
+    def remove_reader(self, fd):
+        raise NotImplementedError
+
+    def add_writer(self, fd, callback, *args):
+        raise NotImplementedError
+
+    def remove_writer(self, fd):
+        raise NotImplementedError
+
+    # Completion based I/O methods returning Futures.
+
+    def sock_recv(self, sock, nbytes):
+        raise NotImplementedError
+
+    def sock_sendall(self, sock, data):
+        raise NotImplementedError
+
+    def sock_connect(self, sock, address):
+        raise NotImplementedError
+
+    def sock_accept(self, sock):
+        raise NotImplementedError
+
+    # Signal handling.
+
+    def add_signal_handler(self, sig, callback, *args):
+        raise NotImplementedError
+
+    def remove_signal_handler(self, sig):
+        raise NotImplementedError
+
+    # Task factory.
+
+    def set_task_factory(self, factory):
+        raise NotImplementedError
+
+    def get_task_factory(self):
+        raise NotImplementedError
+
+    # Error handlers.
+
+    def get_exception_handler(self):
+        raise NotImplementedError
+
+    def set_exception_handler(self, handler):
+        raise NotImplementedError
+
+    def default_exception_handler(self, context):
+        raise NotImplementedError
+
+    def call_exception_handler(self, context):
+        raise NotImplementedError
+
+    # Debug flag management.
+
+    def get_debug(self):
+        raise NotImplementedError
+
+    def set_debug(self, enabled):
+        raise NotImplementedError
+
+
+class AbstractEventLoopPolicy:
+    """Abstract policy for accessing the event loop."""
+
+    def get_event_loop(self):
+        """Get the event loop for the current context.
+
+        Returns an event loop object implementing the BaseEventLoop interface,
+        or raises an exception in case no event loop has been set for the
+        current context and the current policy does not specify to create one.
+
+        It should never return None."""
+        raise NotImplementedError
+
+    def set_event_loop(self, loop):
+        """Set the event loop for the current context to loop."""
+        raise NotImplementedError
+
+    def new_event_loop(self):
+        """Create and return a new event loop object according to this
+        policy's rules. If there's need to set this loop as the event loop for
+        the current context, set_event_loop must be called explicitly."""
+        raise NotImplementedError
+
+    # Child processes handling (Unix only).
+
+    def get_child_watcher(self):
+        "Get the watcher for child processes."
+        raise NotImplementedError
+
+    def set_child_watcher(self, watcher):
+        """Set the watcher for child processes."""
+        raise NotImplementedError
+
+
+class BaseDefaultEventLoopPolicy(AbstractEventLoopPolicy):
+    """Default policy implementation for accessing the event loop.
+
+    In this policy, each thread has its own event loop.  However, we
+    only automatically create an event loop by default for the main
+    thread; other threads by default have no event loop.
+
+    Other policies may have different rules (e.g. a single global
+    event loop, or automatically creating an event loop per thread, or
+    using some other notion of context to which an event loop is
+    associated).
+    """
+
+    _loop_factory = None
+
+    class _Local(threading.local):
+        _loop = None
+        _set_called = False
+
+    def __init__(self):
+        self._local = self._Local()
+
+    def get_event_loop(self):
+        """Get the event loop.
+
+        This may be None or an instance of EventLoop.
+        """
+        if (self._local._loop is None and
+            not self._local._set_called and
+            isinstance(threading.current_thread(), threading._MainThread)):
+            self.set_event_loop(self.new_event_loop())
+        if self._local._loop is None:
+            raise RuntimeError('There is no current event loop in thread %r.'
+                               % threading.current_thread().name)
+        return self._local._loop
+
+    def set_event_loop(self, loop):
+        """Set the event loop."""
+        self._local._set_called = True
+        assert loop is None or isinstance(loop, AbstractEventLoop)
+        self._local._loop = loop
+
+    def new_event_loop(self):
+        """Create a new event loop.
+
+        You must call set_event_loop() to make this the current event
+        loop.
+        """
+        return self._loop_factory()
+
+
+# Event loop policy.  The policy itself is always global, even if the
+# policy's rules say that there is an event loop per thread (or other
+# notion of context).  The default policy is installed by the first
+# call to get_event_loop_policy().
+_event_loop_policy = None
+
+# Lock for protecting the on-the-fly creation of the event loop policy.
+_lock = threading.Lock()
+
+
+# A TLS for the running event loop, used by _get_running_loop.
+class _RunningLoop(threading.local):
+    loop_pid = (None, None)
+
+
+_running_loop = _RunningLoop()
+
+
+def _get_running_loop():
+    """Return the running event loop or None.
+
+    This is a low-level function intended to be used by event loops.
+    This function is thread-specific.
+    """
+    running_loop, pid = _running_loop.loop_pid
+    if running_loop is not None and pid == os.getpid():
+        return running_loop
+
+
+def _set_running_loop(loop):
+    """Set the running event loop.
+
+    This is a low-level function intended to be used by event loops.
+    This function is thread-specific.
+    """
+    _running_loop.loop_pid = (loop, os.getpid())
+
+
+def _init_event_loop_policy():
+    global _event_loop_policy
+    with _lock:
+        if _event_loop_policy is None:  # pragma: no branch
+            from . import DefaultEventLoopPolicy
+            _event_loop_policy = DefaultEventLoopPolicy()
+
+
+def get_event_loop_policy():
+    """Get the current event loop policy."""
+    if _event_loop_policy is None:
+        _init_event_loop_policy()
+    return _event_loop_policy
+
+
+def set_event_loop_policy(policy):
+    """Set the current event loop policy.
+
+    If policy is None, the default policy is restored."""
+    global _event_loop_policy
+    assert policy is None or isinstance(policy, AbstractEventLoopPolicy)
+    _event_loop_policy = policy
+
+
+def get_event_loop():
+    """Return an asyncio event loop.
+
+    When called from a coroutine or a callback (e.g. scheduled with call_soon
+    or similar API), this function will always return the running event loop.
+
+    If there is no running event loop set, the function will return
+    the result of `get_event_loop_policy().get_event_loop()` call.
+    """
+    current_loop = _get_running_loop()
+    if current_loop is not None:
+        return current_loop
+    return get_event_loop_policy().get_event_loop()
+
+
+def set_event_loop(loop):
+    """Equivalent to calling get_event_loop_policy().set_event_loop(loop)."""
+    get_event_loop_policy().set_event_loop(loop)
+
+
+def new_event_loop():
+    """Equivalent to calling get_event_loop_policy().new_event_loop()."""
+    return get_event_loop_policy().new_event_loop()
+
+
+def get_child_watcher():
+    """Equivalent to calling get_event_loop_policy().get_child_watcher()."""
+    return get_event_loop_policy().get_child_watcher()
+
+
+def set_child_watcher(watcher):
+    """Equivalent to calling
+    get_event_loop_policy().set_child_watcher(watcher)."""
+    return get_event_loop_policy().set_child_watcher(watcher)

third_party/python/Lib/asyncio/futures.py

@@ -0,0 +1,442 @@
+"""A Future class similar to the one in PEP 3148."""
+
+__all__ = ['CancelledError', 'TimeoutError', 'InvalidStateError',
+           'Future', 'wrap_future', 'isfuture']
+
+import concurrent.futures
+import logging
+import sys
+import traceback
+
+from . import base_futures
+from . import compat
+from . import events
+
+
+CancelledError = base_futures.CancelledError
+InvalidStateError = base_futures.InvalidStateError
+TimeoutError = base_futures.TimeoutError
+isfuture = base_futures.isfuture
+
+
+_PENDING = base_futures._PENDING
+_CANCELLED = base_futures._CANCELLED
+_FINISHED = base_futures._FINISHED
+
+
+STACK_DEBUG = logging.DEBUG - 1  # heavy-duty debugging
+
+
+class _TracebackLogger:
+    """Helper to log a traceback upon destruction if not cleared.
+
+    This solves a nasty problem with Futures and Tasks that have an
+    exception set: if nobody asks for the exception, the exception is
+    never logged.  This violates the Zen of Python: 'Errors should
+    never pass silently.  Unless explicitly silenced.'
+
+    However, we don't want to log the exception as soon as
+    set_exception() is called: if the calling code is written
+    properly, it will get the exception and handle it properly.  But
+    we *do* want to log it if result() or exception() was never called
+    -- otherwise developers waste a lot of time wondering why their
+    buggy code fails silently.
+
+    An earlier attempt added a __del__() method to the Future class
+    itself, but this backfired because the presence of __del__()
+    prevents garbage collection from breaking cycles.  A way out of
+    this catch-22 is to avoid having a __del__() method on the Future
+    class itself, but instead to have a reference to a helper object
+    with a __del__() method that logs the traceback, where we ensure
+    that the helper object doesn't participate in cycles, and only the
+    Future has a reference to it.
+
+    The helper object is added when set_exception() is called.  When
+    the Future is collected, and the helper is present, the helper
+    object is also collected, and its __del__() method will log the
+    traceback.  When the Future's result() or exception() method is
+    called (and a helper object is present), it removes the helper
+    object, after calling its clear() method to prevent it from
+    logging.
+
+    One downside is that we do a fair amount of work to extract the
+    traceback from the exception, even when it is never logged.  It
+    would seem cheaper to just store the exception object, but that
+    references the traceback, which references stack frames, which may
+    reference the Future, which references the _TracebackLogger, and
+    then the _TracebackLogger would be included in a cycle, which is
+    what we're trying to avoid!  As an optimization, we don't
+    immediately format the exception; we only do the work when
+    activate() is called, which call is delayed until after all the
+    Future's callbacks have run.  Since usually a Future has at least
+    one callback (typically set by 'yield from') and usually that
+    callback extracts the callback, thereby removing the need to
+    format the exception.
+
+    PS. I don't claim credit for this solution.  I first heard of it
+    in a discussion about closing files when they are collected.
+    """
+
+    __slots__ = ('loop', 'source_traceback', 'exc', 'tb')
+
+    def __init__(self, future, exc):
+        self.loop = future._loop
+        self.source_traceback = future._source_traceback
+        self.exc = exc
+        self.tb = None
+
+    def activate(self):
+        exc = self.exc
+        if exc is not None:
+            self.exc = None
+            self.tb = traceback.format_exception(exc.__class__, exc,
+                                                 exc.__traceback__)
+
+    def clear(self):
+        self.exc = None
+        self.tb = None
+
+    def __del__(self):
+        if self.tb:
+            msg = 'Future/Task exception was never retrieved\n'
+            if self.source_traceback:
+                src = ''.join(traceback.format_list(self.source_traceback))
+                msg += 'Future/Task created at (most recent call last):\n'
+                msg += '%s\n' % src.rstrip()
+            msg += ''.join(self.tb).rstrip()
+            self.loop.call_exception_handler({'message': msg})
+
+
+class Future:
+    """This class is *almost* compatible with concurrent.futures.Future.
+
+    Differences:
+
+    - This class is not thread-safe.
+
+    - result() and exception() do not take a timeout argument and
+      raise an exception when the future isn't done yet.
+
+    - Callbacks registered with add_done_callback() are always called
+      via the event loop's call_soon().
+
+    - This class is not compatible with the wait() and as_completed()
+      methods in the concurrent.futures package.
+
+    (In Python 3.4 or later we may be able to unify the implementations.)
+    """
+
+    # Class variables serving as defaults for instance variables.
+    _state = _PENDING
+    _result = None
+    _exception = None
+    _loop = None
+    _source_traceback = None
+
+    # This field is used for a dual purpose:
+    # - Its presence is a marker to declare that a class implements
+    #   the Future protocol (i.e. is intended to be duck-type compatible).
+    #   The value must also be not-None, to enable a subclass to declare
+    #   that it is not compatible by setting this to None.
+    # - It is set by __iter__() below so that Task._step() can tell
+    #   the difference between `yield from Future()` (correct) vs.
+    #   `yield Future()` (incorrect).
+    _asyncio_future_blocking = False
+
+    _log_traceback = False
+
+    def __init__(self, *, loop=None):
+        """Initialize the future.
+
+        The optional event_loop argument allows explicitly setting the event
+        loop object used by the future. If it's not provided, the future uses
+        the default event loop.
+        """
+        if loop is None:
+            self._loop = events.get_event_loop()
+        else:
+            self._loop = loop
+        self._callbacks = []
+        if self._loop.get_debug():
+            self._source_traceback = events.extract_stack(sys._getframe(1))
+
+    _repr_info = base_futures._future_repr_info
+
+    def __repr__(self):
+        return '<%s %s>' % (self.__class__.__name__, ' '.join(self._repr_info()))
+
+    # On Python 3.3 and older, objects with a destructor part of a reference
+    # cycle are never destroyed. It's not more the case on Python 3.4 thanks
+    # to the PEP 442.
+    if compat.PY34:
+        def __del__(self):
+            if not self._log_traceback:
+                # set_exception() was not called, or result() or exception()
+                # has consumed the exception
+                return
+            exc = self._exception
+            context = {
+                'message': ('%s exception was never retrieved'
+                            % self.__class__.__name__),
+                'exception': exc,
+                'future': self,
+            }
+            if self._source_traceback:
+                context['source_traceback'] = self._source_traceback
+            self._loop.call_exception_handler(context)
+
+    def cancel(self):
+        """Cancel the future and schedule callbacks.
+
+        If the future is already done or cancelled, return False.  Otherwise,
+        change the future's state to cancelled, schedule the callbacks and
+        return True.
+        """
+        self._log_traceback = False
+        if self._state != _PENDING:
+            return False
+        self._state = _CANCELLED
+        self._schedule_callbacks()
+        return True
+
+    def _schedule_callbacks(self):
+        """Internal: Ask the event loop to call all callbacks.
+
+        The callbacks are scheduled to be called as soon as possible. Also
+        clears the callback list.
+        """
+        callbacks = self._callbacks[:]
+        if not callbacks:
+            return
+
+        self._callbacks[:] = []
+        for callback in callbacks:
+            self._loop.call_soon(callback, self)
+
+    def cancelled(self):
+        """Return True if the future was cancelled."""
+        return self._state == _CANCELLED
+
+    # Don't implement running(); see http://bugs.python.org/issue18699
+
+    def done(self):
+        """Return True if the future is done.
+
+        Done means either that a result / exception are available, or that the
+        future was cancelled.
+        """
+        return self._state != _PENDING
+
+    def result(self):
+        """Return the result this future represents.
+
+        If the future has been cancelled, raises CancelledError.  If the
+        future's result isn't yet available, raises InvalidStateError.  If
+        the future is done and has an exception set, this exception is raised.
+        """
+        if self._state == _CANCELLED:
+            raise CancelledError
+        if self._state != _FINISHED:
+            raise InvalidStateError('Result is not ready.')
+        self._log_traceback = False
+        if self._exception is not None:
+            raise self._exception
+        return self._result
+
+    def exception(self):
+        """Return the exception that was set on this future.
+
+        The exception (or None if no exception was set) is returned only if
+        the future is done.  If the future has been cancelled, raises
+        CancelledError.  If the future isn't done yet, raises
+        InvalidStateError.
+        """
+        if self._state == _CANCELLED:
+            raise CancelledError
+        if self._state != _FINISHED:
+            raise InvalidStateError('Exception is not set.')
+        self._log_traceback = False
+        return self._exception
+
+    def add_done_callback(self, fn):
+        """Add a callback to be run when the future becomes done.
+
+        The callback is called with a single argument - the future object. If
+        the future is already done when this is called, the callback is
+        scheduled with call_soon.
+        """
+        if self._state != _PENDING:
+            self._loop.call_soon(fn, self)
+        else:
+            self._callbacks.append(fn)
+
+    # New method not in PEP 3148.
+
+    def remove_done_callback(self, fn):
+        """Remove all instances of a callback from the "call when done" list.
+
+        Returns the number of callbacks removed.
+        """
+        filtered_callbacks = [f for f in self._callbacks if f != fn]
+        removed_count = len(self._callbacks) - len(filtered_callbacks)
+        if removed_count:
+            self._callbacks[:] = filtered_callbacks
+        return removed_count
+
+    # So-called internal methods (note: no set_running_or_notify_cancel()).
+
+    def set_result(self, result):
+        """Mark the future done and set its result.
+
+        If the future is already done when this method is called, raises
+        InvalidStateError.
+        """
+        if self._state != _PENDING:
+            raise InvalidStateError('{}: {!r}'.format(self._state, self))
+        self._result = result
+        self._state = _FINISHED
+        self._schedule_callbacks()
+
+    def set_exception(self, exception):
+        """Mark the future done and set an exception.
+
+        If the future is already done when this method is called, raises
+        InvalidStateError.
+        """
+        if self._state != _PENDING:
+            raise InvalidStateError('{}: {!r}'.format(self._state, self))
+        if isinstance(exception, type):
+            exception = exception()
+        if type(exception) is StopIteration:
+            raise TypeError("StopIteration interacts badly with generators "
+                            "and cannot be raised into a Future")
+        self._exception = exception
+        self._state = _FINISHED
+        self._schedule_callbacks()
+        if compat.PY34:
+            self._log_traceback = True
+        else:
+            self._tb_logger = _TracebackLogger(self, exception)
+            # Arrange for the logger to be activated after all callbacks
+            # have had a chance to call result() or exception().
+            self._loop.call_soon(self._tb_logger.activate)
+
+    def __iter__(self):
+        if not self.done():
+            self._asyncio_future_blocking = True
+            yield self  # This tells Task to wait for completion.
+        assert self.done(), "yield from wasn't used with future"
+        return self.result()  # May raise too.
+
+    if compat.PY35:
+        __await__ = __iter__ # make compatible with 'await' expression
+
+
+# Needed for testing purposes.
+_PyFuture = Future
+
+
+def _set_result_unless_cancelled(fut, result):
+    """Helper setting the result only if the future was not cancelled."""
+    if fut.cancelled():
+        return
+    fut.set_result(result)
+
+
+def _set_concurrent_future_state(concurrent, source):
+    """Copy state from a future to a concurrent.futures.Future."""
+    assert source.done()
+    if source.cancelled():
+        concurrent.cancel()
+    if not concurrent.set_running_or_notify_cancel():
+        return
+    exception = source.exception()
+    if exception is not None:
+        concurrent.set_exception(exception)
+    else:
+        result = source.result()
+        concurrent.set_result(result)
+
+
+def _copy_future_state(source, dest):
+    """Internal helper to copy state from another Future.
+
+    The other Future may be a concurrent.futures.Future.
+    """
+    assert source.done()
+    if dest.cancelled():
+        return
+    assert not dest.done()
+    if source.cancelled():
+        dest.cancel()
+    else:
+        exception = source.exception()
+        if exception is not None:
+            dest.set_exception(exception)
+        else:
+            result = source.result()
+            dest.set_result(result)
+
+
+def _chain_future(source, destination):
+    """Chain two futures so that when one completes, so does the other.
+
+    The result (or exception) of source will be copied to destination.
+    If destination is cancelled, source gets cancelled too.
+    Compatible with both asyncio.Future and concurrent.futures.Future.
+    """
+    if not isfuture(source) and not isinstance(source,
+                                               concurrent.futures.Future):
+        raise TypeError('A future is required for source argument')
+    if not isfuture(destination) and not isinstance(destination,
+                                                    concurrent.futures.Future):
+        raise TypeError('A future is required for destination argument')
+    source_loop = source._loop if isfuture(source) else None
+    dest_loop = destination._loop if isfuture(destination) else None
+
+    def _set_state(future, other):
+        if isfuture(future):
+            _copy_future_state(other, future)
+        else:
+            _set_concurrent_future_state(future, other)
+
+    def _call_check_cancel(destination):
+        if destination.cancelled():
+            if source_loop is None or source_loop is dest_loop:
+                source.cancel()
+            else:
+                source_loop.call_soon_threadsafe(source.cancel)
+
+    def _call_set_state(source):
+        if (destination.cancelled() and
+                dest_loop is not None and dest_loop.is_closed()):
+            return
+        if dest_loop is None or dest_loop is source_loop:
+            _set_state(destination, source)
+        else:
+            dest_loop.call_soon_threadsafe(_set_state, destination, source)
+
+    destination.add_done_callback(_call_check_cancel)
+    source.add_done_callback(_call_set_state)
+
+
+def wrap_future(future, *, loop=None):
+    """Wrap concurrent.futures.Future object."""
+    if isfuture(future):
+        return future
+    assert isinstance(future, concurrent.futures.Future), \
+        'concurrent.futures.Future is expected, got {!r}'.format(future)
+    if loop is None:
+        loop = events.get_event_loop()
+    new_future = loop.create_future()
+    _chain_future(future, new_future)
+    return new_future
+
+
+try:
+    import _asyncio
+except ImportError:
+    pass
+else:
+    # _CFuture is needed for tests.
+    Future = _CFuture = _asyncio.Future

