godot/core/os/rw_lock.h
Rémi Verschelde 54418ea659 Remove NO_THREADS fallback code, Godot 4 requires thread support
This also removes `OS::can_use_threads` from the public API since it's always
true.
2022-10-03 11:23:26 +02:00

100 lines
3.4 KiB
C++

/*************************************************************************/
/* rw_lock.h */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur. */
/* Copyright (c) 2014-2022 Godot Engine contributors (cf. AUTHORS.md). */
/* */
/* 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 RW_LOCK_H
#define RW_LOCK_H
#include "core/error/error_list.h"
#include <shared_mutex>
class RWLock {
mutable std::shared_timed_mutex mutex;
public:
// Lock the rwlock, block if locked by someone else
void read_lock() const {
mutex.lock_shared();
}
// Unlock the rwlock, let other threads continue
void read_unlock() const {
mutex.unlock_shared();
}
// Attempt to lock the rwlock, OK on success, ERR_BUSY means it can't lock.
Error read_try_lock() const {
return mutex.try_lock_shared() ? OK : ERR_BUSY;
}
// Lock the rwlock, block if locked by someone else
void write_lock() {
mutex.lock();
}
// Unlock the rwlock, let other thwrites continue
void write_unlock() {
mutex.unlock();
}
// Attempt to lock the rwlock, OK on success, ERR_BUSY means it can't lock.
Error write_try_lock() {
return mutex.try_lock() ? OK : ERR_BUSY;
}
};
class RWLockRead {
const RWLock &lock;
public:
RWLockRead(const RWLock &p_lock) :
lock(p_lock) {
lock.read_lock();
}
~RWLockRead() {
lock.read_unlock();
}
};
class RWLockWrite {
RWLock &lock;
public:
RWLockWrite(RWLock &p_lock) :
lock(p_lock) {
lock.write_lock();
}
~RWLockWrite() {
lock.write_unlock();
}
};
#endif // RW_LOCK_H