src/kqueue.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_KQUEUE
  22 #include <stdio.h>
  23 #include <sys/event.h>
  24 #include "lisp.h"
  25 #include "coding.h"
  26 #include "termhooks.h"
  27 #include "keyboard.h"
  28
  29 \f
  30 /* File handle for kqueue.  */
  31 static int kqueuefd = -1;
  32
  33 /* This is a list, elements are triples (DESCRIPTOR FILE FLAGS CALLBACK)  */
  34 static Lisp_Object watch_list;
  35
  36 #if 0
  37 /* This is the callback function for arriving signals from
  38    g_file_monitor.  It shall create a Lisp event, and put it into
  39    Emacs input queue.  */
  40 static gboolean
  41 dir_monitor_callback (GFileMonitor *monitor,
  42                       GFile *file,
  43                       GFile *other_file,
  44                       GFileMonitorEvent event_type,
  45                       gpointer user_data)
  46 {
  47   Lisp_Object symbol, monitor_object, watch_object, flags;
  48   char *name = g_file_get_parse_name (file);
  49   char *oname = other_file ? g_file_get_parse_name (other_file) : NULL;
  50
  51   /* Determine event symbol.  */
  52   switch (event_type)
  53     {
  54     case G_FILE_MONITOR_EVENT_CHANGED:
  55       symbol = Qchanged;
  56       break;
  57     case G_FILE_MONITOR_EVENT_CHANGES_DONE_HINT:
  58       symbol = Qchanges_done_hint;
  59       break;
  60     case G_FILE_MONITOR_EVENT_DELETED:
  61       symbol = Qdeleted;
  62       break;
  63     case G_FILE_MONITOR_EVENT_CREATED:
  64       symbol = Qcreated;
  65       break;
  66     case G_FILE_MONITOR_EVENT_ATTRIBUTE_CHANGED:
  67       symbol = Qattribute_changed;
  68       break;
  69     case G_FILE_MONITOR_EVENT_PRE_UNMOUNT:
  70       symbol = Qpre_unmount;
  71       break;
  72     case G_FILE_MONITOR_EVENT_UNMOUNTED:
  73       symbol = Qunmounted;
  74       break;
  75     case G_FILE_MONITOR_EVENT_MOVED:
  76       symbol = Qmoved;
  77       break;
  78     default:
  79       goto cleanup;
  80     }
  81
  82   /* Determine callback function.  */
  83   monitor_object = make_pointer_integer (monitor);
  84   eassert (INTEGERP (monitor_object));
  85   watch_object = assq_no_quit (monitor_object, watch_list);
  86
  87   if (CONSP (watch_object))
  88     {
  89       struct input_event event;
  90       Lisp_Object otail = oname ? list1 (build_string (oname)) : Qnil;
  91
  92       /* Check, whether event_type is expected.  */
  93       flags = XCAR (XCDR (XCDR (watch_object)));
  94       if ((!NILP (Fmember (Qchange, flags)) &&
  95            !NILP (Fmember (symbol, list5 (Qchanged, Qchanges_done_hint,
  96                                           Qdeleted, Qcreated, Qmoved)))) ||
  97           (!NILP (Fmember (Qattribute_change, flags)) &&
  98            ((EQ (symbol, Qattribute_changed)))))
  99         {
 100           /* Construct an event.  */
 101           EVENT_INIT (event);
 102           event.kind = FILE_NOTIFY_EVENT;
 103           event.frame_or_window = Qnil;
 104           event.arg = list2 (Fcons (monitor_object,
 105                                     Fcons (symbol,
 106                                            Fcons (build_string (name),
 107                                                   otail))),
 108                              XCAR (XCDR (XCDR (XCDR (watch_object)))));
 109
 110           /* Store it into the input event queue.  */
 111           kbd_buffer_store_event (&event);
 112           // XD_DEBUG_MESSAGE ("%s", XD_OBJECT_TO_STRING (event.arg));
 113         }
 114
 115       /* Cancel monitor if file or directory is deleted.  */
 116       if (!NILP (Fmember (symbol, list2 (Qdeleted, Qmoved))) &&
 117           (strcmp (name, SSDATA (XCAR (XCDR (watch_object)))) == 0) &&
 118           !g_file_monitor_is_cancelled (monitor))
 119         g_file_monitor_cancel (monitor);
 120     }
 121
 122   /* Cleanup.  */
 123  cleanup:
 124   g_free (name);
 125   g_free (oname);
 126
 127   return TRUE;
 128 }
 129 #endif /* 0  */
 130
 131 DEFUN ("kqueue-add-watch", Fkqueue_add_watch, Skqueue_add_watch, 3, 3, 0,
 132        doc: /* Add a watch for filesystem events pertaining to FILE.
