src/inotify_queue.c

   1 /*
   2  * Copyright (C) 2003-2010 The Music Player Daemon Project
   3  * http://www.musicpd.org
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #include "config.h"
  21 #include "inotify_queue.h"
  22 #include "update.h"
  23
  24 #include <glib.h>
  25
  26 #include <string.h>
  27
  28 #undef G_LOG_DOMAIN
  29 #define G_LOG_DOMAIN "inotify"
  30
  31 enum {
  32         /**
  33          * Wait this long after the last change before calling
  34          * update_enqueue().  This increases the probability that
  35          * updates can be bundled.
  36          */
  37         INOTIFY_UPDATE_DELAY_S = 5,
  38 };
  39
  40 static GSList *inotify_queue;
  41 static guint queue_source_id;
  42
  43 void
  44 mpd_inotify_queue_init(void)
  45 {
  46 }
  47
  48 static void
  49 free_callback(gpointer data, G_GNUC_UNUSED gpointer user_data)
  50 {
  51         g_free(data);
  52 }
  53
  54 void
  55 mpd_inotify_queue_finish(void)
  56 {
  57         if (queue_source_id != 0)
  58                 g_source_remove(queue_source_id);
  59
  60         g_slist_foreach(inotify_queue, free_callback, NULL);
  61         g_slist_free(inotify_queue);
  62 }
  63
  64 static gboolean
  65 mpd_inotify_run_update(G_GNUC_UNUSED gpointer data)
  66 {
  67         unsigned id;
  68
  69         while (inotify_queue != NULL) {
  70                 char *uri_utf8 = inotify_queue->data;
  71
  72                 id = update_enqueue(uri_utf8, false);
  73                 if (id == 0)
  74                         /* retry later */
  75                         return true;
  76
  77                 g_debug("updating '%s' job=%u", uri_utf8, id);
  78
  79                 g_free(uri_utf8);
  80                 inotify_queue = g_slist_delete_link(inotify_queue,
  81                                                     inotify_queue);
  82         }
  83
  84         /* done, remove the timer event by returning false */
  85         queue_source_id = 0;
  86         return false;
  87 }
  88
  89 static bool
  90 path_in(const char *path, const char *possible_parent)
  91 {
  92         size_t length = strlen(possible_parent);
  93
  94         return path[0] == 0 ||
  95                 (memcmp(possible_parent, path, length) == 0 &&
  96                  (path[length] == 0 || path[length] == '/'));
  97 }
  98
  99 void
 100 mpd_inotify_enqueue(char *uri_utf8)
 101 {
 102         GSList *old_queue = inotify_queue;
 103
 104         if (queue_source_id != 0)
 105                 g_source_remove(queue_source_id);
 106         queue_source_id = g_timeout_add_seconds(INOTIFY_UPDATE_DELAY_S,
 107                                         mpd_inotify_run_update, NULL);
 108
 109         inotify_queue = NULL;
 110         while (old_queue != NULL) {
 111                 char *current_uri = old_queue->data;
 112
 113                 if (path_in(uri_utf8, current_uri)) {
 114                         /* already enqueued */
 115                         g_free(uri_utf8);
 116                         inotify_queue = g_slist_concat(inotify_queue,
 117                                                        old_queue);
 118                         return;
 119                 }
 120
 121                 old_queue = g_slist_delete_link(old_queue, old_queue);
 122
 123                 if (path_in(current_uri, uri_utf8))
 124                         /* existing path is a sub-path of the new
 125                            path; we can dequeue the existing path and
 126                            update the new path instead */
 127                         g_free(current_uri);
 128                 else
 129                         /* move the existing path to the new queue */
 130                         inotify_queue = g_slist_prepend(inotify_queue,
 131                                                         current_uri);
 132         }
 133
 134         inotify_queue = g_slist_prepend(inotify_queue, uri_utf8);
 135 }