godot/core/os/rw_lock.h
Rémi Verschelde 1426cd3b3a
One Copyright Update to rule them all
As many open source projects have started doing it, we're removing the
current year from the copyright notice, so that we don't need to bump
it every year.

It seems like only the first year of publication is technically
relevant for copyright notices, and even that seems to be something
that many companies stopped listing altogether (in a version controlled
codebase, the commits are a much better source of date of publication
than a hardcoded copyright statement).

We also now list Godot Engine contributors first as we're collectively
the current maintainers of the project, and we clarify that the
"exclusive" copyright of the co-founders covers the timespan before
opensourcing (their further contributions are included as part of Godot
Engine contributors).

Also fixed "cf." Frenchism - it's meant as "refer to / see".

Backported from #70885.
2023-01-10 15:26:54 +01:00

117 lines
3.6 KiB
C++

/**************************************************************************/
/* rw_lock.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 RW_LOCK_H
#define RW_LOCK_H
#include "core/error_list.h"
#if !defined(NO_THREADS)
#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;
}
};
#else
class RWLock {
public:
void read_lock() const {}
void read_unlock() const {}
Error read_try_lock() const { return OK; }
void write_lock() {}
void write_unlock() {}
Error write_try_lock() { return OK; }
};
#endif
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