src/xgselect.c

   1 /* Function for handling the GLib event loop.
   2
   3 Copyright (C) 2009-2013 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 "xgselect.h"
  23
  24 #ifdef HAVE_GLIB
  25
  26 #include <glib.h>
  27 #include <errno.h>
  28 #include "xterm.h"
  29 #include "frame.h"
  30
  31 int
  32 xg_select (int fds_lim, SELECT_TYPE *rfds, SELECT_TYPE *wfds, SELECT_TYPE *efds,
  33            EMACS_TIME *timeout, sigset_t *sigmask)
  34 {
  35   SELECT_TYPE all_rfds, all_wfds;
  36   EMACS_TIME tmo, *tmop = timeout;
  37
  38   GMainContext *context;
  39   int have_wfds = wfds != NULL;
  40   GPollFD gfds_buf[128];
  41   GPollFD *gfds = gfds_buf;
  42   int gfds_size = sizeof gfds_buf / sizeof *gfds_buf;
  43   int n_gfds, retval = 0, our_fds = 0, max_fds = fds_lim - 1;
  44   int i, nfds, tmo_in_millisec;
  45   USE_SAFE_ALLOCA;
  46
  47   if (! (window_system_available (NULL)
  48          && g_main_context_pending (context = g_main_context_default ())))
  49     return pselect (fds_lim, rfds, wfds, efds, timeout, sigmask);
  50
  51   if (rfds) all_rfds = *rfds;
  52   else FD_ZERO (&all_rfds);
  53   if (wfds) all_wfds = *wfds;
  54   else FD_ZERO (&all_wfds);
  55
  56   n_gfds = g_main_context_query (context, G_PRIORITY_LOW, &tmo_in_millisec,
  57                                  gfds, gfds_size);
  58   if (gfds_size < n_gfds)
  59     {
  60       SAFE_NALLOCA (gfds, sizeof *gfds, n_gfds);
  61       gfds_size = n_gfds;
  62       n_gfds = g_main_context_query (context, G_PRIORITY_LOW, &tmo_in_millisec,
  63                                      gfds, gfds_size);
  64     }
  65
  66   for (i = 0; i < n_gfds; ++i)
  67     {
  68       if (gfds[i].events & G_IO_IN)
  69         {
  70           FD_SET (gfds[i].fd, &all_rfds);
  71           if (gfds[i].fd > max_fds) max_fds = gfds[i].fd;
  72         }
  73       if (gfds[i].events & G_IO_OUT)
  74         {
  75           FD_SET (gfds[i].fd, &all_wfds);
  76           if (gfds[i].fd > max_fds) max_fds = gfds[i].fd;
  77           have_wfds = 1;
  78         }
  79     }
  80
  81   SAFE_FREE ();
  82
  83   if (tmo_in_millisec >= 0)
  84     {
  85       tmo = make_emacs_time (tmo_in_millisec / 1000,
  86                              1000 * 1000 * (tmo_in_millisec % 1000));
  87       if (!timeout || EMACS_TIME_LT (tmo, *timeout))
  88         tmop = &tmo;
  89     }
  90
  91   fds_lim = max_fds + 1;
  92   nfds = pselect (fds_lim, &all_rfds, have_wfds ? &all_wfds : NULL,
  93                   efds, tmop, sigmask);
  94
  95   if (nfds < 0)
  96     retval = nfds;
  97   else if (nfds > 0)
  98     {
  99       for (i = 0; i < fds_lim; ++i)
 100         {
 101           if (FD_ISSET (i, &all_rfds))
 102             {
 103               if (rfds && FD_ISSET (i, rfds)) ++retval;
 104               else ++our_fds;
 105             }
 106           else if (rfds)
 107             FD_CLR (i, rfds);
 108
 109           if (have_wfds && FD_ISSET (i, &all_wfds))
 110             {
 111               if (wfds && FD_ISSET (i, wfds)) ++retval;
 112               else ++our_fds;
 113             }
 114           else if (wfds)
 115             FD_CLR (i, wfds);
 116
 117           if (efds && FD_ISSET (i, efds))
 118             ++retval;
 119         }
 120     }
 121
 122   if (our_fds > 0 || (nfds == 0 && tmop == &tmo))
 123     {
 124
 125       /* If Gtk+ is in use eventually gtk_main_iteration will be called,
 126          unless retval is zero.  */
 127 #ifdef USE_GTK
 128       if (retval == 0)
 129 #endif
 130         while (g_main_context_pending (context))
 131           g_main_context_dispatch (context);
 132
 133       /* To not have to recalculate timeout, return like this.  */
 134       if (retval == 0)
 135         {
 136           retval = -1;
 137           errno = EINTR;
 138         }
 139     }
 140
 141   return retval;
 142 }
 143 #endif /* HAVE_GLIB */