src/xgselect.c

   1 /* Function for handling the GLib event loop.
   2
   3 Copyright (C) 2009-2011  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)
  26
  27 #include <glib.h>
  28 #include <errno.h>
  29 #include <setjmp.h>
  30
  31 static GPollFD *gfds;
  32 static int 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         while (n_gfds > gfds_size)
  58           gfds_size *= 2;
  59         xfree (gfds);
  60         gfds = xmalloc (sizeof (*gfds) * gfds_size);
  61       }
  62
  63     n_gfds = g_main_context_query (context,
  64                                    G_PRIORITY_LOW,
  65                                    &tmo_in_millisec,
  66                                    gfds,
  67                                    gfds_size);
  68   } while (n_gfds > gfds_size);
  69
  70   for (i = 0; i < n_gfds; ++i)
  71     {
  72       if (gfds[i].events & G_IO_IN)
  73         {
  74           FD_SET (gfds[i].fd, &all_rfds);
  75           if (gfds[i].fd > max_fds) max_fds = gfds[i].fd;
  76         }
  77       if (gfds[i].events & G_IO_OUT)
  78         {
  79           FD_SET (gfds[i].fd, &all_wfds);
  80           if (gfds[i].fd > max_fds) max_fds = gfds[i].fd;
  81           have_wfds = 1;
  82         }
  83     }
  84
  85   if (tmo_in_millisec >= 0)
  86     {
  87       EMACS_SET_SECS_USECS (tmo, tmo_in_millisec/1000,
  88                             1000 * (tmo_in_millisec % 1000));
  89       if (!timeout) our_tmo = 1;
  90       else
  91         {
  92           EMACS_TIME difference;
  93
  94           EMACS_SUB_TIME (difference, tmo, *timeout);
  95           if (EMACS_TIME_NEG_P (difference)) our_tmo = 1;
  96         }
  97
  98       if (our_tmo) tmop = &tmo;
  99     }
 100
 101   nfds = select (max_fds+1, &all_rfds, have_wfds ? &all_wfds : NULL,
 102                  efds, tmop);
 103
 104   if (nfds < 0)
 105     retval = nfds;
 106   else if (nfds > 0)
 107     {
 108       for (i = 0; i < max_fds+1; ++i)
 109         {
 110           if (FD_ISSET (i, &all_rfds))
 111             {
 112               if (rfds && FD_ISSET (i, rfds)) ++retval;
 113               else ++our_fds;
 114             }
 115           else if (rfds)
 116             FD_CLR (i, rfds);
 117
 118           if (have_wfds && FD_ISSET (i, &all_wfds))
 119             {
 120               if (wfds && FD_ISSET (i, wfds)) ++retval;
 121               else ++our_fds;
 122             }
 123           else if (wfds)
 124             FD_CLR (i, wfds);
 125
 126           if (efds && FD_ISSET (i, efds))
 127             ++retval;
 128         }
 129     }
 130
 131   if (our_fds > 0 || (nfds == 0 && our_tmo))
 132     {
 133
 134       /* If Gtk+ is in use eventually gtk_main_iteration will be called,
 135          unless retval is zero.  */
 136 #ifdef USE_GTK
 137       if (retval == 0)
 138 #endif
 139         while (g_main_context_pending (context))
 140           g_main_context_dispatch (context);
 141
 142       /* To not have to recalculate timeout, return like this.  */
 143       if (retval == 0)
 144         {
 145           retval = -1;
 146           errno = EINTR;
 147         }
 148     }
 149
 150   return retval;
 151 }
 152 #endif /* defined (USE_GTK) || defined (HAVE_GCONF) */
 153
 154 void
 155 xgselect_initialize (void)
 156 {
 157 #if defined (USE_GTK) || defined (HAVE_GCONF)
 158   gfds_size = 128;
 159   gfds = xmalloc (sizeof (*gfds)*gfds_size);
 160 #endif /* defined (USE_GTK) || defined (HAVE_GCONF) */
 161 }