third_party/python/Lib/asyncio/locks.py

@@ -0,0 +1,501 @@
+"""Synchronization primitives."""
+
+__all__ = ['Lock', 'Event', 'Condition', 'Semaphore', 'BoundedSemaphore']
+
+import collections
+
+from . import compat
+from . import events
+from . import futures
+from .coroutines import coroutine
+
+
+class _ContextManager:
+    """Context manager.
+
+    This enables the following idiom for acquiring and releasing a
+    lock around a block:
+
+        with (yield from lock):
+            <block>
+
+    while failing loudly when accidentally using:
+
+        with lock:
+            <block>
+    """
+
+    def __init__(self, lock):
+        self._lock = lock
+
+    def __enter__(self):
+        # We have no use for the "as ..."  clause in the with
+        # statement for locks.
+        return None
+
+    def __exit__(self, *args):
+        try:
+            self._lock.release()
+        finally:
+            self._lock = None  # Crudely prevent reuse.
+
+
+class _ContextManagerMixin:
+    def __enter__(self):
+        raise RuntimeError(
+            '"yield from" should be used as context manager expression')
+
+    def __exit__(self, *args):
+        # This must exist because __enter__ exists, even though that
+        # always raises; that's how the with-statement works.
+        pass
+
+    @coroutine
+    def __iter__(self):
+        # This is not a coroutine.  It is meant to enable the idiom:
+        #
+        #     with (yield from lock):
+        #         <block>
+        #
+        # as an alternative to:
+        #
+        #     yield from lock.acquire()
+        #     try:
+        #         <block>
+        #     finally:
+        #         lock.release()
+        yield from self.acquire()
+        return _ContextManager(self)
+
+    if compat.PY35:
+
+        def __await__(self):
+            # To make "with await lock" work.
+            yield from self.acquire()
+            return _ContextManager(self)
+
+        @coroutine
+        def __aenter__(self):
+            yield from self.acquire()
+            # We have no use for the "as ..."  clause in the with
+            # statement for locks.
+            return None
+
+        @coroutine
+        def __aexit__(self, exc_type, exc, tb):
+            self.release()
+
+
+class Lock(_ContextManagerMixin):
+    """Primitive lock objects.
+
+    A primitive lock is a synchronization primitive that is not owned
+    by a particular coroutine when locked.  A primitive lock is in one
+    of two states, 'locked' or 'unlocked'.
+
+    It is created in the unlocked state.  It has two basic methods,
+    acquire() and release().  When the state is unlocked, acquire()
+    changes the state to locked and returns immediately.  When the
+    state is locked, acquire() blocks until a call to release() in
+    another coroutine changes it to unlocked, then the acquire() call
+    resets it to locked and returns.  The release() method should only
+    be called in the locked state; it changes the state to unlocked
+    and returns immediately.  If an attempt is made to release an
+    unlocked lock, a RuntimeError will be raised.
+
+    When more than one coroutine is blocked in acquire() waiting for
+    the state to turn to unlocked, only one coroutine proceeds when a
+    release() call resets the state to unlocked; first coroutine which
+    is blocked in acquire() is being processed.
+
+    acquire() is a coroutine and should be called with 'yield from'.
+
+    Locks also support the context management protocol.  '(yield from lock)'
+    should be used as the context manager expression.
+
+    Usage:
+
+        lock = Lock()
+        ...
+        yield from lock
+        try:
+            ...
+        finally:
+            lock.release()
+
+    Context manager usage:
+
+        lock = Lock()
+        ...
+        with (yield from lock):
+             ...
+
+    Lock objects can be tested for locking state:
+
+        if not lock.locked():
+           yield from lock
+        else:
+           # lock is acquired
+           ...
+
+    """
+
+    def __init__(self, *, loop=None):
+        self._waiters = collections.deque()
+        self._locked = False
+        if loop is not None:
+            self._loop = loop
+        else:
+            self._loop = events.get_event_loop()
+
+    def __repr__(self):
+        res = super().__repr__()
+        extra = 'locked' if self._locked else 'unlocked'
+        if self._waiters:
+            extra = '{},waiters:{}'.format(extra, len(self._waiters))
+        return '<{} [{}]>'.format(res[1:-1], extra)
+
+    def locked(self):
+        """Return True if lock is acquired."""
+        return self._locked
+
+    @coroutine
+    def acquire(self):
+        """Acquire a lock.
+
+        This method blocks until the lock is unlocked, then sets it to
+        locked and returns True.
+        """
+        if not self._locked and all(w.cancelled() for w in self._waiters):
+            self._locked = True
+            return True
+
+        fut = self._loop.create_future()
+        self._waiters.append(fut)
+
+        # Finally block should be called before the CancelledError
+        # handling as we don't want CancelledError to call
+        # _wake_up_first() and attempt to wake up itself.
+        try:
+            try:
+                yield from fut
+            finally:
+                self._waiters.remove(fut)
+        except futures.CancelledError:
+            if not self._locked:
+                self._wake_up_first()
+            raise
+
+        self._locked = True
+        return True
+
+    def release(self):
+        """Release a lock.
+
+        When the lock is locked, reset it to unlocked, and return.
+        If any other coroutines are blocked waiting for the lock to become
+        unlocked, allow exactly one of them to proceed.
+
+        When invoked on an unlocked lock, a RuntimeError is raised.
+
+        There is no return value.
+        """
+        if self._locked:
+            self._locked = False
+            self._wake_up_first()
+        else:
+            raise RuntimeError('Lock is not acquired.')
+
+    def _wake_up_first(self):
+        """Wake up the first waiter if it isn't done."""
+        try:
+            fut = next(iter(self._waiters))
+        except StopIteration:
+            return
+
+        # .done() necessarily means that a waiter will wake up later on and
+        # either take the lock, or, if it was cancelled and lock wasn't
+        # taken already, will hit this again and wake up a new waiter.
+        if not fut.done():
+            fut.set_result(True)
+
+
+class Event:
+    """Asynchronous equivalent to threading.Event.
+
+    Class implementing event objects. An event manages a flag that can be set
+    to true with the set() method and reset to false with the clear() method.
+    The wait() method blocks until the flag is true. The flag is initially
+    false.
+    """
+
+    def __init__(self, *, loop=None):
+        self._waiters = collections.deque()
+        self._value = False
+        if loop is not None:
+            self._loop = loop
+        else:
+            self._loop = events.get_event_loop()
+
+    def __repr__(self):
+        res = super().__repr__()
+        extra = 'set' if self._value else 'unset'
+        if self._waiters:
+            extra = '{},waiters:{}'.format(extra, len(self._waiters))
+        return '<{} [{}]>'.format(res[1:-1], extra)
+
+    def is_set(self):
+        """Return True if and only if the internal flag is true."""
+        return self._value
+
+    def set(self):
+        """Set the internal flag to true. All coroutines waiting for it to
+        become true are awakened. Coroutine that call wait() once the flag is
+        true will not block at all.
+        """
+        if not self._value:
+            self._value = True
+
+            for fut in self._waiters:
+                if not fut.done():
+                    fut.set_result(True)
+
+    def clear(self):
+        """Reset the internal flag to false. Subsequently, coroutines calling
+        wait() will block until set() is called to set the internal flag
+        to true again."""
+        self._value = False
+
+    @coroutine
+    def wait(self):
+        """Block until the internal flag is true.
+
+        If the internal flag is true on entry, return True
+        immediately.  Otherwise, block until another coroutine calls
+        set() to set the flag to true, then return True.
+        """
+        if self._value:
+            return True
+
+        fut = self._loop.create_future()
+        self._waiters.append(fut)
+        try:
+            yield from fut
+            return True
+        finally:
+            self._waiters.remove(fut)
+
+
+class Condition(_ContextManagerMixin):
+    """Asynchronous equivalent to threading.Condition.
+
+    This class implements condition variable objects. A condition variable
+    allows one or more coroutines to wait until they are notified by another
+    coroutine.
+
+    A new Lock object is created and used as the underlying lock.
+    """
+
+    def __init__(self, lock=None, *, loop=None):
+        if loop is not None:
+            self._loop = loop
+        else:
+            self._loop = events.get_event_loop()
+
+        if lock is None:
+            lock = Lock(loop=self._loop)
+        elif lock._loop is not self._loop:
+            raise ValueError("loop argument must agree with lock")
+
+        self._lock = lock
+        # Export the lock's locked(), acquire() and release() methods.
+        self.locked = lock.locked
+        self.acquire = lock.acquire
+        self.release = lock.release
+
+        self._waiters = collections.deque()
+
+    def __repr__(self):
+        res = super().__repr__()
+        extra = 'locked' if self.locked() else 'unlocked'
+        if self._waiters:
+            extra = '{},waiters:{}'.format(extra, len(self._waiters))
+        return '<{} [{}]>'.format(res[1:-1], extra)
+
+    @coroutine
+    def wait(self):
+        """Wait until notified.
+
+        If the calling coroutine has not acquired the lock when this
+        method is called, a RuntimeError is raised.
+
+        This method releases the underlying lock, and then blocks
+        until it is awakened by a notify() or notify_all() call for
+        the same condition variable in another coroutine.  Once
+        awakened, it re-acquires the lock and returns True.
+        """
+        if not self.locked():
+            raise RuntimeError('cannot wait on un-acquired lock')
+
+        self.release()
+        try:
+            fut = self._loop.create_future()
+            self._waiters.append(fut)
+            try:
+                yield from fut
+                return True
+            finally:
+                self._waiters.remove(fut)
+
+        finally:
+            # Must reacquire lock even if wait is cancelled
+            cancelled = False
+            while True:
+                try:
+                    yield from self.acquire()
+                    break
+                except futures.CancelledError:
+                    cancelled = True
+
+            if cancelled:
+                raise futures.CancelledError
+
+    @coroutine
+    def wait_for(self, predicate):
+        """Wait until a predicate becomes true.
+
+        The predicate should be a callable which result will be
+        interpreted as a boolean value.  The final predicate value is
+        the return value.
+        """
+        result = predicate()
+        while not result:
+            yield from self.wait()
+            result = predicate()
+        return result
+
+    def notify(self, n=1):
+        """By default, wake up one coroutine waiting on this condition, if any.
+        If the calling coroutine has not acquired the lock when this method
+        is called, a RuntimeError is raised.
+
+        This method wakes up at most n of the coroutines waiting for the
+        condition variable; it is a no-op if no coroutines are waiting.
+
+        Note: an awakened coroutine does not actually return from its
+        wait() call until it can reacquire the lock. Since notify() does
+        not release the lock, its caller should.
+        """
+        if not self.locked():
+            raise RuntimeError('cannot notify on un-acquired lock')
+
+        idx = 0
+        for fut in self._waiters:
+            if idx >= n:
+                break
+
+            if not fut.done():
+                idx += 1
+                fut.set_result(False)
+
+    def notify_all(self):
+        """Wake up all threads waiting on this condition. This method acts
+        like notify(), but wakes up all waiting threads instead of one. If the
+        calling thread has not acquired the lock when this method is called,
+        a RuntimeError is raised.
+        """
+        self.notify(len(self._waiters))
+
+
+class Semaphore(_ContextManagerMixin):
+    """A Semaphore implementation.
+
+    A semaphore manages an internal counter which is decremented by each
+    acquire() call and incremented by each release() call. The counter
+    can never go below zero; when acquire() finds that it is zero, it blocks,
+    waiting until some other thread calls release().
+
+    Semaphores also support the context management protocol.
+
+    The optional argument gives the initial value for the internal
+    counter; it defaults to 1. If the value given is less than 0,
+    ValueError is raised.
+    """
+
+    def __init__(self, value=1, *, loop=None):
+        if value < 0:
+            raise ValueError("Semaphore initial value must be >= 0")
+        self._value = value
+        self._waiters = collections.deque()
+        if loop is not None:
+            self._loop = loop
+        else:
+            self._loop = events.get_event_loop()
+
+    def __repr__(self):
+        res = super().__repr__()
+        extra = 'locked' if self.locked() else 'unlocked,value:{}'.format(
+            self._value)
+        if self._waiters:
+            extra = '{},waiters:{}'.format(extra, len(self._waiters))
+        return '<{} [{}]>'.format(res[1:-1], extra)
+
+    def _wake_up_next(self):
+        while self._waiters:
+            waiter = self._waiters.popleft()
+            if not waiter.done():
+                waiter.set_result(None)
+                return
+
+    def locked(self):
+        """Returns True if semaphore can not be acquired immediately."""
+        return self._value == 0
+
+    @coroutine
+    def acquire(self):
+        """Acquire a semaphore.
+
+        If the internal counter is larger than zero on entry,
+        decrement it by one and return True immediately.  If it is
+        zero on entry, block, waiting until some other coroutine has
+        called release() to make it larger than 0, and then return
+        True.
+        """
+        while self._value <= 0:
+            fut = self._loop.create_future()
+            self._waiters.append(fut)
+            try:
+                yield from fut
+            except:
+                # See the similar code in Queue.get.
+                fut.cancel()
+                if self._value > 0 and not fut.cancelled():
+                    self._wake_up_next()
+                raise
+        self._value -= 1
+        return True
+
+    def release(self):
+        """Release a semaphore, incrementing the internal counter by one.
+        When it was zero on entry and another coroutine is waiting for it to
+        become larger than zero again, wake up that coroutine.
+        """
+        self._value += 1
+        self._wake_up_next()
+
+
+class BoundedSemaphore(Semaphore):
+    """A bounded semaphore implementation.
+
+    This raises ValueError in release() if it would increase the value
+    above the initial value.
+    """
+
+    def __init__(self, value=1, *, loop=None):
+        self._bound_value = value
+        super().__init__(value, loop=loop)
+
+    def release(self):
+        if self._value >= self._bound_value:
+            raise ValueError('BoundedSemaphore released too many times')
+        super().release()

third_party/python/Lib/asyncio/log.py

@@ -0,0 +1,7 @@
+"""Logging configuration."""
+
+import logging
+
+
+# Name the logger after the package.
+logger = logging.getLogger(__package__)

third_party/python/Lib/asyncio/proactor_events.py

@@ -0,0 +1,556 @@
+"""Event loop using a proactor and related classes.
+
+A proactor is a "notify-on-completion" multiplexer.  Currently a
+proactor is only implemented on Windows with IOCP.
+"""
+
+__all__ = ['BaseProactorEventLoop']
+
+import socket
+import warnings
+
+from . import base_events
+from . import compat
+from . import constants
+from . import futures
+from . import sslproto
+from . import transports
+from .log import logger
+
+
+class _ProactorBasePipeTransport(transports._FlowControlMixin,
+                                 transports.BaseTransport):
+    """Base class for pipe and socket transports."""
+
+    def __init__(self, loop, sock, protocol, waiter=None,
+                 extra=None, server=None):
+        super().__init__(extra, loop)
+        self._set_extra(sock)
+        self._sock = sock
+        self._protocol = protocol
+        self._server = server
+        self._buffer = None  # None or bytearray.
+        self._read_fut = None
+        self._write_fut = None
+        self._pending_write = 0
+        self._conn_lost = 0
+        self._closing = False  # Set when close() called.
+        self._eof_written = False
+        if self._server is not None:
+            self._server._attach()
+        self._loop.call_soon(self._protocol.connection_made, self)
+        if waiter is not None:
+            # only wake up the waiter when connection_made() has been called
+            self._loop.call_soon(futures._set_result_unless_cancelled,
+                                 waiter, None)
+
+    def __repr__(self):
+        info = [self.__class__.__name__]
+        if self._sock is None:
+            info.append('closed')
+        elif self._closing:
+            info.append('closing')
+        if self._sock is not None:
+            info.append('fd=%s' % self._sock.fileno())
+        if self._read_fut is not None:
+            info.append('read=%s' % self._read_fut)
+        if self._write_fut is not None:
+            info.append("write=%r" % self._write_fut)
+        if self._buffer:
+            bufsize = len(self._buffer)
+            info.append('write_bufsize=%s' % bufsize)
+        if self._eof_written:
+            info.append('EOF written')
+        return '<%s>' % ' '.join(info)
+
+    def _set_extra(self, sock):
+        self._extra['pipe'] = sock
+
+    def set_protocol(self, protocol):
+        self._protocol = protocol
+
+    def get_protocol(self):
+        return self._protocol
+
+    def is_closing(self):
+        return self._closing
+
+    def close(self):
+        if self._closing:
+            return
+        self._closing = True
+        self._conn_lost += 1
+        if not self._buffer and self._write_fut is None:
+            self._loop.call_soon(self._call_connection_lost, None)
+        if self._read_fut is not None:
+            self._read_fut.cancel()
+            self._read_fut = None
+
+    # On Python 3.3 and older, objects with a destructor part of a reference
+    # cycle are never destroyed. It's not more the case on Python 3.4 thanks
+    # to the PEP 442.
+    if compat.PY34:
+        def __del__(self):
+            if self._sock is not None:
+                warnings.warn("unclosed transport %r" % self, ResourceWarning,
+                              source=self)
+                self.close()
+
+    def _fatal_error(self, exc, message='Fatal error on pipe transport'):
+        if isinstance(exc, base_events._FATAL_ERROR_IGNORE):
+            if self._loop.get_debug():
+                logger.debug("%r: %s", self, message, exc_info=True)
+        else:
+            self._loop.call_exception_handler({
+                'message': message,
+                'exception': exc,
+                'transport': self,
+                'protocol': self._protocol,
+            })
+        self._force_close(exc)
+
+    def _force_close(self, exc):
+        if self._closing:
+            return
+        self._closing = True
+        self._conn_lost += 1
+        if self._write_fut:
+            self._write_fut.cancel()
+            self._write_fut = None
+        if self._read_fut:
+            self._read_fut.cancel()
+            self._read_fut = None
+        self._pending_write = 0
+        self._buffer = None
+        self._loop.call_soon(self._call_connection_lost, exc)
+
+    def _call_connection_lost(self, exc):
+        try:
+            self._protocol.connection_lost(exc)
+        finally:
+            # XXX If there is a pending overlapped read on the other
+            # end then it may fail with ERROR_NETNAME_DELETED if we
+            # just close our end.  First calling shutdown() seems to
+            # cure it, but maybe using DisconnectEx() would be better.
+            if hasattr(self._sock, 'shutdown'):
+                self._sock.shutdown(socket.SHUT_RDWR)
+            self._sock.close()
+            self._sock = None
+            server = self._server
+            if server is not None:
+                server._detach()
+                self._server = None
+
+    def get_write_buffer_size(self):
+        size = self._pending_write
+        if self._buffer is not None:
+            size += len(self._buffer)
+        return size
+
+
+class _ProactorReadPipeTransport(_ProactorBasePipeTransport,
+                                 transports.ReadTransport):
+    """Transport for read pipes."""
+
+    def __init__(self, loop, sock, protocol, waiter=None,
+                 extra=None, server=None):
+        super().__init__(loop, sock, protocol, waiter, extra, server)
+        self._paused = False
+        self._reschedule_on_resume = False
+        self._loop.call_soon(self._loop_reading)
+
+    def pause_reading(self):
+        if self._closing or self._paused:
+            return
+        self._paused = True
+        if self._loop.get_debug():
+            logger.debug("%r pauses reading", self)
+
+    def resume_reading(self):
+        if self._closing or not self._paused:
+            return
+        self._paused = False
+        if self._reschedule_on_resume:
+            self._loop.call_soon(self._loop_reading, self._read_fut)
+            self._reschedule_on_resume = False
+        if self._loop.get_debug():
+            logger.debug("%r resumes reading", self)
+
+    def _loop_reading(self, fut=None):
+        if self._paused:
+            self._reschedule_on_resume = True
+            return
+        data = None
+
+        try:
+            if fut is not None:
+                assert self._read_fut is fut or (self._read_fut is None and
+                                                 self._closing)
+                self._read_fut = None
+                data = fut.result()  # deliver data later in "finally" clause
+
+            if self._closing:
+                # since close() has been called we ignore any read data
+                data = None
+                return
+
+            if data == b'':
+                # we got end-of-file so no need to reschedule a new read
+                return
+
+            # reschedule a new read
+            self._read_fut = self._loop._proactor.recv(self._sock, 4096)
+        except ConnectionAbortedError as exc:
+            if not self._closing:
+                self._fatal_error(exc, 'Fatal read error on pipe transport')
+            elif self._loop.get_debug():
+                logger.debug("Read error on pipe transport while closing",
+                             exc_info=True)
+        except ConnectionResetError as exc:
+            self._force_close(exc)
+        except OSError as exc:
+            self._fatal_error(exc, 'Fatal read error on pipe transport')
+        except futures.CancelledError:
+            if not self._closing:
+                raise
+        else:
+            self._read_fut.add_done_callback(self._loop_reading)
+        finally:
+            if data:
+                self._protocol.data_received(data)
+            elif data is not None:
+                if self._loop.get_debug():
+                    logger.debug("%r received EOF", self)
+                keep_open = self._protocol.eof_received()
+                if not keep_open:
+                    self.close()
+
+
+class _ProactorBaseWritePipeTransport(_ProactorBasePipeTransport,
+                                      transports.WriteTransport):
+    """Transport for write pipes."""
+
+    def write(self, data):
+        if not isinstance(data, (bytes, bytearray, memoryview)):
+            msg = ("data argument must be a bytes-like object, not '%s'" %
+                   type(data).__name__)
+            raise TypeError(msg)
+        if self._eof_written:
+            raise RuntimeError('write_eof() already called')
+
+        if not data:
+            return
+
+        if self._conn_lost:
+            if self._conn_lost >= constants.LOG_THRESHOLD_FOR_CONNLOST_WRITES:
+                logger.warning('socket.send() raised exception.')
+            self._conn_lost += 1
+            return
+
+        # Observable states:
+        # 1. IDLE: _write_fut and _buffer both None
+        # 2. WRITING: _write_fut set; _buffer None
+        # 3. BACKED UP: _write_fut set; _buffer a bytearray
+        # We always copy the data, so the caller can't modify it
+        # while we're still waiting for the I/O to happen.
+        if self._write_fut is None:  # IDLE -> WRITING
+            assert self._buffer is None
+            # Pass a copy, except if it's already immutable.
+            self._loop_writing(data=bytes(data))
+        elif not self._buffer:  # WRITING -> BACKED UP
+            # Make a mutable copy which we can extend.
+            self._buffer = bytearray(data)
+            self._maybe_pause_protocol()
+        else:  # BACKED UP
+            # Append to buffer (also copies).
+            self._buffer.extend(data)
+            self._maybe_pause_protocol()
+
+    def _loop_writing(self, f=None, data=None):
+        try:
+            assert f is self._write_fut
+            self._write_fut = None
+            self._pending_write = 0
+            if f:
+                f.result()
+            if data is None:
+                data = self._buffer
+                self._buffer = None
+            if not data:
+                if self._closing:
+                    self._loop.call_soon(self._call_connection_lost, None)
+                if self._eof_written:
+                    self._sock.shutdown(socket.SHUT_WR)
+                # Now that we've reduced the buffer size, tell the
+                # protocol to resume writing if it was paused.  Note that
+                # we do this last since the callback is called immediately
+                # and it may add more data to the buffer (even causing the
+                # protocol to be paused again).
+                self._maybe_resume_protocol()
+            else:
+                self._write_fut = self._loop._proactor.send(self._sock, data)
+                if not self._write_fut.done():
+                    assert self._pending_write == 0
+                    self._pending_write = len(data)
+                    self._write_fut.add_done_callback(self._loop_writing)
+                    self._maybe_pause_protocol()
+                else:
+                    self._write_fut.add_done_callback(self._loop_writing)
+        except ConnectionResetError as exc:
+            self._force_close(exc)
+        except OSError as exc:
+            self._fatal_error(exc, 'Fatal write error on pipe transport')
+
+    def can_write_eof(self):
+        return True
+
+    def write_eof(self):
+        self.close()
+
+    def abort(self):
+        self._force_close(None)
+
+
+class _ProactorWritePipeTransport(_ProactorBaseWritePipeTransport):
+    def __init__(self, *args, **kw):
+        super().__init__(*args, **kw)
+        self._read_fut = self._loop._proactor.recv(self._sock, 16)
+        self._read_fut.add_done_callback(self._pipe_closed)
+
+    def _pipe_closed(self, fut):
+        if fut.cancelled():
+            # the transport has been closed
+            return
+        assert fut.result() == b''
+        if self._closing:
+            assert self._read_fut is None
+            return
+        assert fut is self._read_fut, (fut, self._read_fut)
+        self._read_fut = None
+        if self._write_fut is not None:
+            self._force_close(BrokenPipeError())
+        else:
+            self.close()
+
+
+class _ProactorDuplexPipeTransport(_ProactorReadPipeTransport,
+                                   _ProactorBaseWritePipeTransport,
+                                   transports.Transport):
+    """Transport for duplex pipes."""
+
+    def can_write_eof(self):
+        return False
+
+    def write_eof(self):
+        raise NotImplementedError
+
+
+class _ProactorSocketTransport(_ProactorReadPipeTransport,
+                               _ProactorBaseWritePipeTransport,
+                               transports.Transport):
+    """Transport for connected sockets."""
+
+    def __init__(self, loop, sock, protocol, waiter=None,
+                 extra=None, server=None):
+        super().__init__(loop, sock, protocol, waiter, extra, server)
+        base_events._set_nodelay(sock)
+
+    def _set_extra(self, sock):
+        self._extra['socket'] = sock
+        try:
+            self._extra['sockname'] = sock.getsockname()
+        except (socket.error, AttributeError):
+            if self._loop.get_debug():
+                logger.warning("getsockname() failed on %r",
+                             sock, exc_info=True)
+        if 'peername' not in self._extra:
+            try:
+                self._extra['peername'] = sock.getpeername()
+            except (socket.error, AttributeError):
+                if self._loop.get_debug():
+                    logger.warning("getpeername() failed on %r",
+                                   sock, exc_info=True)
+
+    def can_write_eof(self):
+        return True
+
+    def write_eof(self):
+        if self._closing or self._eof_written:
+            return
+        self._eof_written = True
+        if self._write_fut is None:
+            self._sock.shutdown(socket.SHUT_WR)
+
+
+class BaseProactorEventLoop(base_events.BaseEventLoop):
+
+    def __init__(self, proactor):
+        super().__init__()
+        logger.debug('Using proactor: %s', proactor.__class__.__name__)
+        self._proactor = proactor
+        self._selector = proactor   # convenient alias
+        self._self_reading_future = None
+        self._accept_futures = {}   # socket file descriptor => Future
+        proactor.set_loop(self)
+        self._make_self_pipe()
+
+    def _make_socket_transport(self, sock, protocol, waiter=None,
+                               extra=None, server=None):
+        return _ProactorSocketTransport(self, sock, protocol, waiter,
+                                        extra, server)
+
+    def _make_ssl_transport(self, rawsock, protocol, sslcontext, waiter=None,
+                            *, server_side=False, server_hostname=None,
+                            extra=None, server=None):
+        if not sslproto._is_sslproto_available():
+            raise NotImplementedError("Proactor event loop requires Python 3.5"
+                                      " or newer (ssl.MemoryBIO) to support "
+                                      "SSL")
+
+        ssl_protocol = sslproto.SSLProtocol(self, protocol, sslcontext, waiter,
+                                            server_side, server_hostname)
+        _ProactorSocketTransport(self, rawsock, ssl_protocol,
+                                 extra=extra, server=server)
+        return ssl_protocol._app_transport
+
+    def _make_duplex_pipe_transport(self, sock, protocol, waiter=None,
+                                    extra=None):
+        return _ProactorDuplexPipeTransport(self,
+                                            sock, protocol, waiter, extra)
+
+    def _make_read_pipe_transport(self, sock, protocol, waiter=None,
+                                  extra=None):
+        return _ProactorReadPipeTransport(self, sock, protocol, waiter, extra)
+
+    def _make_write_pipe_transport(self, sock, protocol, waiter=None,
+                                   extra=None):
+        # We want connection_lost() to be called when other end closes
+        return _ProactorWritePipeTransport(self,
+                                           sock, protocol, waiter, extra)
+
+    def close(self):
+        if self.is_running():
+            raise RuntimeError("Cannot close a running event loop")
+        if self.is_closed():
+            return
+
+        # Call these methods before closing the event loop (before calling
+        # BaseEventLoop.close), because they can schedule callbacks with
+        # call_soon(), which is forbidden when the event loop is closed.
+        self._stop_accept_futures()
+        self._close_self_pipe()
+        self._proactor.close()
+        self._proactor = None
+        self._selector = None
+
+        # Close the event loop
+        super().close()
+
+    def sock_recv(self, sock, n):
+        return self._proactor.recv(sock, n)
+
+    def sock_sendall(self, sock, data):
+        return self._proactor.send(sock, data)
+
+    def sock_connect(self, sock, address):
+        return self._proactor.connect(sock, address)
+
+    def sock_accept(self, sock):
+        return self._proactor.accept(sock)
+
+    def _socketpair(self):
+        raise NotImplementedError
+
+    def _close_self_pipe(self):
+        if self._self_reading_future is not None:
+            self._self_reading_future.cancel()
+            self._self_reading_future = None
+        self._ssock.close()
+        self._ssock = None
+        self._csock.close()
+        self._csock = None
+        self._internal_fds -= 1
+
+    def _make_self_pipe(self):
+        # A self-socket, really. :-)
+        self._ssock, self._csock = self._socketpair()
+        self._ssock.setblocking(False)
+        self._csock.setblocking(False)
+        self._internal_fds += 1
+        self.call_soon(self._loop_self_reading)
+
+    def _loop_self_reading(self, f=None):
+        try:
+            if f is not None:
+                f.result()  # may raise
+            f = self._proactor.recv(self._ssock, 4096)
+        except futures.CancelledError:
+            # _close_self_pipe() has been called, stop waiting for data
+            return
+        except Exception as exc:
+            self.call_exception_handler({
+                'message': 'Error on reading from the event loop self pipe',
+                'exception': exc,
+                'loop': self,
+            })
+        else:
+            self._self_reading_future = f
+            f.add_done_callback(self._loop_self_reading)
+
+    def _write_to_self(self):
+        self._csock.send(b'\0')
+
+    def _start_serving(self, protocol_factory, sock,
+                       sslcontext=None, server=None, backlog=100):
+
+        def loop(f=None):
+            try:
+                if f is not None:
+                    conn, addr = f.result()
+                    if self._debug:
+                        logger.debug("%r got a new connection from %r: %r",
+                                     server, addr, conn)
+                    protocol = protocol_factory()
+                    if sslcontext is not None:
+                        self._make_ssl_transport(
+                            conn, protocol, sslcontext, server_side=True,
+                            extra={'peername': addr}, server=server)
+                    else:
+                        self._make_socket_transport(
+                            conn, protocol,
+                            extra={'peername': addr}, server=server)
+                if self.is_closed():
+                    return
+                f = self._proactor.accept(sock)
+            except OSError as exc:
+                if sock.fileno() != -1:
+                    self.call_exception_handler({
+                        'message': 'Accept failed on a socket',
+                        'exception': exc,
+                        'socket': sock,
+                    })
+                    sock.close()
+                elif self._debug:
+                    logger.debug("Accept failed on socket %r",
+                                 sock, exc_info=True)
+            except futures.CancelledError:
+                sock.close()
+            else:
+                self._accept_futures[sock.fileno()] = f
+                f.add_done_callback(loop)
+
+        self.call_soon(loop)
+
+    def _process_events(self, event_list):
+        # Events are processed in the IocpProactor._poll() method
+        pass
+
+    def _stop_accept_futures(self):
+        for future in self._accept_futures.values():
+            future.cancel()
+        self._accept_futures.clear()
+
+    def _stop_serving(self, sock):
+        self._stop_accept_futures()
+        self._proactor._stop_serving(sock)
+        sock.close()

