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 "gfile.h"
  28 #include "gfilemonitor.h"
  29 #include "gfileinfo.h"
  30
  31
  32 static gboolean g_poll_file_monitor_cancel (GFileMonitor* monitor);
  33 static void schedule_poll_timeout (GPollFileMonitor* poll_monitor);
  34
  35 struct _GPollFileMonitor
  36 {
  37   GFileMonitor parent_instance;
  38   GFile *file;
  39   GFileInfo *last_info;
  40   guint timeout;
  41 };
  42
  43 #define POLL_TIME_SECS 5
  44
  45 #define g_poll_file_monitor_get_type _g_poll_file_monitor_get_type
  46 G_DEFINE_TYPE (GPollFileMonitor, g_poll_file_monitor, G_TYPE_FILE_MONITOR)
  47
  48 static void
  49 g_poll_file_monitor_finalize (GObject* object)
  50 {
  51   GPollFileMonitor* poll_monitor;
  52
  53   poll_monitor = G_POLL_FILE_MONITOR (object);
  54
  55   g_object_unref (poll_monitor->file);
  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 safe_strcmp (const char *a,
  79              const char *b)
  80 {
  81   if (a == NULL && b == NULL)
  82     return 0;
  83   if (a == NULL)
  84     return -1;
  85   if (b == NULL)
  86     return 1;
  87
  88   return strcmp (a, b);
  89 }
  90
  91 static int
  92 calc_event_type (GFileInfo *last,
  93                  GFileInfo *new)
  94 {
  95   if (last == NULL && new == NULL)
  96     return -1;
  97
  98   if (last == NULL && new != NULL)
  99     return G_FILE_MONITOR_EVENT_CREATED;
 100
 101   if (last != NULL && new == NULL)
 102     return G_FILE_MONITOR_EVENT_DELETED;
 103
 104   if (safe_strcmp (g_file_info_get_etag (last),
 105                    g_file_info_get_etag (new)))
 106     return G_FILE_MONITOR_EVENT_CHANGED;
 107
 108   if (g_file_info_get_size (last) !=
 109       g_file_info_get_size (new))
 110     return G_FILE_MONITOR_EVENT_CHANGED;
 111
 112   return -1;
 113 }
 114
 115 static void
 116 got_new_info (GObject      *source_object,
 117               GAsyncResult *res,
 118               gpointer      user_data)
 119 {
 120   GPollFileMonitor* poll_monitor = user_data;
 121   GFileInfo *info;
 122   int event;
 123
 124   info = g_file_query_info_finish (poll_monitor->file, res, NULL);
 125
 126   if (!g_file_monitor_is_cancelled (G_FILE_MONITOR (poll_monitor)))
 127     {
 128       event = calc_event_type (poll_monitor->last_info, info);
 129
 130       if (event != -1)
 131         {
 132           g_file_monitor_emit_event (G_FILE_MONITOR (poll_monitor),
 133                                      poll_monitor->file,
 134                                      NULL, event);
 135           /* We're polling so slowly anyway, so always emit the done hint */
 136           if (event == G_FILE_MONITOR_EVENT_CHANGED)
 137             g_file_monitor_emit_event (G_FILE_MONITOR (poll_monitor),
 138                                        poll_monitor->file,
 139                                        NULL, G_FILE_MONITOR_EVENT_CHANGES_DONE_HINT);
 140         }
 141
 142       if (poll_monitor->last_info)
 143         {
 144           g_object_unref (poll_monitor->last_info);
 145           poll_monitor->last_info = NULL;
 146         }
 147
 148       if (info)
 149         poll_monitor->last_info = g_object_ref (info);
 150
 151       schedule_poll_timeout (poll_monitor);
 152     }
 153
 154   if (info)
 155     g_object_unref (info);
 156
 157   g_object_unref (poll_monitor);
 158 }
 159
 160 static gboolean
 161 poll_file_timeout (gpointer data)
 162 {
 163   GPollFileMonitor* poll_monitor = data;
 164
 165   poll_monitor->timeout = FALSE;
 166
 167   g_file_query_info_async (poll_monitor->file, G_FILE_ATTRIBUTE_ETAG_VALUE "," G_FILE_ATTRIBUTE_STANDARD_SIZE,
 168                          0, 0, NULL, got_new_info, g_object_ref (poll_monitor));
 169
 170   return G_SOURCE_REMOVE;
 171 }
 172
 173 static void
 174 schedule_poll_timeout (GPollFileMonitor* poll_monitor)
 175 {
 176   poll_monitor->timeout = g_timeout_add_seconds (POLL_TIME_SECS, poll_file_timeout, poll_monitor);
 177  }
 178
 179 static void
 180 got_initial_info (GObject      *source_object,
 181                   GAsyncResult *res,
 182                   gpointer      user_data)
 183 {
 184   GPollFileMonitor* poll_monitor = user_data;
 185   GFileInfo *info;
 186
 187   info = g_file_query_info_finish (poll_monitor->file, res, NULL);
 188
 189   poll_monitor->last_info = info;
 190
 191   if (!g_file_monitor_is_cancelled (G_FILE_MONITOR (poll_monitor)))
 192     schedule_poll_timeout (poll_monitor);
 193
 194   g_object_unref (poll_monitor);
 195 }
 196
 197 /**
 198  * g_poll_file_monitor_new:
 199  * @file: a #GFile.
 200  *
 201  * Polls @file for changes.
 202  *
 203  * Returns: a new #GFileMonitor for the given #GFile.
 204  **/
 205 GFileMonitor*
 206 _g_poll_file_monitor_new (GFile *file)
 207 {
 208   GPollFileMonitor* poll_monitor;
 209
 210   poll_monitor = g_object_new (G_TYPE_POLL_FILE_MONITOR, NULL);
 211
 212   poll_monitor->file = g_object_ref (file);
 213
 214   g_file_query_info_async (file, G_FILE_ATTRIBUTE_ETAG_VALUE "," G_FILE_ATTRIBUTE_STANDARD_SIZE,
 215                            0, 0, NULL, got_initial_info, g_object_ref (poll_monitor));
 216
 217   return G_FILE_MONITOR (poll_monitor);
 218 }
 219
 220 static gboolean
 221 g_poll_file_monitor_cancel (GFileMonitor* monitor)
 222 {
 223   GPollFileMonitor *poll_monitor = G_POLL_FILE_MONITOR (monitor);
 224
 225   if (poll_monitor->timeout)
 226     {
 227       g_source_remove (poll_monitor->timeout);
 228       poll_monitor->timeout = 0;
 229     }
 230
 231   return TRUE;
 232 }