gio/gpollfilemonitor.c

   1 /* GIO - GLib Input, Output and Streaming Library
   2  *
   3  * Copyright (C) 2006-2007 Red Hat, Inc.
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2.1 of the License, or (at your option) any later version.
   9  *
  10  * This library 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 GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General
  16  * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
  17  *
  18  * Author: Alexander Larsson <alexl@redhat.com>
  19  */
  20
  21 #include "config.h"
  22 #include <string.h>
  23
  24 #include "gpollfilemonitor.h"
  25 #include "gfile.h"
  26 #include "gfilemonitor.h"
  27 #include "gfileinfo.h"
  28
  29
  30 static gboolean g_poll_file_monitor_cancel (GFileMonitor* monitor);
  31 static void schedule_poll_timeout (GPollFileMonitor* poll_monitor);
  32
  33 struct _GPollFileMonitor
  34 {
  35   GFileMonitor parent_instance;
  36   GFile *file;
  37   GFileInfo *last_info;
  38   GSource *timeout;
  39 };
  40
  41 #define POLL_TIME_SECS 5
  42
  43 #define g_poll_file_monitor_get_type _g_poll_file_monitor_get_type
  44 G_DEFINE_TYPE (GPollFileMonitor, g_poll_file_monitor, G_TYPE_FILE_MONITOR)
  45
  46 static void
  47 g_poll_file_monitor_finalize (GObject* object)
  48 {
  49   GPollFileMonitor* poll_monitor;
  50
  51   poll_monitor = G_POLL_FILE_MONITOR (object);
  52
  53   g_poll_file_monitor_cancel (G_FILE_MONITOR (poll_monitor));
  54   g_object_unref (poll_monitor->file);
  55   g_clear_object (&poll_monitor->last_info);
  56
  57   G_OBJECT_CLASS (g_poll_file_monitor_parent_class)->finalize (object);
  58 }
  59
  60
  61 static void
  62 g_poll_file_monitor_class_init (GPollFileMonitorClass* klass)
  63 {
  64   GObjectClass* gobject_class = G_OBJECT_CLASS (klass);
  65   GFileMonitorClass *file_monitor_class = G_FILE_MONITOR_CLASS (klass);
  66
  67   gobject_class->finalize = g_poll_file_monitor_finalize;
  68
  69   file_monitor_class->cancel = g_poll_file_monitor_cancel;
  70 }
  71
  72 static void
  73 g_poll_file_monitor_init (GPollFileMonitor* poll_monitor)
  74 {
  75 }
  76
  77 static int
  78 calc_event_type (GFileInfo *last,
  79                  GFileInfo *new)
  80 {
  81   if (last == NULL && new == NULL)
  82     return -1;
  83
  84   if (last == NULL && new != NULL)
  85     return G_FILE_MONITOR_EVENT_CREATED;
  86
  87   if (last != NULL && new == NULL)
  88     return G_FILE_MONITOR_EVENT_DELETED;
  89
  90   if (g_strcmp0 (g_file_info_get_etag (last), g_file_info_get_etag (new)))
  91     return G_FILE_MONITOR_EVENT_CHANGED;
  92
  93   if (g_file_info_get_size (last) != g_file_info_get_size (new))
  94     return G_FILE_MONITOR_EVENT_CHANGED;
  95
  96   return -1;
  97 }
  98
  99 static void
 100 got_new_info (GObject      *source_object,
 101               GAsyncResult *res,
 102               gpointer      user_data)
 103 {
 104   GPollFileMonitor* poll_monitor = user_data;
 105   GFileInfo *info;
 106   int event;
 107
 108   info = g_file_query_info_finish (poll_monitor->file, res, NULL);
 109
 110   if (!g_file_monitor_is_cancelled (G_FILE_MONITOR (poll_monitor)))
 111     {
 112       event = calc_event_type (poll_monitor->last_info, info);
 113
 114       if (event != -1)
 115         {
 116           g_file_monitor_emit_event (G_FILE_MONITOR (poll_monitor),
 117                                      poll_monitor->file,