third_party/python/Lib/asyncio/protocols.py

@@ -0,0 +1,134 @@
+"""Abstract Protocol class."""
+
+__all__ = ['BaseProtocol', 'Protocol', 'DatagramProtocol',
+           'SubprocessProtocol']
+
+
+class BaseProtocol:
+    """Common base class for protocol interfaces.
+
+    Usually user implements protocols that derived from BaseProtocol
+    like Protocol or ProcessProtocol.
+
+    The only case when BaseProtocol should be implemented directly is
+    write-only transport like write pipe
+    """
+
+    def connection_made(self, transport):
+        """Called when a connection is made.
+
+        The argument is the transport representing the pipe connection.
+        To receive data, wait for data_received() calls.
+        When the connection is closed, connection_lost() is called.
+        """
+
+    def connection_lost(self, exc):
+        """Called when the connection is lost or closed.
+
+        The argument is an exception object or None (the latter
+        meaning a regular EOF is received or the connection was
+        aborted or closed).
+        """
+
+    def pause_writing(self):
+        """Called when the transport's buffer goes over the high-water mark.
+
+        Pause and resume calls are paired -- pause_writing() is called
+        once when the buffer goes strictly over the high-water mark
+        (even if subsequent writes increases the buffer size even
+        more), and eventually resume_writing() is called once when the
+        buffer size reaches the low-water mark.
+
+        Note that if the buffer size equals the high-water mark,
+        pause_writing() is not called -- it must go strictly over.
+        Conversely, resume_writing() is called when the buffer size is
+        equal or lower than the low-water mark.  These end conditions
+        are important to ensure that things go as expected when either
+        mark is zero.
+
+        NOTE: This is the only Protocol callback that is not called
+        through EventLoop.call_soon() -- if it were, it would have no
+        effect when it's most needed (when the app keeps writing
+        without yielding until pause_writing() is called).
+        """
+
+    def resume_writing(self):
+        """Called when the transport's buffer drains below the low-water mark.
+
+        See pause_writing() for details.
+        """
+
+
+class Protocol(BaseProtocol):
+    """Interface for stream protocol.
+
+    The user should implement this interface.  They can inherit from
+    this class but don't need to.  The implementations here do
+    nothing (they don't raise exceptions).
+
+    When the user wants to requests a transport, they pass a protocol
+    factory to a utility function (e.g., EventLoop.create_connection()).
+
+    When the connection is made successfully, connection_made() is
+    called with a suitable transport object.  Then data_received()
+    will be called 0 or more times with data (bytes) received from the
+    transport; finally, connection_lost() will be called exactly once
+    with either an exception object or None as an argument.
+
+    State machine of calls:
+
+      start -> CM [-> DR*] [-> ER?] -> CL -> end
+
+    * CM: connection_made()
+    * DR: data_received()
+    * ER: eof_received()
+    * CL: connection_lost()
+    """
+
+    def data_received(self, data):
+        """Called when some data is received.
+
+        The argument is a bytes object.
+        """
+
+    def eof_received(self):
+        """Called when the other end calls write_eof() or equivalent.
+
+        If this returns a false value (including None), the transport
+        will close itself.  If it returns a true value, closing the
+        transport is up to the protocol.
+        """
+
+
+class DatagramProtocol(BaseProtocol):
+    """Interface for datagram protocol."""
+
+    def datagram_received(self, data, addr):
+        """Called when some datagram is received."""
+
+    def error_received(self, exc):
+        """Called when a send or receive operation raises an OSError.
+
+        (Other than BlockingIOError or InterruptedError.)
+        """
+
+
+class SubprocessProtocol(BaseProtocol):
+    """Interface for protocol for subprocess calls."""
+
+    def pipe_data_received(self, fd, data):
+        """Called when the subprocess writes data into stdout/stderr pipe.
+
+        fd is int file descriptor.
+        data is bytes object.
+        """
+
+    def pipe_connection_lost(self, fd, exc):
+        """Called when a file descriptor associated with the child process is
+        closed.
+
+        fd is the int file descriptor that was closed.
+        """
+
+    def process_exited(self):
+        """Called when subprocess has exited."""

third_party/python/Lib/asyncio/queues.py

@@ -0,0 +1,259 @@
+"""Queues"""
+
+__all__ = ['Queue', 'PriorityQueue', 'LifoQueue', 'QueueFull', 'QueueEmpty']
+
+import collections
+import heapq
+
+from . import compat
+from . import events
+from . import locks
+from .coroutines import coroutine
+
+
+class QueueEmpty(Exception):
+    """Exception raised when Queue.get_nowait() is called on a Queue object
+    which is empty.
+    """
+    pass
+
+
+class QueueFull(Exception):
+    """Exception raised when the Queue.put_nowait() method is called on a Queue
+    object which is full.
+    """
+    pass
+
+
+class Queue:
+    """A queue, useful for coordinating producer and consumer coroutines.
+
+    If maxsize is less than or equal to zero, the queue size is infinite. If it
+    is an integer greater than 0, then "yield from put()" will block when the
+    queue reaches maxsize, until an item is removed by get().
+
+    Unlike the standard library Queue, you can reliably know this Queue's size
+    with qsize(), since your single-threaded asyncio application won't be
+    interrupted between calling qsize() and doing an operation on the Queue.
+    """
+
+    def __init__(self, maxsize=0, *, loop=None):
+        if loop is None:
+            self._loop = events.get_event_loop()
+        else:
+            self._loop = loop
+        self._maxsize = maxsize
+
+        # Futures.
+        self._getters = collections.deque()
+        # Futures.
+        self._putters = collections.deque()
+        self._unfinished_tasks = 0
+        self._finished = locks.Event(loop=self._loop)
+        self._finished.set()
+        self._init(maxsize)
+
+    # These three are overridable in subclasses.
+
+    def _init(self, maxsize):
+        self._queue = collections.deque()
+
+    def _get(self):
+        return self._queue.popleft()
+
+    def _put(self, item):
+        self._queue.append(item)
+
+    # End of the overridable methods.
+
+    def _wakeup_next(self, waiters):
+        # Wake up the next waiter (if any) that isn't cancelled.
+        while waiters:
+            waiter = waiters.popleft()
+            if not waiter.done():
+                waiter.set_result(None)
+                break
+
+    def __repr__(self):
+        return '<{} at {:#x} {}>'.format(
+            type(self).__name__, id(self), self._format())
+
+    def __str__(self):
+        return '<{} {}>'.format(type(self).__name__, self._format())
+
+    def _format(self):
+        result = 'maxsize={!r}'.format(self._maxsize)
+        if getattr(self, '_queue', None):
+            result += ' _queue={!r}'.format(list(self._queue))
+        if self._getters:
+            result += ' _getters[{}]'.format(len(self._getters))
+        if self._putters:
+            result += ' _putters[{}]'.format(len(self._putters))
+        if self._unfinished_tasks:
+            result += ' tasks={}'.format(self._unfinished_tasks)
+        return result
+
+    def qsize(self):
+        """Number of items in the queue."""
+        return len(self._queue)
+
+    @property
+    def maxsize(self):
+        """Number of items allowed in the queue."""
+        return self._maxsize
+
+    def empty(self):
+        """Return True if the queue is empty, False otherwise."""
+        return not self._queue
+
+    def full(self):
+        """Return True if there are maxsize items in the queue.
+
+        Note: if the Queue was initialized with maxsize=0 (the default),
+        then full() is never True.
+        """
+        if self._maxsize <= 0:
+            return False
+        else:
+            return self.qsize() >= self._maxsize
+
+    @coroutine
+    def put(self, item):
+        """Put an item into the queue.
+
+        Put an item into the queue. If the queue is full, wait until a free
+        slot is available before adding item.
+
+        This method is a coroutine.
+        """
+        while self.full():
+            putter = self._loop.create_future()
+            self._putters.append(putter)
+            try:
+                yield from putter
+            except:
+                putter.cancel()  # Just in case putter is not done yet.
+                if not self.full() and not putter.cancelled():
+                    # We were woken up by get_nowait(), but can't take
+                    # the call.  Wake up the next in line.
+                    self._wakeup_next(self._putters)
+                raise
+        return self.put_nowait(item)
+
+    def put_nowait(self, item):
+        """Put an item into the queue without blocking.
+
+        If no free slot is immediately available, raise QueueFull.
+        """
+        if self.full():
+            raise QueueFull
+        self._put(item)
+        self._unfinished_tasks += 1
+        self._finished.clear()
+        self._wakeup_next(self._getters)
+
+    @coroutine
+    def get(self):
+        """Remove and return an item from the queue.
+
+        If queue is empty, wait until an item is available.
+
+        This method is a coroutine.
+        """
+        while self.empty():
+            getter = self._loop.create_future()
+            self._getters.append(getter)
+            try:
+                yield from getter
+            except:
+                getter.cancel()  # Just in case getter is not done yet.
+
+                try:
+                    self._getters.remove(getter)
+                except ValueError:
+                    pass
+
+                if not self.empty() and not getter.cancelled():
+                    # We were woken up by put_nowait(), but can't take
+                    # the call.  Wake up the next in line.
+                    self._wakeup_next(self._getters)
+                raise
+        return self.get_nowait()
+
+    def get_nowait(self):
+        """Remove and return an item from the queue.
+
+        Return an item if one is immediately available, else raise QueueEmpty.
+        """
+        if self.empty():
+            raise QueueEmpty
+        item = self._get()
+        self._wakeup_next(self._putters)
+        return item
+
+    def task_done(self):
+        """Indicate that a formerly enqueued task is complete.
+
+        Used by queue consumers. For each get() used to fetch a task,
+        a subsequent call to task_done() tells the queue that the processing
+        on the task is complete.
+
+        If a join() is currently blocking, it will resume when all items have
+        been processed (meaning that a task_done() call was received for every
+        item that had been put() into the queue).
+
+        Raises ValueError if called more times than there were items placed in
+        the queue.
+        """
+        if self._unfinished_tasks <= 0:
+            raise ValueError('task_done() called too many times')
+        self._unfinished_tasks -= 1
+        if self._unfinished_tasks == 0:
+            self._finished.set()
+
+    @coroutine
+    def join(self):
+        """Block until all items in the queue have been gotten and processed.
+
+        The count of unfinished tasks goes up whenever an item is added to the
+        queue. The count goes down whenever a consumer calls task_done() to
+        indicate that the item was retrieved and all work on it is complete.
+        When the count of unfinished tasks drops to zero, join() unblocks.
+        """
+        if self._unfinished_tasks > 0:
+            yield from self._finished.wait()
+
+
+class PriorityQueue(Queue):
+    """A subclass of Queue; retrieves entries in priority order (lowest first).
+
+    Entries are typically tuples of the form: (priority number, data).
+    """
+
+    def _init(self, maxsize):
+        self._queue = []
+
+    def _put(self, item, heappush=heapq.heappush):
+        heappush(self._queue, item)
+
+    def _get(self, heappop=heapq.heappop):
+        return heappop(self._queue)
+
+
+class LifoQueue(Queue):
+    """A subclass of Queue that retrieves most recently added entries first."""
+
+    def _init(self, maxsize):
+        self._queue = []
+
+    def _put(self, item):
+        self._queue.append(item)
+
+    def _get(self):
+        return self._queue.pop()
+
+
+if not compat.PY35:
+    JoinableQueue = Queue
+    """Deprecated alias for Queue."""
+    __all__.append('JoinableQueue')

