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/**************************************************************************/
/* semaphore.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. */
/**************************************************************************/
#ifndef SEMAPHORE_H
#define SEMAPHORE_H
#include "core/error/error_list.h"
#include "core/typedefs.h"
#include <condition_variable>
#include <mutex>
class Semaphore {
private:
mutable std::mutex mutex;
mutable std::condition_variable condition;
mutable uint32_t count = 0; // Initialized as locked.
public:
_ALWAYS_INLINE_ void post() const {
std::lock_guard lock(mutex);
count++;
condition.notify_one();
}
_ALWAYS_INLINE_ void wait() const {
std::unique_lock lock(mutex);
while (!count) { // Handle spurious wake-ups.
condition.wait(lock);
}
count--;
}
_ALWAYS_INLINE_ bool try_wait() const {
std::lock_guard lock(mutex);
if (count) {
count--;
return true;
} else {
return false;
}
}
};
#endif // SEMAPHORE_H
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