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/*
* Copyright 2011 The WebRTC Project Authors. All rights reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef WEBRTC_BASE_SHAREDEXCLUSIVELOCK_H_
#define WEBRTC_BASE_SHAREDEXCLUSIVELOCK_H_
#include "webrtc/base/constructormagic.h"
#include "webrtc/base/criticalsection.h"
#include "webrtc/base/event.h"
namespace rtc {
// This class provides shared-exclusive lock. It can be used in cases like
// multiple-readers/single-writer model.
class LOCKABLE SharedExclusiveLock {
public:
SharedExclusiveLock();
// Locking/unlocking methods. It is encouraged to use SharedScope or
// ExclusiveScope for protection.
void LockExclusive() EXCLUSIVE_LOCK_FUNCTION();
void UnlockExclusive() UNLOCK_FUNCTION();
void LockShared();
void UnlockShared();
private:
rtc::CriticalSection cs_exclusive_;
rtc::CriticalSection cs_shared_;
rtc::Event shared_count_is_zero_;
int shared_count_;
RTC_DISALLOW_COPY_AND_ASSIGN(SharedExclusiveLock);
};
class SCOPED_LOCKABLE SharedScope {
public:
explicit SharedScope(SharedExclusiveLock* lock) SHARED_LOCK_FUNCTION(lock)
: lock_(lock) {
lock_->LockShared();
}
~SharedScope() UNLOCK_FUNCTION() { lock_->UnlockShared(); }
private:
SharedExclusiveLock* lock_;
RTC_DISALLOW_COPY_AND_ASSIGN(SharedScope);
};
class SCOPED_LOCKABLE ExclusiveScope {
public:
explicit ExclusiveScope(SharedExclusiveLock* lock)
EXCLUSIVE_LOCK_FUNCTION(lock)
: lock_(lock) {
lock_->LockExclusive();
}
~ExclusiveScope() UNLOCK_FUNCTION() { lock_->UnlockExclusive(); }
private:
SharedExclusiveLock* lock_;
RTC_DISALLOW_COPY_AND_ASSIGN(ExclusiveScope);
};
} // namespace rtc
#endif // WEBRTC_BASE_SHAREDEXCLUSIVELOCK_H_
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