third_party/python/Lib/asyncio/sslproto.py

@@ -0,0 +1,701 @@
+import collections
+import warnings
+try:
+    import ssl
+except ImportError:  # pragma: no cover
+    ssl = None
+
+from . import base_events
+from . import compat
+from . import protocols
+from . import transports
+from .log import logger
+
+
+def _create_transport_context(server_side, server_hostname):
+    if server_side:
+        raise ValueError('Server side SSL needs a valid SSLContext')
+
+    # Client side may pass ssl=True to use a default
+    # context; in that case the sslcontext passed is None.
+    # The default is secure for client connections.
+    if hasattr(ssl, 'create_default_context'):
+        # Python 3.4+: use up-to-date strong settings.
+        sslcontext = ssl.create_default_context()
+        if not server_hostname:
+            sslcontext.check_hostname = False
+    else:
+        # Fallback for Python 3.3.
+        sslcontext = ssl.SSLContext(ssl.PROTOCOL_SSLv23)
+        sslcontext.options |= ssl.OP_NO_SSLv2
+        sslcontext.options |= ssl.OP_NO_SSLv3
+        sslcontext.set_default_verify_paths()
+        sslcontext.verify_mode = ssl.CERT_REQUIRED
+    return sslcontext
+
+
+def _is_sslproto_available():
+    return hasattr(ssl, "MemoryBIO")
+
+
+# States of an _SSLPipe.
+_UNWRAPPED = "UNWRAPPED"
+_DO_HANDSHAKE = "DO_HANDSHAKE"
+_WRAPPED = "WRAPPED"
+_SHUTDOWN = "SHUTDOWN"
+
+
+class _SSLPipe(object):
+    """An SSL "Pipe".
+
+    An SSL pipe allows you to communicate with an SSL/TLS protocol instance
+    through memory buffers. It can be used to implement a security layer for an
+    existing connection where you don't have access to the connection's file
+    descriptor, or for some reason you don't want to use it.
+
+    An SSL pipe can be in "wrapped" and "unwrapped" mode. In unwrapped mode,
+    data is passed through untransformed. In wrapped mode, application level
+    data is encrypted to SSL record level data and vice versa. The SSL record
+    level is the lowest level in the SSL protocol suite and is what travels
+    as-is over the wire.
+
+    An SslPipe initially is in "unwrapped" mode. To start SSL, call
+    do_handshake(). To shutdown SSL again, call unwrap().
+    """
+
+    max_size = 256 * 1024   # Buffer size passed to read()
+
+    def __init__(self, context, server_side, server_hostname=None):
+        """
+        The *context* argument specifies the ssl.SSLContext to use.
+
+        The *server_side* argument indicates whether this is a server side or
+        client side transport.
+
+        The optional *server_hostname* argument can be used to specify the
+        hostname you are connecting to. You may only specify this parameter if
+        the _ssl module supports Server Name Indication (SNI).
+        """
+        self._context = context
+        self._server_side = server_side
+        self._server_hostname = server_hostname
+        self._state = _UNWRAPPED
+        self._incoming = ssl.MemoryBIO()
+        self._outgoing = ssl.MemoryBIO()
+        self._sslobj = None
+        self._need_ssldata = False
+        self._handshake_cb = None
+        self._shutdown_cb = None
+
+    @property
+    def context(self):
+        """The SSL context passed to the constructor."""
+        return self._context
+
+    @property
+    def ssl_object(self):
+        """The internal ssl.SSLObject instance.
+
+        Return None if the pipe is not wrapped.
+        """
+        return self._sslobj
+
+    @property
+    def need_ssldata(self):
+        """Whether more record level data is needed to complete a handshake
+        that is currently in progress."""
+        return self._need_ssldata
+
+    @property
+    def wrapped(self):
+        """
+        Whether a security layer is currently in effect.
+
+        Return False during handshake.
+        """
+        return self._state == _WRAPPED
+
+    def do_handshake(self, callback=None):
+        """Start the SSL handshake.
+
+        Return a list of ssldata. A ssldata element is a list of buffers
+
+        The optional *callback* argument can be used to install a callback that
+        will be called when the handshake is complete. The callback will be
+        called with None if successful, else an exception instance.
+        """
+        if self._state != _UNWRAPPED:
+            raise RuntimeError('handshake in progress or completed')
+        self._sslobj = self._context.wrap_bio(
+            self._incoming, self._outgoing,
+            server_side=self._server_side,
+            server_hostname=self._server_hostname)
+        self._state = _DO_HANDSHAKE
+        self._handshake_cb = callback
+        ssldata, appdata = self.feed_ssldata(b'', only_handshake=True)
+        assert len(appdata) == 0
+        return ssldata
+
+    def shutdown(self, callback=None):
+        """Start the SSL shutdown sequence.
+
+        Return a list of ssldata. A ssldata element is a list of buffers
+
+        The optional *callback* argument can be used to install a callback that
+        will be called when the shutdown is complete. The callback will be
+        called without arguments.
+        """
+        if self._state == _UNWRAPPED:
+            raise RuntimeError('no security layer present')
+        if self._state == _SHUTDOWN:
+            raise RuntimeError('shutdown in progress')
+        assert self._state in (_WRAPPED, _DO_HANDSHAKE)
+        self._state = _SHUTDOWN
+        self._shutdown_cb = callback
+        ssldata, appdata = self.feed_ssldata(b'')
+        assert appdata == [] or appdata == [b'']
+        return ssldata
+
+    def feed_eof(self):
+        """Send a potentially "ragged" EOF.
+
+        This method will raise an SSL_ERROR_EOF exception if the EOF is
+        unexpected.
+        """
+        self._incoming.write_eof()
+        ssldata, appdata = self.feed_ssldata(b'')
+        assert appdata == [] or appdata == [b'']
+
+    def feed_ssldata(self, data, only_handshake=False):
+        """Feed SSL record level data into the pipe.
+
+        The data must be a bytes instance. It is OK to send an empty bytes
+        instance. This can be used to get ssldata for a handshake initiated by
+        this endpoint.
+
+        Return a (ssldata, appdata) tuple. The ssldata element is a list of
+        buffers containing SSL data that needs to be sent to the remote SSL.
+
+        The appdata element is a list of buffers containing plaintext data that
+        needs to be forwarded to the application. The appdata list may contain
+        an empty buffer indicating an SSL "close_notify" alert. This alert must
+        be acknowledged by calling shutdown().
+        """
+        if self._state == _UNWRAPPED:
+            # If unwrapped, pass plaintext data straight through.
+            if data:
+                appdata = [data]
+            else:
+                appdata = []
+            return ([], appdata)
+
+        self._need_ssldata = False
+        if data:
+            self._incoming.write(data)
+
+        ssldata = []
+        appdata = []
+        try:
+            if self._state == _DO_HANDSHAKE:
+                # Call do_handshake() until it doesn't raise anymore.
+                self._sslobj.do_handshake()
+                self._state = _WRAPPED
+                if self._handshake_cb:
+                    self._handshake_cb(None)
+                if only_handshake:
+                    return (ssldata, appdata)
+                # Handshake done: execute the wrapped block
+
+            if self._state == _WRAPPED:
+                # Main state: read data from SSL until close_notify
+                while True:
+                    chunk = self._sslobj.read(self.max_size)
+                    appdata.append(chunk)
+                    if not chunk:  # close_notify
+                        break
+
+            elif self._state == _SHUTDOWN:
+                # Call shutdown() until it doesn't raise anymore.
+                self._sslobj.unwrap()
+                self._sslobj = None
+                self._state = _UNWRAPPED
+                if self._shutdown_cb:
+                    self._shutdown_cb()
+
+            elif self._state == _UNWRAPPED:
+                # Drain possible plaintext data after close_notify.
+                appdata.append(self._incoming.read())
+        except (ssl.SSLError, ssl.CertificateError) as exc:
+            if getattr(exc, 'errno', None) not in (
+                    ssl.SSL_ERROR_WANT_READ, ssl.SSL_ERROR_WANT_WRITE,
+                    ssl.SSL_ERROR_SYSCALL):
+                if self._state == _DO_HANDSHAKE and self._handshake_cb:
+                    self._handshake_cb(exc)
+                raise
+            self._need_ssldata = (exc.errno == ssl.SSL_ERROR_WANT_READ)
+
+        # Check for record level data that needs to be sent back.
+        # Happens for the initial handshake and renegotiations.
+        if self._outgoing.pending:
+            ssldata.append(self._outgoing.read())
+        return (ssldata, appdata)
+
+    def feed_appdata(self, data, offset=0):
+        """Feed plaintext data into the pipe.
+
+        Return an (ssldata, offset) tuple. The ssldata element is a list of
+        buffers containing record level data that needs to be sent to the
+        remote SSL instance. The offset is the number of plaintext bytes that
+        were processed, which may be less than the length of data.
+
+        NOTE: In case of short writes, this call MUST be retried with the SAME
+        buffer passed into the *data* argument (i.e. the id() must be the
+        same). This is an OpenSSL requirement. A further particularity is that
+        a short write will always have offset == 0, because the _ssl module
+        does not enable partial writes. And even though the offset is zero,
+        there will still be encrypted data in ssldata.
+        """
+        assert 0 <= offset <= len(data)
+        if self._state == _UNWRAPPED:
+            # pass through data in unwrapped mode
+            if offset < len(data):
+                ssldata = [data[offset:]]
+            else:
+                ssldata = []
+            return (ssldata, len(data))
+
+        ssldata = []
+        view = memoryview(data)
+        while True:
+            self._need_ssldata = False
+            try:
+                if offset < len(view):
+                    offset += self._sslobj.write(view[offset:])
+            except ssl.SSLError as exc:
+                # It is not allowed to call write() after unwrap() until the
+                # close_notify is acknowledged. We return the condition to the
+                # caller as a short write.
+                if exc.reason == 'PROTOCOL_IS_SHUTDOWN':
+                    exc.errno = ssl.SSL_ERROR_WANT_READ
+                if exc.errno not in (ssl.SSL_ERROR_WANT_READ,
+                                     ssl.SSL_ERROR_WANT_WRITE,
+                                     ssl.SSL_ERROR_SYSCALL):
+                    raise
+                self._need_ssldata = (exc.errno == ssl.SSL_ERROR_WANT_READ)
+
+            # See if there's any record level data back for us.
+            if self._outgoing.pending:
+                ssldata.append(self._outgoing.read())
+            if offset == len(view) or self._need_ssldata:
+                break
+        return (ssldata, offset)
+
+
+class _SSLProtocolTransport(transports._FlowControlMixin,
+                            transports.Transport):
+
+    def __init__(self, loop, ssl_protocol):
+        self._loop = loop
+        # SSLProtocol instance
+        self._ssl_protocol = ssl_protocol
+        self._closed = False
+
+    def get_extra_info(self, name, default=None):
+        """Get optional transport information."""
+        return self._ssl_protocol._get_extra_info(name, default)
+
+    def set_protocol(self, protocol):
+        self._ssl_protocol._app_protocol = protocol
+
+    def get_protocol(self):
+        return self._ssl_protocol._app_protocol
+
+    def is_closing(self):
+        return self._closed
+
+    def close(self):
+        """Close the transport.
+
+        Buffered data will be flushed asynchronously.  No more data
+        will be received.  After all buffered data is flushed, the
+        protocol's connection_lost() method will (eventually) called
+        with None as its argument.
+        """
+        self._closed = True
+        self._ssl_protocol._start_shutdown()
+
+    # On Python 3.3 and older, objects with a destructor part of a reference
+    # cycle are never destroyed. It's not more the case on Python 3.4 thanks
+    # to the PEP 442.
+    if compat.PY34:
+        def __del__(self):
+            if not self._closed:
+                warnings.warn("unclosed transport %r" % self, ResourceWarning,
+                              source=self)
+                self.close()
+
+    def pause_reading(self):
+        """Pause the receiving end.
+
+        No data will be passed to the protocol's data_received()
+        method until resume_reading() is called.
+        """
+        self._ssl_protocol._transport.pause_reading()
+
+    def resume_reading(self):
+        """Resume the receiving end.
+
+        Data received will once again be passed to the protocol's
+        data_received() method.
+        """
+        self._ssl_protocol._transport.resume_reading()
+
+    def set_write_buffer_limits(self, high=None, low=None):
+        """Set the high- and low-water limits for write flow control.
+
+        These two values control when to call the protocol's
+        pause_writing() and resume_writing() methods.  If specified,
+        the low-water limit must be less than or equal to the
+        high-water limit.  Neither value can be negative.
+
+        The defaults are implementation-specific.  If only the
+        high-water limit is given, the low-water limit defaults to an
+        implementation-specific value less than or equal to the
+        high-water limit.  Setting high to zero forces low to zero as
+        well, and causes pause_writing() to be called whenever the
+        buffer becomes non-empty.  Setting low to zero causes
+        resume_writing() to be called only once the buffer is empty.
+        Use of zero for either limit is generally sub-optimal as it
+        reduces opportunities for doing I/O and computation
+        concurrently.
+        """
+        self._ssl_protocol._transport.set_write_buffer_limits(high, low)
+
+    def get_write_buffer_size(self):
+        """Return the current size of the write buffer."""
+        return self._ssl_protocol._transport.get_write_buffer_size()
+
+    def write(self, data):
+        """Write some data bytes to the transport.
+
+        This does not block; it buffers the data and arranges for it
+        to be sent out asynchronously.
+        """
+        if not isinstance(data, (bytes, bytearray, memoryview)):
+            raise TypeError("data: expecting a bytes-like instance, got {!r}"
+                                .format(type(data).__name__))
+        if not data:
+            return
+        self._ssl_protocol._write_appdata(data)
+
+    def can_write_eof(self):
+        """Return True if this transport supports write_eof(), False if not."""
+        return False
+
+    def abort(self):
+        """Close the transport immediately.
+
+        Buffered data will be lost.  No more data will be received.
+        The protocol's connection_lost() method will (eventually) be
+        called with None as its argument.
+        """
+        self._ssl_protocol._abort()
+
+
+class SSLProtocol(protocols.Protocol):
+    """SSL protocol.
+
+    Implementation of SSL on top of a socket using incoming and outgoing
+    buffers which are ssl.MemoryBIO objects.
+    """
+
+    def __init__(self, loop, app_protocol, sslcontext, waiter,
+                 server_side=False, server_hostname=None,
+                 call_connection_made=True):
+        if ssl is None:
+            raise RuntimeError('stdlib ssl module not available')
+
+        if not sslcontext:
+            sslcontext = _create_transport_context(server_side, server_hostname)
+
+        self._server_side = server_side
+        if server_hostname and not server_side:
+            self._server_hostname = server_hostname
+        else:
+            self._server_hostname = None
+        self._sslcontext = sslcontext
+        # SSL-specific extra info. More info are set when the handshake
+        # completes.
+        self._extra = dict(sslcontext=sslcontext)
+
+        # App data write buffering
+        self._write_backlog = collections.deque()
+        self._write_buffer_size = 0
+
+        self._waiter = waiter
+        self._loop = loop
+        self._app_protocol = app_protocol
+        self._app_transport = _SSLProtocolTransport(self._loop, self)
+        # _SSLPipe instance (None until the connection is made)
+        self._sslpipe = None
+        self._session_established = False
+        self._in_handshake = False
+        self._in_shutdown = False
+        # transport, ex: SelectorSocketTransport
+        self._transport = None
+        self._call_connection_made = call_connection_made
+
+    def _wakeup_waiter(self, exc=None):
+        if self._waiter is None:
+            return
+        if not self._waiter.cancelled():
+            if exc is not None:
+                self._waiter.set_exception(exc)
+            else:
+                self._waiter.set_result(None)
+        self._waiter = None
+
+    def connection_made(self, transport):
+        """Called when the low-level connection is made.
+
+        Start the SSL handshake.
+        """
+        self._transport = transport
+        self._sslpipe = _SSLPipe(self._sslcontext,
+                                 self._server_side,
+                                 self._server_hostname)
+        self._start_handshake()
+
+    def connection_lost(self, exc):
+        """Called when the low-level connection is lost or closed.
+
+        The argument is an exception object or None (the latter
+        meaning a regular EOF is received or the connection was
+        aborted or closed).
+        """
+        if self._session_established:
+            self._session_established = False
+            self._loop.call_soon(self._app_protocol.connection_lost, exc)
+        self._transport = None
+        self._app_transport = None
+        self._wakeup_waiter(exc)
+
+    def pause_writing(self):
+        """Called when the low-level transport's buffer goes over
+        the high-water mark.
+        """
+        self._app_protocol.pause_writing()
+
+    def resume_writing(self):
+        """Called when the low-level transport's buffer drains below
+        the low-water mark.
+        """
+        self._app_protocol.resume_writing()
+
+    def data_received(self, data):
+        """Called when some SSL data is received.
+
+        The argument is a bytes object.
+        """
+        if self._sslpipe is None:
+            # transport closing, sslpipe is destroyed
+            return
+
+        try:
+            ssldata, appdata = self._sslpipe.feed_ssldata(data)
+        except ssl.SSLError as e:
+            if self._loop.get_debug():
+                logger.warning('%r: SSL error %s (reason %s)',
+                               self, e.errno, e.reason)
+            self._abort()
+            return
+
+        for chunk in ssldata:
+            self._transport.write(chunk)
+
+        for chunk in appdata:
+            if chunk:
+                self._app_protocol.data_received(chunk)
+            else:
+                self._start_shutdown()
+                break
+
+    def eof_received(self):
+        """Called when the other end of the low-level stream
+        is half-closed.
+
+        If this returns a false value (including None), the transport
+        will close itself.  If it returns a true value, closing the
+        transport is up to the protocol.
+        """
+        try:
+            if self._loop.get_debug():
+                logger.debug("%r received EOF", self)
+
+            self._wakeup_waiter(ConnectionResetError)
+
+            if not self._in_handshake:
+                keep_open = self._app_protocol.eof_received()
+                if keep_open:
+                    logger.warning('returning true from eof_received() '
+                                   'has no effect when using ssl')
+        finally:
+            self._transport.close()
+
+    def _get_extra_info(self, name, default=None):
+        if name in self._extra:
+            return self._extra[name]
+        elif self._transport is not None:
+            return self._transport.get_extra_info(name, default)
+        else:
+            return default
+
+    def _start_shutdown(self):
+        if self._in_shutdown:
+            return
+        if self._in_handshake:
+            self._abort()
+        else:
+            self._in_shutdown = True
+            self._write_appdata(b'')
+
+    def _write_appdata(self, data):
+        self._write_backlog.append((data, 0))
+        self._write_buffer_size += len(data)
+        self._process_write_backlog()
+
+    def _start_handshake(self):
+        if self._loop.get_debug():
+            logger.debug("%r starts SSL handshake", self)
+            self._handshake_start_time = self._loop.time()
+        else:
+            self._handshake_start_time = None
+        self._in_handshake = True
+        # (b'', 1) is a special value in _process_write_backlog() to do
+        # the SSL handshake
+        self._write_backlog.append((b'', 1))
+        self._process_write_backlog()
+
+    def _on_handshake_complete(self, handshake_exc):
+        self._in_handshake = False
+
+        sslobj = self._sslpipe.ssl_object
+        try:
+            if handshake_exc is not None:
+                raise handshake_exc
+
+            peercert = sslobj.getpeercert()
+            if not hasattr(self._sslcontext, 'check_hostname'):
+                # Verify hostname if requested, Python 3.4+ uses check_hostname
+                # and checks the hostname in do_handshake()
+                if (self._server_hostname
+                and self._sslcontext.verify_mode != ssl.CERT_NONE):
+                    ssl.match_hostname(peercert, self._server_hostname)
+        except BaseException as exc:
+            if self._loop.get_debug():
+                if isinstance(exc, ssl.CertificateError):
+                    logger.warning("%r: SSL handshake failed "
+                                   "on verifying the certificate",
+                                   self, exc_info=True)
+                else:
+                    logger.warning("%r: SSL handshake failed",
+                                   self, exc_info=True)
+            self._transport.close()
+            if isinstance(exc, Exception):
+                self._wakeup_waiter(exc)
+                return
+            else:
+                raise
+
+        if self._loop.get_debug():
+            dt = self._loop.time() - self._handshake_start_time
+            logger.debug("%r: SSL handshake took %.1f ms", self, dt * 1e3)
+
+        # Add extra info that becomes available after handshake.
+        self._extra.update(peercert=peercert,
+                           cipher=sslobj.cipher(),
+                           compression=sslobj.compression(),
+                           ssl_object=sslobj,
+                           )
+        if self._call_connection_made:
+            self._app_protocol.connection_made(self._app_transport)
+        self._wakeup_waiter()
+        self._session_established = True
+        # In case transport.write() was already called. Don't call
+        # immediately _process_write_backlog(), but schedule it:
+        # _on_handshake_complete() can be called indirectly from
+        # _process_write_backlog(), and _process_write_backlog() is not
+        # reentrant.
+        self._loop.call_soon(self._process_write_backlog)
+
+    def _process_write_backlog(self):
+        # Try to make progress on the write backlog.
+        if self._transport is None or self._sslpipe is None:
+            return
+
+        try:
+            for i in range(len(self._write_backlog)):
+                data, offset = self._write_backlog[0]
+                if data:
+                    ssldata, offset = self._sslpipe.feed_appdata(data, offset)
+                elif offset:
+                    ssldata = self._sslpipe.do_handshake(
+                        self._on_handshake_complete)
+                    offset = 1
+                else:
+                    ssldata = self._sslpipe.shutdown(self._finalize)
+                    offset = 1
+
+                for chunk in ssldata:
+                    self._transport.write(chunk)
+
+                if offset < len(data):
+                    self._write_backlog[0] = (data, offset)
+                    # A short write means that a write is blocked on a read
+                    # We need to enable reading if it is paused!
+                    assert self._sslpipe.need_ssldata
+                    if self._transport._paused:
+                        self._transport.resume_reading()
+                    break
+
+                # An entire chunk from the backlog was processed. We can
+                # delete it and reduce the outstanding buffer size.
+                del self._write_backlog[0]
+                self._write_buffer_size -= len(data)
+        except BaseException as exc:
+            if self._in_handshake:
+                # BaseExceptions will be re-raised in _on_handshake_complete.
+                self._on_handshake_complete(exc)
+            else:
+                self._fatal_error(exc, 'Fatal error on SSL transport')
+            if not isinstance(exc, Exception):
+                # BaseException
+                raise
+
+    def _fatal_error(self, exc, message='Fatal error on transport'):
+        # Should be called from exception handler only.
+        if isinstance(exc, base_events._FATAL_ERROR_IGNORE):
+            if self._loop.get_debug():
+                logger.debug("%r: %s", self, message, exc_info=True)
+        else:
+            self._loop.call_exception_handler({
+                'message': message,
+                'exception': exc,
+                'transport': self._transport,
+                'protocol': self,
+            })
+        if self._transport:
+            self._transport._force_close(exc)
+
+    def _finalize(self):
+        self._sslpipe = None
+
+        if self._transport is not None:
+            self._transport.close()
+
+    def _abort(self):
+        try:
+            if self._transport is not None:
+                self._transport.abort()
+        finally:
+            self._finalize()

third_party/python/Lib/asyncio/streams.py

@@ -0,0 +1,701 @@
+"""Stream-related things."""
+
+__all__ = ['StreamReader', 'StreamWriter', 'StreamReaderProtocol',
+           'open_connection', 'start_server',
+           'IncompleteReadError',
+           'LimitOverrunError',
+           ]
+
+import socket
+
+if hasattr(socket, 'AF_UNIX'):
+    __all__.extend(['open_unix_connection', 'start_unix_server'])
+
+from . import coroutines
+from . import compat
+from . import events
+from . import protocols
+from .coroutines import coroutine
+from .log import logger
+
+
+_DEFAULT_LIMIT = 2 ** 16
+
+
+class IncompleteReadError(EOFError):
+    """
+    Incomplete read error. Attributes:
+
+    - partial: read bytes string before the end of stream was reached
+    - expected: total number of expected bytes (or None if unknown)
+    """
+    def __init__(self, partial, expected):
+        super().__init__("%d bytes read on a total of %r expected bytes"
+                         % (len(partial), expected))
+        self.partial = partial
+        self.expected = expected
+
+    def __reduce__(self):
+        return type(self), (self.partial, self.expected)
+
+
+class LimitOverrunError(Exception):
+    """Reached the buffer limit while looking for a separator.
+
+    Attributes:
+    - consumed: total number of to be consumed bytes.
+    """
+    def __init__(self, message, consumed):
+        super().__init__(message)
+        self.consumed = consumed
+
+    def __reduce__(self):
+        return type(self), (self.args[0], self.consumed)
+
+
+@coroutine
+def open_connection(host=None, port=None, *,
+                    loop=None, limit=_DEFAULT_LIMIT, **kwds):
+    """A wrapper for create_connection() returning a (reader, writer) pair.
+
+    The reader returned is a StreamReader instance; the writer is a
+    StreamWriter instance.
+
+    The arguments are all the usual arguments to create_connection()
+    except protocol_factory; most common are positional host and port,
+    with various optional keyword arguments following.
+
+    Additional optional keyword arguments are loop (to set the event loop
+    instance to use) and limit (to set the buffer limit passed to the
+    StreamReader).
+
+    (If you want to customize the StreamReader and/or
+    StreamReaderProtocol classes, just copy the code -- there's
+    really nothing special here except some convenience.)
+    """
+    if loop is None:
+        loop = events.get_event_loop()
+    reader = StreamReader(limit=limit, loop=loop)
+    protocol = StreamReaderProtocol(reader, loop=loop)
+    transport, _ = yield from loop.create_connection(
+        lambda: protocol, host, port, **kwds)
+    writer = StreamWriter(transport, protocol, reader, loop)
+    return reader, writer
+
+
+@coroutine
+def start_server(client_connected_cb, host=None, port=None, *,
+                 loop=None, limit=_DEFAULT_LIMIT, **kwds):
+    """Start a socket server, call back for each client connected.
+
+    The first parameter, `client_connected_cb`, takes two parameters:
+    client_reader, client_writer.  client_reader is a StreamReader
+    object, while client_writer is a StreamWriter object.  This
+    parameter can either be a plain callback function or a coroutine;
+    if it is a coroutine, it will be automatically converted into a
+    Task.
+
+    The rest of the arguments are all the usual arguments to
+    loop.create_server() except protocol_factory; most common are
+    positional host and port, with various optional keyword arguments
+    following.  The return value is the same as loop.create_server().
+
+    Additional optional keyword arguments are loop (to set the event loop
+    instance to use) and limit (to set the buffer limit passed to the
+    StreamReader).
+
+    The return value is the same as loop.create_server(), i.e. a
+    Server object which can be used to stop the service.
+    """
+    if loop is None:
+        loop = events.get_event_loop()
+
+    def factory():
+        reader = StreamReader(limit=limit, loop=loop)
+        protocol = StreamReaderProtocol(reader, client_connected_cb,
+                                        loop=loop)
+        return protocol
+
+    return (yield from loop.create_server(factory, host, port, **kwds))
+
+
+if hasattr(socket, 'AF_UNIX'):
+    # UNIX Domain Sockets are supported on this platform
+
+    @coroutine
+    def open_unix_connection(path=None, *,
+                             loop=None, limit=_DEFAULT_LIMIT, **kwds):
+        """Similar to `open_connection` but works with UNIX Domain Sockets."""
+        if loop is None:
+            loop = events.get_event_loop()
+        reader = StreamReader(limit=limit, loop=loop)
+        protocol = StreamReaderProtocol(reader, loop=loop)
+        transport, _ = yield from loop.create_unix_connection(
+            lambda: protocol, path, **kwds)
+        writer = StreamWriter(transport, protocol, reader, loop)
+        return reader, writer
+
+    @coroutine
+    def start_unix_server(client_connected_cb, path=None, *,
+                          loop=None, limit=_DEFAULT_LIMIT, **kwds):
+        """Similar to `start_server` but works with UNIX Domain Sockets."""
+        if loop is None:
+            loop = events.get_event_loop()
+
+        def factory():
+            reader = StreamReader(limit=limit, loop=loop)
+            protocol = StreamReaderProtocol(reader, client_connected_cb,
+                                            loop=loop)
+            return protocol
+
+        return (yield from loop.create_unix_server(factory, path, **kwds))
+
+
+class FlowControlMixin(protocols.Protocol):
+    """Reusable flow control logic for StreamWriter.drain().
+
+    This implements the protocol methods pause_writing(),
+    resume_reading() and connection_lost().  If the subclass overrides
+    these it must call the super methods.
+
+    StreamWriter.drain() must wait for _drain_helper() coroutine.
+    """
+
+    def __init__(self, loop=None):
+        if loop is None:
+            self._loop = events.get_event_loop()
+        else:
+            self._loop = loop
+        self._paused = False
+        self._drain_waiter = None
+        self._connection_lost = False
+
+    def pause_writing(self):
+        assert not self._paused
+        self._paused = True
+        if self._loop.get_debug():
+            logger.debug("%r pauses writing", self)
+
+    def resume_writing(self):
+        assert self._paused
+        self._paused = False
+        if self._loop.get_debug():
+            logger.debug("%r resumes writing", self)
+
+        waiter = self._drain_waiter
+        if waiter is not None:
+            self._drain_waiter = None
+            if not waiter.done():
+                waiter.set_result(None)
+
+    def connection_lost(self, exc):
+        self._connection_lost = True
+        # Wake up the writer if currently paused.
+        if not self._paused:
+            return
+        waiter = self._drain_waiter
+        if waiter is None:
+            return
+        self._drain_waiter = None
+        if waiter.done():
+            return
+        if exc is None:
+            waiter.set_result(None)
+        else:
+            waiter.set_exception(exc)
+
+    @coroutine
+    def _drain_helper(self):
+        if self._connection_lost:
+            raise ConnectionResetError('Connection lost')
+        if not self._paused:
+            return
+        waiter = self._drain_waiter
+        assert waiter is None or waiter.cancelled()
+        waiter = self._loop.create_future()
+        self._drain_waiter = waiter
+        yield from waiter
+
+
+class StreamReaderProtocol(FlowControlMixin, protocols.Protocol):
+    """Helper class to adapt between Protocol and StreamReader.
+
+    (This is a helper class instead of making StreamReader itself a
+    Protocol subclass, because the StreamReader has other potential
+    uses, and to prevent the user of the StreamReader to accidentally
+    call inappropriate methods of the protocol.)
+    """
+
+    def __init__(self, stream_reader, client_connected_cb=None, loop=None):
+        super().__init__(loop=loop)
+        self._stream_reader = stream_reader
+        self._stream_writer = None
+        self._client_connected_cb = client_connected_cb
+        self._over_ssl = False
+
+    def connection_made(self, transport):
+        self._stream_reader.set_transport(transport)
+        self._over_ssl = transport.get_extra_info('sslcontext') is not None
+        if self._client_connected_cb is not None:
+            self._stream_writer = StreamWriter(transport, self,
+                                               self._stream_reader,
+                                               self._loop)
+            res = self._client_connected_cb(self._stream_reader,
+                                            self._stream_writer)
+            if coroutines.iscoroutine(res):
+                self._loop.create_task(res)
+
+    def connection_lost(self, exc):
+        if self._stream_reader is not None:
+            if exc is None:
+                self._stream_reader.feed_eof()
+            else:
+                self._stream_reader.set_exception(exc)
+        super().connection_lost(exc)
+        self._stream_reader = None
+        self._stream_writer = None
+
+    def data_received(self, data):
+        self._stream_reader.feed_data(data)
+
+    def eof_received(self):
+        self._stream_reader.feed_eof()
+        if self._over_ssl:
+            # Prevent a warning in SSLProtocol.eof_received:
+            # "returning true from eof_received()
+            # has no effect when using ssl"
+            return False
+        return True
+
+
+class StreamWriter:
+    """Wraps a Transport.
+
+    This exposes write(), writelines(), [can_]write_eof(),
+    get_extra_info() and close().  It adds drain() which returns an
+    optional Future on which you can wait for flow control.  It also
+    adds a transport property which references the Transport
+    directly.
+    """
+
+    def __init__(self, transport, protocol, reader, loop):
+        self._transport = transport
+        self._protocol = protocol
+        # drain() expects that the reader has an exception() method
+        assert reader is None or isinstance(reader, StreamReader)
+        self._reader = reader
+        self._loop = loop
+
+    def __repr__(self):
+        info = [self.__class__.__name__, 'transport=%r' % self._transport]
+        if self._reader is not None:
+            info.append('reader=%r' % self._reader)
+        return '<%s>' % ' '.join(info)
+
+    @property
+    def transport(self):
+        return self._transport
+
+    def write(self, data):
+        self._transport.write(data)
+
+    def writelines(self, data):
+        self._transport.writelines(data)
+
+    def write_eof(self):
+        return self._transport.write_eof()
+
+    def can_write_eof(self):
+        return self._transport.can_write_eof()
+
+    def close(self):
+        return self._transport.close()
+
+    def get_extra_info(self, name, default=None):
+        return self._transport.get_extra_info(name, default)
+
+    @coroutine
+    def drain(self):
+        """Flush the write buffer.
+
+        The intended use is to write
+
+          w.write(data)
+          yield from w.drain()
+        """
+        if self._reader is not None:
+            exc = self._reader.exception()
+            if exc is not None:
+                raise exc
+        if self._transport is not None:
+            if self._transport.is_closing():
+                # Yield to the event loop so connection_lost() may be
+                # called.  Without this, _drain_helper() would return
+                # immediately, and code that calls
+                #     write(...); yield from drain()
+                # in a loop would never call connection_lost(), so it
+                # would not see an error when the socket is closed.
+                yield
+        yield from self._protocol._drain_helper()
+
+
+class StreamReader:
+
+    def __init__(self, limit=_DEFAULT_LIMIT, loop=None):
+        # The line length limit is  a security feature;
+        # it also doubles as half the buffer limit.
+
+        if limit <= 0:
+            raise ValueError('Limit cannot be <= 0')
+
+        self._limit = limit
+        if loop is None:
+            self._loop = events.get_event_loop()
+        else:
+            self._loop = loop
+        self._buffer = bytearray()
+        self._eof = False    # Whether we're done.
+        self._waiter = None  # A future used by _wait_for_data()
+        self._exception = None
+        self._transport = None
+        self._paused = False
+
+    def __repr__(self):
+        info = ['StreamReader']
+        if self._buffer:
+            info.append('%d bytes' % len(self._buffer))
+        if self._eof:
+            info.append('eof')
+        if self._limit != _DEFAULT_LIMIT:
+            info.append('l=%d' % self._limit)
+        if self._waiter:
+            info.append('w=%r' % self._waiter)
+        if self._exception:
+            info.append('e=%r' % self._exception)
+        if self._transport:
+            info.append('t=%r' % self._transport)
+        if self._paused:
+            info.append('paused')
+        return '<%s>' % ' '.join(info)
+
+    def exception(self):
+        return self._exception
+
+    def set_exception(self, exc):
+        self._exception = exc
+
+        waiter = self._waiter
+        if waiter is not None:
+            self._waiter = None
+            if not waiter.cancelled():
+                waiter.set_exception(exc)
+
+    def _wakeup_waiter(self):
+        """Wakeup read*() functions waiting for data or EOF."""
+        waiter = self._waiter
+        if waiter is not None:
+            self._waiter = None
+            if not waiter.cancelled():
+                waiter.set_result(None)
+
+    def set_transport(self, transport):
+        assert self._transport is None, 'Transport already set'
+        self._transport = transport
+
+    def _maybe_resume_transport(self):
+        if self._paused and len(self._buffer) <= self._limit:
+            self._paused = False
+            self._transport.resume_reading()
+
+    def feed_eof(self):
+        self._eof = True
+        self._wakeup_waiter()
+
+    def at_eof(self):
+        """Return True if the buffer is empty and 'feed_eof' was called."""
+        return self._eof and not self._buffer
+
+    def feed_data(self, data):
+        assert not self._eof, 'feed_data after feed_eof'
+
+        if not data:
+            return
+
+        self._buffer.extend(data)
+        self._wakeup_waiter()
+
+        if (self._transport is not None and
+                not self._paused and
+                len(self._buffer) > 2 * self._limit):
+            try:
+                self._transport.pause_reading()
+            except NotImplementedError:
+                # The transport can't be paused.
+                # We'll just have to buffer all data.
+                # Forget the transport so we don't keep trying.
+                self._transport = None
+            else:
+                self._paused = True
+
+    @coroutine
+    def _wait_for_data(self, func_name):
+        """Wait until feed_data() or feed_eof() is called.
+
+        If stream was paused, automatically resume it.
+        """
+        # StreamReader uses a future to link the protocol feed_data() method
+        # to a read coroutine. Running two read coroutines at the same time
+        # would have an unexpected behaviour. It would not possible to know
+        # which coroutine would get the next data.
+        if self._waiter is not None:
+            raise RuntimeError('%s() called while another coroutine is '
+                               'already waiting for incoming data' % func_name)
+
+        assert not self._eof, '_wait_for_data after EOF'
+
+        # Waiting for data while paused will make deadlock, so prevent it.
+        # This is essential for readexactly(n) for case when n > self._limit.
+        if self._paused:
+            self._paused = False
+            self._transport.resume_reading()
+
+        self._waiter = self._loop.create_future()
+        try:
+            yield from self._waiter
+        finally:
+            self._waiter = None
+
+    @coroutine
+    def readline(self):
+        """Read chunk of data from the stream until newline (b'\n') is found.
+
+        On success, return chunk that ends with newline. If only partial
+        line can be read due to EOF, return incomplete line without
+        terminating newline. When EOF was reached while no bytes read, empty
+        bytes object is returned.
+
+        If limit is reached, ValueError will be raised. In that case, if
+        newline was found, complete line including newline will be removed
+        from internal buffer. Else, internal buffer will be cleared. Limit is
+        compared against part of the line without newline.
+
+        If stream was paused, this function will automatically resume it if
+        needed.
+        """
+        sep = b'\n'
+        seplen = len(sep)
+        try:
+            line = yield from self.readuntil(sep)
+        except IncompleteReadError as e:
+            return e.partial
+        except LimitOverrunError as e:
+            if self._buffer.startswith(sep, e.consumed):
+                del self._buffer[:e.consumed + seplen]
+            else:
+                self._buffer.clear()
+            self._maybe_resume_transport()
+            raise ValueError(e.args[0])
+        return line
+
+    @coroutine
+    def readuntil(self, separator=b'\n'):
+        """Read data from the stream until ``separator`` is found.
+
+        On success, the data and separator will be removed from the
+        internal buffer (consumed). Returned data will include the
+        separator at the end.
+
+        Configured stream limit is used to check result. Limit sets the
+        maximal length of data that can be returned, not counting the
+        separator.
+
+        If an EOF occurs and the complete separator is still not found,
+        an IncompleteReadError exception will be raised, and the internal
+        buffer will be reset.  The IncompleteReadError.partial attribute
+        may contain the separator partially.
+
+        If the data cannot be read because of over limit, a
+        LimitOverrunError exception  will be raised, and the data
+        will be left in the internal buffer, so it can be read again.
+        """
+        seplen = len(separator)
+        if seplen == 0:
+            raise ValueError('Separator should be at least one-byte string')
+
+        if self._exception is not None:
+            raise self._exception
+
+        # Consume whole buffer except last bytes, which length is
+        # one less than seplen. Let's check corner cases with
+        # separator='SEPARATOR':
+        # * we have received almost complete separator (without last
+        #   byte). i.e buffer='some textSEPARATO'. In this case we
+        #   can safely consume len(separator) - 1 bytes.
+        # * last byte of buffer is first byte of separator, i.e.
+        #   buffer='abcdefghijklmnopqrS'. We may safely consume
+        #   everything except that last byte, but this require to
+        #   analyze bytes of buffer that match partial separator.
+        #   This is slow and/or require FSM. For this case our
+        #   implementation is not optimal, since require rescanning
+        #   of data that is known to not belong to separator. In
+        #   real world, separator will not be so long to notice
+        #   performance problems. Even when reading MIME-encoded
+        #   messages :)
+
+        # `offset` is the number of bytes from the beginning of the buffer
+        # where there is no occurrence of `separator`.
+        offset = 0
+
+        # Loop until we find `separator` in the buffer, exceed the buffer size,
+        # or an EOF has happened.
+        while True:
+            buflen = len(self._buffer)
+
+            # Check if we now have enough data in the buffer for `separator` to
+            # fit.
+            if buflen - offset >= seplen:
+                isep = self._buffer.find(separator, offset)
+
+                if isep != -1:
+                    # `separator` is in the buffer. `isep` will be used later
+                    # to retrieve the data.
+                    break
+
+                # see upper comment for explanation.
+                offset = buflen + 1 - seplen
+                if offset > self._limit:
+                    raise LimitOverrunError(
+                        'Separator is not found, and chunk exceed the limit',
+                        offset)
+
+            # Complete message (with full separator) may be present in buffer
+            # even when EOF flag is set. This may happen when the last chunk
+            # adds data which makes separator be found. That's why we check for
+            # EOF *ater* inspecting the buffer.
+            if self._eof:
+                chunk = bytes(self._buffer)
+                self._buffer.clear()
+                raise IncompleteReadError(chunk, None)
+
+            # _wait_for_data() will resume reading if stream was paused.
+            yield from self._wait_for_data('readuntil')
+
+        if isep > self._limit:
+            raise LimitOverrunError(
+                'Separator is found, but chunk is longer than limit', isep)
+
+        chunk = self._buffer[:isep + seplen]
+        del self._buffer[:isep + seplen]
+        self._maybe_resume_transport()
+        return bytes(chunk)
+
+    @coroutine
+    def read(self, n=-1):
+        """Read up to `n` bytes from the stream.
+
+        If n is not provided, or set to -1, read until EOF and return all read
+        bytes. If the EOF was received and the internal buffer is empty, return
+        an empty bytes object.
+
+        If n is zero, return empty bytes object immediately.
+
+        If n is positive, this function try to read `n` bytes, and may return
+        less or equal bytes than requested, but at least one byte. If EOF was
+        received before any byte is read, this function returns empty byte
+        object.
+
+        Returned value is not limited with limit, configured at stream
+        creation.
+
+        If stream was paused, this function will automatically resume it if
+        needed.
+        """
+
+        if self._exception is not None:
+            raise self._exception
+
+        if n == 0:
+            return b''
+
+        if n < 0:
+            # This used to just loop creating a new waiter hoping to
+            # collect everything in self._buffer, but that would
+            # deadlock if the subprocess sends more than self.limit
+            # bytes.  So just call self.read(self._limit) until EOF.
+            blocks = []
+            while True:
+                block = yield from self.read(self._limit)
+                if not block:
+                    break
+                blocks.append(block)
+            return b''.join(blocks)
+
+        if not self._buffer and not self._eof:
+            yield from self._wait_for_data('read')
+
+        # This will work right even if buffer is less than n bytes
+        data = bytes(self._buffer[:n])
+        del self._buffer[:n]
+
+        self._maybe_resume_transport()
+        return data
+
+    @coroutine
+    def readexactly(self, n):
+        """Read exactly `n` bytes.
+
+        Raise an IncompleteReadError if EOF is reached before `n` bytes can be
+        read. The IncompleteReadError.partial attribute of the exception will
+        contain the partial read bytes.
+
+        if n is zero, return empty bytes object.
+
+        Returned value is not limited with limit, configured at stream
+        creation.
+
+        If stream was paused, this function will automatically resume it if
+        needed.
+        """
+        if n < 0:
+            raise ValueError('readexactly size can not be less than zero')
+
+        if self._exception is not None:
+            raise self._exception
+
+        if n == 0:
+            return b''
+
+        while len(self._buffer) < n:
+            if self._eof:
+                incomplete = bytes(self._buffer)
+                self._buffer.clear()
+                raise IncompleteReadError(incomplete, n)
+
+            yield from self._wait_for_data('readexactly')
+
+        if len(self._buffer) == n:
+            data = bytes(self._buffer)
+            self._buffer.clear()
+        else:
+            data = bytes(self._buffer[:n])
+            del self._buffer[:n]
+        self._maybe_resume_transport()
+        return data
+
+    if compat.PY35:
+        @coroutine
+        def __aiter__(self):
+            return self
+
+        @coroutine
+        def __anext__(self):
+            val = yield from self.readline()
+            if val == b'':
+                raise StopAsyncIteration
+            return val
+
+    if compat.PY352:
+        # In Python 3.5.2 and greater, __aiter__ should return
+        # the asynchronous iterator directly.
+        def __aiter__(self):
+            return self

