code.delx.au - gnu-emacs/blob - src/gfilenotify.c

   1 /* Filesystem notifications support with glib API.
   2    Copyright (C) 2013-2015 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 "termhooks.h"
  27 #include "keyboard.h"
  28
  29 \f
  30 /* This is a list, elements are triples (DESCRIPTOR FILE FLAGS CALLBACK)  */
  31 static Lisp_Object watch_list;
  32
  33 /* This is the callback function for arriving signals from
  34    g_file_monitor.  It shall create a Lisp event, and put it into
  35    Emacs input queue.  */
  36 static gboolean
  37 dir_monitor_callback (GFileMonitor *monitor,
  38                       GFile *file,
  39                       GFile *other_file,
  40                       GFileMonitorEvent event_type,
  41                       gpointer user_data)
  42 {
  43   Lisp_Object symbol, monitor_object, watch_object, flags;
  44   char *name = g_file_get_parse_name (file);
  45   char *oname = other_file ? g_file_get_parse_name (other_file) : NULL;
  46
  47   /* Determine event symbol.  */
  48   switch (event_type)
  49     {
  50     case G_FILE_MONITOR_EVENT_CHANGED:
  51       symbol = Qchanged;
  52       break;
  53     case G_FILE_MONITOR_EVENT_CHANGES_DONE_HINT:
  54       symbol = Qchanges_done_hint;
  55       break;
  56     case G_FILE_MONITOR_EVENT_DELETED:
  57       symbol = Qdeleted;
  58       break;
  59     case G_FILE_MONITOR_EVENT_CREATED:
  60       symbol = Qcreated;
  61       break;
  62     case G_FILE_MONITOR_EVENT_ATTRIBUTE_CHANGED:
  63       symbol = Qattribute_changed;
  64       break;
  65     case G_FILE_MONITOR_EVENT_PRE_UNMOUNT:
  66       symbol = Qpre_unmount;
  67       break;
  68     case G_FILE_MONITOR_EVENT_UNMOUNTED:
  69       symbol = Qunmounted;
  70       break;
  71     case G_FILE_MONITOR_EVENT_MOVED:
  72       symbol = Qmoved;
  73       break;
  74     default:
  75       goto cleanup;
  76     }
  77
  78   /* Determine callback function.  */
  79   monitor_object = make_pointer_integer (monitor);
  80   eassert (INTEGERP (monitor_object));
  81   watch_object = assq_no_quit (monitor_object, watch_list);
  82
  83   if (CONSP (watch_object))
  84     {
  85       struct input_event event;
  86       Lisp_Object otail = oname ? list1 (build_string (oname)) : Qnil;
  87
  88       /* Check, whether event_type is expected.  */
  89       flags = XCAR (XCDR (XCDR (watch_object)));
  90       if ((!NILP (Fmember (Qchange, flags)) &&
  91            !NILP (Fmember (symbol, list5 (Qchanged, Qchanges_done_hint,
  92                                           Qdeleted, Qcreated, Qmoved)))) ||
  93           (!NILP (Fmember (Qattribute_change, flags)) &&
  94            ((EQ (symbol, Qattribute_changed)))))
  95         {
  96           /* Construct an event.  */
  97           EVENT_INIT (event);
  98           event.kind = FILE_NOTIFY_EVENT;
  99           event.frame_or_window = Qnil;
 100           event.arg = list2 (Fcons (monitor_object,
 101                                     Fcons (symbol,
 102                                            Fcons (build_string (name),
 103                                                   otail))),
 104                              XCAR (XCDR (XCDR (XCDR (watch_object)))));
 105
 106           /* Store it into the input event queue.  */
 107           kbd_buffer_store_event (&event);
 108           // XD_DEBUG_MESSAGE ("%s", XD_OBJECT_TO_STRING (event.arg));
 109         }
 110
 111       /* Cancel monitor if file or directory is deleted.  */
 112       if (!NILP (Fmember (symbol, list2 (Qdeleted, Qmoved))) &&
 113           !g_file_monitor_is_cancelled (monitor))
 114         g_file_monitor_cancel (monitor);
 115     }
 116
 117   /* Cleanup.  */
 118  cleanup:
 119   g_free (name);
 120   g_free (oname);
 121
 122   return TRUE;
 123 }
 124
 125 DEFUN ("gfile-add-watch", Fgfile_add_watch, Sgfile_add_watch, 3, 3, 0,
 126        doc: /* Add a watch for filesystem events pertaining to FILE.
