Implement POSIX threads API

third_party/libcxx/future.cc

@@ -0,0 +1,278 @@
+// clang-format off
+//===------------------------- future.cpp ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "third_party/libcxx/__config"
+
+#ifndef _LIBCPP_HAS_NO_THREADS
+
+#include "third_party/libcxx/future"
+#include "third_party/libcxx/string"
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+class _LIBCPP_HIDDEN __future_error_category
+    : public __do_message
+{
+public:
+    virtual const char* name() const _NOEXCEPT;
+    virtual string message(int ev) const;
+};
+
+const char*
+__future_error_category::name() const _NOEXCEPT
+{
+    return "future";
+}
+
+#if defined(__clang__)
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wswitch"
+#elif defined(__GNUC__) || defined(__GNUG__)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wswitch"
+#endif
+
+string
+__future_error_category::message(int ev) const
+{
+    switch (static_cast<future_errc>(ev))
+    {
+    case future_errc(0):  // For backwards compatibility with C++11 (LWG 2056)
+    case future_errc::broken_promise:
+        return string("The associated promise has been destructed prior "
+                      "to the associated state becoming ready.");
+    case future_errc::future_already_retrieved:
+        return string("The future has already been retrieved from "
+                      "the promise or packaged_task.");
+    case future_errc::promise_already_satisfied:
+        return string("The state of the promise has already been set.");
+    case future_errc::no_state:
+        return string("Operation not permitted on an object without "
+                      "an associated state.");
+    }
+    return string("unspecified future_errc value\n");
+}
+
+#if defined(__clang__)
+#pragma clang diagnostic pop
+#elif defined(__GNUC__) || defined(__GNUG__)
+#pragma GCC diagnostic pop
+#endif
+
+const error_category&
+future_category() _NOEXCEPT
+{
+    static __future_error_category __f;
+    return __f;
+}
+
+future_error::future_error(error_code __ec)
+    : logic_error(__ec.message()),
+      __ec_(__ec)
+{
+}
+
+future_error::~future_error() _NOEXCEPT
+{
+}
+
+void
+__assoc_sub_state::__on_zero_shared() _NOEXCEPT
+{
+    delete this;
+}
+
+void
+__assoc_sub_state::set_value()
+{
+    unique_lock<mutex> __lk(__mut_);
+    if (__has_value())
+        __throw_future_error(future_errc::promise_already_satisfied);
+    __state_ |= __constructed | ready;
+    __cv_.notify_all();
+}
+
+void
+__assoc_sub_state::set_value_at_thread_exit()
+{
+    unique_lock<mutex> __lk(__mut_);
+    if (__has_value())
+        __throw_future_error(future_errc::promise_already_satisfied);
+    __state_ |= __constructed;
+    __thread_local_data()->__make_ready_at_thread_exit(this);
+}
+
+void
+__assoc_sub_state::set_exception(exception_ptr __p)
+{
+    unique_lock<mutex> __lk(__mut_);
+    if (__has_value())
+        __throw_future_error(future_errc::promise_already_satisfied);
+    __exception_ = __p;
+    __state_ |= ready;
+    __cv_.notify_all();
+}
+
+void
+__assoc_sub_state::set_exception_at_thread_exit(exception_ptr __p)
+{
+    unique_lock<mutex> __lk(__mut_);
+    if (__has_value())
+        __throw_future_error(future_errc::promise_already_satisfied);
+    __exception_ = __p;
+    __thread_local_data()->__make_ready_at_thread_exit(this);
+}
+
+void
+__assoc_sub_state::__make_ready()
+{
+    unique_lock<mutex> __lk(__mut_);
+    __state_ |= ready;
+    __cv_.notify_all();
+}
+
+void
+__assoc_sub_state::copy()
+{
+    unique_lock<mutex> __lk(__mut_);
+    __sub_wait(__lk);
+    if (__exception_ != nullptr)
+        rethrow_exception(__exception_);
+}
+
+void
+__assoc_sub_state::wait()
+{
+    unique_lock<mutex> __lk(__mut_);
+    __sub_wait(__lk);
+}
+
+void
+__assoc_sub_state::__sub_wait(unique_lock<mutex>& __lk)
+{
+    if (!__is_ready())
+    {
+        if (__state_ & static_cast<unsigned>(deferred))
+        {
+            __state_ &= ~static_cast<unsigned>(deferred);
+            __lk.unlock();
+            __execute();
+        }
+        else
+            while (!__is_ready())
+                __cv_.wait(__lk);
+    }
+}
+
+void
+__assoc_sub_state::__execute()
+{
+    __throw_future_error(future_errc::no_state);
+}
+
+future<void>::future(__assoc_sub_state* __state)
+    : __state_(__state)
+{
+    __state_->__attach_future();
+}
+
+future<void>::~future()
+{
+    if (__state_)
+        __state_->__release_shared();
+}
+
+void
+future<void>::get()
+{
+    unique_ptr<__shared_count, __release_shared_count> __(__state_);
+    __assoc_sub_state* __s = __state_;
+    __state_ = nullptr;
+    __s->copy();
+}
+
+promise<void>::promise()
+    : __state_(new __assoc_sub_state)
+{
+}
+
+promise<void>::~promise()
+{
+    if (__state_)
+    {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        if (!__state_->__has_value() && __state_->use_count() > 1)
+            __state_->set_exception(make_exception_ptr(
+                      future_error(make_error_code(future_errc::broken_promise))
+                                                      ));
+#endif // _LIBCPP_NO_EXCEPTIONS
+        __state_->__release_shared();
+    }
+}
+
+future<void>
+promise<void>::get_future()
+{
+    if (__state_ == nullptr)
+        __throw_future_error(future_errc::no_state);
+    return future<void>(__state_);
+}
+
+void
+promise<void>::set_value()
+{
+    if (__state_ == nullptr)
+        __throw_future_error(future_errc::no_state);
+    __state_->set_value();
+}
+
+void
+promise<void>::set_exception(exception_ptr __p)
+{
+    if (__state_ == nullptr)
+        __throw_future_error(future_errc::no_state);
+    __state_->set_exception(__p);
+}
+
+void
+promise<void>::set_value_at_thread_exit()
+{
+    if (__state_ == nullptr)
+        __throw_future_error(future_errc::no_state);
+    __state_->set_value_at_thread_exit();
+}
+
+void
+promise<void>::set_exception_at_thread_exit(exception_ptr __p)
+{
+    if (__state_ == nullptr)
+        __throw_future_error(future_errc::no_state);
+    __state_->set_exception_at_thread_exit(__p);
+}
+
+shared_future<void>::~shared_future()
+{
+    if (__state_)
+        __state_->__release_shared();
+}
+
+shared_future<void>&
+shared_future<void>::operator=(const shared_future& __rhs)
+{
+    if (__rhs.__state_)
+        __rhs.__state_->__add_shared();
+    if (__state_)
+        __state_->__release_shared();
+    __state_ = __rhs.__state_;
+    return *this;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // !_LIBCPP_HAS_NO_THREADS