sal/osl/os2/mutex.c

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  30
  31 #include <sys/fmutex.h>
  32
  33 #include "system.h"
  34
  35 #include <osl/mutex.h>
  36 #include <osl/diagnose.h>
  37
  38 /*
  39     Implementation notes:
  40     The void* hidden by oslMutex points to an OS/2 mutex semaphore.
  41 */
  42 typedef struct _oslMutexImpl {
  43     HMTX                                m_Mutex;
  44     int                                 m_Locks;
  45     ULONG                               m_Owner;
  46     ULONG                               m_Requests;
  47 } oslMutexImpl;
  48
  49 // static mutex to control access to private members of oslMutexImpl
  50 static HMTX MutexLock = 0;
  51
  52 /*****************************************************************************/
  53 /* osl_createMutex */
  54 /*****************************************************************************/
  55 oslMutex SAL_CALL osl_createMutex()
  56 {
  57     oslMutexImpl *pMutexImpl;
  58     HMTX hMutex;
  59     APIRET rc;
  60
  61     pMutexImpl= (oslMutexImpl*)calloc(sizeof(oslMutexImpl), 1);
  62     OSL_ASSERT(pMutexImpl); /* alloc successful? */
  63
  64     /* create semaphore */
  65     rc = DosCreateMutexSem( NULL, &pMutexImpl->m_Mutex, 0, FALSE );
  66     if( rc != 0 )
  67     {
  68         free(pMutexImpl);
  69         return NULL;
  70     }
  71
  72     // create static mutex for private members
  73     if (MutexLock == 0)
  74         DosCreateMutexSem( NULL, &MutexLock, 0, FALSE );
  75
  76     return (oslMutex)pMutexImpl;
  77 }
  78
  79 /*****************************************************************************/
  80 /* osl_destroyMutex */
  81 /*****************************************************************************/
  82 void SAL_CALL osl_destroyMutex(oslMutex Mutex)
  83 {
  84     oslMutexImpl *pMutexImpl = (oslMutexImpl *)Mutex;
  85     if (pMutexImpl)
  86     {
  87         DosCloseMutexSem( pMutexImpl->m_Mutex);
  88         free(pMutexImpl);
  89     }
  90 }
  91
  92 /*****************************************************************************/
  93 /* osl_acquireMutex */
  94 /*****************************************************************************/
  95 sal_Bool SAL_CALL osl_acquireMutex(oslMutex Mutex)
  96 {
  97     oslMutexImpl *pMutexImpl = (oslMutexImpl *)Mutex;
  98     APIRET rc = 0;
  99     OSL_ASSERT(Mutex);
 100
 101     DosRequestMutexSem( MutexLock, SEM_INDEFINITE_WAIT );
 102     pMutexImpl->m_Requests++;
 103     DosReleaseMutexSem( MutexLock);
 104
 105     rc = DosRequestMutexSem( pMutexImpl->m_Mutex, SEM_INDEFINITE_WAIT );
 106
 107     DosRequestMutexSem( MutexLock, SEM_INDEFINITE_WAIT );
 108     pMutexImpl->m_Requests--;
 109     if (pMutexImpl->m_Locks++ == 0)
 110         pMutexImpl->m_Owner = _gettid();
 111     DosReleaseMutexSem( MutexLock);
 112
 113     return( rc == 0 );
 114 }
 115
 116 /*****************************************************************************/
 117 /* osl_tryToAcquireMutex */
 118 /*****************************************************************************/
 119 sal_Bool SAL_CALL osl_tryToAcquireMutex(oslMutex Mutex)
 120 {
 121     sal_Bool     ret = sal_False;
 122     oslMutexImpl *pMutexImpl = (oslMutexImpl *)Mutex;
 123     OSL_ASSERT(Mutex);
 124
 125     DosRequestMutexSem( MutexLock, SEM_INDEFINITE_WAIT );
 126
 127     if ( ((pMutexImpl->m_Requests == 0) && (pMutexImpl->m_Locks == 0)) ||
 128          (pMutexImpl->m_Owner == _gettid()) )
 129         ret = osl_acquireMutex(Mutex);
 130
 131     DosReleaseMutexSem( MutexLock);
 132
 133     return ret;
 134 }
 135
 136 /*****************************************************************************/
 137 /* osl_releaseMutex */
 138 /*****************************************************************************/
 139 sal_Bool SAL_CALL osl_releaseMutex(oslMutex Mutex)
 140 {
 141     oslMutexImpl *pMutexImpl = (oslMutexImpl *)Mutex;
 142     APIRET rc;
 143     OSL_ASSERT(Mutex);
 144
 145     DosRequestMutexSem( MutexLock, SEM_INDEFINITE_WAIT );
 146
 147     if (--(pMutexImpl->m_Locks) == 0)
 148         pMutexImpl->m_Owner = 0;
 149
 150     DosReleaseMutexSem( MutexLock);
 151
 152     rc = DosReleaseMutexSem( pMutexImpl->m_Mutex);
 153
 154     return sal_True;
 155 }
 156
 157
 158
 159 /*****************************************************************************/
 160 /* osl_getGlobalMutex */
 161 /*****************************************************************************/
 162
 163 oslMutex g_Mutex = NULL;
 164
 165 oslMutex * SAL_CALL osl_getGlobalMutex(void)
 166 {
 167     if (g_Mutex == NULL)
 168         g_Mutex = osl_createMutex();
 169     return &g_Mutex;
 170 }