gecko-dev/mozglue/misc/RWLock_posix.cpp
Gerald Squelart 97bc60386d Bug 1757100 - Move minimal platform-dependent part of RWLock to mozglue/misc/PlatformRWLock.h&cpp - r=glandium,xpcom-reviewers
This is consistent with how xpcom's Mutex has its platform-dependent code in mozglue, and will allow readers-writer locks in mozglue without duplication.

Differential Revision: https://phabricator.services.mozilla.com/D139669
2022-02-27 23:32:55 +00:00

65 lines
2.2 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifdef XP_WIN
# error This file should only be compiled on non-Windows platforms.
#endif
#include "mozilla/PlatformRWLock.h"
#include "mozilla/Assertions.h"
#include <errno.h>
// NOLINTNEXTLINE(cppcoreguidelines-pro-type-member-init)
mozilla::detail::RWLockImpl::RWLockImpl() {
MOZ_RELEASE_ASSERT(pthread_rwlock_init(&mRWLock, nullptr) == 0,
"pthread_rwlock_init failed");
}
mozilla::detail::RWLockImpl::~RWLockImpl() {
MOZ_RELEASE_ASSERT(pthread_rwlock_destroy(&mRWLock) == 0,
"pthread_rwlock_destroy failed");
}
bool mozilla::detail::RWLockImpl::tryReadLock() {
int rv = pthread_rwlock_tryrdlock(&mRWLock);
// We allow EDEADLK here because it has been observed returned on macos when
// the write lock is held by the current thread.
MOZ_RELEASE_ASSERT(rv == 0 || rv == EBUSY || rv == EDEADLK,
"pthread_rwlock_tryrdlock failed");
return rv == 0;
}
void mozilla::detail::RWLockImpl::readLock() {
MOZ_RELEASE_ASSERT(pthread_rwlock_rdlock(&mRWLock) == 0,
"pthread_rwlock_rdlock failed");
}
void mozilla::detail::RWLockImpl::readUnlock() {
MOZ_RELEASE_ASSERT(pthread_rwlock_unlock(&mRWLock) == 0,
"pthread_rwlock_unlock failed");
}
bool mozilla::detail::RWLockImpl::tryWriteLock() {
int rv = pthread_rwlock_trywrlock(&mRWLock);
// We allow EDEADLK here because it has been observed returned on macos when
// the write lock is held by the current thread.
MOZ_RELEASE_ASSERT(rv == 0 || rv == EBUSY || rv == EDEADLK,
"pthread_rwlock_trywrlock failed");
return rv == 0;
}
void mozilla::detail::RWLockImpl::writeLock() {
MOZ_RELEASE_ASSERT(pthread_rwlock_wrlock(&mRWLock) == 0,
"pthread_rwlock_wrlock failed");
}
void mozilla::detail::RWLockImpl::writeUnlock() {
MOZ_RELEASE_ASSERT(pthread_rwlock_unlock(&mRWLock) == 0,
"pthread_rwlock_unlock failed");
}