old-autovect-branch/libjava/gnu/java/nio/natSelectorImplWin32.cc

   1 // natSelectorImplWin32.cc
   2
   3 /* Copyright (C) 2003, 2004  Free Software Foundation
   4
   5    This file is part of libgcj.
   6
   7 This software is copyrighted work licensed under the terms of the
   8 Libgcj License.  Please consult the file "LIBGCJ_LICENSE" for
   9 details.  */
  10
  11 #include <config.h>
  12 #include <platform.h>
  13
  14 #include <gnu/java/nio/VMSelector.h>
  15 #include <java/lang/Thread.h>
  16
  17 jint
  18 gnu::java::nio::VMSelector::select (jintArray read, jintArray write,
  19                                     jintArray except, jlong timeout)
  20 {
  21   // FIXME: The API for implSelect is biased towards POSIX implementations.
  22   jint* pReadFD = elements (read);
  23   int nNbReadFDs = JvGetArrayLength (read);
  24
  25   jint* pWriteFD = elements (write);
  26   int nNbWriteFDs = JvGetArrayLength (write);
  27
  28   int nNbEvents = nNbReadFDs + nNbWriteFDs;
  29
  30   // Create and initialize our event wrapper array
  31
  32   // FIXME: We're creating fresh WSAEVENTs for each call.
  33   // This is inefficient. It would probably be better to cache these
  34   // in the Win32 socket implementation class.
  35   WSAEventWrapper aArray[nNbEvents];
  36
  37   int nCurIndex = 0;
  38   for (int i=0; i < nNbReadFDs; ++i)
  39     aArray[nCurIndex++].init(pReadFD[i], FD_ACCEPT | FD_READ);
  40
  41   for (int i=0; i < nNbWriteFDs; ++i)
  42     aArray[nCurIndex++].init(pWriteFD[i], FD_WRITE);
  43
  44   // Build our array of WSAEVENTs to wait on. Also throw in our thread's
  45   // interrupt event in order to detect thread interruption.
  46   HANDLE arh[nNbEvents + 1];
  47   for (int i=0; i < nNbEvents; ++i)
  48     arh[i] = aArray[i].getEventHandle();
  49   arh[nNbEvents] = _Jv_Win32GetInterruptEvent ();
  50
  51   // A timeout value of 0 needs to be treated as infinite.
  52   if (timeout <= 0)
  53     timeout = WSA_INFINITE;
  54
  55   // Do the select.
  56   DWORD dwRet = WSAWaitForMultipleEvents (nNbEvents+1, arh, 0, timeout, false);
  57
  58   if (dwRet == WSA_WAIT_FAILED)
  59     _Jv_ThrowIOException ();
  60
  61   // Before we do anything else, clear output file descriptor arrays.
  62   memset(pReadFD, 0, sizeof(jint) * nNbReadFDs);
  63   memset(pWriteFD, 0, sizeof(jint) * nNbWriteFDs);
  64   memset(elements (except), 0, sizeof(jint) * JvGetArrayLength (except));
  65
  66   if (dwRet == DWORD(WSA_WAIT_EVENT_0 + nNbEvents))
  67     {
  68       // We were interrupted. Set the current thread's interrupt
  69       // status and get out of here, with nothing selected..
  70       ::java::lang::Thread::currentThread ()->interrupt ();
  71       return 0;
  72     }
  73   else if (dwRet < DWORD(WSA_WAIT_EVENT_0 + nNbEvents))
  74     {
  75       int nSelectedEventIndex = dwRet - WSA_WAIT_EVENT_0;
  76
  77       // Record the selected file descriptor.
  78       // FIXME: This implementation only allows one file descriptor
  79       // to be selected at a time. Remedy this by looping on
  80       // WSAWaitForMultipleEvents 'til nothing more is selected.
  81       jint fd = aArray[nSelectedEventIndex].getFD();
  82       if (nSelectedEventIndex < nNbReadFDs)
  83         pReadFD[0] = fd;
  84       else
  85         pWriteFD[0] = fd;
  86
  87       return 1;
  88     }
  89   else
  90     // None of the event objects was signalled, so nothing was
  91     // selected.
  92     return 0;
  93 }