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Merge pull request #87893 from vittorioromeo/extract_safe_binary_mutex
Extract `SafeBinaryMutex` to separate header
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,124 @@ | ||
| /**************************************************************************/ | ||
| /* safe_binary_mutex.h */ | ||
| /**************************************************************************/ | ||
| /* This file is part of: */ | ||
| /* GODOT ENGINE */ | ||
| /* https://godotengine.org */ | ||
| /**************************************************************************/ | ||
| /* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */ | ||
| /* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur. */ | ||
| /* */ | ||
| /* Permission is hereby granted, free of charge, to any person obtaining */ | ||
| /* a copy of this software and associated documentation files (the */ | ||
| /* "Software"), to deal in the Software without restriction, including */ | ||
| /* without limitation the rights to use, copy, modify, merge, publish, */ | ||
| /* distribute, sublicense, and/or sell copies of the Software, and to */ | ||
| /* permit persons to whom the Software is furnished to do so, subject to */ | ||
| /* the following conditions: */ | ||
| /* */ | ||
| /* The above copyright notice and this permission notice shall be */ | ||
| /* included in all copies or substantial portions of the Software. */ | ||
| /* */ | ||
| /* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */ | ||
| /* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */ | ||
| /* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. */ | ||
| /* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */ | ||
| /* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */ | ||
| /* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */ | ||
| /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ | ||
| /**************************************************************************/ | ||
|
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| #ifndef SAFE_BINARY_MUTEX_H | ||
| #define SAFE_BINARY_MUTEX_H | ||
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| #include "core/error/error_macros.h" | ||
| #include "core/os/mutex.h" | ||
| #include "core/typedefs.h" | ||
|
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| #ifdef THREADS_ENABLED | ||
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| // A very special kind of mutex, used in scenarios where these | ||
| // requirements hold at the same time: | ||
| // - Must be used with a condition variable (only binary mutexes are suitable). | ||
| // - Must have recursive semnantics (or simulate, as this one does). | ||
| // The implementation keeps the lock count in TS. Therefore, only | ||
| // one object of each version of the template can exists; hence the Tag argument. | ||
| // Tags must be unique across the Godot codebase. | ||
| // Also, don't forget to declare the thread_local variable on each use. | ||
| template <int Tag> | ||
| class SafeBinaryMutex { | ||
| friend class MutexLock<SafeBinaryMutex>; | ||
|
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| using StdMutexType = THREADING_NAMESPACE::mutex; | ||
|
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| mutable THREADING_NAMESPACE::mutex mutex; | ||
| static thread_local uint32_t count; | ||
|
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| public: | ||
| _ALWAYS_INLINE_ void lock() const { | ||
| if (++count == 1) { | ||
| mutex.lock(); | ||
| } | ||
| } | ||
|
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| _ALWAYS_INLINE_ void unlock() const { | ||
| DEV_ASSERT(count); | ||
| if (--count == 0) { | ||
| mutex.unlock(); | ||
| } | ||
| } | ||
|
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| _ALWAYS_INLINE_ bool try_lock() const { | ||
| if (count) { | ||
| count++; | ||
| return true; | ||
| } else { | ||
| if (mutex.try_lock()) { | ||
| count++; | ||
| return true; | ||
| } else { | ||
| return false; | ||
| } | ||
| } | ||
| } | ||
|
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| ~SafeBinaryMutex() { | ||
| DEV_ASSERT(!count); | ||
| } | ||
| }; | ||
|
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| // This specialization is needed so manual locking and MutexLock can be used | ||
| // at the same time on a SafeBinaryMutex. | ||
| template <int Tag> | ||
| class MutexLock<SafeBinaryMutex<Tag>> { | ||
| friend class ConditionVariable; | ||
|
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| THREADING_NAMESPACE::unique_lock<THREADING_NAMESPACE::mutex> lock; | ||
|
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| public: | ||
| _ALWAYS_INLINE_ explicit MutexLock(const SafeBinaryMutex<Tag> &p_mutex) : | ||
| lock(p_mutex.mutex) { | ||
| SafeBinaryMutex<Tag>::count++; | ||
| }; | ||
| _ALWAYS_INLINE_ ~MutexLock() { | ||
| SafeBinaryMutex<Tag>::count--; | ||
| }; | ||
| }; | ||
|
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| #else // No threads. | ||
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| template <int Tag> | ||
| class SafeBinaryMutex : public MutexImpl { | ||
| static thread_local uint32_t count; | ||
| }; | ||
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| template <int Tag> | ||
| class MutexLock<SafeBinaryMutex<Tag>> { | ||
| public: | ||
| MutexLock(const SafeBinaryMutex<Tag> &p_mutex) {} | ||
| ~MutexLock() {} | ||
| }; | ||
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| #endif // THREADS_ENABLED | ||
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| #endif // SAFE_BINARY_MUTEX_H |