337 lines
11 KiB
C
337 lines
11 KiB
C
/* Filesystem notifications support with glib API.
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Copyright (C) 2013-2024 Free Software Foundation, Inc.
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This file is part of GNU Emacs.
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GNU Emacs is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or (at
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your option) any later version.
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GNU Emacs is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>. */
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#include <config.h>
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#include <gio/gio.h>
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#include "lisp.h"
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#include "coding.h"
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#include "termhooks.h"
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#include "keyboard.h"
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/* This is a list, elements are quadruples (DESCRIPTOR FILE FLAGS CALLBACK) */
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static Lisp_Object watch_list;
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/* This is the callback function for arriving signals from
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g_file_monitor. It shall create a Lisp event, and put it into
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Emacs input queue. */
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static gboolean
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dir_monitor_callback (GFileMonitor *monitor,
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GFile *file,
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GFile *other_file,
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GFileMonitorEvent event_type,
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gpointer user_data)
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{
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Lisp_Object symbol, monitor_object, watch_object, flags;
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char *name = g_file_get_parse_name (file);
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char *oname = other_file ? g_file_get_parse_name (other_file) : NULL;
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/* Determine event symbol. */
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switch (event_type)
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{
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case G_FILE_MONITOR_EVENT_CHANGED:
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symbol = Qchanged;
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break;
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case G_FILE_MONITOR_EVENT_CHANGES_DONE_HINT:
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symbol = Qchanges_done_hint;
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break;
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case G_FILE_MONITOR_EVENT_DELETED:
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symbol = Qdeleted;
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break;
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case G_FILE_MONITOR_EVENT_CREATED:
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symbol = Qcreated;
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break;
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case G_FILE_MONITOR_EVENT_ATTRIBUTE_CHANGED:
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symbol = Qattribute_changed;
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break;
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case G_FILE_MONITOR_EVENT_PRE_UNMOUNT:
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symbol = Qpre_unmount;
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break;
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case G_FILE_MONITOR_EVENT_UNMOUNTED:
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symbol = Qunmounted;
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break;
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case G_FILE_MONITOR_EVENT_MOVED:
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symbol = Qmoved;
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break;
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default:
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goto cleanup;
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}
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/* Determine callback function. */
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monitor_object = make_pointer_integer (monitor);
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watch_object = assq_no_quit (monitor_object, watch_list);
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if (CONSP (watch_object))
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{
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struct input_event event;
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Lisp_Object otail = oname ? list1 (build_string (oname)) : Qnil;
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/* Check, whether event_type is expected. */
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flags = XCAR (XCDR (XCDR (watch_object)));
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if ((!NILP (Fmember (Qchange, flags))
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&& !NILP (Fmember (symbol, list5 (Qchanged, Qchanges_done_hint,
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Qdeleted, Qcreated, Qmoved))))
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|| (!NILP (Fmember (Qattribute_change, flags))
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&& EQ (symbol, Qattribute_changed))
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|| (!NILP (Fmember (Qwatch_mounts, flags))
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&& EQ (symbol, Qunmounted)))
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{
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/* Construct an event. */
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EVENT_INIT (event);
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event.kind = FILE_NOTIFY_EVENT;
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event.frame_or_window = Qnil;
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event.arg = list2 (Fcons (monitor_object,
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Fcons (symbol,
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Fcons (build_string (name),
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otail))),
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XCAR (XCDR (XCDR (XCDR (watch_object)))));
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/* Store it into the input event queue. */
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kbd_buffer_store_event (&event);
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/* XD_DEBUG_MESSAGE ("%s", XD_OBJECT_TO_STRING (event.arg)); */
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}
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/* Cancel monitor if file or directory is deleted or unmounted. */
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if (!NILP (Fmember (symbol, list3 (Qdeleted, Qmoved, Qunmounted)))
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&& strcmp (name, SSDATA (XCAR (XCDR (watch_object)))) == 0
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&& !g_file_monitor_is_cancelled (monitor))
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g_file_monitor_cancel (monitor);
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}
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/* Cleanup. */
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cleanup:
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g_free (name);
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g_free (oname);
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return TRUE;
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}
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DEFUN ("gfile-add-watch", Fgfile_add_watch, Sgfile_add_watch, 3, 3, 0,
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doc: /* Add a watch for filesystem events pertaining to FILE.
