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 */
24class SkCondVar {
25public:
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
58private:
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