 133
 134 This arranges for filesystem events pertaining to FILE to be reported
 135 to Emacs.  Use `gfile-rm-watch' to cancel the watch.
 136
 137 Value is a descriptor for the added watch.  If the file cannot be
 138 watched for some reason, this function signals a `file-notify-error' error.
 139
 140 FLAGS is a list of conditions to set what will be watched for.  It can
 141 include the following symbols:
 142
 143   `change'           -- watch for file changes
 144   `attribute-change' -- watch for file attributes changes, like
 145                         permissions or modification time
 146   `watch-mounts'     -- watch for mount events
 147   `send-moved'       -- pair `deleted' and `created' events caused by
 148                         file renames and send a single `renamed' event
 149                         instead
 150
 151 When any event happens, Emacs will call the CALLBACK function passing
 152 it a single argument EVENT, which is of the form
 153
 154   (DESCRIPTOR ACTION FILE [FILE1])
 155
 156 DESCRIPTOR is the same object as the one returned by this function.
 157 ACTION is the description of the event.  It could be any one of the
 158 following:
 159
 160   `changed'           -- FILE has changed
 161   `changes-done-hint' -- a hint that this was probably the last change
 162                          in a set of changes
 163   `deleted'           -- FILE was deleted
 164   `created'           -- FILE was created
 165   `attribute-changed' -- a FILE attribute was changed
 166   `pre-unmount'       -- the FILE location will soon be unmounted
 167   `unmounted'         -- the FILE location was unmounted
 168   `moved'             -- FILE was moved to FILE1
 169
 170 FILE is the name of the file whose event is being reported.  FILE1
 171 will be reported only in case of the `moved' event.  */)
 172   (Lisp_Object file, Lisp_Object flags, Lisp_Object callback)
 173 {
 174   Lisp_Object watch_object;
 175   GFile *gfile;
 176   GFileMonitor *monitor;
 177   GFileMonitorFlags gflags = G_FILE_MONITOR_NONE;
 178   GError *gerror = NULL;
 179
 180   /* Check parameters.  */
 181   CHECK_STRING (file);
 182   file = Fdirectory_file_name (Fexpand_file_name (file, Qnil));
 183   if (NILP (Ffile_exists_p (file)))
 184     report_file_error ("File does not exist", file);
 185
 186   CHECK_LIST (flags);
 187
 188   if (!FUNCTIONP (callback))
 189     wrong_type_argument (Qinvalid_function, callback);
 190
 191   /* Create GFile name.  */
 192   //  gfile = g_file_new_for_path (SSDATA (ENCODE_FILE (file)));
 193
 194   /* Assemble flags.  */
 195   //  if (!NILP (Fmember (Qwatch_mounts, flags)))
 196   //    gflags |= G_FILE_MONITOR_WATCH_MOUNTS;
 197   //  if (!NILP (Fmember (Qsend_moved, flags)))
 198   //    gflags |= G_FILE_MONITOR_SEND_MOVED;
 199
 200   if (kqueuefd < 0)
 201     {
 202       kqueuefd = kqueue ();
 203       if (kqueuefd < 0)
 204         report_file_notify_error ("File watching is not available", Qnil);
 205       watch_list = Qnil;
 206       //      add_read_fd (inotifyfd, &inotify_callback, NULL);
 207     }
 208
 209
 210 }
 211 #if 0
 212
 213   mask = aspect_to_inotifymask (aspect);
 214   encoded_file_name = ENCODE_FILE (file_name);
 215   watchdesc = inotify_add_watch (inotifyfd, SSDATA (encoded_file_name), mask);
 216   if (watchdesc == -1)
 217     report_file_notify_error ("Could not add watch for file", file_name);
 218
 219   /* Enable watch.  */
 220   monitor = g_file_monitor (gfile, gflags, NULL, &gerror);
 221   g_object_unref (gfile);
 222   if (gerror)
 223     {
 224       char msg[1024];
 225       strcpy (msg, gerror->message);
 226       g_error_free (gerror);
 227       xsignal1 (Qfile_notify_error, build_string (msg));
 228     }
 229   if (! monitor)
 230     xsignal2 (Qfile_notify_error, build_string ("Cannot watch file"), file);
 231
 232   Lisp_Object watch_descriptor = make_pointer_integer (monitor);
 233
 234   /* Check the dicey assumption that make_pointer_integer is safe.  */
 235   if (! INTEGERP (watch_descriptor))
 236     {
 237       g_object_unref (monitor);
 238       xsignal2 (Qfile_notify_error, build_string ("Unsupported file watcher"),
 239                 file);
 240     }
 241
 242   /* The default rate limit is 800 msec.  We adapt this.  */
 243   g_file_monitor_set_rate_limit (monitor, 100);
 244
 245   /* Subscribe to the "changed" signal.  */
 246   g_signal_connect (monitor, "changed",
 247                     (GCallback) dir_monitor_callback, NULL);
 248
 249   /* Store watch object in watch list.  */
 250   watch_object = list4 (watch_descriptor, file, flags, callback);
 251   watch_list = Fcons (watch_object, watch_list);
 252
 253   return watch_descriptor;
 254 }
 255
 256 DEFUN ("gfile-rm-watch", Fgfile_rm_watch, Sgfile_rm_watch, 1, 1, 0,
 257        doc: /* Remove an existing WATCH-DESCRIPTOR.
