src/xgselect.c

   1 /* Function for handling the GLib event loop.
   2
   3 Copyright (C) 2009-2012  Free Software Foundation, Inc.
   4
   5 This file is part of GNU Emacs.
   6
   7 GNU Emacs is free software: you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation, either version 3 of the License, or
  10 (at your option) any later version.
  11
  12 GNU Emacs is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GNU Emacs.  If not, see <http§://www.gnu.org/licenses/>.  */
  19
  20 #include <config.h>
  21
  22 #include <setjmp.h>
  23 #include "xgselect.h"
  24
  25 #if defined (USE_GTK) || defined (HAVE_GCONF) || defined (HAVE_GSETTINGS)
  26
  27 #include <glib.h>
  28 #include <errno.h>
  29 #include <setjmp.h>
  30
  31 static GPollFD *gfds;
  32 static ptrdiff_t gfds_size;
  33
  34 int
  35 xg_select (int max_fds, SELECT_TYPE *rfds, SELECT_TYPE *wfds, SELECT_TYPE *efds,
  36            EMACS_TIME *timeout)
  37 {
  38   SELECT_TYPE all_rfds, all_wfds;
  39   EMACS_TIME tmo, *tmop = timeout;
  40
  41   GMainContext *context = g_main_context_default ();
  42   int have_wfds = wfds != NULL;
  43   int n_gfds = 0, our_tmo = 0, retval = 0, our_fds = 0;
  44   int i, nfds, tmo_in_millisec;
  45
  46   if (rfds) memcpy (&all_rfds, rfds, sizeof (all_rfds));
  47   else FD_ZERO (&all_rfds);
  48   if (wfds) memcpy (&all_wfds, wfds, sizeof (all_rfds));
  49   else FD_ZERO (&all_wfds);
  50
  51   /* Update event sources in GLib. */
  52   g_main_context_pending (context);
  53
  54   do {
  55     if (n_gfds > gfds_size)
  56       {
  57         xfree (gfds);
  58         gfds = xpalloc (0, &gfds_size, n_gfds - gfds_size, INT_MAX,
  59                         sizeof *gfds);
  60       }
  61
  62     n_gfds = g_main_context_query (context,
  63                                    G_PRIORITY_LOW,
  64                                    &tmo_in_millisec,
  65                                    gfds,
  66                                    gfds_size);
  67   } while (n_gfds > gfds_size);
  68
  69   for (i = 0; i < n_gfds; ++i)
  70     {
  71       if (gfds[i].events & G_IO_IN)
  72         {
  73           FD_SET (gfds[i].fd, &all_rfds);
  74           if (gfds[i].fd > max_fds) max_fds = gfds[i].fd;
  75         }
  76       if (gfds[i].events & G_IO_OUT)
  77         {
  78           FD_SET (gfds[i].fd, &all_wfds);
  79           if (gfds[i].fd > max_fds) max_fds = gfds[i].fd;
  80           have_wfds = 1;
  81         }
  82     }
  83
  84   if (tmo_in_millisec >= 0)
  85     {
  86       EMACS_SET_SECS_USECS (tmo, tmo_in_millisec/1000,
  87                             1000 * (tmo_in_millisec % 1000));
  88       if (!timeout) our_tmo = 1;
  89       else
  90         {
  91           EMACS_TIME difference;
  92
  93           EMACS_SUB_TIME (difference, tmo, *timeout);
  94           if (EMACS_TIME_NEG_P (difference)) our_tmo = 1;
  95         }
  96
  97       if (our_tmo) tmop = &tmo;
  98     }
  99
 100   nfds = select (max_fds+1, &all_rfds, have_wfds ? &all_wfds : NULL,
 101                  efds, tmop);
 102
 103   if (nfds < 0)
 104     retval = nfds;
 105   else if (nfds > 0)
 106     {
 107       for (i = 0; i < max_fds+1; ++i)
 108         {
 109           if (FD_ISSET (i, &all_rfds))
 110             {
 111               if (rfds && FD_ISSET (i, rfds)) ++retval;
 112               else ++our_fds;
 113             }
 114           else if (rfds)
 115             FD_CLR (i, rfds);
 116
 117           if (have_wfds && FD_ISSET (i, &all_wfds))
 118             {
 119               if (wfds && FD_ISSET (i, wfds)) ++retval;
 120               else ++our_fds;
 121             }
 122           else if (wfds)
 123             FD_CLR (i, wfds);
 124
 125           if (efds && FD_ISSET (i, efds))
 126             ++retval;
 127         }
 128     }
 129
 130   if (our_fds > 0 || (nfds == 0 && our_tmo))
 131     {
 132
 133       /* If Gtk+ is in use eventually gtk_main_iteration will be called,
 134          unless retval is zero.  */
 135 #ifdef USE_GTK
 136       if (retval == 0)
 137 #endif
 138         while (g_main_context_pending (context))
 139           g_main_context_dispatch (context);
 140
 141       /* To not have to recalculate timeout, return like this.  */
 142       if (retval == 0)
 143         {
 144           retval = -1;
 145           errno = EINTR;
 146         }
 147     }
 148
 149   return retval;
 150 }
 151 #endif /* USE_GTK || HAVE_GCONF || HAVE_GSETTINGS */
 152
 153 void
 154 xgselect_initialize (void)
 155 {
 156 #if defined (USE_GTK) || defined (HAVE_GCONF) || defined (HAVE_GSETTINGS)
 157   gfds_size = 128;
 158   gfds = xmalloc (sizeof (*gfds)*gfds_size);
 159 #endif
 160 }