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      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:
     39     SkBaseMutex() {
     40         InitializeCriticalSection(&fStorage);
     41         SkDEBUGCODE(fOwner = 0;)
     42     }
     43 
     44     ~SkBaseMutex() {
     45         SkASSERT(0 == fOwner);
     46         DeleteCriticalSection(&fStorage);
     47     }
     48 
     49     void acquire() {
     50         EnterCriticalSection(&fStorage);
     51         SkDEBUGCODE(fOwner = GetCurrentThreadId();)
     52     }
     53 
     54     void release() {
     55         this->assertHeld();
     56         SkDEBUGCODE(fOwner = 0;)
     57         LeaveCriticalSection(&fStorage);
     58     }
     59 
     60     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