native_client_sdk/src/libraries/third_party/pthreads-win32/w32_CancelableWait.c

   1 /*
   2  * w32_CancelableWait.c
   3  *
   4  * Description:
   5  * This translation unit implements miscellaneous thread functions.
   6  *
   7  * --------------------------------------------------------------------------
   8  *
   9  *      Pthreads-win32 - POSIX Threads Library for Win32
  10  *      Copyright(C) 1998 John E. Bossom
  11  *      Copyright(C) 1999,2005 Pthreads-win32 contributors
  12  *
  13  *      Contact Email: rpj@callisto.canberra.edu.au
  14  *
  15  *      The current list of contributors is contained
  16  *      in the file CONTRIBUTORS included with the source
  17  *      code distribution. The list can also be seen at the
  18  *      following World Wide Web location:
  19  *      http://sources.redhat.com/pthreads-win32/contributors.html
  20  *
  21  *      This library is free software; you can redistribute it and/or
  22  *      modify it under the terms of the GNU Lesser General Public
  23  *      License as published by the Free Software Foundation; either
  24  *      version 2 of the License, or (at your option) any later version.
  25  *
  26  *      This library is distributed in the hope that it will be useful,
  27  *      but WITHOUT ANY WARRANTY; without even the implied warranty of
  28  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  29  *      Lesser General Public License for more details.
  30  *
  31  *      You should have received a copy of the GNU Lesser General Public
  32  *      License along with this library in the file COPYING.LIB;
  33  *      if not, write to the Free Software Foundation, Inc.,
  34  *      59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  35  */
  36
  37 #include "pthread.h"
  38 #include "implement.h"
  39
  40
  41 static INLINE int
  42 ptw32_cancelable_wait (HANDLE waitHandle, DWORD timeout)
  43      /*
  44       * -------------------------------------------------------------------
  45       * This provides an extra hook into the pthread_cancel
  46       * mechanism that will allow you to wait on a Windows handle and make it a
  47       * cancellation point. This function blocks until the given WIN32 handle is
  48       * signaled or pthread_cancel has been called. It is implemented using
  49       * WaitForMultipleObjects on 'waitHandle' and a manually reset WIN32
  50       * event used to implement pthread_cancel.
  51       *
  52       * Given this hook it would be possible to implement more of the cancellation
  53       * points.
  54       * -------------------------------------------------------------------
  55       */
  56 {
  57   int result;
  58   pthread_t self;
  59   ptw32_thread_t * sp;
  60   HANDLE handles[2];
  61   DWORD nHandles = 1;
  62   DWORD status;
  63
  64   handles[0] = waitHandle;
  65
  66   self = pthread_self();
  67   sp = (ptw32_thread_t *) self.p;
  68
  69   if (sp != NULL)
  70     {
  71       /*
  72        * Get cancelEvent handle
  73        */
  74       if (sp->cancelState == PTHREAD_CANCEL_ENABLE)
  75         {
  76
  77           if ((handles[1] = sp->cancelEvent) != NULL)
  78             {
  79               nHandles++;
  80             }
  81         }
  82     }
  83   else
  84     {
  85       handles[1] = NULL;
  86     }
  87
  88   status = WaitForMultipleObjects (nHandles, handles, PTW32_FALSE, timeout);
  89
  90   switch (status - WAIT_OBJECT_0)
  91     {
  92     case 0:
  93       /*
  94        * Got the handle.
  95        * In the event that both handles are signalled, the smallest index
  96        * value (us) is returned. As it has been arranged, this ensures that
  97        * we don't drop a signal that we should act on (i.e. semaphore,
  98        * mutex, or condition variable etc).
  99        */
 100       result = 0;
 101       break;
 102
 103     case 1:
 104       /*
 105        * Got cancel request.
 106        * In the event that both handles are signaled, the cancel will
 107        * be ignored (see case 0 comment).
 108        */
 109       ResetEvent (handles[1]);
 110
 111       if (sp != NULL)
 112         {
 113           ptw32_mcs_local_node_t stateLock;
 114           /*
 115            * Should handle POSIX and implicit POSIX threads..
 116            * Make sure we haven't been async-canceled in the meantime.
 117            */
 118           ptw32_mcs_lock_acquire (&sp->stateLock, &stateLock);
 119           if (sp->state < PThreadStateCanceling)
 120             {
 121               sp->state = PThreadStateCanceling;
 122               sp->cancelState = PTHREAD_CANCEL_DISABLE;
 123               ptw32_mcs_lock_release (&stateLock);
 124               ptw32_throw (PTW32_EPS_CANCEL);
 125
 126               /* Never reached */
 127             }
 128           ptw32_mcs_lock_release (&stateLock);
 129         }
 130
 131       /* Should never get to here. */
 132       result = EINVAL;
 133       break;
 134
 135     default:
 136       if (status == WAIT_TIMEOUT)
 137         {
 138           result = ETIMEDOUT;
 139         }
 140       else
 141         {
 142           result = EINVAL;
 143         }
 144       break;
 145     }
 146
 147   return (result);
 148
 149 }                               /* CancelableWait */
 150
 151 int
 152 pthreadCancelableWait (HANDLE waitHandle)
 153 {
 154   return (ptw32_cancelable_wait (waitHandle, INFINITE));
 155 }
 156
 157 int
 158 pthreadCancelableTimedWait (HANDLE waitHandle, DWORD timeout)
 159 {
 160   return (ptw32_cancelable_wait (waitHandle, timeout));
 161 }