gio/gasynchelper.c

   1 /* GIO - GLib Input, Output and Streaming Library
   2  *
   3  * Copyright (C) 2006-2007 Red Hat, Inc.
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2.1 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General
  16  * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
  17  *
  18  * Author: Alexander Larsson <alexl@redhat.com>
  19  */
  20
  21 #include "config.h"
  22
  23 #include "gasynchelper.h"
  24
  25
  26 /*< private >
  27  * SECTION:gasynchelper
  28  * @short_description: Asynchronous Helper Functions
  29  * @include: gio/gio.h
  30  * @see_also: #GAsyncResult
  31  *
  32  * Provides helper functions for asynchronous operations.
  33  *
  34  **/
  35
  36 #ifdef G_OS_WIN32
  37 gboolean
  38 _g_win32_overlap_wait_result (HANDLE           hfile,
  39                               OVERLAPPED      *overlap,
  40                               DWORD           *transferred,
  41                               GCancellable    *cancellable)
  42 {
  43   GPollFD pollfd[2];
  44   gboolean result = FALSE;
  45   gint num, npoll;
  46
  47   pollfd[0].fd = (gint)overlap->hEvent;
  48   pollfd[0].events = G_IO_IN;
  49   num = 1;
  50
  51   if (g_cancellable_make_pollfd (cancellable, &pollfd[1]))
  52     num++;
  53
  54 loop:
  55   npoll = g_poll (pollfd, num, -1);
  56   if (npoll <= 0)
  57     /* error out, should never happen */
  58     goto end;
  59
  60   if (g_cancellable_is_cancelled (cancellable))
  61     {
  62       /* CancelIO only cancels pending operations issued by the
  63        * current thread and since we're doing only sync operations,
  64        * this is safe.... */
  65       /* CancelIoEx is only Vista+. Since we have only one overlap
  66        * operaton on this thread, we can just use: */
  67       result = CancelIo (hfile);
  68       g_warn_if_fail (result);
  69     }
  70
  71   result = GetOverlappedResult (overlap->hEvent, overlap, transferred, FALSE);
  72   if (result == FALSE &&
  73       GetLastError () == ERROR_IO_INCOMPLETE &&
  74       !g_cancellable_is_cancelled (cancellable))
  75     goto loop;
  76
  77 end:
  78   if (num > 1)
  79     g_cancellable_release_fd (cancellable);
  80
  81   return result;
  82 }
  83 #endif