third_party/python/Lib/asyncio/subprocess.py

@@ -0,0 +1,226 @@
+__all__ = ['create_subprocess_exec', 'create_subprocess_shell']
+
+import subprocess
+
+from . import events
+from . import protocols
+from . import streams
+from . import tasks
+from .coroutines import coroutine
+from .log import logger
+
+
+PIPE = subprocess.PIPE
+STDOUT = subprocess.STDOUT
+DEVNULL = subprocess.DEVNULL
+
+
+class SubprocessStreamProtocol(streams.FlowControlMixin,
+                               protocols.SubprocessProtocol):
+    """Like StreamReaderProtocol, but for a subprocess."""
+
+    def __init__(self, limit, loop):
+        super().__init__(loop=loop)
+        self._limit = limit
+        self.stdin = self.stdout = self.stderr = None
+        self._transport = None
+        self._process_exited = False
+        self._pipe_fds = []
+
+    def __repr__(self):
+        info = [self.__class__.__name__]
+        if self.stdin is not None:
+            info.append('stdin=%r' % self.stdin)
+        if self.stdout is not None:
+            info.append('stdout=%r' % self.stdout)
+        if self.stderr is not None:
+            info.append('stderr=%r' % self.stderr)
+        return '<%s>' % ' '.join(info)
+
+    def connection_made(self, transport):
+        self._transport = transport
+
+        stdout_transport = transport.get_pipe_transport(1)
+        if stdout_transport is not None:
+            self.stdout = streams.StreamReader(limit=self._limit,
+                                               loop=self._loop)
+            self.stdout.set_transport(stdout_transport)
+            self._pipe_fds.append(1)
+
+        stderr_transport = transport.get_pipe_transport(2)
+        if stderr_transport is not None:
+            self.stderr = streams.StreamReader(limit=self._limit,
+                                               loop=self._loop)
+            self.stderr.set_transport(stderr_transport)
+            self._pipe_fds.append(2)
+
+        stdin_transport = transport.get_pipe_transport(0)
+        if stdin_transport is not None:
+            self.stdin = streams.StreamWriter(stdin_transport,
+                                              protocol=self,
+                                              reader=None,
+                                              loop=self._loop)
+
+    def pipe_data_received(self, fd, data):
+        if fd == 1:
+            reader = self.stdout
+        elif fd == 2:
+            reader = self.stderr
+        else:
+            reader = None
+        if reader is not None:
+            reader.feed_data(data)
+
+    def pipe_connection_lost(self, fd, exc):
+        if fd == 0:
+            pipe = self.stdin
+            if pipe is not None:
+                pipe.close()
+            self.connection_lost(exc)
+            return
+        if fd == 1:
+            reader = self.stdout
+        elif fd == 2:
+            reader = self.stderr
+        else:
+            reader = None
+        if reader != None:
+            if exc is None:
+                reader.feed_eof()
+            else:
+                reader.set_exception(exc)
+
+        if fd in self._pipe_fds:
+            self._pipe_fds.remove(fd)
+        self._maybe_close_transport()
+
+    def process_exited(self):
+        self._process_exited = True
+        self._maybe_close_transport()
+
+    def _maybe_close_transport(self):
+        if len(self._pipe_fds) == 0 and self._process_exited:
+            self._transport.close()
+            self._transport = None
+
+
+class Process:
+    def __init__(self, transport, protocol, loop):
+        self._transport = transport
+        self._protocol = protocol
+        self._loop = loop
+        self.stdin = protocol.stdin
+        self.stdout = protocol.stdout
+        self.stderr = protocol.stderr
+        self.pid = transport.get_pid()
+
+    def __repr__(self):
+        return '<%s %s>' % (self.__class__.__name__, self.pid)
+
+    @property
+    def returncode(self):
+        return self._transport.get_returncode()
+
+    @coroutine
+    def wait(self):
+        """Wait until the process exit and return the process return code.
+
+        This method is a coroutine."""
+        return (yield from self._transport._wait())
+
+    def send_signal(self, signal):
+        self._transport.send_signal(signal)
+
+    def terminate(self):
+        self._transport.terminate()
+
+    def kill(self):
+        self._transport.kill()
+
+    @coroutine
+    def _feed_stdin(self, input):
+        debug = self._loop.get_debug()
+        self.stdin.write(input)
+        if debug:
+            logger.debug('%r communicate: feed stdin (%s bytes)',
+                        self, len(input))
+        try:
+            yield from self.stdin.drain()
+        except (BrokenPipeError, ConnectionResetError) as exc:
+            # communicate() ignores BrokenPipeError and ConnectionResetError
+            if debug:
+                logger.debug('%r communicate: stdin got %r', self, exc)
+
+        if debug:
+            logger.debug('%r communicate: close stdin', self)
+        self.stdin.close()
+
+    @coroutine
+    def _noop(self):
+        return None
+
+    @coroutine
+    def _read_stream(self, fd):
+        transport = self._transport.get_pipe_transport(fd)
+        if fd == 2:
+            stream = self.stderr
+        else:
+            assert fd == 1
+            stream = self.stdout
+        if self._loop.get_debug():
+            name = 'stdout' if fd == 1 else 'stderr'
+            logger.debug('%r communicate: read %s', self, name)
+        output = yield from stream.read()
+        if self._loop.get_debug():
+            name = 'stdout' if fd == 1 else 'stderr'
+            logger.debug('%r communicate: close %s', self, name)
+        transport.close()
+        return output
+
+    @coroutine
+    def communicate(self, input=None):
+        if input is not None:
+            stdin = self._feed_stdin(input)
+        else:
+            stdin = self._noop()
+        if self.stdout is not None:
+            stdout = self._read_stream(1)
+        else:
+            stdout = self._noop()
+        if self.stderr is not None:
+            stderr = self._read_stream(2)
+        else:
+            stderr = self._noop()
+        stdin, stdout, stderr = yield from tasks.gather(stdin, stdout, stderr,
+                                                        loop=self._loop)
+        yield from self.wait()
+        return (stdout, stderr)
+
+
+@coroutine
+def create_subprocess_shell(cmd, stdin=None, stdout=None, stderr=None,
+                            loop=None, limit=streams._DEFAULT_LIMIT, **kwds):
+    if loop is None:
+        loop = events.get_event_loop()
+    protocol_factory = lambda: SubprocessStreamProtocol(limit=limit,
+                                                        loop=loop)
+    transport, protocol = yield from loop.subprocess_shell(
+                                            protocol_factory,
+                                            cmd, stdin=stdin, stdout=stdout,
+                                            stderr=stderr, **kwds)
+    return Process(transport, protocol, loop)
+
+@coroutine
+def create_subprocess_exec(program, *args, stdin=None, stdout=None,
+                           stderr=None, loop=None,
+                           limit=streams._DEFAULT_LIMIT, **kwds):
+    if loop is None:
+        loop = events.get_event_loop()
+    protocol_factory = lambda: SubprocessStreamProtocol(limit=limit,
+                                                        loop=loop)
+    transport, protocol = yield from loop.subprocess_exec(
+                                            protocol_factory,
+                                            program, *args,
+                                            stdin=stdin, stdout=stdout,
+                                            stderr=stderr, **kwds)
+    return Process(transport, protocol, loop)

