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