268 lines
9 KiB
Python
268 lines
9 KiB
Python
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# Adapted from https://gist.github.com/akaihola/1415730#file-streamingjson-py
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# Copyright (c) Django Software Foundation and individual contributors.
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# All rights reserved.
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# Redistribution and use in source and binary forms, with or without modification,
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# are permitted provided that the following conditions are met:
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# 1. Redistributions of source code must retain the above copyright notice,
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# this list of conditions and the following disclaimer.
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# 2. Redistributions in binary form must reproduce the above copyright
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# notice, this list of conditions and the following disclaimer in the
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# documentation and/or other materials provided with the distribution.
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# 3. Neither the name of Django nor the names of its contributors may be used
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# to endorse or promote products derived from this software without
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# specific prior written permission.
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
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# ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
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# ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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import collections
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import json
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from json.encoder import encode_basestring, encode_basestring_ascii, FLOAT_REPR, INFINITY
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from types import GeneratorType
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class StreamingJSONEncoder(json.JSONEncoder):
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def iterencode(self, o, _one_shot=False):
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"""Encode the given object and yield each string
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representation as available.
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For example::
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for chunk in StreamingJSONEncoder().iterencode(bigobject):
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mysocket.write(chunk)
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This method is a verbatim copy of
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:meth:`json.JSONEncoder.iterencode`. It is
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needed because we need to call our patched
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:func:`streamingjsonencoder._make_iterencode`.
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"""
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if self.check_circular:
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markers = {}
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else:
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markers = None
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if self.ensure_ascii:
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_encoder = encode_basestring_ascii
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else:
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_encoder = encode_basestring
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if self.encoding != 'utf-8':
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def _encoder(o, _orig_encoder=_encoder, _encoding=self.encoding):
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if isinstance(o, str):
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o = o.decode(_encoding)
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return _orig_encoder(o)
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def floatstr(o, allow_nan=self.allow_nan, _repr=FLOAT_REPR, _inf=INFINITY, _neginf=-INFINITY):
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# Check for specials. Note that this type of test is processor- and/or
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# platform-specific, so do tests which don't depend on the internals.
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if o != o:
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text = 'NaN'
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elif o == _inf:
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text = 'Infinity'
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elif o == _neginf:
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text = '-Infinity'
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else:
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return _repr(o)
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if not allow_nan:
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raise ValueError("Out of range float values are not JSON compliant: %r"
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% (o,))
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return text
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_iterencode = _make_iterencode(
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markers, self.default, _encoder, self.indent, floatstr,
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self.key_separator, self.item_separator, self.sort_keys,
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self.skipkeys, _one_shot)
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return _iterencode(o, 0)
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def _make_iterencode(markers, _default, _encoder, _indent, _floatstr, _key_separator,
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_item_separator, _sort_keys, _skipkeys, _one_shot, False=False, True=True,
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ValueError=ValueError, basestring=basestring, dict=dict, float=float,
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GeneratorType=GeneratorType, id=id, int=int, isinstance=isinstance, list=list,
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long=long, str=str, tuple=tuple):
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"""
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This is a patched version of
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:func:`django.utils.simplejson.encoder.iterencode`. Whenever it encounters
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a generator in the data structure, it encodes it as a JSON list.