 127
 128 This arranges for filesystem events pertaining to FILE to be reported
 129 to Emacs.  Use `gfile-rm-watch' to cancel the watch.
 130
 131 Value is a descriptor for the added watch.  If the file cannot be
 132 watched for some reason, this function signals a `file-notify-error' error.
 133
 134 FLAGS is a list of conditions to set what will be watched for.  It can
 135 include the following symbols:
 136
 137   `change'           -- watch for file changes
 138   `attribute-change' -- watch for file attributes changes, like
 139                         permissions or modification time
 140   `watch-mounts'     -- watch for mount events
 141   `send-moved'       -- pair `deleted' and `created' events caused by
 142                         file renames and send a single `renamed' event
 143                         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_object;
 169   GFile *gfile;
 170   GFileMonitor *monitor;
 171   GFileMonitorFlags gflags = G_FILE_MONITOR_NONE;
 172   GError *gerror = NULL;
 173
 174   /* Check parameters.  */
 175   CHECK_STRING (file);
 176   file = Fdirectory_file_name (Fexpand_file_name (file, Qnil));
 177   if (NILP (Ffile_exists_p (file)))
 178     report_file_error ("File does not exist", file);
 179
 180   CHECK_LIST (flags);
 181
 182   if (!FUNCTIONP (callback))
 183     wrong_type_argument (Qinvalid_function, callback);
 184
 185   /* Create GFile name.  */
 186   gfile = g_file_new_for_path (SSDATA (ENCODE_FILE (file)));
 187
 188   /* Assemble flags.  */
 189   if (!NILP (Fmember (Qwatch_mounts, flags)))
 190     gflags |= G_FILE_MONITOR_WATCH_MOUNTS;
 191   if (!NILP (Fmember (Qsend_moved, flags)))
 192     gflags |= G_FILE_MONITOR_SEND_MOVED;
 193
 194   /* Enable watch.  */
 195   monitor = g_file_monitor (gfile, gflags, NULL, &gerror);
 196   g_object_unref (gfile);
 197   if (gerror)
 198     {
 199       char msg[1024];
 200       strcpy (msg, gerror->message);
 201       g_error_free (gerror);
 202       xsignal1 (Qfile_notify_error, build_string (msg));
 203     }
 204   if (! monitor)
 205     xsignal2 (Qfile_notify_error, build_string ("Cannot watch file"), file);
 206
 207   Lisp_Object watch_descriptor = make_pointer_integer (monitor);
 208
 209   /* Check the dicey assumption that make_pointer_integer is safe.  */
 210   if (! INTEGERP (watch_descriptor))
 211     {
 212       g_object_unref (monitor);
 213       xsignal2 (Qfile_notify_error, build_string ("Unsupported file watcher"),
 214                 file);
 215     }
 216
 217   /* The default rate limit is 800 msec.  We adapt this.  */
 218   g_file_monitor_set_rate_limit (monitor, 100);
 219
 220   /* Subscribe to the "changed" signal.  */
 221   g_signal_connect (monitor, "changed",
 222                     (GCallback) dir_monitor_callback, NULL);
 223
 224   /* Store watch object in watch list.  */
 225   watch_object = list4 (watch_descriptor, file, flags, callback);
 226   watch_list = Fcons (watch_object, watch_list);
 227
 228   return watch_descriptor;
 229 }
 230
 231 DEFUN ("gfile-rm-watch", Fgfile_rm_watch, Sgfile_rm_watch, 1, 1, 0,
 232        doc: /* Remove an existing WATCH-DESCRIPTOR.