 118                                      NULL, event);
 119           /* We're polling so slowly anyway, so always emit the done hint */
 120           if (!g_file_monitor_is_cancelled (G_FILE_MONITOR (poll_monitor)) &&
 121              (event == G_FILE_MONITOR_EVENT_CHANGED || event == G_FILE_MONITOR_EVENT_CREATED))
 122             g_file_monitor_emit_event (G_FILE_MONITOR (poll_monitor),
 123                                        poll_monitor->file,
 124                                        NULL, G_FILE_MONITOR_EVENT_CHANGES_DONE_HINT);
 125         }
 126
 127       if (poll_monitor->last_info)
 128         {
 129           g_object_unref (poll_monitor->last_info);
 130           poll_monitor->last_info = NULL;
 131         }
 132
 133       if (info)
 134         poll_monitor->last_info = g_object_ref (info);
 135
 136       schedule_poll_timeout (poll_monitor);
 137     }
 138
 139   if (info)
 140     g_object_unref (info);
 141
 142   g_object_unref (poll_monitor);
 143 }
 144
 145 static gboolean
 146 poll_file_timeout (gpointer data)
 147 {
 148   GPollFileMonitor* poll_monitor = data;
 149
 150   g_source_unref (poll_monitor->timeout);
 151   poll_monitor->timeout = NULL;
 152
 153   g_file_query_info_async (poll_monitor->file, G_FILE_ATTRIBUTE_ETAG_VALUE "," G_FILE_ATTRIBUTE_STANDARD_SIZE,
 154                          0, 0, NULL, got_new_info, g_object_ref (poll_monitor));
 155
 156   return G_SOURCE_REMOVE;
 157 }
 158
 159 static void
 160 schedule_poll_timeout (GPollFileMonitor* poll_monitor)
 161 {
 162   poll_monitor->timeout = g_timeout_source_new_seconds (POLL_TIME_SECS);
 163   g_source_set_callback (poll_monitor->timeout, poll_file_timeout, poll_monitor, NULL);
 164   g_source_attach (poll_monitor->timeout, g_main_context_get_thread_default ());
 165 }
 166
 167 static void
 168 got_initial_info (GObject      *source_object,
 169                   GAsyncResult *res,
 170                   gpointer      user_data)
 171 {
 172   GPollFileMonitor* poll_monitor = user_data;
 173   GFileInfo *info;
 174
 175   info = g_file_query_info_finish (poll_monitor->file, res, NULL);
 176
 177   poll_monitor->last_info = info;
 178
 179   if (!g_file_monitor_is_cancelled (G_FILE_MONITOR (poll_monitor)))
 180     schedule_poll_timeout (poll_monitor);
 181
 182   g_object_unref (poll_monitor);
 183 }
 184
 185 /**
 186  * _g_poll_file_monitor_new:
 187  * @file: a #GFile.
 188  *
 189  * Polls @file for changes.
 190  *
 191  * Returns: a new #GFileMonitor for the given #GFile.
 192  **/
 193 GFileMonitor*
 194 _g_poll_file_monitor_new (GFile *file)
 195 {
 196   GPollFileMonitor* poll_monitor;
 197
 198   poll_monitor = g_object_new (G_TYPE_POLL_FILE_MONITOR, NULL);
 199
 200   poll_monitor->file = g_object_ref (file);
 201
 202   g_file_query_info_async (file, G_FILE_ATTRIBUTE_ETAG_VALUE "," G_FILE_ATTRIBUTE_STANDARD_SIZE,
 203                            0, 0, NULL, got_initial_info, g_object_ref (poll_monitor));
 204
 205   return G_FILE_MONITOR (poll_monitor);
 206 }
 207
 208 static gboolean
 209 g_poll_file_monitor_cancel (GFileMonitor* monitor)
 210 {
 211   GPollFileMonitor *poll_monitor = G_POLL_FILE_MONITOR (monitor);
 212
 213   if (poll_monitor->timeout)
 214     {
 215       g_source_destroy (poll_monitor->timeout);
 216       g_source_unref (poll_monitor->timeout);
 217       poll_monitor->timeout = NULL;
 218     }
 219
 220   return TRUE;
 221 }