reactos/win32ss/gdi/eng/semaphor.c

   1 #include <win32k.h>
   2
   3 #define NDEBUG
   4 #include <debug.h>
   5
   6 /*
   7  * @implemented
   8  */
   9 HSEMAPHORE
  10 APIENTRY
  11 EngCreateSemaphore ( VOID )
  12 {
  13   // www.osr.com/ddk/graphics/gdifncs_95lz.htm
  14   PERESOURCE psem = ExAllocatePoolWithTag( NonPagedPool, sizeof(ERESOURCE), GDITAG_SEMAPHORE );
  15   if ( !psem )
  16     return NULL;
  17   if ( !NT_SUCCESS(ExInitializeResourceLite ( psem )) )
  18   {
  19     ExFreePoolWithTag ( psem, GDITAG_SEMAPHORE );
  20     return NULL;
  21   }
  22   return (HSEMAPHORE)psem;
  23 }
  24
  25 VOID
  26 FASTCALL
  27 IntGdiAcquireSemaphore ( HSEMAPHORE hsem )
  28 {
  29   KeEnterCriticalRegion();
  30   ExAcquireResourceExclusiveLite ( (PERESOURCE)hsem, TRUE );
  31 }
  32
  33 /*
  34  * @implemented
  35  */
  36 VOID
  37 APIENTRY
  38 EngAcquireSemaphore ( IN HSEMAPHORE hsem )
  39 {
  40   // www.osr.com/ddk/graphics/gdifncs_14br.htm
  41   PTHREADINFO W32Thread;
  42   ASSERT(hsem);
  43   IntGdiAcquireSemaphore ( hsem );
  44   W32Thread = PsGetThreadWin32Thread(PsGetCurrentThread());
  45   if (W32Thread) W32Thread->dwEngAcquireCount++;
  46 }
  47
  48
  49 VOID
  50 FASTCALL
  51 IntGdiReleaseSemaphore ( HSEMAPHORE hsem )
  52 {
  53   ExReleaseResourceLite ( (PERESOURCE)hsem );
  54   KeLeaveCriticalRegion();
  55 }
  56
  57 /*
  58  * @implemented
  59  */
  60 VOID
  61 APIENTRY
  62 EngReleaseSemaphore ( IN HSEMAPHORE hsem )
  63 {
  64   // www.osr.com/ddk/graphics/gdifncs_5u3r.htm
  65   PTHREADINFO W32Thread;
  66   ASSERT(hsem);
  67   W32Thread = PsGetThreadWin32Thread(PsGetCurrentThread());
  68   if (W32Thread) --W32Thread->dwEngAcquireCount;
  69   IntGdiReleaseSemaphore ( hsem );
  70 }
  71
  72 VOID
  73 NTAPI
  74 EngAcquireSemaphoreShared(
  75     IN HSEMAPHORE hsem)
  76 {
  77     PTHREADINFO pti;
  78
  79     ASSERT(hsem);
  80     ExEnterCriticalRegionAndAcquireResourceShared((PERESOURCE)hsem);
  81     pti = PsGetThreadWin32Thread(PsGetCurrentThread());
  82     if (pti) ++pti->dwEngAcquireCount;
  83 }
  84
  85 /*
  86  * @implemented
  87  */
  88 VOID
  89 APIENTRY
  90 EngDeleteSemaphore ( IN HSEMAPHORE hsem )
  91 {
  92   // www.osr.com/ddk/graphics/gdifncs_13c7.htm
  93   ASSERT ( hsem );
  94
  95   ExDeleteResourceLite((PERESOURCE)hsem);
  96
  97   ExFreePoolWithTag( (PVOID)hsem, GDITAG_SEMAPHORE);
  98 }
  99
 100 /*
 101  * @implemented
 102  */
 103 BOOL
 104 APIENTRY
 105 EngIsSemaphoreOwned ( IN HSEMAPHORE hsem )
 106 {
 107   // www.osr.com/ddk/graphics/gdifncs_6wmf.htm
 108   ASSERT(hsem);
 109   return (((PERESOURCE)hsem)->ActiveCount > 0);
 110 }
 111
 112 /*
 113  * @implemented
 114  */
 115 BOOL
 116 APIENTRY
 117 EngIsSemaphoreOwnedByCurrentThread ( IN HSEMAPHORE hsem )
 118 {
 119   // www.osr.com/ddk/graphics/gdifncs_9yxz.htm
 120   ASSERT(hsem);
 121   return ExIsResourceAcquiredExclusiveLite ( (PERESOURCE)hsem );
 122 }
 123
 124 /*
 125  * @implemented
 126  */
 127 BOOL APIENTRY
 128 EngInitializeSafeSemaphore(
 129    OUT ENGSAFESEMAPHORE *Semaphore)
 130 {
 131    HSEMAPHORE hSem;
 132
 133    if (InterlockedIncrement(&Semaphore->lCount) == 1)
 134    {
 135       /* Create the semaphore */
 136       hSem = EngCreateSemaphore();
 137       if (hSem == 0)
 138       {
 139          InterlockedDecrement(&Semaphore->lCount);
 140          return FALSE;
 141       }
 142       /* FIXME: Not thread-safe! Check result of InterlockedCompareExchangePointer
 143                 and delete semaphore if already initialized! */
 144       (void)InterlockedExchangePointer((volatile PVOID *)&Semaphore->hsem, hSem);
 145    }
 146    else
 147    {
 148       /* Wait for the other thread to create the semaphore */
 149       ASSERT(Semaphore->lCount > 1);
 150       ASSERT_IRQL_LESS_OR_EQUAL(PASSIVE_LEVEL);
 151       while (Semaphore->hsem == NULL);
 152    }
 153
 154    return TRUE;
 155 }
 156
 157 /*
 158  * @implemented
 159  */
 160 VOID APIENTRY
 161 EngDeleteSafeSemaphore(
 162    IN OUT ENGSAFESEMAPHORE *Semaphore)
 163 {
 164    if (InterlockedDecrement(&Semaphore->lCount) == 0)
 165    {
 166       /* FIXME: Not thread-safe! Use result of InterlockedCompareExchangePointer! */
 167       EngDeleteSemaphore(Semaphore->hsem);
 168       (void)InterlockedExchangePointer((volatile PVOID *)&Semaphore->hsem, NULL);
 169    }
 170 }
 171
 172 /* EOF */