src/xgselect.c

   1 /* Function for handling the GLib event loop.
   2    Copyright (C) 2009, 2010
   3      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 #if defined (USE_GTK) || defined (HAVE_GCONF)
  23 #include <glib.h>
  24 #include <errno.h>
  25 #include <setjmp.h>
  26 #include "xgselect.h"
  27
  28 static GPollFD *gfds;
  29 static int gfds_size;
  30
  31 int
  32 xg_select (max_fds, rfds, wfds, efds, timeout)
  33      int max_fds;
  34      SELECT_TYPE *rfds;
  35      SELECT_TYPE *wfds;
  36      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 = g_main_context_default ();
  43   int have_wfds = wfds != NULL;
  44   int n_gfds = 0, our_tmo = 0, retval = 0, our_fds = 0;
  45   int prio, i, nfds, tmo_in_millisec;
  46
  47   if (rfds) memcpy (&all_rfds, rfds, sizeof (all_rfds));
  48   else FD_ZERO (&all_rfds);
  49   if (wfds) memcpy (&all_wfds, wfds, sizeof (all_rfds));
  50   else FD_ZERO (&all_wfds);
  51
  52   /* Update event sources in GLib. */
  53   g_main_context_pending (context);
  54
  55   do {
  56     if (n_gfds > gfds_size)
  57       {
  58         while (n_gfds > gfds_size)
  59           gfds_size *= 2;
  60         xfree (gfds);
  61         gfds = xmalloc (sizeof (*gfds) * gfds_size);
  62       }
  63
  64     n_gfds = g_main_context_query (context,
  65                                    G_PRIORITY_LOW,
  66                                    &tmo_in_millisec,
  67                                    gfds,
  68                                    gfds_size);
  69   } while (n_gfds > gfds_size);
  70
  71   for (i = 0; i < n_gfds; ++i)
  72     {
  73       if (gfds[i].events & G_IO_IN)
  74         {
  75           FD_SET (gfds[i].fd, &all_rfds);
  76           if (gfds[i].fd > max_fds) max_fds = gfds[i].fd;
  77         }
  78       if (gfds[i].events & G_IO_OUT)
  79         {
  80           FD_SET (gfds[i].fd, &all_wfds);
  81           if (gfds[i].fd > max_fds) max_fds = gfds[i].fd;
  82           have_wfds = 1;
  83         }
  84     }
  85
  86   if (tmo_in_millisec >= 0)
  87     {
  88       EMACS_SET_SECS_USECS (tmo, tmo_in_millisec/1000,
  89                             1000 * (tmo_in_millisec % 1000));
  90       if (!timeout) our_tmo = 1;
  91       else
  92         {
  93           EMACS_TIME difference;
  94
  95           EMACS_SUB_TIME (difference, tmo, *timeout);
  96           if (EMACS_TIME_NEG_P (difference)) our_tmo = 1;
  97         }
  98
  99       if (our_tmo) tmop = &tmo;
 100     }
 101
 102   nfds = select (max_fds+1, &all_rfds, have_wfds ? &all_wfds : NULL,
 103                  efds, tmop);
 104
 105   if (nfds < 0)
 106     retval = nfds;
 107   else if (nfds > 0)
 108     {
 109       for (i = 0; i < max_fds+1; ++i)
 110         {
 111           if (FD_ISSET (i, &all_rfds))
 112             {
 113               if (rfds && FD_ISSET (i, rfds)) ++retval;
 114               else ++our_fds;
 115             }
 116           if (have_wfds && FD_ISSET (i, &all_wfds))
 117             {
 118               if (wfds && FD_ISSET (i, wfds)) ++retval;
 119               else ++our_fds;
 120             }
 121           if (efds && FD_ISSET (i, efds))
 122             ++retval;
 123         }
 124     }
 125
 126   if (our_fds > 0 || (nfds == 0 && our_tmo))
 127     {
 128
 129       /* If Gtk+ is in use eventually gtk_main_iteration will be called,
 130          unless retval is zero.  */
 131 #ifdef USE_GTK
 132       if (retval == 0)
 133 #endif
 134         while (g_main_context_pending (context))
 135           g_main_context_dispatch (context);
 136
 137       /* To not have to recalculate timeout, return like this.  */
 138       if (retval == 0)
 139         {
 140           retval = -1;
 141           errno = EINTR;
 142         }
 143     }
 144
 145   return retval;
 146 }
 147 #endif /* defined (USE_GTK) || defined (HAVE_GCONF) */
 148
 149 void
 150 xgselect_initialize ()
 151 {
 152 #if defined (USE_GTK) || defined (HAVE_GCONF)
 153   gfds_size = 128;
 154   gfds = xmalloc (sizeof (*gfds)*gfds_size);
 155 #endif /* defined (USE_GTK) || defined (HAVE_GCONF) */
 156 }
 157
 158 /* arch-tag: c5873ee3-d1f6-44f9-9f3b-b14f70fd0e6a
 159    (do not change this comment) */