1 /* 2 * Copyright 2012 Google Inc. 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8 #ifndef SkCondVar_DEFINED 9 #define SkCondVar_DEFINED 10 11 #ifdef SK_USE_POSIX_THREADS 12 #include <pthread.h> 13 #elif defined(SK_BUILD_FOR_WIN32) 14 #include <Windows.h> 15 #endif 16 17 /** 18 * Condition variable for blocking access to shared data from other threads and 19 * controlling which threads are awake. 20 * 21 * Currently only supported on platforms with posix threads and Windows Vista and 22 * above. 23 */ 24 class SkCondVar { 25 public: 26 SkCondVar(); 27 ~SkCondVar(); 28 29 /** 30 * Lock a mutex. Must be done before calling the other functions on this object. 31 */ 32 void lock(); 33 34 /** 35 * Unlock the mutex. 36 */ 37 void unlock(); 38 39 /** 40 * Pause the calling thread. Will be awoken when signal() or broadcast() is called. 41 * Must be called while lock() is held (but gives it up while waiting). Once awoken, 42 * the calling thread will hold the lock once again. 43 */ 44 void wait(); 45 46 /** 47 * Wake one thread waiting on this condition. Must be called while lock() 48 * is held. 49 */ 50 void signal(); 51 52 /** 53 * Wake all threads waiting on this condition. Must be called while lock() 54 * is held. 55 */ 56 void broadcast(); 57 58 private: 59 #ifdef SK_USE_POSIX_THREADS 60 pthread_mutex_t fMutex; 61 pthread_cond_t fCond; 62 #elif defined(SK_BUILD_FOR_WIN32) 63 CRITICAL_SECTION fCriticalSection; 64 CONDITION_VARIABLE fCondition; 65 #endif 66 }; 67 68 #endif 69