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This arranges for filesystem events pertaining to FILE to be reported
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to Emacs. Use `gfile-rm-watch' to cancel the watch.
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Value is a descriptor for the added watch. If the file cannot be
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watched for some reason, this function signals a `file-notify-error' error.
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FLAGS is a list of conditions to set what will be watched for. It can
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include the following symbols:
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`change' -- watch for file changes
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`attribute-change' -- watch for file attributes changes, like
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permissions or modification time
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`watch-mounts' -- watch for mount events
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`send-moved' -- pair `deleted' and `created' events caused by
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file renames and send a single `renamed' event
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instead
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When any event happens, Emacs will call the CALLBACK function passing
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it a single argument EVENT, which is of the form
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(DESCRIPTOR ACTION FILE [FILE1])
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DESCRIPTOR is the same object as the one returned by this function.
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ACTION is the description of the event. It could be any one of the
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following:
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`changed' -- FILE has changed
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`changes-done-hint' -- a hint that this was probably the last change
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in a set of changes
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`deleted' -- FILE was deleted
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`created' -- FILE was created
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`attribute-changed' -- a FILE attribute was changed
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`pre-unmount' -- the FILE location will soon be unmounted
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`unmounted' -- the FILE location was unmounted
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`moved' -- FILE was moved to FILE1
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FILE is the name of the file whose event is being reported. FILE1
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will be reported only in case of the `moved' event. */)
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(Lisp_Object file, Lisp_Object flags, Lisp_Object callback)
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{
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Lisp_Object watch_object;
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GFile *gfile;
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GFileMonitor *monitor;
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GFileMonitorFlags gflags = G_FILE_MONITOR_NONE;
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GError *gerror = NULL;
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/* Check parameters. */
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CHECK_STRING (file);
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file = Fdirectory_file_name (Fexpand_file_name (file, Qnil));
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if (NILP (Ffile_exists_p (file)))
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report_file_error ("File does not exist", file);
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if (!FUNCTIONP (callback))
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wrong_type_argument (Qinvalid_function, callback);
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/* Assemble flags. */
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if (!NILP (Fmember (Qwatch_mounts, flags)))
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gflags |= G_FILE_MONITOR_WATCH_MOUNTS;
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if (!NILP (Fmember (Qsend_moved, flags)))
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gflags |= G_FILE_MONITOR_SEND_MOVED;
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/* Create GFile name. */
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gfile = g_file_new_for_path (SSDATA (ENCODE_FILE (file)));
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/* Enable watch. */
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monitor = g_file_monitor (gfile, gflags, NULL, &gerror);
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g_object_unref (gfile);
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if (gerror)
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{
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char msg[1024];
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strcpy (msg, gerror->message);
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g_error_free (gerror);
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xsignal1 (Qfile_notify_error, build_string (msg));
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}
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if (! monitor)
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xsignal2 (Qfile_notify_error, build_string ("Cannot watch file"), file);
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Lisp_Object watch_descriptor = make_pointer_integer_unsafe (monitor);
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if (! (FIXNUMP (watch_descriptor)
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&& XFIXNUMPTR (watch_descriptor) == monitor))
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{
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g_object_unref (monitor);
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xsignal2 (Qfile_notify_error, build_string ("Unsupported file watcher"),
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file);
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}
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/* The default rate limit is 800 msec. We adapt this. */
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g_file_monitor_set_rate_limit (monitor, 100);
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/* Subscribe to the "changed" signal. */
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g_signal_connect (monitor, "changed",
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(GCallback) dir_monitor_callback, NULL);
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/* Store watch object in watch list. */
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watch_object = list4 (watch_descriptor, file, flags, callback);
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watch_list = Fcons (watch_object, watch_list);
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return watch_descriptor;
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}
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DEFUN ("gfile-rm-watch", Fgfile_rm_watch, Sgfile_rm_watch, 1, 1, 0,
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doc: /* Remove an existing WATCH-DESCRIPTOR.
