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f4d76853b9
This fixes a rare but possible deadlock, maybe due to undefined behavior. The new implementation is safer, at the cost of some added boilerplate.
90 lines
3.9 KiB
C++
90 lines
3.9 KiB
C++
/**************************************************************************/
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/* condition_variable.h */
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/**************************************************************************/
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/* This file is part of: */
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/* GODOT ENGINE */
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/* https://godotengine.org */
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/**************************************************************************/
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/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
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/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur. */
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/* */
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/* Permission is hereby granted, free of charge, to any person obtaining */
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/* a copy of this software and associated documentation files (the */
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/* "Software"), to deal in the Software without restriction, including */
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/* without limitation the rights to use, copy, modify, merge, publish, */
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/* distribute, sublicense, and/or sell copies of the Software, and to */
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/* permit persons to whom the Software is furnished to do so, subject to */
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/* the following conditions: */
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/* */
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/* The above copyright notice and this permission notice shall be */
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/* included in all copies or substantial portions of the Software. */
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/* */
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/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
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/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
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/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. */
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/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
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/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
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/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
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/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
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/**************************************************************************/
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#ifndef CONDITION_VARIABLE_H
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#define CONDITION_VARIABLE_H
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#include "core/os/mutex.h"
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#include "core/os/safe_binary_mutex.h"
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#ifdef THREADS_ENABLED
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#ifdef MINGW_ENABLED
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#define MINGW_STDTHREAD_REDUNDANCY_WARNING
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#include "thirdparty/mingw-std-threads/mingw.condition_variable.h"
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#define THREADING_NAMESPACE mingw_stdthread
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#else
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#include <condition_variable>
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#define THREADING_NAMESPACE std
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#endif
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// An object one or multiple threads can wait on a be notified by some other.
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// Normally, you want to use a semaphore for such scenarios, but when the
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// condition is something different than a count being greater than zero
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// (which is the built-in logic in a semaphore) or you want to provide your
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// own mutex to tie the wait-notify to some other behavior, you need to use this.
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class ConditionVariable {
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mutable THREADING_NAMESPACE::condition_variable condition;
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public:
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template <typename BinaryMutexT>
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_ALWAYS_INLINE_ void wait(const MutexLock<BinaryMutexT> &p_lock) const {
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condition.wait(const_cast<THREADING_NAMESPACE::unique_lock<THREADING_NAMESPACE::mutex> &>(p_lock._get_lock()));
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}
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template <int Tag>
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_ALWAYS_INLINE_ void wait(const MutexLock<SafeBinaryMutex<Tag>> &p_lock) const {
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condition.wait(const_cast<THREADING_NAMESPACE::unique_lock<THREADING_NAMESPACE::mutex> &>(p_lock.mutex._get_lock()));
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}
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_ALWAYS_INLINE_ void notify_one() const {
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condition.notify_one();
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}
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_ALWAYS_INLINE_ void notify_all() const {
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condition.notify_all();
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}
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};
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#else // No threads.
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class ConditionVariable {
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public:
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template <typename BinaryMutexT>
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void wait(const MutexLock<BinaryMutexT> &p_lock) const {}
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void notify_one() const {}
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void notify_all() const {}
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};
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#endif // THREADS_ENABLED
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#endif // CONDITION_VARIABLE_H
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