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"""
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def _iterencode_list(lst, _current_indent_level):
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if not lst:
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# note: empty generators aren't caught here, see below
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yield '[]'
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return
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if markers is not None:
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markerid = id(lst)
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if markerid in markers:
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raise ValueError("Circular reference detected")
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markers[markerid] = lst
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buf = '['
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if _indent is not None:
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_current_indent_level += 1
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newline_indent = '\n' + (' ' * (_indent * _current_indent_level))
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separator = _item_separator + newline_indent
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buf += newline_indent
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else:
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newline_indent = None
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separator = _item_separator
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first = True
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for value in lst:
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if first:
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first = False
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else:
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buf = separator
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if isinstance(value, basestring):
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yield buf + _encoder(value)
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elif value is None:
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yield buf + 'null'
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elif value is True:
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yield buf + 'true'
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elif value is False:
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yield buf + 'false'
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elif isinstance(value, (int, long)):
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yield buf + str(value)
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elif isinstance(value, float):
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yield buf + _floatstr(value)
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else:
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yield buf
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if isinstance(value, (list, tuple, GeneratorType)):
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chunks = _iterencode_list(value, _current_indent_level)
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elif isinstance(value, dict):
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chunks = _iterencode_dict(value, _current_indent_level)
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else:
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chunks = _iterencode(value, _current_indent_level)
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for chunk in chunks:
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yield chunk
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if first:
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# we had an empty generator
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yield buf
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if newline_indent is not None:
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_current_indent_level -= 1
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yield '\n' + (' ' * (_indent * _current_indent_level))
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yield ']'
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if markers is not None:
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del markers[markerid]
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def _iterencode_dict(dct, _current_indent_level):
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if not dct:
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yield '{}'
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return
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if markers is not None:
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markerid = id(dct)
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if markerid in markers:
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raise ValueError("Circular reference detected")
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markers[markerid] = dct
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yield '{'
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if _indent is not None:
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_current_indent_level += 1
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newline_indent = '\n' + (' ' * (_indent * _current_indent_level))
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item_separator = _item_separator + newline_indent
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yield newline_indent
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else:
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newline_indent = None
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item_separator = _item_separator
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first = True
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if _sort_keys:
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items = dct.items()
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items.sort(key=lambda kv: kv[0])
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else:
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items = dct.iteritems()
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for key, value in items:
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if isinstance(key, basestring):
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pass
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# JavaScript is weakly typed for these, so it makes sense to
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# also allow them. Many encoders seem to do something like this.
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elif isinstance(key, float):
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key = _floatstr(key)
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elif isinstance(key, (int, long)):
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key = str(key)
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elif key is True:
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key = 'true'
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elif key is False:
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key = 'false'
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elif key is None:
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key = 'null'
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elif _skipkeys:
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continue
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else:
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raise TypeError("key %r is not a string" % (key,))
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if first:
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first = False
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else:
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yield item_separator
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yield _encoder(key)
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yield _key_separator
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if isinstance(value, basestring):
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yield _encoder(value)
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elif value is None:
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yield 'null'
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elif value is True:
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yield 'true'
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elif value is False:
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yield 'false'
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elif isinstance(value, (int, long)):
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yield str(value)
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elif isinstance(value, float):
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yield _floatstr(value)
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else:
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if isinstance(value, collections.Mapping):
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chunks = _iterencode_dict(value, _current_indent_level)
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elif isinstance(value, collections.Iterable):
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chunks = _iterencode_list(value, _current_indent_level)
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else:
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chunks = _iterencode(value, _current_indent_level)
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for chunk in chunks:
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yield chunk
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if newline_indent is not None:
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_current_indent_level -= 1
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yield '\n' + (' ' * (_indent * _current_indent_level))
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yield '}'
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if markers is not None:
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del markers[markerid]
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def _iterencode(o, _current_indent_level):
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if isinstance(o, basestring):
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yield _encoder(o)
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elif o is None:
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yield 'null'
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elif o is True:
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yield 'true'
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elif o is False:
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yield 'false'
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elif isinstance(o, (int, long)):
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yield str(o)
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elif isinstance(o, float):
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yield _floatstr(o)
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elif isinstance(o, collections.Mapping):
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for chunk in _iterencode_dict(o, _current_indent_level):
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yield chunk
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elif isinstance(o, collections.Iterable):
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for chunk in _iterencode_list(o, _current_indent_level):
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yield chunk
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else:
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if markers is not None:
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markerid = id(o)
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if markerid in markers:
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raise ValueError("Circular reference detected")
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markers[markerid] = o
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o = _default(o)
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for chunk in _iterencode(o, _current_indent_level):
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yield chunk
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if markers is not None:
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del markers[markerid]
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return _iterencode
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