henrike@webrtc.org | 0e118e7 | 2013-07-10 00:45:36 +0000 | [diff] [blame] | 1 | /* |
| 2 | * libjingle |
| 3 | * Copyright 2011, Google Inc. |
| 4 | * |
| 5 | * Redistribution and use in source and binary forms, with or without |
| 6 | * modification, are permitted provided that the following conditions are met: |
| 7 | * |
| 8 | * 1. Redistributions of source code must retain the above copyright notice, |
| 9 | * this list of conditions and the following disclaimer. |
| 10 | * 2. Redistributions in binary form must reproduce the above copyright notice, |
| 11 | * this list of conditions and the following disclaimer in the documentation |
| 12 | * and/or other materials provided with the distribution. |
| 13 | * 3. The name of the author may not be used to endorse or promote products |
| 14 | * derived from this software without specific prior written permission. |
| 15 | * |
| 16 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED |
| 17 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF |
| 18 | * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO |
| 19 | * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| 20 | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| 21 | * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; |
| 22 | * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, |
| 23 | * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR |
| 24 | * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF |
| 25 | * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 26 | */ |
| 27 | |
| 28 | #ifndef TALK_BASE_SHAREDEXCLUSIVELOCK_H_ |
| 29 | #define TALK_BASE_SHAREDEXCLUSIVELOCK_H_ |
| 30 | |
| 31 | #include "talk/base/constructormagic.h" |
| 32 | #include "talk/base/criticalsection.h" |
| 33 | #include "talk/base/event.h" |
| 34 | |
| 35 | namespace talk_base { |
| 36 | |
| 37 | // This class provides shared-exclusive lock. It can be used in cases like |
| 38 | // multiple-readers/single-writer model. |
wjia@webrtc.org | ee78a38 | 2014-02-10 23:20:15 +0000 | [diff] [blame] | 39 | class SharedExclusiveLock { |
henrike@webrtc.org | 0e118e7 | 2013-07-10 00:45:36 +0000 | [diff] [blame] | 40 | public: |
| 41 | SharedExclusiveLock(); |
| 42 | |
| 43 | // Locking/unlocking methods. It is encouraged to use SharedScope or |
| 44 | // ExclusiveScope for protection. |
wjia@webrtc.org | ee78a38 | 2014-02-10 23:20:15 +0000 | [diff] [blame] | 45 | void LockExclusive(); |
| 46 | void UnlockExclusive(); |
henrike@webrtc.org | 0e118e7 | 2013-07-10 00:45:36 +0000 | [diff] [blame] | 47 | void LockShared(); |
| 48 | void UnlockShared(); |
| 49 | |
| 50 | private: |
| 51 | talk_base::CriticalSection cs_exclusive_; |
| 52 | talk_base::CriticalSection cs_shared_; |
| 53 | talk_base::Event shared_count_is_zero_; |
| 54 | int shared_count_; |
| 55 | |
| 56 | DISALLOW_COPY_AND_ASSIGN(SharedExclusiveLock); |
| 57 | }; |
| 58 | |
wjia@webrtc.org | ee78a38 | 2014-02-10 23:20:15 +0000 | [diff] [blame] | 59 | class SharedScope { |
henrike@webrtc.org | 0e118e7 | 2013-07-10 00:45:36 +0000 | [diff] [blame] | 60 | public: |
wjia@webrtc.org | ee78a38 | 2014-02-10 23:20:15 +0000 | [diff] [blame] | 61 | explicit SharedScope(SharedExclusiveLock* lock) : lock_(lock) { |
henrike@webrtc.org | 0e118e7 | 2013-07-10 00:45:36 +0000 | [diff] [blame] | 62 | lock_->LockShared(); |
| 63 | } |
| 64 | |
wjia@webrtc.org | ee78a38 | 2014-02-10 23:20:15 +0000 | [diff] [blame] | 65 | ~SharedScope() { |
henrike@webrtc.org | 0e118e7 | 2013-07-10 00:45:36 +0000 | [diff] [blame] | 66 | lock_->UnlockShared(); |
| 67 | } |
| 68 | |
| 69 | private: |
| 70 | SharedExclusiveLock* lock_; |
| 71 | |
| 72 | DISALLOW_COPY_AND_ASSIGN(SharedScope); |
| 73 | }; |
| 74 | |
wjia@webrtc.org | ee78a38 | 2014-02-10 23:20:15 +0000 | [diff] [blame] | 75 | class ExclusiveScope { |
henrike@webrtc.org | 0e118e7 | 2013-07-10 00:45:36 +0000 | [diff] [blame] | 76 | public: |
wjia@webrtc.org | ee78a38 | 2014-02-10 23:20:15 +0000 | [diff] [blame] | 77 | explicit ExclusiveScope(SharedExclusiveLock* lock) : lock_(lock) { |
henrike@webrtc.org | 0e118e7 | 2013-07-10 00:45:36 +0000 | [diff] [blame] | 78 | lock_->LockExclusive(); |
| 79 | } |
| 80 | |
wjia@webrtc.org | ee78a38 | 2014-02-10 23:20:15 +0000 | [diff] [blame] | 81 | ~ExclusiveScope() { |
henrike@webrtc.org | 0e118e7 | 2013-07-10 00:45:36 +0000 | [diff] [blame] | 82 | lock_->UnlockExclusive(); |
| 83 | } |
| 84 | |
| 85 | private: |
| 86 | SharedExclusiveLock* lock_; |
| 87 | |
| 88 | DISALLOW_COPY_AND_ASSIGN(ExclusiveScope); |
| 89 | }; |
| 90 | |
| 91 | } // namespace talk_base |
| 92 | |
| 93 | #endif // TALK_BASE_SHAREDEXCLUSIVELOCK_H_ |