src/gfilenotify.c

   1 /* Filesystem notifications support with glib API.
   2    Copyright (C) 2013 Free Software Foundation, Inc.
   3
   4 This file is part of GNU Emacs.
   5
   6 GNU Emacs is free software: you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation, either version 3 of the License, or
   9 (at your option) any later version.
  10
  11 GNU Emacs is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
  18
  19 #include <config.h>
  20
  21 #ifdef HAVE_GFILENOTIFY
  22 #include <stdio.h>
  23 #include <gio/gio.h>
  24 #include "lisp.h"
  25 #include "coding.h"
  26 #include "frame.h"
  27 #include "termhooks.h"
  28 #include "keyboard.h"
  29 #include "process.h"
  30
  31 \f
  32 /* Subroutines.  */
  33 static Lisp_Object Qgfile_add_watch;
  34 static Lisp_Object Qgfile_rm_watch;
  35
  36 /* Filter objects.  */
  37 static Lisp_Object Qwatch_mounts;      /* G_FILE_MONITOR_WATCH_MOUNTS  */
  38 static Lisp_Object Qsend_moved;        /* G_FILE_MONITOR_SEND_MOVED  */
  39
  40 /* Event types.  */
  41 static Lisp_Object Qchanged;           /* G_FILE_MONITOR_EVENT_CHANGED  */
  42 static Lisp_Object Qchanges_done_hint; /* G_FILE_MONITOR_EVENT_CHANGES_DONE_HINT  */
  43 static Lisp_Object Qdeleted;           /* G_FILE_MONITOR_EVENT_DELETED  */
  44 static Lisp_Object Qcreated;           /* G_FILE_MONITOR_EVENT_CREATED  */
  45 static Lisp_Object Qattribute_changed; /* G_FILE_MONITOR_EVENT_ATTRIBUTE_CHANGED  */
  46 static Lisp_Object Qpre_unmount;       /* G_FILE_MONITOR_EVENT_PRE_UNMOUNT  */
  47 static Lisp_Object Qunmounted;         /* G_FILE_MONITOR_EVENT_UNMOUNTED  */
  48 static Lisp_Object Qmoved;             /* G_FILE_MONITOR_EVENT_MOVED  */
  49
  50 static Lisp_Object watch_list;
  51
  52 /* This is the callback function for arriving signals from
  53    g_file_monitor.  It shall create a Lisp event, and put it into
  54    Emacs input queue.  */
  55 static gboolean
  56 dir_monitor_callback (GFileMonitor *monitor,
  57                       GFile *file,
  58                       GFile *other_file,
  59                       GFileMonitorEvent event_type,
  60                       gpointer user_data)
  61 {
  62   Lisp_Object symbol, monitor_object, watch_object;
  63   char *name = g_file_get_parse_name (file);
  64   char *oname = other_file ? g_file_get_parse_name (other_file) : NULL;
  65
  66   /* Determine event symbol.  */
  67   switch (event_type)
  68     {
  69     case G_FILE_MONITOR_EVENT_CHANGED:
  70       symbol = Qchanged;
  71       break;
  72     case G_FILE_MONITOR_EVENT_CHANGES_DONE_HINT:
  73       symbol = Qchanges_done_hint;
  74       break;
  75     case G_FILE_MONITOR_EVENT_DELETED:
  76       symbol = Qdeleted;
  77       break;
  78     case G_FILE_MONITOR_EVENT_CREATED:
  79       symbol = Qcreated;
  80       break;
  81     case G_FILE_MONITOR_EVENT_ATTRIBUTE_CHANGED:
  82       symbol = Qattribute_changed;
  83       break;
  84     case G_FILE_MONITOR_EVENT_PRE_UNMOUNT:
  85       symbol = Qpre_unmount;
  86       break;
  87     case G_FILE_MONITOR_EVENT_UNMOUNTED:
  88       symbol = Qunmounted;
  89       break;
  90     case G_FILE_MONITOR_EVENT_MOVED:
  91       symbol = Qmoved;
  92       break;
  93     default:
  94       goto cleanup;
  95     }
  96
  97   /* Determine callback function.  */