third_party/python/Lib/asyncio/tasks.py

@@ -0,0 +1,726 @@
+"""Support for tasks, coroutines and the scheduler."""
+
+__all__ = ['Task',
+           'FIRST_COMPLETED', 'FIRST_EXCEPTION', 'ALL_COMPLETED',
+           'wait', 'wait_for', 'as_completed', 'sleep', 'async',
+           'gather', 'shield', 'ensure_future', 'run_coroutine_threadsafe',
+           ]
+
+import concurrent.futures
+import functools
+import inspect
+import warnings
+import weakref
+
+from . import base_tasks
+from . import compat
+from . import coroutines
+from . import events
+from . import futures
+from .coroutines import coroutine
+
+
+class Task(futures.Future):
+    """A coroutine wrapped in a Future."""
+
+    # An important invariant maintained while a Task not done:
+    #
+    # - Either _fut_waiter is None, and _step() is scheduled;
+    # - or _fut_waiter is some Future, and _step() is *not* scheduled.
+    #
+    # The only transition from the latter to the former is through
+    # _wakeup().  When _fut_waiter is not None, one of its callbacks
+    # must be _wakeup().
+
+    # Weak set containing all tasks alive.
+    _all_tasks = weakref.WeakSet()
+
+    # Dictionary containing tasks that are currently active in
+    # all running event loops.  {EventLoop: Task}
+    _current_tasks = {}
+
+    # If False, don't log a message if the task is destroyed whereas its
+    # status is still pending
+    _log_destroy_pending = True
+
+    @classmethod
+    def current_task(cls, loop=None):
+        """Return the currently running task in an event loop or None.
+
+        By default the current task for the current event loop is returned.
+
+        None is returned when called not in the context of a Task.
+        """
+        if loop is None:
+            loop = events.get_event_loop()
+        return cls._current_tasks.get(loop)
+
+    @classmethod
+    def all_tasks(cls, loop=None):
+        """Return a set of all tasks for an event loop.
+
+        By default all tasks for the current event loop are returned.
+        """
+        if loop is None:
+            loop = events.get_event_loop()
+        return {t for t in cls._all_tasks if t._loop is loop}
+
+    def __init__(self, coro, *, loop=None):
+        assert coroutines.iscoroutine(coro), repr(coro)
+        super().__init__(loop=loop)
+        if self._source_traceback:
+            del self._source_traceback[-1]
+        self._coro = coro
+        self._fut_waiter = None
+        self._must_cancel = False
+        self._loop.call_soon(self._step)
+        self.__class__._all_tasks.add(self)
+
+    # On Python 3.3 or older, objects with a destructor that are part of a
+    # reference cycle are never destroyed. That's not the case any more on
+    # Python 3.4 thanks to the PEP 442.
+    if compat.PY34:
+        def __del__(self):
+            if self._state == futures._PENDING and self._log_destroy_pending:
+                context = {
+                    'task': self,
+                    'message': 'Task was destroyed but it is pending!',
+                }
+                if self._source_traceback:
+                    context['source_traceback'] = self._source_traceback
+                self._loop.call_exception_handler(context)
+            futures.Future.__del__(self)
+
+    def _repr_info(self):
+        return base_tasks._task_repr_info(self)
+
+    def get_stack(self, *, limit=None):
+        """Return the list of stack frames for this task's coroutine.
+
+        If the coroutine is not done, this returns the stack where it is
+        suspended.  If the coroutine has completed successfully or was
+        cancelled, this returns an empty list.  If the coroutine was
+        terminated by an exception, this returns the list of traceback
+        frames.
+
+        The frames are always ordered from oldest to newest.
+
+        The optional limit gives the maximum number of frames to
+        return; by default all available frames are returned.  Its
+        meaning differs depending on whether a stack or a traceback is
+        returned: the newest frames of a stack are returned, but the
+        oldest frames of a traceback are returned.  (This matches the
+        behavior of the traceback module.)
+
+        For reasons beyond our control, only one stack frame is
+        returned for a suspended coroutine.
+        """
+        return base_tasks._task_get_stack(self, limit)
+
+    def print_stack(self, *, limit=None, file=None):
+        """Print the stack or traceback for this task's coroutine.
+
+        This produces output similar to that of the traceback module,
+        for the frames retrieved by get_stack().  The limit argument
+        is passed to get_stack().  The file argument is an I/O stream
+        to which the output is written; by default output is written
+        to sys.stderr.
+        """
+        return base_tasks._task_print_stack(self, limit, file)
+
+    def cancel(self):
+        """Request that this task cancel itself.
+
+        This arranges for a CancelledError to be thrown into the
+        wrapped coroutine on the next cycle through the event loop.
+        The coroutine then has a chance to clean up or even deny
+        the request using try/except/finally.
+
+        Unlike Future.cancel, this does not guarantee that the
+        task will be cancelled: the exception might be caught and
+        acted upon, delaying cancellation of the task or preventing
+        cancellation completely.  The task may also return a value or
+        raise a different exception.
+
+        Immediately after this method is called, Task.cancelled() will
+        not return True (unless the task was already cancelled).  A
+        task will be marked as cancelled when the wrapped coroutine
+        terminates with a CancelledError exception (even if cancel()
+        was not called).
+        """
+        self._log_traceback = False
+        if self.done():
+            return False
+        if self._fut_waiter is not None:
+            if self._fut_waiter.cancel():
+                # Leave self._fut_waiter; it may be a Task that
+                # catches and ignores the cancellation so we may have
+                # to cancel it again later.
+                return True
+        # It must be the case that self._step is already scheduled.
+        self._must_cancel = True
+        return True
+
+    def _step(self, exc=None):
+        assert not self.done(), \
+            '_step(): already done: {!r}, {!r}'.format(self, exc)
+        if self._must_cancel:
+            if not isinstance(exc, futures.CancelledError):
+                exc = futures.CancelledError()
+            self._must_cancel = False
+        coro = self._coro
+        self._fut_waiter = None
+
+        self.__class__._current_tasks[self._loop] = self
+        # Call either coro.throw(exc) or coro.send(None).
+        try:
+            if exc is None:
+                # We use the `send` method directly, because coroutines
+                # don't have `__iter__` and `__next__` methods.
+                result = coro.send(None)
+            else:
+                result = coro.throw(exc)
+        except StopIteration as exc:
+            if self._must_cancel:
+                # Task is cancelled right before coro stops.
+                self._must_cancel = False
+                self.set_exception(futures.CancelledError())
+            else:
+                self.set_result(exc.value)
+        except futures.CancelledError:
+            super().cancel()  # I.e., Future.cancel(self).
+        except Exception as exc:
+            self.set_exception(exc)
+        except BaseException as exc:
+            self.set_exception(exc)
+            raise
+        else:
+            blocking = getattr(result, '_asyncio_future_blocking', None)
+            if blocking is not None:
+                # Yielded Future must come from Future.__iter__().
+                if result._loop is not self._loop:
+                    self._loop.call_soon(
+                        self._step,
+                        RuntimeError(
+                            'Task {!r} got Future {!r} attached to a '
+                            'different loop'.format(self, result)))
+                elif blocking:
+                    if result is self:
+                        self._loop.call_soon(
+                            self._step,
+                            RuntimeError(
+                                'Task cannot await on itself: {!r}'.format(
+                                    self)))
+                    else:
+                        result._asyncio_future_blocking = False
+                        result.add_done_callback(self._wakeup)
+                        self._fut_waiter = result
+                        if self._must_cancel:
+                            if self._fut_waiter.cancel():
+                                self._must_cancel = False
+                else:
+                    self._loop.call_soon(
+                        self._step,
+                        RuntimeError(
+                            'yield was used instead of yield from '
+                            'in task {!r} with {!r}'.format(self, result)))
+            elif result is None:
+                # Bare yield relinquishes control for one event loop iteration.
+                self._loop.call_soon(self._step)
+            elif inspect.isgenerator(result):
+                # Yielding a generator is just wrong.
+                self._loop.call_soon(
+                    self._step,
+                    RuntimeError(
+                        'yield was used instead of yield from for '
+                        'generator in task {!r} with {!r}'.format(
+                            self, result)))
+            else:
+                # Yielding something else is an error.
+                self._loop.call_soon(
+                    self._step,
+                    RuntimeError(
+                        'Task got bad yield: {!r}'.format(result)))
+        finally:
+            self.__class__._current_tasks.pop(self._loop)
+            self = None  # Needed to break cycles when an exception occurs.
+
+    def _wakeup(self, future):
+        try:
+            future.result()
+        except Exception as exc:
+            # This may also be a cancellation.
+            self._step(exc)
+        else:
+            # Don't pass the value of `future.result()` explicitly,
+            # as `Future.__iter__` and `Future.__await__` don't need it.
+            # If we call `_step(value, None)` instead of `_step()`,
+            # Python eval loop would use `.send(value)` method call,
+            # instead of `__next__()`, which is slower for futures
+            # that return non-generator iterators from their `__iter__`.
+            self._step()
+        self = None  # Needed to break cycles when an exception occurs.
+
+
+_PyTask = Task
+
+
+try:
+    import _asyncio
+except ImportError:
+    pass
+else:
+    # _CTask is needed for tests.
+    Task = _CTask = _asyncio.Task
+
+
+# wait() and as_completed() similar to those in PEP 3148.
+
+FIRST_COMPLETED = concurrent.futures.FIRST_COMPLETED
+FIRST_EXCEPTION = concurrent.futures.FIRST_EXCEPTION
+ALL_COMPLETED = concurrent.futures.ALL_COMPLETED
+
+
+@coroutine
+def wait(fs, *, loop=None, timeout=None, return_when=ALL_COMPLETED):
+    """Wait for the Futures and coroutines given by fs to complete.
+
+    The sequence futures must not be empty.
+
+    Coroutines will be wrapped in Tasks.
+
+    Returns two sets of Future: (done, pending).
+
+    Usage:
+
+        done, pending = yield from asyncio.wait(fs)
+
+    Note: This does not raise TimeoutError! Futures that aren't done
+    when the timeout occurs are returned in the second set.
+    """
+    if futures.isfuture(fs) or coroutines.iscoroutine(fs):
+        raise TypeError("expect a list of futures, not %s" % type(fs).__name__)
+    if not fs:
+        raise ValueError('Set of coroutines/Futures is empty.')
+    if return_when not in (FIRST_COMPLETED, FIRST_EXCEPTION, ALL_COMPLETED):
+        raise ValueError('Invalid return_when value: {}'.format(return_when))
+
+    if loop is None:
+        loop = events.get_event_loop()
+
+    fs = {ensure_future(f, loop=loop) for f in set(fs)}
+
+    return (yield from _wait(fs, timeout, return_when, loop))
+
+
+def _release_waiter(waiter, *args):
+    if not waiter.done():
+        waiter.set_result(None)
+
+
+@coroutine
+def wait_for(fut, timeout, *, loop=None):
+    """Wait for the single Future or coroutine to complete, with timeout.
+
+    Coroutine will be wrapped in Task.
+
+    Returns result of the Future or coroutine.  When a timeout occurs,
+    it cancels the task and raises TimeoutError.  To avoid the task
+    cancellation, wrap it in shield().
+
+    If the wait is cancelled, the task is also cancelled.
+
+    This function is a coroutine.
+    """
+    if loop is None:
+        loop = events.get_event_loop()
+
+    if timeout is None:
+        return (yield from fut)
+
+    waiter = loop.create_future()
+    timeout_handle = loop.call_later(timeout, _release_waiter, waiter)
+    cb = functools.partial(_release_waiter, waiter)
+
+    fut = ensure_future(fut, loop=loop)
+    fut.add_done_callback(cb)
+
+    try:
+        # wait until the future completes or the timeout
+        try:
+            yield from waiter
+        except futures.CancelledError:
+            fut.remove_done_callback(cb)
+            fut.cancel()
+            raise
+
+        if fut.done():
+            return fut.result()
+        else:
+            fut.remove_done_callback(cb)
+            fut.cancel()
+            raise futures.TimeoutError()
+    finally:
+        timeout_handle.cancel()
+
+
+@coroutine
+def _wait(fs, timeout, return_when, loop):
+    """Internal helper for wait() and wait_for().
+
+    The fs argument must be a collection of Futures.
+    """
+    assert fs, 'Set of Futures is empty.'
+    waiter = loop.create_future()
+    timeout_handle = None
+    if timeout is not None:
+        timeout_handle = loop.call_later(timeout, _release_waiter, waiter)
+    counter = len(fs)
+
+    def _on_completion(f):
+        nonlocal counter
+        counter -= 1
+        if (counter <= 0 or
+            return_when == FIRST_COMPLETED or
+            return_when == FIRST_EXCEPTION and (not f.cancelled() and
+                                                f.exception() is not None)):
+            if timeout_handle is not None:
+                timeout_handle.cancel()
+            if not waiter.done():
+                waiter.set_result(None)
+
+    for f in fs:
+        f.add_done_callback(_on_completion)
+
+    try:
+        yield from waiter
+    finally:
+        if timeout_handle is not None:
+            timeout_handle.cancel()
+
+    done, pending = set(), set()
+    for f in fs:
+        f.remove_done_callback(_on_completion)
+        if f.done():
+            done.add(f)
+        else:
+            pending.add(f)
+    return done, pending
+
+
+# This is *not* a @coroutine!  It is just an iterator (yielding Futures).
+def as_completed(fs, *, loop=None, timeout=None):
+    """Return an iterator whose values are coroutines.
+
+    When waiting for the yielded coroutines you'll get the results (or
+    exceptions!) of the original Futures (or coroutines), in the order
+    in which and as soon as they complete.
+
+    This differs from PEP 3148; the proper way to use this is:
+
+        for f in as_completed(fs):
+            result = yield from f  # The 'yield from' may raise.
+            # Use result.
+
+    If a timeout is specified, the 'yield from' will raise
+    TimeoutError when the timeout occurs before all Futures are done.
+
+    Note: The futures 'f' are not necessarily members of fs.
+    """
+    if futures.isfuture(fs) or coroutines.iscoroutine(fs):
+        raise TypeError("expect a list of futures, not %s" % type(fs).__name__)
+    loop = loop if loop is not None else events.get_event_loop()
+    todo = {ensure_future(f, loop=loop) for f in set(fs)}
+    from .queues import Queue  # Import here to avoid circular import problem.
+    done = Queue(loop=loop)
+    timeout_handle = None
+
+    def _on_timeout():
+        for f in todo:
+            f.remove_done_callback(_on_completion)
+            done.put_nowait(None)  # Queue a dummy value for _wait_for_one().
+        todo.clear()  # Can't do todo.remove(f) in the loop.
+
+    def _on_completion(f):
+        if not todo:
+            return  # _on_timeout() was here first.
+        todo.remove(f)
+        done.put_nowait(f)
+        if not todo and timeout_handle is not None:
+            timeout_handle.cancel()
+
+    @coroutine
+    def _wait_for_one():
+        f = yield from done.get()
+        if f is None:
+            # Dummy value from _on_timeout().
+            raise futures.TimeoutError
+        return f.result()  # May raise f.exception().
+
+    for f in todo:
+        f.add_done_callback(_on_completion)
+    if todo and timeout is not None:
+        timeout_handle = loop.call_later(timeout, _on_timeout)
+    for _ in range(len(todo)):
+        yield _wait_for_one()
+
+
+@coroutine
+def sleep(delay, result=None, *, loop=None):
+    """Coroutine that completes after a given time (in seconds)."""
+    if delay == 0:
+        yield
+        return result
+
+    if loop is None:
+        loop = events.get_event_loop()
+    future = loop.create_future()
+    h = future._loop.call_later(delay,
+                                futures._set_result_unless_cancelled,
+                                future, result)
+    try:
+        return (yield from future)
+    finally:
+        h.cancel()
+
+
+def async_(coro_or_future, *, loop=None):
+    """Wrap a coroutine in a future.
+
+    If the argument is a Future, it is returned directly.
+
+    This function is deprecated in 3.5. Use asyncio.ensure_future() instead.
+    """
+
+    warnings.warn("asyncio.async() function is deprecated, use ensure_future()",
+                  DeprecationWarning,
+                  stacklevel=2)
+
+    return ensure_future(coro_or_future, loop=loop)
+
+# Silence DeprecationWarning:
+globals()['async'] = async_
+async_.__name__ = 'async'
+del async_
+
+
+def ensure_future(coro_or_future, *, loop=None):
+    """Wrap a coroutine or an awaitable in a future.
+
+    If the argument is a Future, it is returned directly.
+    """
+    if futures.isfuture(coro_or_future):
+        if loop is not None and loop is not coro_or_future._loop:
+            raise ValueError('loop argument must agree with Future')
+        return coro_or_future
+    elif coroutines.iscoroutine(coro_or_future):
+        if loop is None:
+            loop = events.get_event_loop()
+        task = loop.create_task(coro_or_future)
+        if task._source_traceback:
+            del task._source_traceback[-1]
+        return task
+    elif compat.PY35 and inspect.isawaitable(coro_or_future):
+        return ensure_future(_wrap_awaitable(coro_or_future), loop=loop)
+    else:
+        raise TypeError('An asyncio.Future, a coroutine or an awaitable is '
+                        'required')
+
+
+@coroutine
+def _wrap_awaitable(awaitable):
+    """Helper for asyncio.ensure_future().
+
+    Wraps awaitable (an object with __await__) into a coroutine
+    that will later be wrapped in a Task by ensure_future().
+    """
+    return (yield from awaitable.__await__())
+
+
+class _GatheringFuture(futures.Future):
+    """Helper for gather().
+
+    This overrides cancel() to cancel all the children and act more
+    like Task.cancel(), which doesn't immediately mark itself as
+    cancelled.
+    """
+
+    def __init__(self, children, *, loop=None):
+        super().__init__(loop=loop)
+        self._children = children
+        self._cancel_requested = False
+
+    def cancel(self):
+        if self.done():
+            return False
+        ret = False
+        for child in self._children:
+            if child.cancel():
+                ret = True
+        if ret:
+            # If any child tasks were actually cancelled, we should
+            # propagate the cancellation request regardless of
+            # *return_exceptions* argument.  See issue 32684.
+            self._cancel_requested = True
+        return ret
+
+
+def gather(*coros_or_futures, loop=None, return_exceptions=False):
+    """Return a future aggregating results from the given coroutines
+    or futures.
+
+    Coroutines will be wrapped in a future and scheduled in the event
+    loop. They will not necessarily be scheduled in the same order as
+    passed in.
+
+    All futures must share the same event loop.  If all the tasks are
+    done successfully, the returned future's result is the list of
+    results (in the order of the original sequence, not necessarily
+    the order of results arrival).  If *return_exceptions* is True,
+    exceptions in the tasks are treated the same as successful
+    results, and gathered in the result list; otherwise, the first
+    raised exception will be immediately propagated to the returned
+    future.
+
+    Cancellation: if the outer Future is cancelled, all children (that
+    have not completed yet) are also cancelled.  If any child is
+    cancelled, this is treated as if it raised CancelledError --
+    the outer Future is *not* cancelled in this case.  (This is to
+    prevent the cancellation of one child to cause other children to
+    be cancelled.)
+    """
+    if not coros_or_futures:
+        if loop is None:
+            loop = events.get_event_loop()
+        outer = loop.create_future()
+        outer.set_result([])
+        return outer
+
+    arg_to_fut = {}
+    for arg in set(coros_or_futures):
+        if not futures.isfuture(arg):
+            fut = ensure_future(arg, loop=loop)
+            if loop is None:
+                loop = fut._loop
+            # The caller cannot control this future, the "destroy pending task"
+            # warning should not be emitted.
+            fut._log_destroy_pending = False
+        else:
+            fut = arg
+            if loop is None:
+                loop = fut._loop
+            elif fut._loop is not loop:
+                raise ValueError("futures are tied to different event loops")
+        arg_to_fut[arg] = fut
+
+    children = [arg_to_fut[arg] for arg in coros_or_futures]
+    nchildren = len(children)
+    outer = _GatheringFuture(children, loop=loop)
+    nfinished = 0
+    results = [None] * nchildren
+
+    def _done_callback(i, fut):
+        nonlocal nfinished
+        if outer.done():
+            if not fut.cancelled():
+                # Mark exception retrieved.
+                fut.exception()
+            return
+
+        if fut.cancelled():
+            res = futures.CancelledError()
+            if not return_exceptions:
+                outer.set_exception(res)
+                return
+        elif fut._exception is not None:
+            res = fut.exception()  # Mark exception retrieved.
+            if not return_exceptions:
+                outer.set_exception(res)
+                return
+        else:
+            res = fut._result
+        results[i] = res
+        nfinished += 1
+        if nfinished == nchildren:
+            if outer._cancel_requested:
+                outer.set_exception(futures.CancelledError())
+            else:
+                outer.set_result(results)
+
+    for i, fut in enumerate(children):
+        fut.add_done_callback(functools.partial(_done_callback, i))
+    return outer
+
+
+def shield(arg, *, loop=None):
+    """Wait for a future, shielding it from cancellation.
+
+    The statement
+
+        res = yield from shield(something())
+
+    is exactly equivalent to the statement
+
+        res = yield from something()
+
+    *except* that if the coroutine containing it is cancelled, the
+    task running in something() is not cancelled.  From the POV of
+    something(), the cancellation did not happen.  But its caller is
+    still cancelled, so the yield-from expression still raises
+    CancelledError.  Note: If something() is cancelled by other means
+    this will still cancel shield().
+
+    If you want to completely ignore cancellation (not recommended)
+    you can combine shield() with a try/except clause, as follows:
+
+        try:
+            res = yield from shield(something())
+        except CancelledError:
+            res = None
+    """
+    inner = ensure_future(arg, loop=loop)
+    if inner.done():
+        # Shortcut.
+        return inner
+    loop = inner._loop
+    outer = loop.create_future()
+
+    def _done_callback(inner):
+        if outer.cancelled():
+            if not inner.cancelled():
+                # Mark inner's result as retrieved.
+                inner.exception()
+            return
+
+        if inner.cancelled():
+            outer.cancel()
+        else:
+            exc = inner.exception()
+            if exc is not None:
+                outer.set_exception(exc)
+            else:
+                outer.set_result(inner.result())
+
+    inner.add_done_callback(_done_callback)
+    return outer
+
+
+def run_coroutine_threadsafe(coro, loop):
+    """Submit a coroutine object to a given event loop.
+
+    Return a concurrent.futures.Future to access the result.
+    """
+    if not coroutines.iscoroutine(coro):
+        raise TypeError('A coroutine object is required')
+    future = concurrent.futures.Future()
+
+    def callback():
+        try:
+            futures._chain_future(ensure_future(coro, loop=loop), future)
+        except Exception as exc:
+            if future.set_running_or_notify_cancel():
+                future.set_exception(exc)
+            raise
+
+    loop.call_soon_threadsafe(callback)
+    return future

third_party/python/Lib/asyncio/test_utils.py

@@ -0,0 +1,537 @@
+"""Utilities shared by tests."""
+
+import collections
+import contextlib
+import io
+import logging
+import os
+import re
+import socket
+import socketserver
+import sys
+import tempfile
+import threading
+import time
+import unittest
+import weakref
+
+from unittest import mock
+
+from http.server import HTTPServer
+from wsgiref.simple_server import WSGIRequestHandler, WSGIServer
+
+try:
+    import ssl
+except ImportError:  # pragma: no cover
+    ssl = None
+
+from . import base_events
+from . import compat
+from . import events
+from . import futures
+from . import selectors
+from . import tasks
+from .coroutines import coroutine
+from .log import logger
+from test import support
+
+
+if sys.platform == 'win32':  # pragma: no cover
+    from .windows_utils import socketpair
+else:
+    from socket import socketpair  # pragma: no cover
+
+
+def data_file(filename):
+    if hasattr(support, 'TEST_HOME_DIR'):
+        fullname = os.path.join(support.TEST_HOME_DIR, filename)
+        if os.path.isfile(fullname):
+            return fullname
+    fullname = os.path.join(os.path.dirname(os.__file__), 'test', filename)
+    if os.path.isfile(fullname):
+        return fullname
+    raise FileNotFoundError(filename)
+
+
+ONLYCERT = data_file('ssl_cert.pem')
+ONLYKEY = data_file('ssl_key.pem')
+
+
+def dummy_ssl_context():
+    if ssl is None:
+        return None
+    else:
+        return ssl.SSLContext(ssl.PROTOCOL_SSLv23)
+
+
+def run_briefly(loop):
+    @coroutine
+    def once():
+        pass
+    gen = once()
+    t = loop.create_task(gen)
+    # Don't log a warning if the task is not done after run_until_complete().
+    # It occurs if the loop is stopped or if a task raises a BaseException.
+    t._log_destroy_pending = False
+    try:
+        loop.run_until_complete(t)
+    finally:
+        gen.close()
+
+
+def run_until(loop, pred, timeout=30):
+    deadline = time.time() + timeout
+    while not pred():
+        if timeout is not None:
+            timeout = deadline - time.time()
+            if timeout <= 0:
+                raise futures.TimeoutError()
+        loop.run_until_complete(tasks.sleep(0.001, loop=loop))
+
+
+def run_once(loop):
+    """Legacy API to run once through the event loop.
+
+    This is the recommended pattern for test code.  It will poll the
+    selector once and run all callbacks scheduled in response to I/O
+    events.
+    """
+    loop.call_soon(loop.stop)
+    loop.run_forever()
+
+
+class SilentWSGIRequestHandler(WSGIRequestHandler):
+
+    def get_stderr(self):
+        return io.StringIO()
+
+    def log_message(self, format, *args):
+        pass
+
+
+class SilentWSGIServer(WSGIServer):
+
+    request_timeout = 2
+
+    def get_request(self):
+        request, client_addr = super().get_request()
+        request.settimeout(self.request_timeout)
+        return request, client_addr
+
+    def handle_error(self, request, client_address):
+        pass
+
+
+class SSLWSGIServerMixin:
+
+    def finish_request(self, request, client_address):
+        # The relative location of our test directory (which
+        # contains the ssl key and certificate files) differs
+        # between the stdlib and stand-alone asyncio.
+        # Prefer our own if we can find it.
+        keyfile = ONLYKEY
+        certfile = ONLYCERT
+        context = ssl.SSLContext()
+        context.load_cert_chain(certfile, keyfile)
+
+        ssock = context.wrap_socket(request, server_side=True)
+        try:
+            self.RequestHandlerClass(ssock, client_address, self)
+            ssock.close()
+        except OSError:
+            # maybe socket has been closed by peer
+            pass
+
+
+class SSLWSGIServer(SSLWSGIServerMixin, SilentWSGIServer):
+    pass
+
+
+def _run_test_server(*, address, use_ssl=False, server_cls, server_ssl_cls):
+
+    def app(environ, start_response):
+        status = '200 OK'
+        headers = [('Content-type', 'text/plain')]
+        start_response(status, headers)
+        return [b'Test message']
+
+    # Run the test WSGI server in a separate thread in order not to
+    # interfere with event handling in the main thread
+    server_class = server_ssl_cls if use_ssl else server_cls
+    httpd = server_class(address, SilentWSGIRequestHandler)
+    httpd.set_app(app)
+    httpd.address = httpd.server_address
+    server_thread = threading.Thread(
+        target=lambda: httpd.serve_forever(poll_interval=0.05))
+    server_thread.start()
+    try:
+        yield httpd
+    finally:
+        httpd.shutdown()
+        httpd.server_close()
+        server_thread.join()
+
+
+if hasattr(socket, 'AF_UNIX'):
+
+    class UnixHTTPServer(socketserver.UnixStreamServer, HTTPServer):
+
+        def server_bind(self):
+            socketserver.UnixStreamServer.server_bind(self)
+            self.server_name = '127.0.0.1'
+            self.server_port = 80
+
+
+    class UnixWSGIServer(UnixHTTPServer, WSGIServer):
+
+        request_timeout = 2
+
+        def server_bind(self):
+            UnixHTTPServer.server_bind(self)
+            self.setup_environ()
+
+        def get_request(self):
+            request, client_addr = super().get_request()
+            request.settimeout(self.request_timeout)
+            # Code in the stdlib expects that get_request
+            # will return a socket and a tuple (host, port).
+            # However, this isn't true for UNIX sockets,
+            # as the second return value will be a path;
+            # hence we return some fake data sufficient
+            # to get the tests going
+            return request, ('127.0.0.1', '')
+
+
+    class SilentUnixWSGIServer(UnixWSGIServer):
+
+        def handle_error(self, request, client_address):
+            pass
+
+
+    class UnixSSLWSGIServer(SSLWSGIServerMixin, SilentUnixWSGIServer):
+        pass
+
+
+    def gen_unix_socket_path():
+        with tempfile.NamedTemporaryFile() as file:
+            return file.name
+
+
+    @contextlib.contextmanager
+    def unix_socket_path():
+        path = gen_unix_socket_path()
+        try:
+            yield path
+        finally:
+            try:
+                os.unlink(path)
+            except OSError:
+                pass
+
+
+    @contextlib.contextmanager
+    def run_test_unix_server(*, use_ssl=False):
+        with unix_socket_path() as path:
+            yield from _run_test_server(address=path, use_ssl=use_ssl,
+                                        server_cls=SilentUnixWSGIServer,
+                                        server_ssl_cls=UnixSSLWSGIServer)
+
+
+@contextlib.contextmanager
+def run_test_server(*, host='127.0.0.1', port=0, use_ssl=False):
+    yield from _run_test_server(address=(host, port), use_ssl=use_ssl,
+                                server_cls=SilentWSGIServer,
+                                server_ssl_cls=SSLWSGIServer)
+
+
+def make_test_protocol(base):
+    dct = {}
+    for name in dir(base):
+        if name.startswith('__') and name.endswith('__'):
+            # skip magic names
+            continue
+        dct[name] = MockCallback(return_value=None)
+    return type('TestProtocol', (base,) + base.__bases__, dct)()
+
+
+class TestSelector(selectors.BaseSelector):
+
+    def __init__(self):
+        self.keys = {}
+
+    def register(self, fileobj, events, data=None):
+        key = selectors.SelectorKey(fileobj, 0, events, data)
+        self.keys[fileobj] = key
+        return key
+
+    def unregister(self, fileobj):
+        return self.keys.pop(fileobj)
+
+    def select(self, timeout):
+        return []
+
+    def get_map(self):
+        return self.keys
+
+
+class TestLoop(base_events.BaseEventLoop):
+    """Loop for unittests.
+
+    It manages self time directly.
+    If something scheduled to be executed later then
+    on next loop iteration after all ready handlers done
+    generator passed to __init__ is calling.
+
+    Generator should be like this:
+
+        def gen():
+            ...
+            when = yield ...
+            ... = yield time_advance
+
+    Value returned by yield is absolute time of next scheduled handler.
+    Value passed to yield is time advance to move loop's time forward.
+    """
+
+    def __init__(self, gen=None):
+        super().__init__()
+
+        if gen is None:
+            def gen():
+                yield
+            self._check_on_close = False
+        else:
+            self._check_on_close = True
+
+        self._gen = gen()
+        next(self._gen)
+        self._time = 0
+        self._clock_resolution = 1e-9
+        self._timers = []
+        self._selector = TestSelector()
+
+        self.readers = {}
+        self.writers = {}
+        self.reset_counters()
+
+        self._transports = weakref.WeakValueDictionary()
+
+    def time(self):
+        return self._time
+
+    def advance_time(self, advance):
+        """Move test time forward."""
+        if advance:
+            self._time += advance
+
+    def close(self):
+        super().close()
+        if self._check_on_close:
+            try:
+                self._gen.send(0)
+            except StopIteration:
+                pass
+            else:  # pragma: no cover
+                raise AssertionError("Time generator is not finished")
+
+    def _add_reader(self, fd, callback, *args):
+        self.readers[fd] = events.Handle(callback, args, self)
+
+    def _remove_reader(self, fd):
+        self.remove_reader_count[fd] += 1
+        if fd in self.readers:
+            del self.readers[fd]
+            return True
+        else:
+            return False
+
+    def assert_reader(self, fd, callback, *args):
+        if fd not in self.readers:
+            raise AssertionError(f'fd {fd} is not registered')
+        handle = self.readers[fd]
+        if handle._callback != callback:
+            raise AssertionError(
+                f'unexpected callback: {handle._callback} != {callback}')
+        if handle._args != args:
+            raise AssertionError(
+                f'unexpected callback args: {handle._args} != {args}')
+
+    def assert_no_reader(self, fd):
+        if fd in self.readers:
+            raise AssertionError(f'fd {fd} is registered')
+
+    def _add_writer(self, fd, callback, *args):
+        self.writers[fd] = events.Handle(callback, args, self)
+
+    def _remove_writer(self, fd):
+        self.remove_writer_count[fd] += 1
+        if fd in self.writers:
+            del self.writers[fd]
+            return True
+        else:
+            return False
+
+    def assert_writer(self, fd, callback, *args):
+        assert fd in self.writers, 'fd {} is not registered'.format(fd)
+        handle = self.writers[fd]
+        assert handle._callback == callback, '{!r} != {!r}'.format(
+            handle._callback, callback)
+        assert handle._args == args, '{!r} != {!r}'.format(
+            handle._args, args)
+
+    def _ensure_fd_no_transport(self, fd):
+        try:
+            transport = self._transports[fd]
+        except KeyError:
+            pass
+        else:
+            raise RuntimeError(
+                'File descriptor {!r} is used by transport {!r}'.format(
+                    fd, transport))
+
+    def add_reader(self, fd, callback, *args):
+        """Add a reader callback."""
+        self._ensure_fd_no_transport(fd)
+        return self._add_reader(fd, callback, *args)
+
+    def remove_reader(self, fd):
+        """Remove a reader callback."""
+        self._ensure_fd_no_transport(fd)
+        return self._remove_reader(fd)
+
+    def add_writer(self, fd, callback, *args):
+        """Add a writer callback.."""
+        self._ensure_fd_no_transport(fd)
+        return self._add_writer(fd, callback, *args)
+
+    def remove_writer(self, fd):
+        """Remove a writer callback."""
+        self._ensure_fd_no_transport(fd)
+        return self._remove_writer(fd)
+
+    def reset_counters(self):
+        self.remove_reader_count = collections.defaultdict(int)
+        self.remove_writer_count = collections.defaultdict(int)
+
+    def _run_once(self):
+        super()._run_once()
+        for when in self._timers:
+            advance = self._gen.send(when)
+            self.advance_time(advance)
+        self._timers = []
+
+    def call_at(self, when, callback, *args):
+        self._timers.append(when)
+        return super().call_at(when, callback, *args)
+
+    def _process_events(self, event_list):
+        return
+
+    def _write_to_self(self):
+        pass
+
+
+def MockCallback(**kwargs):
+    return mock.Mock(spec=['__call__'], **kwargs)
+
+
+class MockPattern(str):
+    """A regex based str with a fuzzy __eq__.
+
+    Use this helper with 'mock.assert_called_with', or anywhere
+    where a regex comparison between strings is needed.
+
+    For instance:
+       mock_call.assert_called_with(MockPattern('spam.*ham'))
+    """
+    def __eq__(self, other):
+        return bool(re.search(str(self), other, re.S))
+
+
+def get_function_source(func):
+    source = events._get_function_source(func)
+    if source is None:
+        raise ValueError("unable to get the source of %r" % (func,))
+    return source
+
+
+class TestCase(unittest.TestCase):
+    @staticmethod
+    def close_loop(loop):
+        executor = loop._default_executor
+        if executor is not None:
+            executor.shutdown(wait=True)
+        loop.close()
+
+    def set_event_loop(self, loop, *, cleanup=True):
+        assert loop is not None
+        # ensure that the event loop is passed explicitly in asyncio
+        events.set_event_loop(None)
+        if cleanup:
+            self.addCleanup(self.close_loop, loop)
+
+    def new_test_loop(self, gen=None):
+        loop = TestLoop(gen)
+        self.set_event_loop(loop)
+        return loop
+
+    def unpatch_get_running_loop(self):
+        events._get_running_loop = self._get_running_loop
+
+    def setUp(self):
+        self._get_running_loop = events._get_running_loop
+        events._get_running_loop = lambda: None
+        self._thread_cleanup = support.threading_setup()
+
+    def tearDown(self):
+        self.unpatch_get_running_loop()
+
+        events.set_event_loop(None)
+
+        # Detect CPython bug #23353: ensure that yield/yield-from is not used
+        # in an except block of a generator
+        self.assertEqual(sys.exc_info(), (None, None, None))
+
+        self.doCleanups()
+        support.threading_cleanup(*self._thread_cleanup)
+        support.reap_children()
+
+    if not compat.PY34:
+        # Python 3.3 compatibility
+        def subTest(self, *args, **kwargs):
+            class EmptyCM:
+                def __enter__(self):
+                    pass
+                def __exit__(self, *exc):
+                    pass
+            return EmptyCM()
+
+
+@contextlib.contextmanager
+def disable_logger():
+    """Context manager to disable asyncio logger.
+
+    For example, it can be used to ignore warnings in debug mode.
+    """
+    old_level = logger.level
+    try:
+        logger.setLevel(logging.CRITICAL+1)
+        yield
+    finally:
+        logger.setLevel(old_level)
+
+
+def mock_nonblocking_socket(proto=socket.IPPROTO_TCP, type=socket.SOCK_STREAM,
+                            family=socket.AF_INET):
+    """Create a mock of a non-blocking socket."""
+    sock = mock.MagicMock(socket.socket)
+    sock.proto = proto
+    sock.type = type
+    sock.family = family
+    sock.gettimeout.return_value = 0.0
+    return sock
+
+
+def force_legacy_ssl_support():
+    return mock.patch('asyncio.sslproto._is_sslproto_available',
+                      return_value=False)