 233
 234 WATCH-DESCRIPTOR should be an object returned by `gfile-add-watch'.  */)
 235      (Lisp_Object watch_descriptor)
 236 {
 237   Lisp_Object watch_object = assq_no_quit (watch_descriptor, watch_list);
 238
 239   if (! CONSP (watch_object))
 240     xsignal2 (Qfile_notify_error, build_string ("Not a watch descriptor"),
 241               watch_descriptor);
 242
 243   eassert (INTEGERP (watch_descriptor));
 244   GFileMonitor *monitor = XINTPTR (watch_descriptor);
 245   if (!g_file_monitor_is_cancelled (monitor) &&
 246       !g_file_monitor_cancel (monitor))
 247       xsignal2 (Qfile_notify_error, build_string ("Could not rm watch"),
 248                 watch_descriptor);
 249
 250   /* Remove watch descriptor from watch list.  */
 251   watch_list = Fdelq (watch_object, watch_list);
 252
 253   /* Cleanup.  */
 254   g_object_unref (monitor);
 255
 256   return Qt;
 257 }
 258
 259 DEFUN ("gfile-valid-p", Fgfile_valid_p, Sgfile_valid_p, 1, 1, 0,
 260        doc: /* "Check a watch specified by its WATCH-DESCRIPTOR.
 261
 262 WATCH-DESCRIPTOR should be an object returned by `gfile-add-watch'.
 263
 264 A watch can become invalid if the file or directory it watches is
 265 deleted, or if the watcher thread exits abnormally for any other
 266 reason.  Removing the watch by calling `gfile-rm-watch' also makes it
 267 invalid.  */)
 268      (Lisp_Object watch_descriptor)
 269 {
 270   Lisp_Object watch_object = Fassoc (watch_descriptor, watch_list);
 271   if (NILP (watch_object))
 272     return Qnil;
 273   else
 274     {
 275       GFileMonitor *monitor = XINTPTR (watch_descriptor);
 276       return g_file_monitor_is_cancelled (monitor) ? Qnil : Qt;
 277     }
 278 }
 279
 280 \f
 281 void
 282 globals_of_gfilenotify (void)
 283 {
 284 #if ! GLIB_CHECK_VERSION (2, 36, 0)
 285   g_type_init ();
 286 #endif
 287   watch_list = Qnil;
 288 }
 289
 290 void
 291 syms_of_gfilenotify (void)
 292 {
 293   defsubr (&Sgfile_add_watch);
 294   defsubr (&Sgfile_rm_watch);
 295   defsubr (&Sgfile_valid_p);
 296
 297   /* Filter objects.  */
 298   DEFSYM (Qchange, "change");
 299   DEFSYM (Qattribute_change, "attribute-change");
 300   DEFSYM (Qwatch_mounts, "watch-mounts"); /* G_FILE_MONITOR_WATCH_MOUNTS  */
 301   DEFSYM (Qsend_moved, "send-moved");   /* G_FILE_MONITOR_SEND_MOVED  */
 302
 303   /* Event types.  */
 304   DEFSYM (Qchanged, "changed"); /* G_FILE_MONITOR_EVENT_CHANGED  */
 305   DEFSYM (Qchanges_done_hint, "changes-done-hint");
 306                                 /* G_FILE_MONITOR_EVENT_CHANGES_DONE_HINT  */
 307   DEFSYM (Qdeleted, "deleted"); /* G_FILE_MONITOR_EVENT_DELETED  */
 308   DEFSYM (Qcreated, "created"); /* G_FILE_MONITOR_EVENT_CREATED  */
 309   DEFSYM (Qattribute_changed, "attribute-changed");
 310                                 /* G_FILE_MONITOR_EVENT_ATTRIBUTE_CHANGED  */
 311   DEFSYM (Qpre_unmount, "pre-unmount"); /* G_FILE_MONITOR_EVENT_PRE_UNMOUNT  */
 312   DEFSYM (Qunmounted, "unmounted");     /* G_FILE_MONITOR_EVENT_UNMOUNTED  */
 313   DEFSYM (Qmoved, "moved");     /* G_FILE_MONITOR_EVENT_MOVED  */
 314
 315   staticpro (&watch_list);
 316
 317   Fprovide (intern_c_string ("gfilenotify"), Qnil);
 318
 319 }
 320
 321 #endif /* HAVE_GFILENOTIFY  */