gecko-dev/mozglue/misc/PlatformMutex.h

75 строки
2.0 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/. */
#ifndef mozilla_PlatformMutex_h
#define mozilla_PlatformMutex_h
#include "mozilla/Atomics.h"
#include "mozilla/Attributes.h"
#include "mozilla/Move.h"
#include "mozilla/RecordReplay.h"
#if !defined(XP_WIN)
# include <pthread.h>
#endif
namespace mozilla {
namespace detail {
class ConditionVariableImpl;
class MutexImpl
{
public:
struct PlatformData;
explicit MFBT_API MutexImpl(recordreplay::Behavior aRecorded = recordreplay::Behavior::Preserve);
MFBT_API ~MutexImpl();
protected:
MFBT_API void lock();
MFBT_API void unlock();
private:
MutexImpl(const MutexImpl&) = delete;
void operator=(const MutexImpl&) = delete;
MutexImpl(MutexImpl&&) = delete;
void operator=(MutexImpl&&) = delete;
bool operator==(const MutexImpl& rhs) = delete;
void mutexLock();
#ifdef XP_DARWIN
bool mutexTryLock();
#endif
PlatformData* platformData();
#if !defined(XP_WIN)
void* platformData_[sizeof(pthread_mutex_t) / sizeof(void*)];
static_assert(sizeof(pthread_mutex_t) / sizeof(void*) != 0 &&
sizeof(pthread_mutex_t) % sizeof(void*) == 0,
"pthread_mutex_t must have pointer alignment");
#ifdef XP_DARWIN
// Moving average of the number of spins it takes to acquire the mutex if we
// have to wait. May be accessed by multiple threads concurrently. Getting the
// latest value is not essential hence relaxed memory ordering is sufficient.
mozilla::Atomic<int32_t, mozilla::MemoryOrdering::Relaxed,
recordreplay::Behavior::DontPreserve> averageSpins;
#endif
#else
void* platformData_[6];
#endif
friend class mozilla::detail::ConditionVariableImpl;
};
} // namespace detail
} // namespace mozilla
#endif // mozilla_PlatformMutex_h