third_party/python/Lib/asyncio/transports.py

@@ -0,0 +1,306 @@
+"""Abstract Transport class."""
+
+from asyncio import compat
+
+__all__ = ['BaseTransport', 'ReadTransport', 'WriteTransport',
+           'Transport', 'DatagramTransport', 'SubprocessTransport',
+           ]
+
+
+class BaseTransport:
+    """Base class for transports."""
+
+    def __init__(self, extra=None):
+        if extra is None:
+            extra = {}
+        self._extra = extra
+
+    def get_extra_info(self, name, default=None):
+        """Get optional transport information."""
+        return self._extra.get(name, default)
+
+    def is_closing(self):
+        """Return True if the transport is closing or closed."""
+        raise NotImplementedError
+
+    def close(self):
+        """Close the transport.
+
+        Buffered data will be flushed asynchronously.  No more data
+        will be received.  After all buffered data is flushed, the
+        protocol's connection_lost() method will (eventually) called
+        with None as its argument.
+        """
+        raise NotImplementedError
+
+    def set_protocol(self, protocol):
+        """Set a new protocol."""
+        raise NotImplementedError
+
+    def get_protocol(self):
+        """Return the current protocol."""
+        raise NotImplementedError
+
+
+class ReadTransport(BaseTransport):
+    """Interface for read-only transports."""
+
+    def pause_reading(self):
+        """Pause the receiving end.
+
+        No data will be passed to the protocol's data_received()
+        method until resume_reading() is called.
+        """
+        raise NotImplementedError
+
+    def resume_reading(self):
+        """Resume the receiving end.
+
+        Data received will once again be passed to the protocol's
+        data_received() method.
+        """
+        raise NotImplementedError
+
+
+class WriteTransport(BaseTransport):
+    """Interface for write-only transports."""
+
+    def set_write_buffer_limits(self, high=None, low=None):
+        """Set the high- and low-water limits for write flow control.
+
+        These two values control when to call the protocol's
+        pause_writing() and resume_writing() methods.  If specified,
+        the low-water limit must be less than or equal to the
+        high-water limit.  Neither value can be negative.
+
+        The defaults are implementation-specific.  If only the
+        high-water limit is given, the low-water limit defaults to an
+        implementation-specific value less than or equal to the
+        high-water limit.  Setting high to zero forces low to zero as
+        well, and causes pause_writing() to be called whenever the
+        buffer becomes non-empty.  Setting low to zero causes
+        resume_writing() to be called only once the buffer is empty.
+        Use of zero for either limit is generally sub-optimal as it
+        reduces opportunities for doing I/O and computation
+        concurrently.
+        """
+        raise NotImplementedError
+
+    def get_write_buffer_size(self):
+        """Return the current size of the write buffer."""
+        raise NotImplementedError
+
+    def write(self, data):
+        """Write some data bytes to the transport.
+
+        This does not block; it buffers the data and arranges for it
+        to be sent out asynchronously.
+        """
+        raise NotImplementedError
+
+    def writelines(self, list_of_data):
+        """Write a list (or any iterable) of data bytes to the transport.
+
+        The default implementation concatenates the arguments and
+        calls write() on the result.
+        """
+        data = compat.flatten_list_bytes(list_of_data)
+        self.write(data)
+
+    def write_eof(self):
+        """Close the write end after flushing buffered data.
+
+        (This is like typing ^D into a UNIX program reading from stdin.)
+
+        Data may still be received.
+        """
+        raise NotImplementedError
+
+    def can_write_eof(self):
+        """Return True if this transport supports write_eof(), False if not."""
+        raise NotImplementedError
+
+    def abort(self):
+        """Close the transport immediately.
+
+        Buffered data will be lost.  No more data will be received.
+        The protocol's connection_lost() method will (eventually) be
+        called with None as its argument.
+        """
+        raise NotImplementedError
+
+
+class Transport(ReadTransport, WriteTransport):
+    """Interface representing a bidirectional transport.
+
+    There may be several implementations, but typically, the user does
+    not implement new transports; rather, the platform provides some
+    useful transports that are implemented using the platform's best
+    practices.
+
+    The user never instantiates a transport directly; they call a
+    utility function, passing it a protocol factory and other
+    information necessary to create the transport and protocol.  (E.g.
+    EventLoop.create_connection() or EventLoop.create_server().)
+
+    The utility function will asynchronously create a transport and a
+    protocol and hook them up by calling the protocol's
+    connection_made() method, passing it the transport.
+
+    The implementation here raises NotImplemented for every method
+    except writelines(), which calls write() in a loop.
+    """
+
+
+class DatagramTransport(BaseTransport):
+    """Interface for datagram (UDP) transports."""
+
+    def sendto(self, data, addr=None):
+        """Send data to the transport.
+
+        This does not block; it buffers the data and arranges for it
+        to be sent out asynchronously.
+        addr is target socket address.
+        If addr is None use target address pointed on transport creation.
+        """
+        raise NotImplementedError
+
+    def abort(self):
+        """Close the transport immediately.
+
+        Buffered data will be lost.  No more data will be received.
+        The protocol's connection_lost() method will (eventually) be
+        called with None as its argument.
+        """
+        raise NotImplementedError
+
+
+class SubprocessTransport(BaseTransport):
+
+    def get_pid(self):
+        """Get subprocess id."""
+        raise NotImplementedError
+
+    def get_returncode(self):
+        """Get subprocess returncode.
+
+        See also
+        http://docs.python.org/3/library/subprocess#subprocess.Popen.returncode
+        """
+        raise NotImplementedError
+
+    def get_pipe_transport(self, fd):
+        """Get transport for pipe with number fd."""
+        raise NotImplementedError
+
+    def send_signal(self, signal):
+        """Send signal to subprocess.
+
+        See also:
+        docs.python.org/3/library/subprocess#subprocess.Popen.send_signal
+        """
+        raise NotImplementedError
+
+    def terminate(self):
+        """Stop the subprocess.
+
+        Alias for close() method.
+
+        On Posix OSs the method sends SIGTERM to the subprocess.
+        On Windows the Win32 API function TerminateProcess()
+         is called to stop the subprocess.
+
+        See also:
+        http://docs.python.org/3/library/subprocess#subprocess.Popen.terminate
+        """
+        raise NotImplementedError
+
+    def kill(self):
+        """Kill the subprocess.
+
+        On Posix OSs the function sends SIGKILL to the subprocess.
+        On Windows kill() is an alias for terminate().
+
+        See also:
+        http://docs.python.org/3/library/subprocess#subprocess.Popen.kill
+        """
+        raise NotImplementedError
+
+
+class _FlowControlMixin(Transport):
+    """All the logic for (write) flow control in a mix-in base class.
+
+    The subclass must implement get_write_buffer_size().  It must call
+    _maybe_pause_protocol() whenever the write buffer size increases,
+    and _maybe_resume_protocol() whenever it decreases.  It may also
+    override set_write_buffer_limits() (e.g. to specify different
+    defaults).
+
+    The subclass constructor must call super().__init__(extra).  This
+    will call set_write_buffer_limits().
+
+    The user may call set_write_buffer_limits() and
+    get_write_buffer_size(), and their protocol's pause_writing() and
+    resume_writing() may be called.
+    """
+
+    def __init__(self, extra=None, loop=None):
+        super().__init__(extra)
+        assert loop is not None
+        self._loop = loop
+        self._protocol_paused = False
+        self._set_write_buffer_limits()
+
+    def _maybe_pause_protocol(self):
+        size = self.get_write_buffer_size()
+        if size <= self._high_water:
+            return
+        if not self._protocol_paused:
+            self._protocol_paused = True
+            try:
+                self._protocol.pause_writing()
+            except Exception as exc:
+                self._loop.call_exception_handler({
+                    'message': 'protocol.pause_writing() failed',
+                    'exception': exc,
+                    'transport': self,
+                    'protocol': self._protocol,
+                })
+
+    def _maybe_resume_protocol(self):
+        if (self._protocol_paused and
+            self.get_write_buffer_size() <= self._low_water):
+            self._protocol_paused = False
+            try:
+                self._protocol.resume_writing()
+            except Exception as exc:
+                self._loop.call_exception_handler({
+                    'message': 'protocol.resume_writing() failed',
+                    'exception': exc,
+                    'transport': self,
+                    'protocol': self._protocol,
+                })
+
+    def get_write_buffer_limits(self):
+        return (self._low_water, self._high_water)
+
+    def _set_write_buffer_limits(self, high=None, low=None):
+        if high is None:
+            if low is None:
+                high = 64*1024
+            else:
+                high = 4*low
+        if low is None:
+            low = high // 4
+        if not high >= low >= 0:
+            raise ValueError('high (%r) must be >= low (%r) must be >= 0' %
+                             (high, low))
+        self._high_water = high
+        self._low_water = low
+
+    def set_write_buffer_limits(self, high=None, low=None):
+        self._set_write_buffer_limits(high=high, low=low)
+        self._maybe_pause_protocol()
+
+    def get_write_buffer_size(self):
+        raise NotImplementedError

