| /* |
| * Copyright (c) 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. |
| */ |
| |
| #include "rw_lock_generic.h" |
| |
| #include "condition_variable_wrapper.h" |
| #include "critical_section_wrapper.h" |
| |
| namespace webrtc { |
| RWLockWrapperGeneric::RWLockWrapperGeneric() |
| : _readersActive(0), |
| _writerActive(false), |
| _readersWaiting(0), |
| _writersWaiting(0) |
| { |
| _critSectPtr = CriticalSectionWrapper::CreateCriticalSection(); |
| _readCondPtr = ConditionVariableWrapper::CreateConditionVariable(); |
| _writeCondPtr = ConditionVariableWrapper::CreateConditionVariable(); |
| } |
| |
| RWLockWrapperGeneric::~RWLockWrapperGeneric() |
| { |
| delete _writeCondPtr; |
| delete _readCondPtr; |
| delete _critSectPtr; |
| } |
| |
| int RWLockWrapperGeneric::Init() |
| { |
| return 0; |
| } |
| |
| void RWLockWrapperGeneric::AcquireLockExclusive() |
| { |
| _critSectPtr->Enter(); |
| |
| if (_writerActive || _readersActive > 0) |
| { |
| ++_writersWaiting; |
| |
| while (_writerActive || _readersActive > 0) |
| { |
| _writeCondPtr->SleepCS(*_critSectPtr); |
| } |
| |
| --_writersWaiting; |
| } |
| _writerActive = true; |
| _critSectPtr->Leave(); |
| } |
| |
| void RWLockWrapperGeneric::ReleaseLockExclusive() |
| { |
| _critSectPtr->Enter(); |
| |
| _writerActive = false; |
| |
| if (_writersWaiting > 0) |
| { |
| _writeCondPtr->Wake(); |
| |
| }else if (_readersWaiting > 0) |
| { |
| _readCondPtr->WakeAll(); |
| } |
| _critSectPtr->Leave(); |
| } |
| |
| void RWLockWrapperGeneric::AcquireLockShared() |
| { |
| _critSectPtr->Enter(); |
| |
| if (_writerActive || _writersWaiting > 0) |
| { |
| ++_readersWaiting; |
| |
| while (_writerActive || _writersWaiting > 0) |
| { |
| _readCondPtr->SleepCS(*_critSectPtr); |
| } |
| --_readersWaiting; |
| } |
| ++_readersActive; |
| _critSectPtr->Leave(); |
| } |
| |
| void RWLockWrapperGeneric::ReleaseLockShared() |
| { |
| _critSectPtr->Enter(); |
| |
| --_readersActive; |
| |
| if (_readersActive == 0 && _writersWaiting > 0) |
| { |
| _writeCondPtr->Wake(); |
| } |
| _critSectPtr->Leave(); |
| } |
| } // namespace webrtc |