ghc/rts/win32/IOManager.c

   1 /* IOManager.c
   2  *
   3  * Non-blocking / asynchronous I/O for Win32.
   4  *
   5  * (c) sof, 2002-2003.
   6  */
   7 #include "IOManager.h"
   8 #include "WorkQueue.h"
   9 #include <stdio.h>
  10 #include <stdlib.h>
  11 #include <io.h>
  12 #include <winsock.h>
  13 #include <process.h>
  14
  15 /*
  16  * Internal state maintained by the IO manager.
  17  */
  18 typedef struct IOManagerState {
  19   CritSection      manLock;
  20   WorkQueue*       workQueue;
  21   int              numWorkers;
  22   int              workersIdle;
  23   HANDLE           hExitEvent;
  24   unsigned int     requestID;
  25 } IOManagerState;
  26
  27 /* ToDo: wrap up this state via a IOManager handle instead? */
  28 static IOManagerState* ioMan;
  29
  30 /*
  31  * The routine executed by each worker thread.
  32  */
  33 static
  34 unsigned
  35 WINAPI
  36 IOWorkerProc(PVOID param)
  37 {
  38   HANDLE  hWaits[2];
  39   DWORD   rc;
  40   IOManagerState* iom = (IOManagerState*)param;
  41   WorkQueue* pq = iom->workQueue;
  42   WorkItem*  work;
  43   int        len = 0, fd = 0;
  44   DWORD      errCode;
  45   void*      complData;
  46
  47   hWaits[0] = (HANDLE)iom->hExitEvent;
  48   hWaits[1] = GetWorkQueueHandle(pq);
  49
  50   while (1) {
  51     /* The error code is communicated back on completion of request; reset. */
  52     errCode = 0;
  53
  54     EnterCriticalSection(&iom->manLock);
  55     iom->workersIdle++;
  56     LeaveCriticalSection(&iom->manLock);
  57
  58     rc = WaitForMultipleObjects( 2, hWaits, FALSE, INFINITE );
  59
  60     EnterCriticalSection(&iom->manLock);
  61     iom->workersIdle--;
  62     LeaveCriticalSection(&iom->manLock);
  63
  64     if ( WAIT_OBJECT_0 == rc ) {
  65       /* shutdown */
  66 #if 0
  67       fprintf(stderr, "shutting down...\n"); fflush(stderr);
  68 #endif
  69       return 0;
  70     } else if ( (WAIT_OBJECT_0 + 1) == rc ) {
  71       /* work item available, fetch it. */
  72 #if 0
  73       fprintf(stderr, "work available...\n"); fflush(stderr);
  74 #endif
  75       if (FetchWork(pq,(void**)&work)) {
  76         if ( work->workKind & WORKER_READ ) {
  77           if ( work->workKind & WORKER_FOR_SOCKET ) {
  78             len = recv(work->workData.ioData.fd,
  79                        work->workData.ioData.buf,
  80                        work->workData.ioData.len,
  81                        0);
  82             if (len == SOCKET_ERROR) {
  83               errCode = WSAGetLastError();
  84             }
  85           } else {
  86             len = read(work->workData.ioData.fd,
  87                        work->workData.ioData.buf,
  88                        work->workData.ioData.len);
  89             if (len == -1) { errCode = errno; }
  90           }
  91           complData = work->workData.ioData.buf;
  92           fd = work->workData.ioData.fd;
  93         } else if ( work->workKind & WORKER_WRITE ) {
  94           if ( work->workKind & WORKER_FOR_SOCKET ) {
  95             len = send(work->workData.ioData.fd,
  96                        work->workData.ioData.buf,
  97                        work->workData.ioData.len,
  98                        0);
  99             if (len == SOCKET_ERROR) {
 100               errCode = WSAGetLastError();
 101             }
 102           } else {
 103             len = write(work->workData.ioData.fd,
 104                         work->workData.ioData.buf,
 105                         work->workData.ioData.len);
 106             if (len == -1) { errCode = errno; }
 107           }
 108           complData = work->workData.ioData.buf;
 109           fd = work->workData.ioData.fd;
 110         } else if ( work->workKind & WORKER_DELAY ) {
 111           /* very approximate implementation of threadDelay */
 112           Sleep(work->workData.delayData.msecs);
 113           len = work->workData.delayData.msecs;
 114           complData = NULL;
 115           fd = 0;
 116           errCode = 0;
 117         } else if ( work->workKind & WORKER_DO_PROC ) {
 118             /* perform operation/proc on behalf of Haskell thread. */
 119             if (work->workData.procData.proc) {
 120                 /* The procedure is assumed to encode result + success/failure
 121                  * via its param.