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WATCH-DESCRIPTOR should be an object returned by `gfile-add-watch'. */)
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(Lisp_Object watch_descriptor)
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{
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Lisp_Object watch_object = assq_no_quit (watch_descriptor, watch_list);
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if (! CONSP (watch_object))
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xsignal2 (Qfile_notify_error, build_string ("Not a watch descriptor"),
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watch_descriptor);
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eassert (FIXNUMP (watch_descriptor));
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GFileMonitor *monitor = XFIXNUMPTR (watch_descriptor);
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if (!g_file_monitor_is_cancelled (monitor)
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&& !g_file_monitor_cancel (monitor))
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xsignal2 (Qfile_notify_error, build_string ("Could not rm watch"),
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watch_descriptor);
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/* Remove watch descriptor from watch list. */
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watch_list = Fdelq (watch_object, watch_list);
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/* Cleanup. */
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g_object_unref (monitor);
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return Qt;
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}
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DEFUN ("gfile-valid-p", Fgfile_valid_p, Sgfile_valid_p, 1, 1, 0,
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doc: /* Check a watch specified by its WATCH-DESCRIPTOR.
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WATCH-DESCRIPTOR should be an object returned by `gfile-add-watch'.
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A watch can become invalid if the file or directory it watches is
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deleted, or if the watcher thread exits abnormally for any other
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reason. Removing the watch by calling `gfile-rm-watch' also makes it
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invalid. */)
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(Lisp_Object watch_descriptor)
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{
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Lisp_Object watch_object = Fassoc (watch_descriptor, watch_list, Qnil);
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if (NILP (watch_object))
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return Qnil;
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else
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{
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GFileMonitor *monitor = XFIXNUMPTR (watch_descriptor);
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return g_file_monitor_is_cancelled (monitor) ? Qnil : Qt;
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}
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}
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DEFUN ("gfile-monitor-name", Fgfile_monitor_name, Sgfile_monitor_name, 1, 1, 0,
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doc: /* Return the internal monitor name for WATCH-DESCRIPTOR.
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The result is a symbol, either `GInotifyFileMonitor',
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`GKqueueFileMonitor', `GFamFileMonitor', or `GPollFileMonitor'.
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WATCH-DESCRIPTOR should be an object returned by `gfile-add-watch'.
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If WATCH-DESCRIPTOR is not valid, nil is returned. */)
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(Lisp_Object watch_descriptor)
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{
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if (NILP (Fgfile_valid_p (watch_descriptor)))
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return Qnil;
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else
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{
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GFileMonitor *monitor = XFIXNUMPTR (watch_descriptor);
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return intern (G_OBJECT_TYPE_NAME (monitor));
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}
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}
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void
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globals_of_gfilenotify (void)
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{
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#if ! GLIB_CHECK_VERSION (2, 36, 0)
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g_type_init ();
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#endif
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watch_list = Qnil;
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}
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void
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syms_of_gfilenotify (void)
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{
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defsubr (&Sgfile_add_watch);
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defsubr (&Sgfile_rm_watch);
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defsubr (&Sgfile_valid_p);
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defsubr (&Sgfile_monitor_name);
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/* Filter objects. */
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DEFSYM (Qchange, "change");
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DEFSYM (Qattribute_change, "attribute-change");
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DEFSYM (Qwatch_mounts, "watch-mounts"); /* G_FILE_MONITOR_WATCH_MOUNTS */
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DEFSYM (Qsend_moved, "send-moved"); /* G_FILE_MONITOR_SEND_MOVED */
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/* Event types. */
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DEFSYM (Qchanged, "changed"); /* G_FILE_MONITOR_EVENT_CHANGED */
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DEFSYM (Qchanges_done_hint, "changes-done-hint");
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/* G_FILE_MONITOR_EVENT_CHANGES_DONE_HINT */
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DEFSYM (Qdeleted, "deleted"); /* G_FILE_MONITOR_EVENT_DELETED */
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DEFSYM (Qcreated, "created"); /* G_FILE_MONITOR_EVENT_CREATED */
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DEFSYM (Qattribute_changed, "attribute-changed");
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/* G_FILE_MONITOR_EVENT_ATTRIBUTE_CHANGED */
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DEFSYM (Qpre_unmount, "pre-unmount"); /* G_FILE_MONITOR_EVENT_PRE_UNMOUNT */
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DEFSYM (Qunmounted, "unmounted"); /* G_FILE_MONITOR_EVENT_UNMOUNTED */
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DEFSYM (Qmoved, "moved"); /* G_FILE_MONITOR_EVENT_MOVED */
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staticpro (&watch_list);
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Fprovide (intern_c_string ("gfilenotify"), Qnil);
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}
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