rts/Globals.c

   1 /* -----------------------------------------------------------------------------
   2  *
   3  * (c) The GHC Team, 1995-2009
   4  *
   5  * The RTS stores some "global" values on behalf of libraries, so that
   6  * some libraries can ensure that certain top-level things are shared
   7  * even when multiple versions of the library are loaded.  e.g. see
   8  * Data.Typeable and GHC.Conc.
   9  *
  10  * If/when we switch to a dynamically-linked GHCi, this can all go
  11  * away, because there would be just one copy of each library.
  12  *
  13  * ---------------------------------------------------------------------------*/
  14
  15 #include "PosixSource.h"
  16 #include "Rts.h"
  17
  18 #include "Globals.h"
  19 #include "Stable.h"
  20
  21 typedef enum {
  22     TypeableStore,
  23     GHCConcSignalSignalHandlerStore,
  24     GHCConcWindowsPendingDelaysStore,
  25     GHCConcWindowsIOManagerThreadStore,
  26     GHCConcWindowsProddingStore,
  27     SystemEventThreadEventManagerStore,
  28     SystemEventThreadIOManagerThreadStore,
  29     MaxStoreKey
  30 } StoreKey;
  31
  32 #ifdef THREADED_RTS
  33 Mutex globalStoreLock;
  34 #endif
  35
  36 static StgStablePtr store[MaxStoreKey];
  37
  38 void
  39 initGlobalStore(void)
  40 {
  41     nat i;
  42     for (i=0; i < MaxStoreKey; i++) {
  43         store[i] = 0;
  44     }
  45 #ifdef THREADED_RTS
  46     initMutex(&globalStoreLock);
  47 #endif
  48 }
  49
  50 void
  51 exitGlobalStore(void)
  52 {
  53     nat i;
  54 #ifdef THREADED_RTS
  55     closeMutex(&globalStoreLock);
  56 #endif
  57     for (i=0; i < MaxStoreKey; i++) {
  58         if (store[i] != 0) {
  59             freeStablePtr(store[i]);
  60             store[i] = 0;
  61         }
  62     }
  63 }
  64
  65 static StgStablePtr getOrSetKey(StoreKey key, StgStablePtr ptr)
  66 {
  67     StgStablePtr ret = store[key];
  68     if(ret==0) {
  69 #ifdef THREADED_RTS
  70         ACQUIRE_LOCK(&globalStoreLock);
  71         ret = store[key];
  72         if(ret==0) {
  73 #endif
  74             store[key] = ret = ptr;
  75 #ifdef THREADED_RTS
  76         }
  77         RELEASE_LOCK(&globalStoreLock);
  78 #endif
  79     }
  80     return ret;
  81 }
  82
  83
  84 StgStablePtr
  85 getOrSetTypeableStore(StgStablePtr ptr)
  86 {
  87     return getOrSetKey(TypeableStore,ptr);
  88 }
  89
  90 StgStablePtr
  91 getOrSetGHCConcSignalSignalHandlerStore(StgStablePtr ptr)
  92 {
  93     return getOrSetKey(GHCConcSignalSignalHandlerStore,ptr);
  94 }
  95
  96 StgStablePtr
  97 getOrSetGHCConcWindowsPendingDelaysStore(StgStablePtr ptr)
  98 {
  99     return getOrSetKey(GHCConcWindowsPendingDelaysStore,ptr);
 100 }
 101
 102 StgStablePtr
 103 getOrSetGHCConcWindowsIOManagerThreadStore(StgStablePtr ptr)
 104 {
 105     return getOrSetKey(GHCConcWindowsIOManagerThreadStore,ptr);
 106 }
 107
 108 StgStablePtr
 109 getOrSetGHCConcWindowsProddingStore(StgStablePtr ptr)
 110 {
 111     return getOrSetKey(GHCConcWindowsProddingStore,ptr);
 112 }
 113
 114 StgStablePtr
 115 getOrSetSystemEventThreadEventManagerStore(StgStablePtr ptr)
 116 {
 117     return getOrSetKey(SystemEventThreadEventManagerStore,ptr);
 118 }
 119
 120 StgStablePtr
 121 getOrSetSystemEventThreadIOManagerThreadStore(StgStablePtr ptr)
 122 {
 123     return getOrSetKey(SystemEventThreadIOManagerThreadStore,ptr);
 124 }