michael@0: /*
michael@0:  * Copyright 2012 Google Inc.
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: #ifndef SkCondVar_DEFINED
michael@0: #define SkCondVar_DEFINED
michael@0: 
michael@0: #ifdef SK_USE_POSIX_THREADS
michael@0: #include <pthread.h>
michael@0: #elif defined(SK_BUILD_FOR_WIN32)
michael@0: #include <windows.h>
michael@0: #endif
michael@0: 
michael@0: /**
michael@0:  * Condition variable for blocking access to shared data from other threads and
michael@0:  * controlling which threads are awake.
michael@0:  *
michael@0:  * Currently only supported on platforms with posix threads and Windows Vista and
michael@0:  * above.
michael@0:  */
michael@0: class SkCondVar {
michael@0: public:
michael@0:     SkCondVar();
michael@0:     ~SkCondVar();
michael@0: 
michael@0:     /**
michael@0:      * Lock a mutex. Must be done before calling the other functions on this object.
michael@0:      */
michael@0:     void lock();
michael@0: 
michael@0:     /**
michael@0:      * Unlock the mutex.
michael@0:      */
michael@0:     void unlock();
michael@0: 
michael@0:     /**
michael@0:      * Pause the calling thread. Will be awoken when signal() or broadcast() is called.
michael@0:      * Must be called while lock() is held (but gives it up while waiting). Once awoken,
michael@0:      * the calling thread will hold the lock once again.
michael@0:      */
michael@0:     void wait();
michael@0: 
michael@0:     /**
michael@0:      * Wake one thread waiting on this condition. Must be called while lock()
michael@0:      * is held.
michael@0:      */
michael@0:     void signal();
michael@0: 
michael@0:     /**
michael@0:      * Wake all threads waiting on this condition. Must be called while lock()
michael@0:      * is held.
michael@0:      */
michael@0:     void broadcast();
michael@0: 
michael@0: private:
michael@0: #ifdef SK_USE_POSIX_THREADS
michael@0:     pthread_mutex_t  fMutex;
michael@0:     pthread_cond_t   fCond;
michael@0: #elif defined(SK_BUILD_FOR_WIN32)
michael@0:     CRITICAL_SECTION   fCriticalSection;
michael@0:     CONDITION_VARIABLE fCondition;
michael@0: #endif
michael@0: };
michael@0: 
michael@0: #endif