1 /* 2 * Copyright (c) 2011 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #ifndef RTC_BASE_SYNCHRONIZATION_RW_LOCK_WRAPPER_H_ 12 #define RTC_BASE_SYNCHRONIZATION_RW_LOCK_WRAPPER_H_ 13 14 #include "rtc_base/thread_annotations.h" 15 16 // Note, Windows pre-Vista version of RW locks are not supported natively. For 17 // these OSs regular critical sections have been used to approximate RW lock 18 // functionality and will therefore have worse performance. 19 20 namespace webrtc { 21 22 class RTC_LOCKABLE RWLockWrapper { 23 public: 24 static RWLockWrapper* CreateRWLock(); ~RWLockWrapper()25 virtual ~RWLockWrapper() {} 26 27 virtual void AcquireLockExclusive() RTC_EXCLUSIVE_LOCK_FUNCTION() = 0; 28 virtual void ReleaseLockExclusive() RTC_UNLOCK_FUNCTION() = 0; 29 30 virtual void AcquireLockShared() RTC_SHARED_LOCK_FUNCTION() = 0; 31 virtual void ReleaseLockShared() RTC_UNLOCK_FUNCTION() = 0; 32 }; 33 34 // RAII extensions of the RW lock. Prevents Acquire/Release missmatches and 35 // provides more compact locking syntax. 36 class RTC_SCOPED_LOCKABLE ReadLockScoped { 37 public: ReadLockScoped(RWLockWrapper & rw_lock)38 explicit ReadLockScoped(RWLockWrapper& rw_lock) 39 RTC_SHARED_LOCK_FUNCTION(rw_lock) 40 : rw_lock_(rw_lock) { 41 rw_lock_.AcquireLockShared(); 42 } 43 RTC_UNLOCK_FUNCTION()44 ~ReadLockScoped() RTC_UNLOCK_FUNCTION() { rw_lock_.ReleaseLockShared(); } 45 46 private: 47 RWLockWrapper& rw_lock_; 48 }; 49 50 class RTC_SCOPED_LOCKABLE WriteLockScoped { 51 public: WriteLockScoped(RWLockWrapper & rw_lock)52 explicit WriteLockScoped(RWLockWrapper& rw_lock) 53 RTC_EXCLUSIVE_LOCK_FUNCTION(rw_lock) 54 : rw_lock_(rw_lock) { 55 rw_lock_.AcquireLockExclusive(); 56 } 57 RTC_UNLOCK_FUNCTION()58 ~WriteLockScoped() RTC_UNLOCK_FUNCTION() { rw_lock_.ReleaseLockExclusive(); } 59 60 private: 61 RWLockWrapper& rw_lock_; 62 }; 63 64 } // namespace webrtc 65 66 #endif // RTC_BASE_SYNCHRONIZATION_RW_LOCK_WRAPPER_H_ 67