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 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, write to the
  17  * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  18  * Boston, MA 02111-1307, USA.
  19  *
  20  * Author: Alexander Larsson <alexl@redhat.com>
  21  */
  22
  23 #include <config.h>
  24 #include <string.h>
  25
  26 #include "gpollfilemonitor.h"
  27 #include "gfilemonitor.h"
  28
  29 #include "gioalias.h"
  30
  31 static gboolean g_poll_file_monitor_cancel (GFileMonitor* monitor);
  32 static void schedule_poll_timeout (GPollFileMonitor* poll_monitor);
  33
  34 struct _GPollFileMonitor
  35 {
  36   GFileMonitor parent_instance;
  37   GFile *file;
  38   GFileInfo *last_info;
  39   guint timeout;
  40 };
  41
  42 #define POLL_TIME_SECS 5
  43
  44 #define g_poll_file_monitor_get_type _g_poll_file_monitor_get_type
  45 G_DEFINE_TYPE (GPollFileMonitor, g_poll_file_monitor, G_TYPE_FILE_MONITOR)
  46
  47 static void
  48 g_poll_file_monitor_finalize (GObject* object)
  49 {
  50   GPollFileMonitor* poll_monitor;
  51
  52   poll_monitor = G_POLL_FILE_MONITOR (object);
  53
  54   g_object_unref (poll_monitor->file);
  55
  56   if (G_OBJECT_CLASS (g_poll_file_monitor_parent_class)->finalize)
  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 safe_strcmp (const char *a, const char *b)
  79 {
  80   if (a == NULL && b == NULL)
  81     return 0;
  82   if (a == NULL)
  83     return -1;
  84   if (b == NULL)
  85     return 1;
  86
  87   return strcmp (a, b);
  88 }
  89
  90 static int
  91 calc_event_type (GFileInfo *last,
  92                  GFileInfo *new)
  93 {
  94   if (last == NULL && new == NULL)
  95     return -1;
  96
  97   if (last == NULL && new != NULL)
  98     return G_FILE_MONITOR_EVENT_CREATED;
  99
 100   if (last != NULL && new == NULL)
 101     return G_FILE_MONITOR_EVENT_DELETED;
 102
 103   if (safe_strcmp (g_file_info_get_etag (last),
 104                    g_file_info_get_etag (new)))
 105     return G_FILE_MONITOR_EVENT_CHANGED;
 106
 107   if (g_file_info_get_size (last) !=
 108       g_file_info_get_size (new))
 109     return G_FILE_MONITOR_EVENT_CHANGED;
 110
 111   return -1;
 112 }
 113
 114 static void
 115 got_new_info (GObject *source_object,
 116               GAsyncResult *res,
 117               gpointer user_data)
 118 {
 119   GPollFileMonitor* poll_monitor = user_data;
 120   GFileInfo *info;
 121   int event;
 122
 123   info = g_file_query_info_finish (poll_monitor->file, res, NULL);
 124
 125   if (!g_file_monitor_is_cancelled (G_FILE_MONITOR (poll_monitor)))
 126     {
 127       event = calc_event_type (poll_monitor->last_info, info);
 128
 129       if (event != -1)
 130         {
 131           g_file_monitor_emit_event (G_FILE_MONITOR (poll_monitor),
 132                                      poll_monitor->file,
 133                                      NULL, event);
 134           /* We're polling so slowly anyway, so always emit the done hint */
 135           if (event == G_FILE_MONITOR_EVENT_CHANGED)
 136             g_file_monitor_emit_event (G_FILE_MONITOR (poll_monitor),
 137                                        poll_monitor->file,
 138                                        NULL, G_FILE_MONITOR_EVENT_CHANGES_DONE_HINT);
 139         }
 140
 141       if (poll_monitor->last_info)
 142         {
 143           g_object_unref (poll_monitor->last_info);
 144           poll_monitor->last_info = NULL;
 145         }
 146
 147       if (info)
 148         poll_monitor->last_info = g_object_ref (info);
 149
 150       schedule_poll_timeout (poll_monitor);
 151     }
 152
 153   if (info)
 154     g_object_unref (info);
 155
 156   g_object_unref (poll_monitor);
 157 }
 158
 159 static gboolean
 160 poll_file_timeout (gpointer data)
 161 {
 162   GPollFileMonitor* poll_monitor = data;
 163
 164   poll_monitor->timeout = FALSE;
 165
 166   g_file_query_info_async (poll_monitor->file, G_FILE_ATTRIBUTE_ETAG_VALUE "," G_FILE_ATTRIBUTE_STD_SIZE,
 167                          0, 0, NULL, got_new_info, g_object_ref (poll_monitor));
 168
 169   return FALSE;
 170 }
 171
 172 static void
 173 schedule_poll_timeout (GPollFileMonitor* poll_monitor)
 174 {
 175   poll_monitor->timeout = g_timeout_add_seconds (POLL_TIME_SECS, poll_file_timeout, poll_monitor);
 176  }
 177
 178 static void
 179 got_initial_info (GObject *source_object,
 180                   GAsyncResult *res,
 181                   gpointer user_data)
 182 {
 183   GPollFileMonitor* poll_monitor = user_data;
 184   GFileInfo *info;
 185
 186   info = g_file_query_info_finish (poll_monitor->file, res, NULL);
 187
 188   poll_monitor->last_info = info;
 189
 190   if (!g_file_monitor_is_cancelled (G_FILE_MONITOR (poll_monitor)))
 191     schedule_poll_timeout (poll_monitor);
 192
 193   g_object_unref (poll_monitor);
 194 }
 195
 196 /**
 197  * g_poll_file_monitor_new:
 198  * @file: a #GFile.
 199  *
 200  * Polls @file for changes.
 201  *
 202  * Returns: a new #GFileMonitor for the given #GFile.
 203  **/
 204 GFileMonitor*
 205 _g_poll_file_monitor_new (GFile *file)
 206 {
 207   GPollFileMonitor* poll_monitor;
 208
 209   poll_monitor = g_object_new (G_TYPE_POLL_FILE_MONITOR, NULL);
 210
 211   poll_monitor->file = g_object_ref (file);
 212
 213   g_file_query_info_async (file, G_FILE_ATTRIBUTE_ETAG_VALUE "," G_FILE_ATTRIBUTE_STD_SIZE,
 214                            0, 0, NULL, got_initial_info, g_object_ref (poll_monitor));
 215
 216   return G_FILE_MONITOR (poll_monitor);
 217 }
 218
 219 static gboolean
 220 g_poll_file_monitor_cancel (GFileMonitor* monitor)
 221 {
 222   GPollFileMonitor *poll_monitor = G_POLL_FILE_MONITOR (monitor);
 223
 224   if (poll_monitor->timeout)
 225     {
 226       g_source_remove (poll_monitor->timeout);
 227       poll_monitor->timeout = 0;
 228     }
 229
 230   return TRUE;
 231 }