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 #include "talk/base/sharedexclusivelock.h" 29 30 namespace talk_base { 31 32 SharedExclusiveLock::SharedExclusiveLock() 33 : shared_count_is_zero_(true, true), 34 shared_count_(0) { 35 } 36 37 void SharedExclusiveLock::LockExclusive() { 38 cs_exclusive_.Enter(); 39 shared_count_is_zero_.Wait(talk_base::kForever); 40 } 41 42 void SharedExclusiveLock::UnlockExclusive() { 43 cs_exclusive_.Leave(); 44 } 45 46 void SharedExclusiveLock::LockShared() { 47 CritScope exclusive_scope(&cs_exclusive_); 48 CritScope shared_scope(&cs_shared_); 49 if (++shared_count_ == 1) { 50 shared_count_is_zero_.Reset(); 51 } 52 } 53 54 void SharedExclusiveLock::UnlockShared() { 55 CritScope shared_scope(&cs_shared_); 56 if (--shared_count_ == 0) { 57 shared_count_is_zero_.Set(); 58 } 59 } 60 61 } // namespace talk_base 62
