src/WINNT/afsapplib/al_task.cpp

   1 /*
   2  * Copyright 2000, International Business Machines Corporation and others.
   3  * All Rights Reserved.
   4  *
   5  * This software has been released under the terms of the IBM Public
   6  * License.  For details, see the LICENSE file in the top-level source
   7  * directory or online at http://www.openafs.org/dl/license10.html
   8  */
   9
  10 #include <winsock2.h>
  11 #include <ws2tcpip.h>
  12
  13 extern "C" {
  14 #include <afs/param.h>
  15 #include <afs/stds.h>
  16 }
  17
  18 #include <WINNT/afsapplib.h>
  19
  20
  21 /*
  22  * VARIABLES __________________________________________________________________
  23  *
  24  */
  25
  26 static LPTASKQUEUE_PARAMS ptqp = NULL;
  27
  28 typedef struct TASKQUEUEITEM
  29    {
  30    struct TASKQUEUEITEM *pNext;
  31    int idTask;
  32    HWND hReply;
  33    PVOID lpUser;
  34    } TASKQUEUEITEM, *LPTASKQUEUEITEM;
  35
  36 static LPTASKQUEUEITEM pTaskQueuePop = NULL;
  37 static LPTASKQUEUEITEM pTaskQueuePushAfter = NULL;
  38 static CRITICAL_SECTION csTaskQueue;
  39
  40 static size_t nThreadsRunning = 0;
  41 static size_t nRequestsActive = 0;
  42
  43
  44
  45 /*
  46  * PROTOTYPES _________________________________________________________________
  47  *
  48  */
  49
  50 DWORD WINAPI Task_ThreadProc (PVOID lp);
  51
  52
  53 /*
  54  * ROUTINES ___________________________________________________________________
  55  *
  56  */
  57
  58 void AfsAppLib_InitTaskQueue (LPTASKQUEUE_PARAMS lpp)
  59 {
  60    if (ptqp != NULL)
  61       {
  62       Delete (ptqp);
  63       ptqp = NULL;
  64       }
  65
  66    if (lpp && lpp->fnCreateTaskPacket && lpp->fnPerformTask && lpp->fnFreeTaskPacket)
  67       {
  68       ptqp = New (TASKQUEUE_PARAMS);
  69       memcpy (ptqp, lpp, sizeof(TASKQUEUE_PARAMS));
  70       }
  71 }
  72
  73
  74 void StartTask (int idTask, HWND hReply, PVOID lpUser)
  75 {
  76    if (!ptqp)
  77       return;
  78
  79    static BOOL fStarted = FALSE;
  80    if (!fStarted)
  81       {
  82       fStarted = TRUE;
  83       InitializeCriticalSection (&csTaskQueue);
  84       }
  85
  86    // Then push this notification onto our TaskQueue, so that the task
  87    // thread will pop off each request in turn and take a look at it.
  88    // Ideally, PostThreadMessage() and GetMessage() would implement all this
  89    // garbage, but that doesn't work properly for some reason...
  90    //
  91    EnterCriticalSection (&csTaskQueue);
  92
  93    if ((++nRequestsActive) > nThreadsRunning)
  94       {
  95       if ((!ptqp->nThreadsMax) || (nThreadsRunning < (size_t)(ptqp->nThreadsMax)))
  96          {
  97          DWORD dwThreadID;
  98          HANDLE hThread;
  99          if ((hThread = CreateThread (NULL, 0, (LPTHREAD_START_ROUTINE)Task_ThreadProc, 0, 0, &dwThreadID)) != NULL)
 100             {
 101             SetThreadPriority (hThread, THREAD_PRIORITY_BELOW_NORMAL);
 102             ++nThreadsRunning;
 103             }
 104          }
 105       }
 106
 107    LPTASKQUEUEITEM lptqi = New (TASKQUEUEITEM);
 108    lptqi->pNext = NULL;
 109    lptqi->idTask = idTask;
 110    lptqi->hReply = hReply;
 111    lptqi->lpUser = lpUser;
 112
 113    if (pTaskQueuePushAfter != NULL)
 114       pTaskQueuePushAfter->pNext = lptqi;
 115    pTaskQueuePushAfter = lptqi;
 116
 117    if (pTaskQueuePop == NULL)
 118       pTaskQueuePop = lptqi;
 119
 120    LeaveCriticalSection (&csTaskQueue);
 121 }
 122
 123
 124 DWORD WINAPI Task_ThreadProc (PVOID lp)
 125 {
 126    BOOL fJustDidTask = FALSE;
 127
 128    for (;;)
 129       {
 130       BOOL fFound = FALSE;
 131       TASKQUEUEITEM tqi;
 132
 133       EnterCriticalSection (&csTaskQueue);
 134
 135       if (fJustDidTask)
 136          {
 137          --nRequestsActive;
 138          fJustDidTask = FALSE;
 139          }
 140
 141       if (pTaskQueuePop != NULL)
 142          {
 143          LPTASKQUEUEITEM lptqiNext = pTaskQueuePop->pNext;
 144          tqi = *pTaskQueuePop;
 145          Delete (pTaskQueuePop);
 146          if (pTaskQueuePushAfter == pTaskQueuePop)
 147             pTaskQueuePushAfter = NULL;
 148          pTaskQueuePop = lptqiNext;
 149          fFound = TRUE;
 150          fJustDidTask = TRUE;
 151          }
 152
 153       // is this thread unnecessary?--that is, if we couldn't find anything
 154       // to do, then kill off all threads.
 155       //
 156       if (!fFound)
 157          {
 158          --nThreadsRunning;
 159          LeaveCriticalSection (&csTaskQueue);
 160          break;
 161          }
 162
 163       LeaveCriticalSection (&csTaskQueue);
 164
 165       if (fFound)
 166          {
 167          LPTASKPACKET ptp;
 168          if ((ptp = (*ptqp->fnCreateTaskPacket)(tqi.idTask, tqi.hReply, tqi.lpUser)) != NULL)
 169             {
 170             (*ptqp->fnPerformTask)(ptp);
 171             }
 172
 173          if (tqi.hReply && IsWindow (tqi.hReply))
 174             {
 175             PostMessage (tqi.hReply, WM_ENDTASK, 0, (LPARAM)ptp);
 176             }
 177          else if (ptp != NULL)
 178             {
 179             (*ptqp->fnFreeTaskPacket)(ptp);
 180             }
 181          }
 182       }
 183
 184    return 0;
 185 }
 186