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 #include "SkCondVar.h"
9
10 #if defined(SK_BUILD_FOR_WIN32)
11 static void (WINAPI *initialize_condition_variable)(PCONDITION_VARIABLE);
12 static BOOL (WINAPI *sleep_condition_variable)(PCONDITION_VARIABLE, PCRITICAL_SECTION, DWORD);
13 static void (WINAPI *wake_condition_variable)(PCONDITION_VARIABLE);
14 static void (WINAPI *wake_all_condition_variable)(PCONDITION_VARIABLE);
15
16 template <typename T>
set_fn_ptr(T * ptr,FARPROC fn)17 static void set_fn_ptr(T* ptr, FARPROC fn) { *ptr = reinterpret_cast<T>(fn); }
18 #endif
19
Supported()20 bool SkCondVar::Supported() {
21 #ifdef SK_BUILD_FOR_WIN32
22 // If we're >= Vista we'll find these functions. Otherwise (XP) SkCondVar is not supported.
23 HMODULE kernel32 = GetModuleHandleA("kernel32.dll");
24 set_fn_ptr(&initialize_condition_variable,
25 GetProcAddress(kernel32, "InitializeConditionVariable"));
26 set_fn_ptr(&sleep_condition_variable,
27 GetProcAddress(kernel32, "SleepConditionVariableCS"));
28 set_fn_ptr(&wake_condition_variable,
29 GetProcAddress(kernel32, "WakeConditionVariable"));
30 set_fn_ptr(&wake_all_condition_variable,
31 GetProcAddress(kernel32, "WakeAllConditionVariable"));
32 return initialize_condition_variable
33 && sleep_condition_variable
34 && wake_condition_variable
35 && wake_all_condition_variable;
36 #else
37 return true;
38 #endif
39 }
40
SkCondVar()41 SkCondVar::SkCondVar() {
42 #ifdef SK_BUILD_FOR_WIN32
43 InitializeCriticalSection(&fCriticalSection);
44 SkASSERT(initialize_condition_variable);
45 initialize_condition_variable(&fCondition);
46 #else
47 pthread_mutex_init(&fMutex, NULL /* default mutex attr */);
48 pthread_cond_init(&fCond, NULL /* default cond attr */);
49 #endif
50 }
51
~SkCondVar()52 SkCondVar::~SkCondVar() {
53 #ifdef SK_BUILD_FOR_WIN32
54 DeleteCriticalSection(&fCriticalSection);
55 // No need to clean up fCondition.
56 #else
57 pthread_mutex_destroy(&fMutex);
58 pthread_cond_destroy(&fCond);
59 #endif
60 }
61
lock()62 void SkCondVar::lock() {
63 #ifdef SK_BUILD_FOR_WIN32
64 EnterCriticalSection(&fCriticalSection);
65 #else
66 pthread_mutex_lock(&fMutex);
67 #endif
68 }
69
unlock()70 void SkCondVar::unlock() {
71 #ifdef SK_BUILD_FOR_WIN32
72 LeaveCriticalSection(&fCriticalSection);
73 #else
74 pthread_mutex_unlock(&fMutex);
75 #endif
76 }
77
wait()78 void SkCondVar::wait() {
79 #ifdef SK_BUILD_FOR_WIN32
80 SkASSERT(sleep_condition_variable);
81 sleep_condition_variable(&fCondition, &fCriticalSection, INFINITE);
82 #else
83 pthread_cond_wait(&fCond, &fMutex);
84 #endif
85 }
86
signal()87 void SkCondVar::signal() {
88 #ifdef SK_BUILD_FOR_WIN32
89 SkASSERT(wake_condition_variable);
90 wake_condition_variable(&fCondition);
91 #else
92 pthread_cond_signal(&fCond);
93 #endif
94 }
95
broadcast()96 void SkCondVar::broadcast() {
97 #ifdef SK_BUILD_FOR_WIN32
98 SkASSERT(wake_all_condition_variable);
99 wake_all_condition_variable(&fCondition);
100 #else
101 pthread_cond_broadcast(&fCond);
102 #endif
103 }
104