third_party/python/Lib/asyncio/windows_events.py

@@ -0,0 +1,779 @@
+"""Selector and proactor event loops for Windows."""
+
+import _winapi
+import errno
+import math
+import socket
+import struct
+import weakref
+
+from . import events
+from . import base_subprocess
+from . import futures
+from . import proactor_events
+from . import selector_events
+from . import tasks
+from . import windows_utils
+from . import _overlapped
+from .coroutines import coroutine
+from .log import logger
+
+
+__all__ = ['SelectorEventLoop', 'ProactorEventLoop', 'IocpProactor',
+           'DefaultEventLoopPolicy',
+           ]
+
+
+NULL = 0
+INFINITE = 0xffffffff
+ERROR_CONNECTION_REFUSED = 1225
+ERROR_CONNECTION_ABORTED = 1236
+
+# Initial delay in seconds for connect_pipe() before retrying to connect
+CONNECT_PIPE_INIT_DELAY = 0.001
+
+# Maximum delay in seconds for connect_pipe() before retrying to connect
+CONNECT_PIPE_MAX_DELAY = 0.100
+
+
+class _OverlappedFuture(futures.Future):
+    """Subclass of Future which represents an overlapped operation.
+
+    Cancelling it will immediately cancel the overlapped operation.
+    """
+
+    def __init__(self, ov, *, loop=None):
+        super().__init__(loop=loop)
+        if self._source_traceback:
+            del self._source_traceback[-1]
+        self._ov = ov
+
+    def _repr_info(self):
+        info = super()._repr_info()
+        if self._ov is not None:
+            state = 'pending' if self._ov.pending else 'completed'
+            info.insert(1, 'overlapped=<%s, %#x>' % (state, self._ov.address))
+        return info
+
+    def _cancel_overlapped(self):
+        if self._ov is None:
+            return
+        try:
+            self._ov.cancel()
+        except OSError as exc:
+            context = {
+                'message': 'Cancelling an overlapped future failed',
+                'exception': exc,
+                'future': self,
+            }
+            if self._source_traceback:
+                context['source_traceback'] = self._source_traceback
+            self._loop.call_exception_handler(context)
+        self._ov = None
+
+    def cancel(self):
+        self._cancel_overlapped()
+        return super().cancel()
+
+    def set_exception(self, exception):
+        super().set_exception(exception)
+        self._cancel_overlapped()
+
+    def set_result(self, result):
+        super().set_result(result)
+        self._ov = None
+
+
+class _BaseWaitHandleFuture(futures.Future):
+    """Subclass of Future which represents a wait handle."""
+
+    def __init__(self, ov, handle, wait_handle, *, loop=None):
+        super().__init__(loop=loop)
+        if self._source_traceback:
+            del self._source_traceback[-1]
+        # Keep a reference to the Overlapped object to keep it alive until the
+        # wait is unregistered
+        self._ov = ov
+        self._handle = handle
+        self._wait_handle = wait_handle
+
+        # Should we call UnregisterWaitEx() if the wait completes
+        # or is cancelled?
+        self._registered = True
+
+    def _poll(self):
+        # non-blocking wait: use a timeout of 0 millisecond
+        return (_winapi.WaitForSingleObject(self._handle, 0) ==
+                _winapi.WAIT_OBJECT_0)
+
+    def _repr_info(self):
+        info = super()._repr_info()
+        info.append('handle=%#x' % self._handle)
+        if self._handle is not None:
+            state = 'signaled' if self._poll() else 'waiting'
+            info.append(state)
+        if self._wait_handle is not None:
+            info.append('wait_handle=%#x' % self._wait_handle)
+        return info
+
+    def _unregister_wait_cb(self, fut):
+        # The wait was unregistered: it's not safe to destroy the Overlapped
+        # object
+        self._ov = None
+
+    def _unregister_wait(self):
+        if not self._registered:
+            return
+        self._registered = False
+
+        wait_handle = self._wait_handle
+        self._wait_handle = None
+        try:
+            _overlapped.UnregisterWait(wait_handle)
+        except OSError as exc:
+            if exc.winerror != _overlapped.ERROR_IO_PENDING:
+                context = {
+                    'message': 'Failed to unregister the wait handle',
+                    'exception': exc,
+                    'future': self,
+                }
+                if self._source_traceback:
+                    context['source_traceback'] = self._source_traceback
+                self._loop.call_exception_handler(context)
+                return
+            # ERROR_IO_PENDING means that the unregister is pending
+
+        self._unregister_wait_cb(None)
+
+    def cancel(self):
+        self._unregister_wait()
+        return super().cancel()
+
+    def set_exception(self, exception):
+        self._unregister_wait()
+        super().set_exception(exception)
+
+    def set_result(self, result):
+        self._unregister_wait()
+        super().set_result(result)
+
+
+class _WaitCancelFuture(_BaseWaitHandleFuture):
+    """Subclass of Future which represents a wait for the cancellation of a
+    _WaitHandleFuture using an event.
+    """
+
+    def __init__(self, ov, event, wait_handle, *, loop=None):
+        super().__init__(ov, event, wait_handle, loop=loop)
+
+        self._done_callback = None
+
+    def cancel(self):
+        raise RuntimeError("_WaitCancelFuture must not be cancelled")
+
+    def set_result(self, result):
+        super().set_result(result)
+        if self._done_callback is not None:
+            self._done_callback(self)
+
+    def set_exception(self, exception):
+        super().set_exception(exception)
+        if self._done_callback is not None:
+            self._done_callback(self)
+
+
+class _WaitHandleFuture(_BaseWaitHandleFuture):
+    def __init__(self, ov, handle, wait_handle, proactor, *, loop=None):
+        super().__init__(ov, handle, wait_handle, loop=loop)
+        self._proactor = proactor
+        self._unregister_proactor = True
+        self._event = _overlapped.CreateEvent(None, True, False, None)
+        self._event_fut = None
+
+    def _unregister_wait_cb(self, fut):
+        if self._event is not None:
+            _winapi.CloseHandle(self._event)
+            self._event = None
+            self._event_fut = None
+
+        # If the wait was cancelled, the wait may never be signalled, so
+        # it's required to unregister it. Otherwise, IocpProactor.close() will
+        # wait forever for an event which will never come.
+        #
+        # If the IocpProactor already received the event, it's safe to call
+        # _unregister() because we kept a reference to the Overlapped object
+        # which is used as a unique key.
+        self._proactor._unregister(self._ov)
+        self._proactor = None
+
+        super()._unregister_wait_cb(fut)
+
+    def _unregister_wait(self):
+        if not self._registered:
+            return
+        self._registered = False
+
+        wait_handle = self._wait_handle
+        self._wait_handle = None
+        try:
+            _overlapped.UnregisterWaitEx(wait_handle, self._event)
+        except OSError as exc:
+            if exc.winerror != _overlapped.ERROR_IO_PENDING:
+                context = {
+                    'message': 'Failed to unregister the wait handle',
+                    'exception': exc,
+                    'future': self,
+                }
+                if self._source_traceback:
+                    context['source_traceback'] = self._source_traceback
+                self._loop.call_exception_handler(context)
+                return
+            # ERROR_IO_PENDING is not an error, the wait was unregistered
+
+        self._event_fut = self._proactor._wait_cancel(self._event,
+                                                      self._unregister_wait_cb)
+
+
+class PipeServer(object):
+    """Class representing a pipe server.
+
+    This is much like a bound, listening socket.
+    """
+    def __init__(self, address):
+        self._address = address
+        self._free_instances = weakref.WeakSet()
+        # initialize the pipe attribute before calling _server_pipe_handle()
+        # because this function can raise an exception and the destructor calls
+        # the close() method
+        self._pipe = None
+        self._accept_pipe_future = None
+        self._pipe = self._server_pipe_handle(True)
+
+    def _get_unconnected_pipe(self):
+        # Create new instance and return previous one.  This ensures
+        # that (until the server is closed) there is always at least
+        # one pipe handle for address.  Therefore if a client attempt
+        # to connect it will not fail with FileNotFoundError.
+        tmp, self._pipe = self._pipe, self._server_pipe_handle(False)
+        return tmp
+
+    def _server_pipe_handle(self, first):
+        # Return a wrapper for a new pipe handle.
+        if self.closed():
+            return None
+        flags = _winapi.PIPE_ACCESS_DUPLEX | _winapi.FILE_FLAG_OVERLAPPED
+        if first:
+            flags |= _winapi.FILE_FLAG_FIRST_PIPE_INSTANCE
+        h = _winapi.CreateNamedPipe(
+            self._address, flags,
+            _winapi.PIPE_TYPE_MESSAGE | _winapi.PIPE_READMODE_MESSAGE |
+            _winapi.PIPE_WAIT,
+            _winapi.PIPE_UNLIMITED_INSTANCES,
+            windows_utils.BUFSIZE, windows_utils.BUFSIZE,
+            _winapi.NMPWAIT_WAIT_FOREVER, _winapi.NULL)
+        pipe = windows_utils.PipeHandle(h)
+        self._free_instances.add(pipe)
+        return pipe
+
+    def closed(self):
+        return (self._address is None)
+
+    def close(self):
+        if self._accept_pipe_future is not None:
+            self._accept_pipe_future.cancel()
+            self._accept_pipe_future = None
+        # Close all instances which have not been connected to by a client.
+        if self._address is not None:
+            for pipe in self._free_instances:
+                pipe.close()
+            self._pipe = None
+            self._address = None
+            self._free_instances.clear()
+
+    __del__ = close
+
+
+class _WindowsSelectorEventLoop(selector_events.BaseSelectorEventLoop):
+    """Windows version of selector event loop."""
+
+    def _socketpair(self):
+        return windows_utils.socketpair()
+
+
+class ProactorEventLoop(proactor_events.BaseProactorEventLoop):
+    """Windows version of proactor event loop using IOCP."""
+
+    def __init__(self, proactor=None):
+        if proactor is None:
+            proactor = IocpProactor()
+        super().__init__(proactor)
+
+    def _socketpair(self):
+        return windows_utils.socketpair()
+
+    @coroutine
+    def create_pipe_connection(self, protocol_factory, address):
+        f = self._proactor.connect_pipe(address)
+        pipe = yield from f
+        protocol = protocol_factory()
+        trans = self._make_duplex_pipe_transport(pipe, protocol,
+                                                 extra={'addr': address})
+        return trans, protocol
+
+    @coroutine
+    def start_serving_pipe(self, protocol_factory, address):
+        server = PipeServer(address)
+
+        def loop_accept_pipe(f=None):
+            pipe = None
+            try:
+                if f:
+                    pipe = f.result()
+                    server._free_instances.discard(pipe)
+
+                    if server.closed():
+                        # A client connected before the server was closed:
+                        # drop the client (close the pipe) and exit
+                        pipe.close()
+                        return
+
+                    protocol = protocol_factory()
+                    self._make_duplex_pipe_transport(
+                        pipe, protocol, extra={'addr': address})
+
+                pipe = server._get_unconnected_pipe()
+                if pipe is None:
+                    return
+
+                f = self._proactor.accept_pipe(pipe)
+            except OSError as exc:
+                if pipe and pipe.fileno() != -1:
+                    self.call_exception_handler({
+                        'message': 'Pipe accept failed',
+                        'exception': exc,
+                        'pipe': pipe,
+                    })
+                    pipe.close()
+                elif self._debug:
+                    logger.warning("Accept pipe failed on pipe %r",
+                                   pipe, exc_info=True)
+            except futures.CancelledError:
+                if pipe:
+                    pipe.close()
+            else:
+                server._accept_pipe_future = f
+                f.add_done_callback(loop_accept_pipe)
+
+        self.call_soon(loop_accept_pipe)
+        return [server]
+
+    @coroutine
+    def _make_subprocess_transport(self, protocol, args, shell,
+                                   stdin, stdout, stderr, bufsize,
+                                   extra=None, **kwargs):
+        waiter = self.create_future()
+        transp = _WindowsSubprocessTransport(self, protocol, args, shell,
+                                             stdin, stdout, stderr, bufsize,
+                                             waiter=waiter, extra=extra,
+                                             **kwargs)
+        try:
+            yield from waiter
+        except Exception as exc:
+            # Workaround CPython bug #23353: using yield/yield-from in an
+            # except block of a generator doesn't clear properly sys.exc_info()
+            err = exc
+        else:
+            err = None
+
+        if err is not None:
+            transp.close()
+            yield from transp._wait()
+            raise err
+
+        return transp
+
+
+class IocpProactor:
+    """Proactor implementation using IOCP."""
+
+    def __init__(self, concurrency=0xffffffff):
+        self._loop = None
+        self._results = []
+        self._iocp = _overlapped.CreateIoCompletionPort(
+            _overlapped.INVALID_HANDLE_VALUE, NULL, 0, concurrency)
+        self._cache = {}
+        self._registered = weakref.WeakSet()
+        self._unregistered = []
+        self._stopped_serving = weakref.WeakSet()
+
+    def __repr__(self):
+        return ('<%s overlapped#=%s result#=%s>'
+                % (self.__class__.__name__, len(self._cache),
+                   len(self._results)))
+
+    def set_loop(self, loop):
+        self._loop = loop
+
+    def select(self, timeout=None):
+        if not self._results:
+            self._poll(timeout)
+        tmp = self._results
+        self._results = []
+        return tmp
+
+    def _result(self, value):
+        fut = self._loop.create_future()
+        fut.set_result(value)
+        return fut
+
+    def recv(self, conn, nbytes, flags=0):
+        self._register_with_iocp(conn)
+        ov = _overlapped.Overlapped(NULL)
+        try:
+            if isinstance(conn, socket.socket):
+                ov.WSARecv(conn.fileno(), nbytes, flags)
+            else:
+                ov.ReadFile(conn.fileno(), nbytes)
+        except BrokenPipeError:
+            return self._result(b'')
+
+        def finish_recv(trans, key, ov):
+            try:
+                return ov.getresult()
+            except OSError as exc:
+                if exc.winerror == _overlapped.ERROR_NETNAME_DELETED:
+                    raise ConnectionResetError(*exc.args)
+                else:
+                    raise
+
+        return self._register(ov, conn, finish_recv)
+
+    def send(self, conn, buf, flags=0):
+        self._register_with_iocp(conn)
+        ov = _overlapped.Overlapped(NULL)
+        if isinstance(conn, socket.socket):
+            ov.WSASend(conn.fileno(), buf, flags)
+        else:
+            ov.WriteFile(conn.fileno(), buf)
+
+        def finish_send(trans, key, ov):
+            try:
+                return ov.getresult()
+            except OSError as exc:
+                if exc.winerror == _overlapped.ERROR_NETNAME_DELETED:
+                    raise ConnectionResetError(*exc.args)
+                else:
+                    raise
+
+        return self._register(ov, conn, finish_send)
+
+    def accept(self, listener):
+        self._register_with_iocp(listener)
+        conn = self._get_accept_socket(listener.family)
+        ov = _overlapped.Overlapped(NULL)
+        ov.AcceptEx(listener.fileno(), conn.fileno())
+
+        def finish_accept(trans, key, ov):
+            ov.getresult()
+            # Use SO_UPDATE_ACCEPT_CONTEXT so getsockname() etc work.
+            buf = struct.pack('@P', listener.fileno())
+            conn.setsockopt(socket.SOL_SOCKET,
+                            _overlapped.SO_UPDATE_ACCEPT_CONTEXT, buf)
+            conn.settimeout(listener.gettimeout())
+            return conn, conn.getpeername()
+
+        @coroutine
+        def accept_coro(future, conn):
+            # Coroutine closing the accept socket if the future is cancelled
+            try:
+                yield from future
+            except futures.CancelledError:
+                conn.close()
+                raise
+
+        future = self._register(ov, listener, finish_accept)
+        coro = accept_coro(future, conn)
+        tasks.ensure_future(coro, loop=self._loop)
+        return future
+
+    def connect(self, conn, address):
+        self._register_with_iocp(conn)
+        # The socket needs to be locally bound before we call ConnectEx().
+        try:
+            _overlapped.BindLocal(conn.fileno(), conn.family)
+        except OSError as e:
+            if e.winerror != errno.WSAEINVAL:
+                raise
+            # Probably already locally bound; check using getsockname().
+            if conn.getsockname()[1] == 0:
+                raise
+        ov = _overlapped.Overlapped(NULL)
+        ov.ConnectEx(conn.fileno(), address)
+
+        def finish_connect(trans, key, ov):
+            ov.getresult()
+            # Use SO_UPDATE_CONNECT_CONTEXT so getsockname() etc work.
+            conn.setsockopt(socket.SOL_SOCKET,
+                            _overlapped.SO_UPDATE_CONNECT_CONTEXT, 0)
+            return conn
+
+        return self._register(ov, conn, finish_connect)
+
+    def accept_pipe(self, pipe):
+        self._register_with_iocp(pipe)
+        ov = _overlapped.Overlapped(NULL)
+        connected = ov.ConnectNamedPipe(pipe.fileno())
+
+        if connected:
+            # ConnectNamePipe() failed with ERROR_PIPE_CONNECTED which means
+            # that the pipe is connected. There is no need to wait for the
+            # completion of the connection.
+            return self._result(pipe)
+
+        def finish_accept_pipe(trans, key, ov):
+            ov.getresult()
+            return pipe
+
+        return self._register(ov, pipe, finish_accept_pipe)
+
+    @coroutine
+    def connect_pipe(self, address):
+        delay = CONNECT_PIPE_INIT_DELAY
+        while True:
+            # Unfortunately there is no way to do an overlapped connect to a pipe.
+            # Call CreateFile() in a loop until it doesn't fail with
+            # ERROR_PIPE_BUSY
+            try:
+                handle = _overlapped.ConnectPipe(address)
+                break
+            except OSError as exc:
+                if exc.winerror != _overlapped.ERROR_PIPE_BUSY:
+                    raise
+
+            # ConnectPipe() failed with ERROR_PIPE_BUSY: retry later
+            delay = min(delay * 2, CONNECT_PIPE_MAX_DELAY)
+            yield from tasks.sleep(delay, loop=self._loop)
+
+        return windows_utils.PipeHandle(handle)
+
+    def wait_for_handle(self, handle, timeout=None):
+        """Wait for a handle.
+
+        Return a Future object. The result of the future is True if the wait
+        completed, or False if the wait did not complete (on timeout).
+        """
+        return self._wait_for_handle(handle, timeout, False)
+
+    def _wait_cancel(self, event, done_callback):
+        fut = self._wait_for_handle(event, None, True)
+        # add_done_callback() cannot be used because the wait may only complete
+        # in IocpProactor.close(), while the event loop is not running.
+        fut._done_callback = done_callback
+        return fut
+
+    def _wait_for_handle(self, handle, timeout, _is_cancel):
+        if timeout is None:
+            ms = _winapi.INFINITE
+        else:
+            # RegisterWaitForSingleObject() has a resolution of 1 millisecond,
+            # round away from zero to wait *at least* timeout seconds.
+            ms = math.ceil(timeout * 1e3)
+
+        # We only create ov so we can use ov.address as a key for the cache.
+        ov = _overlapped.Overlapped(NULL)
+        wait_handle = _overlapped.RegisterWaitWithQueue(
+            handle, self._iocp, ov.address, ms)
+        if _is_cancel:
+            f = _WaitCancelFuture(ov, handle, wait_handle, loop=self._loop)
+        else:
+            f = _WaitHandleFuture(ov, handle, wait_handle, self,
+                                  loop=self._loop)
+        if f._source_traceback:
+            del f._source_traceback[-1]
+
+        def finish_wait_for_handle(trans, key, ov):
+            # Note that this second wait means that we should only use
+            # this with handles types where a successful wait has no
+            # effect.  So events or processes are all right, but locks
+            # or semaphores are not.  Also note if the handle is
+            # signalled and then quickly reset, then we may return
+            # False even though we have not timed out.
+            return f._poll()
+
+        self._cache[ov.address] = (f, ov, 0, finish_wait_for_handle)
+        return f
+
+    def _register_with_iocp(self, obj):
+        # To get notifications of finished ops on this objects sent to the
+        # completion port, were must register the handle.
+        if obj not in self._registered:
+            self._registered.add(obj)
+            _overlapped.CreateIoCompletionPort(obj.fileno(), self._iocp, 0, 0)
+            # XXX We could also use SetFileCompletionNotificationModes()
+            # to avoid sending notifications to completion port of ops
+            # that succeed immediately.
+
+    def _register(self, ov, obj, callback):
+        # Return a future which will be set with the result of the
+        # operation when it completes.  The future's value is actually
+        # the value returned by callback().
+        f = _OverlappedFuture(ov, loop=self._loop)
+        if f._source_traceback:
+            del f._source_traceback[-1]
+        if not ov.pending:
+            # The operation has completed, so no need to postpone the
+            # work.  We cannot take this short cut if we need the
+            # NumberOfBytes, CompletionKey values returned by
+            # PostQueuedCompletionStatus().
+            try:
+                value = callback(None, None, ov)
+            except OSError as e:
+                f.set_exception(e)
+            else:
+                f.set_result(value)
+            # Even if GetOverlappedResult() was called, we have to wait for the
+            # notification of the completion in GetQueuedCompletionStatus().
+            # Register the overlapped operation to keep a reference to the
+            # OVERLAPPED object, otherwise the memory is freed and Windows may
+            # read uninitialized memory.
+
+        # Register the overlapped operation for later.  Note that
+        # we only store obj to prevent it from being garbage
+        # collected too early.
+        self._cache[ov.address] = (f, ov, obj, callback)
+        return f
+
+    def _unregister(self, ov):
+        """Unregister an overlapped object.
+
+        Call this method when its future has been cancelled. The event can
+        already be signalled (pending in the proactor event queue). It is also
+        safe if the event is never signalled (because it was cancelled).
+        """
+        self._unregistered.append(ov)
+
+    def _get_accept_socket(self, family):
+        s = socket.socket(family)
+        s.settimeout(0)
+        return s
+
+    def _poll(self, timeout=None):
+        if timeout is None:
+            ms = INFINITE
+        elif timeout < 0:
+            raise ValueError("negative timeout")
+        else:
+            # GetQueuedCompletionStatus() has a resolution of 1 millisecond,
+            # round away from zero to wait *at least* timeout seconds.
+            ms = math.ceil(timeout * 1e3)
+            if ms >= INFINITE:
+                raise ValueError("timeout too big")
+
+        while True:
+            status = _overlapped.GetQueuedCompletionStatus(self._iocp, ms)
+            if status is None:
+                break
+            ms = 0
+
+            err, transferred, key, address = status
+            try:
+                f, ov, obj, callback = self._cache.pop(address)
+            except KeyError:
+                if self._loop.get_debug():
+                    self._loop.call_exception_handler({
+                        'message': ('GetQueuedCompletionStatus() returned an '
+                                    'unexpected event'),
+                        'status': ('err=%s transferred=%s key=%#x address=%#x'
+                                   % (err, transferred, key, address)),
+                    })
+
+                # key is either zero, or it is used to return a pipe
+                # handle which should be closed to avoid a leak.
+                if key not in (0, _overlapped.INVALID_HANDLE_VALUE):
+                    _winapi.CloseHandle(key)
+                continue
+
+            if obj in self._stopped_serving:
+                f.cancel()
+            # Don't call the callback if _register() already read the result or
+            # if the overlapped has been cancelled
+            elif not f.done():
+                try:
+                    value = callback(transferred, key, ov)
+                except OSError as e:
+                    f.set_exception(e)
+                    self._results.append(f)
+                else:
+                    f.set_result(value)
+                    self._results.append(f)
+
+        # Remove unregisted futures
+        for ov in self._unregistered:
+            self._cache.pop(ov.address, None)
+        self._unregistered.clear()
+
+    def _stop_serving(self, obj):
+        # obj is a socket or pipe handle.  It will be closed in
+        # BaseProactorEventLoop._stop_serving() which will make any
+        # pending operations fail quickly.
+        self._stopped_serving.add(obj)
+
+    def close(self):
+        # Cancel remaining registered operations.
+        for address, (fut, ov, obj, callback) in list(self._cache.items()):
+            if fut.cancelled():
+                # Nothing to do with cancelled futures
+                pass
+            elif isinstance(fut, _WaitCancelFuture):
+                # _WaitCancelFuture must not be cancelled
+                pass
+            else:
+                try:
+                    fut.cancel()
+                except OSError as exc:
+                    if self._loop is not None:
+                        context = {
+                            'message': 'Cancelling a future failed',
+                            'exception': exc,
+                            'future': fut,
+                        }
+                        if fut._source_traceback:
+                            context['source_traceback'] = fut._source_traceback
+                        self._loop.call_exception_handler(context)
+
+        while self._cache:
+            if not self._poll(1):
+                logger.debug('taking long time to close proactor')
+
+        self._results = []
+        if self._iocp is not None:
+            _winapi.CloseHandle(self._iocp)
+            self._iocp = None
+
+    def __del__(self):
+        self.close()
+
+
+class _WindowsSubprocessTransport(base_subprocess.BaseSubprocessTransport):
+
+    def _start(self, args, shell, stdin, stdout, stderr, bufsize, **kwargs):
+        self._proc = windows_utils.Popen(
+            args, shell=shell, stdin=stdin, stdout=stdout, stderr=stderr,
+            bufsize=bufsize, **kwargs)
+
+        def callback(f):
+            returncode = self._proc.poll()
+            self._process_exited(returncode)
+
+        f = self._loop._proactor.wait_for_handle(int(self._proc._handle))
+        f.add_done_callback(callback)
+
+
+SelectorEventLoop = _WindowsSelectorEventLoop
+
+
+class _WindowsDefaultEventLoopPolicy(events.BaseDefaultEventLoopPolicy):
+    _loop_factory = SelectorEventLoop
+
+
+DefaultEventLoopPolicy = _WindowsDefaultEventLoopPolicy

third_party/python/Lib/asyncio/windows_utils.py

@@ -0,0 +1,224 @@
+"""
+Various Windows specific bits and pieces
+"""
+
+import sys
+
+if sys.platform != 'win32':  # pragma: no cover
+    raise ImportError('win32 only')
+
+import _winapi
+import itertools
+import msvcrt
+import os
+import socket
+import subprocess
+import tempfile
+import warnings
+
+
+__all__ = ['socketpair', 'pipe', 'Popen', 'PIPE', 'PipeHandle']
+
+
+# Constants/globals
+
+
+BUFSIZE = 8192
+PIPE = subprocess.PIPE
+STDOUT = subprocess.STDOUT
+_mmap_counter = itertools.count()
+
+
+if hasattr(socket, 'socketpair'):
+    # Since Python 3.5, socket.socketpair() is now also available on Windows
+    socketpair = socket.socketpair
+else:
+    # Replacement for socket.socketpair()
+    def socketpair(family=socket.AF_INET, type=socket.SOCK_STREAM, proto=0):
+        """A socket pair usable as a self-pipe, for Windows.
+
+        Origin: https://gist.github.com/4325783, by Geert Jansen.
+        Public domain.
+        """
+        if family == socket.AF_INET:
+            host = '127.0.0.1'
+        elif family == socket.AF_INET6:
+            host = '::1'
+        else:
+            raise ValueError("Only AF_INET and AF_INET6 socket address "
+                             "families are supported")
+        if type != socket.SOCK_STREAM:
+            raise ValueError("Only SOCK_STREAM socket type is supported")
+        if proto != 0:
+            raise ValueError("Only protocol zero is supported")
+
+        # We create a connected TCP socket. Note the trick with setblocking(0)
+        # that prevents us from having to create a thread.
+        lsock = socket.socket(family, type, proto)
+        try:
+            lsock.bind((host, 0))
+            lsock.listen(1)
+            # On IPv6, ignore flow_info and scope_id
+            addr, port = lsock.getsockname()[:2]
+            csock = socket.socket(family, type, proto)
+            try:
+                csock.setblocking(False)
+                try:
+                    csock.connect((addr, port))
+                except (BlockingIOError, InterruptedError):
+                    pass
+                csock.setblocking(True)
+                ssock, _ = lsock.accept()
+            except:
+                csock.close()
+                raise
+        finally:
+            lsock.close()
+        return (ssock, csock)
+
+
+# Replacement for os.pipe() using handles instead of fds
+
+
+def pipe(*, duplex=False, overlapped=(True, True), bufsize=BUFSIZE):
+    """Like os.pipe() but with overlapped support and using handles not fds."""
+    address = tempfile.mktemp(prefix=r'\\.\pipe\python-pipe-%d-%d-' %
+                              (os.getpid(), next(_mmap_counter)))
+
+    if duplex:
+        openmode = _winapi.PIPE_ACCESS_DUPLEX
+        access = _winapi.GENERIC_READ | _winapi.GENERIC_WRITE
+        obsize, ibsize = bufsize, bufsize
+    else:
+        openmode = _winapi.PIPE_ACCESS_INBOUND
+        access = _winapi.GENERIC_WRITE
+        obsize, ibsize = 0, bufsize
+
+    openmode |= _winapi.FILE_FLAG_FIRST_PIPE_INSTANCE
+
+    if overlapped[0]:
+        openmode |= _winapi.FILE_FLAG_OVERLAPPED
+
+    if overlapped[1]:
+        flags_and_attribs = _winapi.FILE_FLAG_OVERLAPPED
+    else:
+        flags_and_attribs = 0
+
+    h1 = h2 = None
+    try:
+        h1 = _winapi.CreateNamedPipe(
+            address, openmode, _winapi.PIPE_WAIT,
+            1, obsize, ibsize, _winapi.NMPWAIT_WAIT_FOREVER, _winapi.NULL)
+
+        h2 = _winapi.CreateFile(
+            address, access, 0, _winapi.NULL, _winapi.OPEN_EXISTING,
+            flags_and_attribs, _winapi.NULL)
+
+        ov = _winapi.ConnectNamedPipe(h1, overlapped=True)
+        ov.GetOverlappedResult(True)
+        return h1, h2
+    except:
+        if h1 is not None:
+            _winapi.CloseHandle(h1)
+        if h2 is not None:
+            _winapi.CloseHandle(h2)
+        raise
+
+
+# Wrapper for a pipe handle
+
+
+class PipeHandle:
+    """Wrapper for an overlapped pipe handle which is vaguely file-object like.
+
+    The IOCP event loop can use these instead of socket objects.
+    """
+    def __init__(self, handle):
+        self._handle = handle
+
+    def __repr__(self):
+        if self._handle is not None:
+            handle = 'handle=%r' % self._handle
+        else:
+            handle = 'closed'
+        return '<%s %s>' % (self.__class__.__name__, handle)
+
+    @property
+    def handle(self):
+        return self._handle
+
+    def fileno(self):
+        if self._handle is None:
+            raise ValueError("I/O operatioon on closed pipe")
+        return self._handle
+
+    def close(self, *, CloseHandle=_winapi.CloseHandle):
+        if self._handle is not None:
+            CloseHandle(self._handle)
+            self._handle = None
+
+    def __del__(self):
+        if self._handle is not None:
+            warnings.warn("unclosed %r" % self, ResourceWarning,
+                          source=self)
+            self.close()
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, t, v, tb):
+        self.close()
+
+
+# Replacement for subprocess.Popen using overlapped pipe handles
+
+
+class Popen(subprocess.Popen):
+    """Replacement for subprocess.Popen using overlapped pipe handles.
+
+    The stdin, stdout, stderr are None or instances of PipeHandle.
+    """
+    def __init__(self, args, stdin=None, stdout=None, stderr=None, **kwds):
+        assert not kwds.get('universal_newlines')
+        assert kwds.get('bufsize', 0) == 0
+        stdin_rfd = stdout_wfd = stderr_wfd = None
+        stdin_wh = stdout_rh = stderr_rh = None
+        if stdin == PIPE:
+            stdin_rh, stdin_wh = pipe(overlapped=(False, True), duplex=True)
+            stdin_rfd = msvcrt.open_osfhandle(stdin_rh, os.O_RDONLY)
+        else:
+            stdin_rfd = stdin
+        if stdout == PIPE:
+            stdout_rh, stdout_wh = pipe(overlapped=(True, False))
+            stdout_wfd = msvcrt.open_osfhandle(stdout_wh, 0)
+        else:
+            stdout_wfd = stdout
+        if stderr == PIPE:
+            stderr_rh, stderr_wh = pipe(overlapped=(True, False))
+            stderr_wfd = msvcrt.open_osfhandle(stderr_wh, 0)
+        elif stderr == STDOUT:
+            stderr_wfd = stdout_wfd
+        else:
+            stderr_wfd = stderr
+        try:
+            super().__init__(args, stdin=stdin_rfd, stdout=stdout_wfd,
+                             stderr=stderr_wfd, **kwds)
+        except:
+            for h in (stdin_wh, stdout_rh, stderr_rh):
+                if h is not None:
+                    _winapi.CloseHandle(h)
+            raise
+        else:
+            if stdin_wh is not None:
+                self.stdin = PipeHandle(stdin_wh)
+            if stdout_rh is not None:
+                self.stdout = PipeHandle(stdout_rh)
+            if stderr_rh is not None:
+                self.stderr = PipeHandle(stderr_rh)
+        finally:
+            if stdin == PIPE:
+                os.close(stdin_rfd)
+            if stdout == PIPE:
+                os.close(stdout_wfd)
+            if stderr == PIPE:
+                os.close(stderr_wfd)