  98   monitor_object = XIL ((intptr_t) monitor);
  99   eassert (INTEGERP (monitor_object));
 100   watch_object = assq_no_quit (monitor_object, watch_list);
 101
 102   if (CONSP (watch_object))
 103     {
 104       /* Construct an event.  */
 105       struct input_event event;
 106       Lisp_Object otail = oname ? list1 (build_string (oname)) : Qnil;
 107       EVENT_INIT (event);
 108       event.kind = FILE_NOTIFY_EVENT;
 109       event.frame_or_window = Qnil;
 110       event.arg = list2 (Fcons (monitor_object,
 111                                 Fcons (symbol,
 112                                        Fcons (build_string (name),
 113                                               otail))),
 114                          XCDR (watch_object));
 115
 116       /* Store it into the input event queue.  */
 117       kbd_buffer_store_event (&event);
 118     }
 119
 120   /* Cleanup.  */
 121  cleanup:
 122   g_free (name);
 123   g_free (oname);
 124
 125   return TRUE;
 126 }
 127
 128 DEFUN ("gfile-add-watch", Fgfile_add_watch, Sgfile_add_watch, 3, 3, 0,
 129        doc: /* Add a watch for filesystem events pertaining to FILE.
 130
 131 This arranges for filesystem events pertaining to FILE to be reported
 132 to Emacs.  Use `gfile-rm-watch' to cancel the watch.
 133
 134 Value is a descriptor for the added watch.  If the file cannot be
 135 watched for some reason, this function signals a `file-error' error.
 136
 137 FLAGS is a list of conditions to set what will be watched for.  It can
 138 include the following symbols:
 139
 140   'watch-mounts' -- watch for mount events
 141   'send-moved'   -- pair 'deleted' and 'created' events caused by file
 142                     renames (moves) and send a single 'event-moved'
 143                     event instead
 144
 145 When any event happens, Emacs will call the CALLBACK function passing
 146 it a single argument EVENT, which is of the form
 147
 148   (DESCRIPTOR ACTION FILE [FILE1])
 149
 150 DESCRIPTOR is the same object as the one returned by this function.
 151 ACTION is the description of the event.  It could be any one of the
 152 following:
 153
 154   'changed'           -- FILE has changed
 155   'changes-done-hint' -- a hint that this was probably the last change
 156                          in a set of changes
 157   'deleted'           -- FILE was deleted
 158   'created'           -- FILE was created
 159   'attribute-changed' -- a FILE attribute was changed
 160   'pre-unmount'       -- the FILE location will soon be unmounted
 161   'unmounted'         -- the FILE location was unmounted
 162   'moved'             -- FILE was moved to FILE1
 163
 164 FILE is the name of the file whose event is being reported.  FILE1
 165 will be reported only in case of the 'moved' event.  */)
 166   (Lisp_Object file, Lisp_Object flags, Lisp_Object callback)
 167 {
 168   Lisp_Object watch_descriptor, watch_object;
 169   GFile *gfile;
 170   GFileMonitor *monitor;
 171   GFileMonitorFlags gflags = G_FILE_MONITOR_NONE;
 172
 173   /* Check parameters.  */
 174   CHECK_STRING (file);
 175   file = Fdirectory_file_name (Fexpand_file_name (file, Qnil));
 176   if (NILP (Ffile_exists_p (file)))
 177     report_file_error ("File does not exists", Fcons (file, Qnil));
 178
 179   CHECK_LIST (flags);
 180
 181   if (!FUNCTIONP (callback))
