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      1 /*-------------------------------------------------------------------------
      2  * drawElements Thread Library
      3  * ---------------------------
      4  *
      5  * Copyright 2014 The Android Open Source Project
      6  *
      7  * Licensed under the Apache License, Version 2.0 (the "License");
      8  * you may not use this file except in compliance with the License.
      9  * You may obtain a copy of the License at
     10  *
     11  *      http://www.apache.org/licenses/LICENSE-2.0
     12  *
     13  * Unless required by applicable law or agreed to in writing, software
     14  * distributed under the License is distributed on an "AS IS" BASIS,
     15  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     16  * See the License for the specific language governing permissions and
     17  * limitations under the License.
     18  *
     19  *//*!
     20  * \file
     21  * \brief Win32 implementation of mutex.
     22  *//*--------------------------------------------------------------------*/
     23 
     24 #include "deMutex.h"
     25 
     26 #if (DE_OS == DE_OS_WIN32 || DE_OS == DE_OS_WINCE)
     27 
     28 #include "deMemory.h"
     29 
     30 #define VC_EXTRALEAN
     31 #define WIN32_LEAN_AND_MEAN
     32 #define NOMINMAX
     33 #include <windows.h>
     34 
     35 /* Critical section objects are more lightweight than mutexes on Win32. */
     36 #define USE_CRITICAL_SECTION 1
     37 
     38 #if defined(USE_CRITICAL_SECTION)
     39 
     40 enum
     41 {
     42 	CRITICAL_SECTION_SPIN_COUNT	= 2048
     43 };
     44 
     45 DE_STATIC_ASSERT(sizeof(deMutex) >= sizeof(CRITICAL_SECTION*));
     46 
     47 deMutex deMutex_create (const deMutexAttributes* attributes)
     48 {
     49 	CRITICAL_SECTION* criticalSection = (CRITICAL_SECTION*)deMalloc(sizeof(CRITICAL_SECTION));
     50 	if (!criticalSection)
     51 		return 0;
     52 
     53 	DE_UNREF(attributes);
     54 	/* \note [2012-11-05 pyry] Critical sections are always recursive. */
     55 
     56 	if (!InitializeCriticalSectionAndSpinCount(criticalSection, CRITICAL_SECTION_SPIN_COUNT))
     57 	{
     58 		deFree(criticalSection);
     59 		return 0;
     60 	}
     61 
     62 	return (deMutex)criticalSection;
     63 }
     64 
     65 void deMutex_destroy (deMutex mutex)
     66 {
     67 	DeleteCriticalSection((CRITICAL_SECTION*)mutex);
     68 	deFree((CRITICAL_SECTION*)mutex);
     69 }
     70 
     71 void deMutex_lock (deMutex mutex)
     72 {
     73 	EnterCriticalSection((CRITICAL_SECTION*)mutex);
     74 }
     75 
     76 void deMutex_unlock (deMutex mutex)
     77 {
     78 	LeaveCriticalSection((CRITICAL_SECTION*)mutex);
     79 }
     80 
     81 deBool deMutex_tryLock (deMutex mutex)
     82 {
     83 	return TryEnterCriticalSection((CRITICAL_SECTION*)mutex) == TRUE;
     84 }
     85 
     86 #else
     87 
     88 DE_STATIC_ASSERT(sizeof(deMutex) >= sizeof(HANDLE));
     89 
     90 deMutex deMutex_create (const deMutexAttributes* attributes)
     91 {
     92 	HANDLE handle = DE_NULL;
     93 
     94 	DE_UNREF(attributes);
     95 	/* \note [2009-11-12 pyry] Created mutex is always recursive. */
     96 
     97 	handle = CreateMutex(DE_NULL, FALSE, DE_NULL);
     98 	return (deMutex)handle;
     99 }
    100 
    101 void deMutex_destroy (deMutex mutex)
    102 {
    103 	HANDLE handle = (HANDLE)mutex;
    104 	CloseHandle(handle);
    105 }
    106 
    107 void deMutex_lock (deMutex mutex)
    108 {
    109 	HANDLE	handle	= (HANDLE)mutex;
    110 	DWORD	ret		= WaitForSingleObject(handle, INFINITE);
    111 	DE_ASSERT(ret == WAIT_OBJECT_0);
    112 }
    113 
    114 void deMutex_unlock (deMutex mutex)
    115 {
    116 	HANDLE	handle	= (HANDLE)mutex;
    117 	BOOL	ret		= ReleaseMutex(handle);
    118 	DE_ASSERT(ret == TRUE);
    119 }
    120 
    121 deBool deMutex_tryLock (deMutex mutex)
    122 {
    123 	HANDLE	handle	= (HANDLE)mutex;
    124 	DWORD	ret		= WaitForSingleObject(handle, 0);
    125 	return (ret == WAIT_OBJECT_0);
    126 }
    127 
    128 #endif /* USE_CRITICAL_SECTION */
    129 
    130 #endif /* DE_OS */
    131