1 /*
2  * Copyright 2013 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 SkMutex_win_DEFINED
9 #define SkMutex_win_DEFINED
10 
11 /** Windows CriticalSection based mutex. */
12 
13 #ifndef WIN32_LEAN_AND_MEAN
14 #  define WIN32_LEAN_AND_MEAN
15 #  define WIN32_IS_MEAN_WAS_LOCALLY_DEFINED
16 #endif
17 #ifndef NOMINMAX
18 #  define NOMINMAX
19 #  define NOMINMAX_WAS_LOCALLY_DEFINED
20 #endif
21 #
22 #include <windows.h>
23 #
24 #ifdef WIN32_IS_MEAN_WAS_LOCALLY_DEFINED
25 #  undef WIN32_IS_MEAN_WAS_LOCALLY_DEFINED
26 #  undef WIN32_LEAN_AND_MEAN
27 #endif
28 #ifdef NOMINMAX_WAS_LOCALLY_DEFINED
29 #  undef NOMINMAX_WAS_LOCALLY_DEFINED
30 #  undef NOMINMAX
31 #endif
32 
33 // On Windows, SkBaseMutex and SkMutex are the same thing,
34 // we can't easily get rid of static initializers. However,
35 // we preserve the same inheritance pattern as other platforms
36 // so that we can forward-declare cleanly.
37 struct SkBaseMutex {
38 public:
SkBaseMutexSkBaseMutex39     SkBaseMutex() {
40         InitializeCriticalSection(&fStorage);
41         SkDEBUGCODE(fOwner = 0;)
42     }
43 
~SkBaseMutexSkBaseMutex44     ~SkBaseMutex() {
45         SkASSERT(0 == fOwner);
46         DeleteCriticalSection(&fStorage);
47     }
48 
acquireSkBaseMutex49     void acquire() {
50         EnterCriticalSection(&fStorage);
51         SkDEBUGCODE(fOwner = GetCurrentThreadId();)
52     }
53 
releaseSkBaseMutex54     void release() {
55         this->assertHeld();
56         SkDEBUGCODE(fOwner = 0;)
57         LeaveCriticalSection(&fStorage);
58     }
59 
assertHeldSkBaseMutex60     void assertHeld() {
61         SkASSERT(GetCurrentThreadId() == fOwner);
62     }
63 
64 protected:
65     CRITICAL_SECTION fStorage;
66     SkDEBUGCODE(DWORD fOwner;)
67 
68 private:
69     SkBaseMutex(const SkBaseMutex&);
70     SkBaseMutex& operator=(const SkBaseMutex&);
71 };
72 
73 class SkMutex : public SkBaseMutex { };
74 
75 // Windows currently provides no documented means of POD initializing a CRITICAL_SECTION.
76 // As a result, it is illegal to SK_DECLARE_STATIC_MUTEX in a function.
77 #define SK_DECLARE_STATIC_MUTEX(name) namespace{} static SkBaseMutex name
78 
79 #endif
80