 182     wrong_type_argument (Qinvalid_function, callback);
 183
 184   /* Create GFile name.  */
 185   gfile = g_file_new_for_path (SSDATA (ENCODE_FILE (file)));
 186
 187   /* Assemble flags.  */
 188   if (!NILP (Fmember (Qwatch_mounts, flags)))
 189     gflags |= G_FILE_MONITOR_WATCH_MOUNTS;
 190   if (!NILP (Fmember (Qsend_moved, flags)))
 191     gflags |= G_FILE_MONITOR_SEND_MOVED;
 192
 193   /* Enable watch.  */
 194   monitor = g_file_monitor (gfile, gflags, NULL, NULL);
 195   if (! monitor)
 196     xsignal2 (Qfile_error, build_string ("Cannot watch file"), file);
 197
 198   /* On all known glib platforms, converting MONITOR directly to a
 199      Lisp_Object value results is a Lisp integer, which is safe.  This
 200      assumption is dicey, though, so check it now.  */
 201   watch_descriptor = XIL ((intptr_t) monitor);
 202   if (! INTEGERP (watch_descriptor))
 203     {
 204       g_object_unref (monitor);
 205       xsignal2 (Qfile_error, build_string ("Unsupported file watcher"), file);
 206     }
 207
 208   g_signal_connect (monitor, "changed",
 209                     (GCallback) dir_monitor_callback, NULL);
 210
 211   /* Store watch object in watch list.  */
 212   watch_object = Fcons (watch_descriptor, callback);
 213   watch_list = Fcons (watch_object, watch_list);
 214
 215   return watch_descriptor;
 216 }
 217
 218 DEFUN ("gfile-rm-watch", Fgfile_rm_watch, Sgfile_rm_watch, 1, 1, 0,
 219        doc: /* Remove an existing WATCH-DESCRIPTOR.
 220
 221 WATCH-DESCRIPTOR should be an object returned by `gfile-add-watch'.  */)
 222      (Lisp_Object watch_descriptor)
 223 {
 224   intptr_t int_monitor;
 225   GFileMonitor *monitor;
 226   Lisp_Object watch_object = assq_no_quit (watch_descriptor, watch_list);
 227
 228   if (! CONSP (watch_object))
 229     xsignal2 (Qfile_error, build_string ("Not a watch descriptor"),
 230               watch_descriptor);
 231
 232   eassert (INTEGERP (watch_descriptor));
 233   int_monitor = XLI (watch_descriptor);
 234   monitor = (GFileMonitor *) int_monitor;
 235   if (!g_file_monitor_cancel (monitor))
 236     xsignal2 (Qfile_error, build_string ("Could not rm watch"),
 237               watch_descriptor);
 238
 239   /* Remove watch descriptor from watch list. */
 240   watch_list = Fdelq (watch_object, watch_list);
 241
 242   /* Cleanup.  */
 243   g_object_unref (monitor);
 244
 245   return Qt;
 246 }
 247
 248 \f
 249 void
 250 globals_of_gfilenotify (void)
 251 {
 252   g_type_init ();
 253   watch_list = Qnil;
 254 }
 255
 256 void
 257 syms_of_gfilenotify (void)
 258 {
 259
 260   DEFSYM (Qgfile_add_watch, "gfile-add-watch");
 261   defsubr (&Sgfile_add_watch);
 262
 263   DEFSYM (Qgfile_rm_watch, "gfile-rm-watch");
 264   defsubr (&Sgfile_rm_watch);
 265
 266   DEFSYM (Qwatch_mounts, "watch-mounts");
 267   DEFSYM (Qsend_moved, "send-moved");
 268   DEFSYM (Qchanged, "changed");
 269   DEFSYM (Qchanges_done_hint, "changes-done-hint");
 270   DEFSYM (Qdeleted, "deleted");
 271   DEFSYM (Qcreated, "created");
 272   DEFSYM (Qattribute_changed, "attribute-changed");
 273   DEFSYM (Qpre_unmount, "pre-unmount");
 274   DEFSYM (Qunmounted, "unmounted");
 275   DEFSYM (Qmoved, "moved");
 276
 277   staticpro (&watch_list);
 278
 279   Fprovide (intern_c_string ("gfilenotify"), Qnil);
 280
 281 }
 282
 283 #endif /* HAVE_GFILENOTIFY  */