 122                  */
 123                 work->workData.procData.proc(work->workData.procData.param);
 124                 errCode=0;
 125             } else {
 126                 errCode=1;
 127             }
 128             complData = work->workData.procData.param;
 129         } else {
 130           fprintf(stderr, "unknown work request type (%d) , ignoring.\n", work->workKind);
 131           fflush(stderr);
 132           continue;
 133         }
 134         work->onCompletion(work->requestID,
 135                            fd,
 136                            len,
 137                            complData,
 138                            errCode);
 139         /* Free the WorkItem */
 140         free(work);
 141       } else {
 142           fprintf(stderr, "unable to fetch work; fatal.\n"); fflush(stderr);
 143           return 1;
 144       }
 145     } else {
 146           fprintf(stderr, "waiting failed; fatal.\n"); fflush(stderr);
 147           return 1;
 148     }
 149   }
 150   return 0;
 151 }
 152
 153 static
 154 BOOL
 155 NewIOWorkerThread(IOManagerState* iom)
 156 {
 157   unsigned threadId;
 158   return ( 0 != _beginthreadex(NULL,
 159                                0,
 160                                IOWorkerProc,
 161                                (LPVOID)iom,
 162                                0,
 163                                &threadId) );
 164 }
 165
 166 BOOL
 167 StartIOManager(void)
 168 {
 169   HANDLE hExit;
 170   WorkQueue* wq;
 171
 172   wq = NewWorkQueue();
 173   if ( !wq ) return FALSE;
 174
 175   ioMan = (IOManagerState*)malloc(sizeof(IOManagerState));
 176
 177   if (!ioMan) {
 178     FreeWorkQueue(wq);
 179     return FALSE;
 180   }
 181
 182   /* A manual-reset event */
 183   hExit = CreateEvent ( NULL, TRUE, FALSE, NULL );
 184   if ( !hExit ) {
 185     FreeWorkQueue(wq);
 186     free(ioMan);
 187     return FALSE;
 188   }
 189
 190   ioMan->hExitEvent = hExit;
 191   InitializeCriticalSection(&ioMan->manLock);
 192   ioMan->workQueue   = wq;
 193   ioMan->numWorkers  = 0;
 194   ioMan->workersIdle = 0;
 195   ioMan->requestID   = 1;
 196
 197   return TRUE;
 198 }
 199
 200 /*
 201  * Function: AddIORequest()
 202  *
 203  * Conduit to underlying WorkQueue's SubmitWork(); adds IO
 204  * request to work queue, returning without blocking.
 205  */
 206 int
 207 AddIORequest ( int   fd,
 208                BOOL  forWriting,
 209                BOOL  isSocket,
 210                int   len,
 211                char* buffer,
 212                CompletionProc onCompletion)
 213 {
 214   WorkItem* wItem = (WorkItem*)malloc(sizeof(WorkItem));
 215   if (!ioMan || !wItem) return 0;
 216
 217   /* Fill in the blanks */
 218   wItem->workKind     = ( isSocket   ? WORKER_FOR_SOCKET : 0 ) |
 219                         ( forWriting ? WORKER_WRITE : WORKER_READ );
 220   wItem->workData.ioData.fd  = fd;
 221   wItem->workData.ioData.len = len;
 222   wItem->workData.ioData.buf = buffer;
 223
 224   wItem->onCompletion        = onCompletion;
 225   wItem->requestID           = ioMan->requestID++;
 226
 227   EnterCriticalSection(&ioMan->manLock);
 228   /* If there are no worker threads available, create one.
 229    *
 230    * If this turns out to be too aggressive a policy, refine.
 231    */
 232 #if 0
 233   fprintf(stderr, "AddIORequest: %d\n", ioMan->workersIdle); fflush(stderr);
 234 #endif
 235   if ( ioMan->workersIdle == 0 ) {
 236     ioMan->numWorkers++;
 237     NewIOWorkerThread(ioMan);
 238   }
 239   LeaveCriticalSection(&ioMan->manLock);
 240
 241   if (SubmitWork(ioMan->workQueue,wItem)) {
 242     return wItem->requestID;
 243   } else {
 244     return 0;
 245   }
 246 }
 247
 248 /*
 249  * Function: AddDelayRequest()
 250  *
 251  */
 252 BOOL
 253 AddDelayRequest ( unsigned int   msecs,
 254                   CompletionProc onCompletion)
 255 {
 256   WorkItem* wItem = (WorkItem*)malloc(sizeof(WorkItem));
 257   if (!ioMan || !wItem) return FALSE;
 258
 259   /* Fill in the blanks */
 260   wItem->workKind     = WORKER_DELAY;
 261   wItem->workData.delayData.msecs = msecs;
 262   wItem->onCompletion = onCompletion;
 263   wItem->requestID    = ioMan->requestID++;
 264
 265   EnterCriticalSection(&ioMan->manLock);
 266   if ( ioMan->workersIdle == 0 ) {
 267     ioMan->numWorkers++;
 268     NewIOWorkerThread(ioMan);
 269   }
 270   LeaveCriticalSection(&ioMan->manLock);
 271
 272   if (SubmitWork(ioMan->workQueue,wItem)) {
 273     return wItem->requestID;
 274   } else {
 275     return 0;
 276   }
 277 }
 278
 279 /*
 280  * Function: AddDelayRequest()
 281  *
 282  */
 283 BOOL
 284 AddProcRequest ( void* proc,
 285                  void* param,
 286                  CompletionProc onCompletion)
 287 {
 288   WorkItem* wItem = (WorkItem*)malloc(sizeof(WorkItem));
 289   if (!ioMan || !wItem) return FALSE;
 290
 291   /* Fill in the blanks */
 292   wItem->workKind     = WORKER_DO_PROC;
 293   wItem->workData.procData.proc  = proc;
 294   wItem->workData.procData.param = param;
 295   wItem->onCompletion = onCompletion;
 296   wItem->requestID    = ioMan->requestID++;
 297
 298   EnterCriticalSection(&ioMan->manLock);
 299   if ( ioMan->workersIdle == 0 ) {
 300     ioMan->numWorkers++;
 301     NewIOWorkerThread(ioMan);
 302   }
 303   LeaveCriticalSection(&ioMan->manLock);
 304
 305   if (SubmitWork(ioMan->workQueue,wItem)) {
 306     return wItem->requestID;
 307   } else {
 308     return 0;
 309   }
 310 }
 311
 312 void ShutdownIOManager()
 313 {
 314   SetEvent(ioMan->hExitEvent);
 315   free(ioMan);
 316   ioMan = NULL;
 317 }