1 /* 2 * Copyright 2011 Google Inc. All Rights Reserved. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef SFNTLY_CPP_SRC_SFNTLY_PORT_LOCK_H_ 18 #define SFNTLY_CPP_SRC_SFNTLY_PORT_LOCK_H_ 19 20 #if defined (WIN32) 21 #include <windows.h> 22 #else // Assume pthread. 23 #include <pthread.h> 24 #include <errno.h> 25 #endif 26 27 #include "sfntly/port/type.h" 28 29 namespace sfntly { 30 31 #if defined (WIN32) 32 typedef CRITICAL_SECTION OSLockType; 33 #else // Assume pthread. 34 typedef pthread_mutex_t OSLockType; 35 #endif 36 37 class Lock { 38 public: 39 Lock(); 40 ~Lock(); 41 42 // If the lock is not held, take it and return true. If the lock is already 43 // held by something else, immediately return false. 44 bool Try(); 45 46 // Take the lock, blocking until it is available if necessary. 47 void Acquire(); 48 49 // Release the lock. This must only be called by the lock's holder: after 50 // a successful call to Try, or a call to Lock. 51 void Unlock(); 52 53 private: 54 OSLockType os_lock_; 55 NO_COPY_AND_ASSIGN(Lock); 56 }; 57 58 // A helper class that acquires the given Lock while the AutoLock is in scope. 59 class AutoLock { 60 public: 61 explicit AutoLock(Lock& lock) : lock_(lock) { 62 lock_.Acquire(); 63 } 64 65 ~AutoLock() { 66 lock_.Unlock(); 67 } 68 69 private: 70 Lock& lock_; 71 NO_COPY_AND_ASSIGN(AutoLock); 72 }; 73 74 } // namespace sfntly 75 76 #endif // SFNTLY_CPP_SRC_SFNTLY_PORT_LOCK_H_ 77
