dep/src/zthread/macos/FastLock.h

   1 /*
   2  * Copyright (c) 2005, Eric Crahen
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a copy
   5  * of this software and associated documentation files (the "Software"), to deal
   6  * in the Software without restriction, including without limitation the rights
   7  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   8  * copies of the Software, and to permit persons to whom the Software is furnished
   9  * to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice shall be included in all
  12  * copies or substantial portions of the Software.
  13  *
  14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  17  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
  18  * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  19  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  20  *
  21  */
  22
  23 #ifndef __ZTFASTLOCK_H__
  24 #define __ZTFASTLOCK_H__
  25
  26 #include "zthread/NonCopyable.h"
  27 #include "zthread/Exceptions.h"
  28
  29 #include <assert.h>
  30 #include <CoreServices/CoreServices.h>
  31 //#include <Multiprocessing.h>
  32
  33 namespace ZThread {
  34
  35 /**
  36  * @class FastLock
  37  *
  38  * @author Eric Crahen <http://www.code-foo.com>
  39  * @date <2003-07-16T23:25:31-0400>
  40  * @version 2.1.6
  41  *
  42  */
  43 class FastLock : private NonCopyable {
  44
  45   MPCriticalRegionID _mtx;
  46
  47  public:
  48
  49   /**
  50    * Create a new FastLock. No safety or state checks are performed.
  51    *
  52    * @exception Initialization_Exception - not thrown
  53    */
  54   inline FastLock() {
  55
  56     // Apple TN1071
  57     static bool init = MPLibraryIsLoaded();
  58
  59     if(!init || MPCreateCriticalRegion(&_mtx) != noErr) {
  60       assert(0);
  61       throw Initialization_Exception();
  62     }
  63
  64   }
  65
  66   /**
  67    * Destroy a FastLock. No safety or state checks are performed.
  68    */
  69   inline ~FastLock() throw () {
  70
  71     OSStatus status = MPDeleteCriticalRegion(_mtx);
  72     if(status != noErr)
  73       assert(false);
  74
  75   }
  76
  77   /**
  78    * Acquire an exclusive lock. No safety or state checks are performed.
  79    *
  80    * @exception Synchronization_Exception - not thrown
  81    */
  82   inline void acquire() {
  83
  84     if(MPEnterCriticalRegion(_mtx, kDurationForever) != noErr)
  85       throw Synchronization_Exception();
  86
  87   }
  88
  89   /**
  90    * Try to acquire an exclusive lock. No safety or state checks are performed.
  91    * This function returns immediately regardless of the value of the timeout
  92    *
  93    * @param timeout Unused
  94    * @return bool
  95    * @exception Synchronization_Exception - not thrown
  96    */
  97   inline bool tryAcquire(unsigned long timeout=0) {
  98
  99     OSStatus status =
 100       MPEnterCriticalRegion(_mtx, kDurationMillisecond * timeout);
 101
 102     switch(status) {
 103       case kMPTimeoutErr:
 104         return false;
 105
 106       case noErr:
 107         return true;
 108
 109     }
 110
 111     assert(0);
 112     throw Synchronization_Exception();
 113
 114   }
 115
 116   /**
 117    * Release an exclusive lock. No safety or state checks are performed.
 118    * The caller should have already acquired the lock, and release it
 119    * only once.
 120    *
 121    * @exception Synchronization_Exception - not thrown
 122    */
 123   inline void release() {
 124
 125     if(MPExitCriticalRegion(_mtx) != noErr)
 126       throw Synchronization_Exception();
 127
 128   }
 129
 130
 131 }; /* FastLock */
 132
 133
 134 };
 135
 136 #endif
 137
 138
 139