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 #include "xterm.h"
  31
  32 static GPollFD *gfds;
  33 static ptrdiff_t gfds_size;
  34
  35 int
  36 xg_select (int fds_lim, SELECT_TYPE *rfds, SELECT_TYPE *wfds, SELECT_TYPE *efds,
  37            EMACS_TIME *timeout)
  38 {
  39   SELECT_TYPE all_rfds, all_wfds;
  40   EMACS_TIME tmo, *tmop = timeout;
  41
  42   GMainContext *context;
  43   int have_wfds = wfds != NULL;
  44   int n_gfds = 0, our_tmo = 0, retval = 0, our_fds = 0, max_fds = fds_lim - 1;
  45   int i, nfds, tmo_in_millisec;
  46
  47   if (!x_in_use)
  48     return select (fds_lim, rfds, wfds, efds, timeout);
  49
  50   if (rfds) memcpy (&all_rfds, rfds, sizeof (all_rfds));
  51   else FD_ZERO (&all_rfds);
  52   if (wfds) memcpy (&all_wfds, wfds, sizeof (all_rfds));
  53   else FD_ZERO (&all_wfds);
  54
  55   /* Update event sources in GLib. */
  56   context = g_main_context_default ();
  57   g_main_context_pending (context);
  58
  59   do {
  60     if (n_gfds > gfds_size)
  61       {
  62         xfree (gfds);
  63         gfds = xpalloc (0, &gfds_size, n_gfds - gfds_size, INT_MAX,
  64                         sizeof *gfds);
  65       }
  66
  67     n_gfds = g_main_context_query (context,
  68                                    G_PRIORITY_LOW,
  69                                    &tmo_in_millisec,
  70                                    gfds,
  71                                    gfds_size);
  72   } while (n_gfds > gfds_size);
  73
  74   for (i = 0; i < n_gfds; ++i)
  75     {
  76       if (gfds[i].events & G_IO_IN)
  77         {
  78           FD_SET (gfds[i].fd, &all_rfds);
  79           if (gfds[i].fd > max_fds) max_fds = gfds[i].fd;
  80         }
  81       if (gfds[i].events & G_IO_OUT)
  82         {
  83           FD_SET (gfds[i].fd, &all_wfds);
  84           if (gfds[i].fd > max_fds) max_fds = gfds[i].fd;
  85           have_wfds = 1;
  86         }
  87     }
  88
  89   if (tmo_in_millisec >= 0)
  90     {
  91       EMACS_SET_SECS_USECS (tmo, tmo_in_millisec/1000,
  92                             1000 * (tmo_in_millisec % 1000));
  93       if (!timeout) our_tmo = 1;
  94       else
  95         {
  96           EMACS_TIME difference;
  97
  98           EMACS_SUB_TIME (difference, tmo, *timeout);
  99           if (EMACS_TIME_NEG_P (difference)) our_tmo = 1;
 100         }
 101
 102       if (our_tmo) tmop = &tmo;
 103     }
 104
 105   fds_lim = max_fds + 1;
 106   nfds = select (fds_lim, &all_rfds, have_wfds ? &all_wfds : NULL, efds, tmop);
 107
 108   if (nfds < 0)
 109     retval = nfds;
 110   else if (nfds > 0)
 111     {
 112       for (i = 0; i < fds_lim; ++i)
 113         {
 114           if (FD_ISSET (i, &all_rfds))
 115             {
 116               if (rfds && FD_ISSET (i, rfds)) ++retval;
 117               else ++our_fds;
 118             }
 119           else if (rfds)
 120             FD_CLR (i, rfds);
 121
 122           if (have_wfds && FD_ISSET (i, &all_wfds))
 123             {
 124               if (wfds && FD_ISSET (i, wfds)) ++retval;
 125               else ++our_fds;
 126             }
 127           else if (wfds)
 128             FD_CLR (i, wfds);
 129
 130           if (efds && FD_ISSET (i, efds))
 131             ++retval;
 132         }
 133     }
 134
 135   if (our_fds > 0 || (nfds == 0 && our_tmo))
 136     {
 137
 138       /* If Gtk+ is in use eventually gtk_main_iteration will be called,
 139          unless retval is zero.  */
 140 #ifdef USE_GTK
 141       if (retval == 0)
 142 #endif
 143         while (g_main_context_pending (context))
 144           g_main_context_dispatch (context);
 145
 146       /* To not have to recalculate timeout, return like this.  */
 147       if (retval == 0)
 148         {
 149           retval = -1;
 150           errno = EINTR;
 151         }
 152     }
 153
 154   return retval;
 155 }
 156 #endif /* USE_GTK || HAVE_GCONF || HAVE_GSETTINGS */
 157
 158 void
 159 xgselect_initialize (void)
 160 {
 161 #if defined (USE_GTK) || defined (HAVE_GCONF) || defined (HAVE_GSETTINGS)
 162   gfds_size = 128;
 163   gfds = xmalloc (sizeof (*gfds)*gfds_size);
 164 #endif
 165 }