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 static gboolean g_poll_file_monitor_cancel (GFileMonitor* monitor);
  30 static void schedule_poll_timeout (GPollFileMonitor* poll_monitor);
  31
  32 struct _GPollFileMonitor
  33 {
  34   GFileMonitor parent_instance;
  35   GFile *file;
  36   GFileInfo *last_info;
  37   guint timeout;
  38 };
  39
  40 #define POLL_TIME_SECS 5
  41
  42 G_DEFINE_TYPE (GPollFileMonitor, g_poll_file_monitor, G_TYPE_FILE_MONITOR)
  43
  44 static void
  45 g_poll_file_monitor_finalize (GObject* object)
  46 {
  47   GPollFileMonitor* poll_monitor;
  48
  49   poll_monitor = G_POLL_FILE_MONITOR (object);
  50
  51   g_object_unref (poll_monitor->file);
  52
  53   if (G_OBJECT_CLASS (g_poll_file_monitor_parent_class)->finalize)
  54     (*G_OBJECT_CLASS (g_poll_file_monitor_parent_class)->finalize) (object);
  55 }
  56
  57
  58 static void
  59 g_poll_file_monitor_class_init (GPollFileMonitorClass* klass)
  60 {
  61   GObjectClass* gobject_class = G_OBJECT_CLASS (klass);
  62   GFileMonitorClass *file_monitor_class = G_FILE_MONITOR_CLASS (klass);
  63
  64   gobject_class->finalize = g_poll_file_monitor_finalize;
  65
  66   file_monitor_class->cancel = g_poll_file_monitor_cancel;
  67 }
  68
  69 static void
  70 g_poll_file_monitor_init (GPollFileMonitor* poll_monitor)
  71 {
  72 }
  73
  74 static int
  75 safe_strcmp (const char *a, const char *b)
  76 {
  77   if (a == NULL && b == NULL)
  78     return 0;
  79   if (a == NULL)
  80     return -1;
  81   if (b == NULL)
  82     return 1;
  83
  84   return strcmp (a, b);
  85 }
  86
  87 static int
  88 calc_event_type (GFileInfo *last,
  89                  GFileInfo *new)
  90 {
  91   if (last == NULL && new == NULL)
  92     return -1;
  93
  94   if (last == NULL && new != NULL)
  95     return G_FILE_MONITOR_EVENT_CREATED;
  96
  97   if (last != NULL && new == NULL)
  98     return G_FILE_MONITOR_EVENT_DELETED;
  99
 100   if (safe_strcmp (g_file_info_get_etag (last),
 101                    g_file_info_get_etag (new)))
 102     return G_FILE_MONITOR_EVENT_CHANGED;
 103
 104   if (g_file_info_get_size (last) !=
 105       g_file_info_get_size (new))
 106     return G_FILE_MONITOR_EVENT_CHANGED;
 107
 108   return -1;
 109 }
 110
 111 static void
 112 got_new_info (GObject *source_object,
 113               GAsyncResult *res,
 114               gpointer user_data)
 115 {
 116   GPollFileMonitor* poll_monitor = user_data;
 117   GFileInfo *info;
 118   int event;
 119
 120   info = g_file_query_info_finish (poll_monitor->file, res, NULL);
 121
 122   if (!g_file_monitor_is_cancelled (G_FILE_MONITOR (poll_monitor)))
 123     {
 124       event = calc_event_type (poll_monitor->last_info, info);
 125
 126       if (event != -1)
 127         {
 128           g_file_monitor_emit_event (G_FILE_MONITOR (poll_monitor),
 129                                      poll_monitor->file,
 130                                      NULL, event);
 131           /* We're polling so slowly anyway, so always emit the done hint */
 132           if (event == G_FILE_MONITOR_EVENT_CHANGED)
 133             g_file_monitor_emit_event (G_FILE_MONITOR (poll_monitor),
 134                                        poll_monitor->file,
 135                                        NULL, G_FILE_MONITOR_EVENT_CHANGES_DONE_HINT);
 136         }
 137
 138       if (poll_monitor->last_info)
 139         {
 140           g_object_unref (poll_monitor->last_info);
 141           poll_monitor->last_info = NULL;
 142         }
 143
 144       if (info)
 145         poll_monitor->last_info = g_object_ref (info);
 146
 147       schedule_poll_timeout (poll_monitor);
 148     }
 149
 150   if (info)
 151     g_object_unref (info);
 152
 153   g_object_unref (poll_monitor);
 154 }
 155
 156 static gboolean
 157 poll_file_timeout (gpointer data)
 158 {
 159   GPollFileMonitor* poll_monitor = data;
 160
 161   poll_monitor->timeout = FALSE;
 162
 163   g_file_query_info_async (poll_monitor->file, G_FILE_ATTRIBUTE_ETAG_VALUE "," G_FILE_ATTRIBUTE_STD_SIZE,
 164                          0, 0, NULL, got_new_info, g_object_ref (poll_monitor));
 165
 166   return FALSE;
 167 }
 168
 169 static void
 170 schedule_poll_timeout (GPollFileMonitor* poll_monitor)
 171 {
 172   poll_monitor->timeout = g_timeout_add_seconds (POLL_TIME_SECS, poll_file_timeout, poll_monitor);
 173  }
 174
 175 static void
 176 got_initial_info (GObject *source_object,
 177                   GAsyncResult *res,
 178                   gpointer user_data)
 179 {
 180   GPollFileMonitor* poll_monitor = user_data;
 181   GFileInfo *info;
 182
 183   info = g_file_query_info_finish (poll_monitor->file, res, NULL);
 184
 185   poll_monitor->last_info = info;
 186
 187   if (!g_file_monitor_is_cancelled (G_FILE_MONITOR (poll_monitor)))
 188     schedule_poll_timeout (poll_monitor);
 189
 190   g_object_unref (poll_monitor);
 191 }
 192
 193 /**
 194  * g_poll_file_monitor_new:
 195  * @file:
 196  *
 197  * Returns a new #GFileMonitor for the given #GFile.
 198  **/
 199 GFileMonitor*
 200 g_poll_file_monitor_new (GFile *file)
 201 {
 202   GPollFileMonitor* poll_monitor;
 203
 204   poll_monitor = g_object_new (G_TYPE_POLL_FILE_MONITOR, NULL);
 205
 206   poll_monitor->file = g_object_ref (file);
 207
 208   g_file_query_info_async (file, G_FILE_ATTRIBUTE_ETAG_VALUE "," G_FILE_ATTRIBUTE_STD_SIZE,
 209                            0, 0, NULL, got_initial_info, g_object_ref (poll_monitor));
 210
 211   return G_FILE_MONITOR (poll_monitor);
 212 }
 213
 214 static gboolean
 215 g_poll_file_monitor_cancel (GFileMonitor* monitor)
 216 {
 217   GPollFileMonitor *poll_monitor = G_POLL_FILE_MONITOR (monitor);
 218
 219   if (poll_monitor->timeout)
 220     {
 221       g_source_remove (poll_monitor->timeout);
 222       poll_monitor->timeout = 0;
 223     }
 224
 225   return TRUE;
 226 }