 258
 259 WATCH-DESCRIPTOR should be an object returned by `gfile-add-watch'.  */)
 260      (Lisp_Object watch_descriptor)
 261 {
 262   Lisp_Object watch_object = assq_no_quit (watch_descriptor, watch_list);
 263
 264   if (! CONSP (watch_object))
 265     xsignal2 (Qfile_notify_error, build_string ("Not a watch descriptor"),
 266               watch_descriptor);
 267
 268   eassert (INTEGERP (watch_descriptor));
 269   GFileMonitor *monitor = XINTPTR (watch_descriptor);
 270   if (!g_file_monitor_is_cancelled (monitor) &&
 271       !g_file_monitor_cancel (monitor))
 272       xsignal2 (Qfile_notify_error, build_string ("Could not rm watch"),
 273                 watch_descriptor);
 274
 275   /* Remove watch descriptor from watch list.  */
 276   watch_list = Fdelq (watch_object, watch_list);
 277
 278   /* Cleanup.  */
 279   g_object_unref (monitor);
 280
 281   return Qt;
 282 }
 283
 284 DEFUN ("gfile-valid-p", Fgfile_valid_p, Sgfile_valid_p, 1, 1, 0,
 285        doc: /* "Check a watch specified by its WATCH-DESCRIPTOR.
 286
 287 WATCH-DESCRIPTOR should be an object returned by `gfile-add-watch'.
 288
 289 A watch can become invalid if the file or directory it watches is
 290 deleted, or if the watcher thread exits abnormally for any other
 291 reason.  Removing the watch by calling `gfile-rm-watch' also makes it
 292 invalid.  */)
 293      (Lisp_Object watch_descriptor)
 294 {
 295   Lisp_Object watch_object = Fassoc (watch_descriptor, watch_list);
 296   if (NILP (watch_object))
 297     return Qnil;
 298   else
 299     {
 300       GFileMonitor *monitor = XINTPTR (watch_descriptor);
 301       return g_file_monitor_is_cancelled (monitor) ? Qnil : Qt;
 302     }
 303 }
 304 #endif /* 0  */
 305
 306 \f
 307 void
 308 globals_of_kqueue (void)
 309 {
 310   watch_list = Qnil;
 311 }
 312
 313 void
 314 syms_of_kqueue (void)
 315 {
 316   defsubr (&Skqueue_add_watch);
 317   //  defsubr (&Skqueue_rm_watch);
 318   //  defsubr (&Skqueue_valid_p);
 319
 320   /* Filter objects.  */
 321   DEFSYM (Qchange, "change");
 322   DEFSYM (Qattribute_change, "attribute-change");
 323   DEFSYM (Qwatch_mounts, "watch-mounts"); /* G_FILE_MONITOR_WATCH_MOUNTS  */
 324   DEFSYM (Qsend_moved, "send-moved");   /* G_FILE_MONITOR_SEND_MOVED  */
 325
 326   /* Event types.  */
 327   DEFSYM (Qdelete, "delete");   /* NOTE_DELETE  */
 328   DEFSYM (Qwrite, "write");     /* NOTE_WRITE  */
 329   DEFSYM (Qextend, "extend");   /* NOTE_EXTEND  */
 330   DEFSYM (Qattrib, "attrib");   /* NOTE_ATTRIB  */
 331   DEFSYM (Qlink, "link");       /* NOTE_LINK  */
 332   DEFSYM (Qrename, "rename");   /* NOTE_RENAME  */
 333
 334   staticpro (&watch_list);
 335
 336   Fprovide (intern_c_string ("kqueue"), Qnil);
 337 }
 338
 339 #endif /* HAVE_KQUEUE  */