4ddcdc031b
- Based on C++11's `mutex` - No more need to allocate-deallocate or check for null - No pointer anymore, just a member variable - Platform-specific implementations no longer needed - Simpler for `NO_THREADS` - `BinaryMutex` added for special cases as the non-recursive version - `MutexLock` now takes a reference. At this point the cases of null `Mutex`es are rare. If you ever need that, just don't use `MutexLock`. - `ScopedMutexLock` is dropped and replaced by `MutexLock`, because they were pretty much the same.
120 lines
4 KiB
C++
120 lines
4 KiB
C++
/*************************************************************************/
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/* mutex.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) 2007-2021 Juan Linietsky, Ariel Manzur. */
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/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md). */
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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 MUTEX_H
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#define MUTEX_H
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#include "core/error_list.h"
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#include "core/typedefs.h"
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#if !defined(NO_THREADS)
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#include <mutex>
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template <class StdMutexT>
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class MutexImpl {
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mutable StdMutexT mutex;
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friend class MutexLock;
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public:
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_ALWAYS_INLINE_ void lock() const {
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mutex.lock();
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}
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_ALWAYS_INLINE_ void unlock() const {
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mutex.unlock();
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}
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_ALWAYS_INLINE_ Error try_lock() const {
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return mutex.try_lock() ? OK : ERR_BUSY;
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}
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};
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// This is written this way instead of being a template to overcome a limitation of C++ pre-17
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// that would require MutexLock to be used like this: MutexLock<Mutex> lock;
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class MutexLock {
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union {
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std::recursive_mutex *recursive_mutex;
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std::mutex *mutex;
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};
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bool recursive;
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public:
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_ALWAYS_INLINE_ explicit MutexLock(const MutexImpl<std::recursive_mutex> &p_mutex) :
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recursive_mutex(&p_mutex.mutex),
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recursive(true) {
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recursive_mutex->lock();
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}
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_ALWAYS_INLINE_ explicit MutexLock(const MutexImpl<std::mutex> &p_mutex) :
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mutex(&p_mutex.mutex),
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recursive(false) {
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mutex->lock();
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}
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_ALWAYS_INLINE_ ~MutexLock() {
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if (recursive) {
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recursive_mutex->unlock();
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} else {
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mutex->unlock();
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}
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}
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};
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using Mutex = MutexImpl<std::recursive_mutex>; // Recursive, for general use
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using BinaryMutex = MutexImpl<std::mutex>; // Non-recursive, handle with care
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extern template class MutexImpl<std::recursive_mutex>;
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extern template class MutexImpl<std::mutex>;
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#else
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class FakeMutex {
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FakeMutex() {}
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};
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template <class MutexT>
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class MutexImpl {
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public:
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_ALWAYS_INLINE_ void lock() const {}
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_ALWAYS_INLINE_ void unlock() const {}
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_ALWAYS_INLINE_ Error try_lock() const { return OK; }
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};
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class MutexLock {
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public:
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explicit MutexLock(const MutexImpl<FakeMutex> &p_mutex) {}
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};
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using Mutex = MutexImpl<FakeMutex>;
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using BinaryMutex = MutexImpl<FakeMutex>; // Non-recursive, handle with care
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#endif // !NO_THREADS
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#endif // MUTEX_H
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