| /* |
| * 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 SharedExclusiveLock { |
| public: |
| SharedExclusiveLock(); |
| |
| // Locking/unlocking methods. It is encouraged to use SharedScope or |
| // ExclusiveScope for protection. |
| void LockExclusive(); |
| void UnlockExclusive(); |
| void LockShared(); |
| void UnlockShared(); |
| |
| private: |
| rtc::CriticalSection cs_exclusive_; |
| rtc::CriticalSection cs_shared_; |
| rtc::Event shared_count_is_zero_; |
| int shared_count_; |
| |
| DISALLOW_COPY_AND_ASSIGN(SharedExclusiveLock); |
| }; |
| |
| class SharedScope { |
| public: |
| explicit SharedScope(SharedExclusiveLock* lock) : lock_(lock) { |
| lock_->LockShared(); |
| } |
| |
| ~SharedScope() { |
| lock_->UnlockShared(); |
| } |
| |
| private: |
| SharedExclusiveLock* lock_; |
| |
| DISALLOW_COPY_AND_ASSIGN(SharedScope); |
| }; |
| |
| class ExclusiveScope { |
| public: |
| explicit ExclusiveScope(SharedExclusiveLock* lock) : lock_(lock) { |
| lock_->LockExclusive(); |
| } |
| |
| ~ExclusiveScope() { |
| lock_->UnlockExclusive(); |
| } |
| |
| private: |
| SharedExclusiveLock* lock_; |
| |
| DISALLOW_COPY_AND_ASSIGN(ExclusiveScope); |
| }; |
| |
| } // namespace rtc |
| |
| #endif // WEBRTC_BASE_SHAREDEXCLUSIVELOCK_H_ |