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// Copyright 2018 The Cobalt Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef STARBOARD_COMMON_RECURSIVE_MUTEX_H_
#define STARBOARD_COMMON_RECURSIVE_MUTEX_H_
#include "starboard/common/mutex.h"
#include "starboard/configuration.h"
#include "starboard/thread.h"
namespace starboard {
// A cross platform RecursiveMutex implementation. It is intended to replace
// std::recursive_mutex.
class RecursiveMutex {
public:
RecursiveMutex();
~RecursiveMutex();
// The caller is blocked only if the mutex is being held by another thread.
// If the caller already have the RecursiveMutex, Release() will succeed.
// Otherwise Acquire() will block the caller until mutex is released.
void Acquire();
// The caller releases the mutex only when it calls Release() as many times
// as Release().
void Release();
// Non-blocking function.
// Acquires the RecursiveMutex if the mutex is free and returns true.
// Only returns false if mutex is being held by another thread.
bool AcquireTry();
private:
Mutex mutex_;
SbThreadId owner_id_;
// Only the owner is able to modify recurse_count_.
size_t recurse_count_;
SB_DISALLOW_COPY_AND_ASSIGN(RecursiveMutex);
};
class ScopedRecursiveLock {
public:
explicit ScopedRecursiveLock(RecursiveMutex& mutex);
~ScopedRecursiveLock();
private:
RecursiveMutex& mutex_;
SB_DISALLOW_COPY_AND_ASSIGN(ScopedRecursiveLock);
};
} // namespace starboard
#endif // STARBOARD_COMMON_RECURSIVE_MUTEX_H_