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, 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   guint 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_object_unref (poll_monitor->file);
  54
  55   G_OBJECT_CLASS (g_poll_file_monitor_parent_class)->finalize (object);
  56 }
  57
  58
  59 static void
  60 g_poll_file_monitor_class_init (GPollFileMonitorClass* klass)
  61 {
  62   GObjectClass* gobject_class = G_OBJECT_CLASS (klass);
  63   GFileMonitorClass *file_monitor_class = G_FILE_MONITOR_CLASS (klass);
  64
  65   gobject_class->finalize = g_poll_file_monitor_finalize;
  66
  67   file_monitor_class->cancel = g_poll_file_monitor_cancel;
  68 }
  69
  70 static void
  71 g_poll_file_monitor_init (GPollFileMonitor* poll_monitor)
  72 {
  73 }
  74
  75 static int
  76 safe_strcmp (const char *a,
  77              const char *b)
  78 {
  79   if (a == NULL && b == NULL)
  80     return 0;
  81   if (a == NULL)
  82     return -1;
  83   if (b == NULL)
  84     return 1;
  85
  86   return strcmp (a, b);
  87 }
  88
  89 static int
  90 calc_event_type (GFileInfo *last,
  91                  GFileInfo *new)
  92 {
  93   if (last == NULL && new == NULL)
  94     return -1;
  95
  96   if (last == NULL && new != NULL)
  97     return G_FILE_MONITOR_EVENT_CREATED;
  98
  99   if (last != NULL && new == NULL)
 100     return G_FILE_MONITOR_EVENT_DELETED;
 101
 102   if (safe_strcmp (g_file_info_get_etag (last),
 103                    g_file_info_get_etag (new)))
 104     return G_FILE_MONITOR_EVENT_CHANGED;
 105
 106   if (g_file_info_get_size (last) !=
 107       g_file_info_get_size (new))
 108     return G_FILE_MONITOR_EVENT_CHANGED;
 109
 110   return -1;
 111 }
 112
 113 static void
 114 got_new_info (GObject      *source_object,
 115               GAsyncResult *res,
 116               gpointer      user_data)
 117 {
 118   GPollFileMonitor* poll_monitor = user_data;
 119   GFileInfo *info;
 120   int event;
 121
 122   info = g_file_query_info_finish (poll_monitor->file, res, NULL);
 123
 124   if (!g_file_monitor_is_cancelled (G_FILE_MONITOR (poll_monitor)))
 125     {
 126       event = calc_event_type (poll_monitor->last_info, info);
 127
 128       if (event != -1)
 129         {
 130           g_file_monitor_emit_event (G_FILE_MONITOR (poll_monitor),
 131                                      poll_monitor->file,
 132                                      NULL, event);
 133           /* We're polling so slowly anyway, so always emit the done hint */
 134           if (event == G_FILE_MONITOR_EVENT_CHANGED)
 135             g_file_monitor_emit_event (G_FILE_MONITOR (poll_monitor),
 136                                        poll_monitor->file,
 137                                        NULL, G_FILE_MONITOR_EVENT_CHANGES_DONE_HINT);
 138         }
 139
 140       if (poll_monitor->last_info)
 141         {
 142           g_object_unref (poll_monitor->last_info);
 143           poll_monitor->last_info = NULL;
 144         }
 145
 146       if (info)
 147         poll_monitor->last_info = g_object_ref (info);
 148
 149       schedule_poll_timeout (poll_monitor);
 150     }
 151
 152   if (info)
 153     g_object_unref (info);
 154
 155   g_object_unref (poll_monitor);
 156 }
 157
 158 static gboolean
 159 poll_file_timeout (gpointer data)
 160 {
 161   GPollFileMonitor* poll_monitor = data;
 162
 163   poll_monitor->timeout = FALSE;
 164
 165   g_file_query_info_async (poll_monitor->file, G_FILE_ATTRIBUTE_ETAG_VALUE "," G_FILE_ATTRIBUTE_STANDARD_SIZE,
 166                          0, 0, NULL, got_new_info, g_object_ref (poll_monitor));
 167
 168   return G_SOURCE_REMOVE;
 169 }
 170
 171 static void
 172 schedule_poll_timeout (GPollFileMonitor* poll_monitor)
 173 {
 174   poll_monitor->timeout = g_timeout_add_seconds (POLL_TIME_SECS, poll_file_timeout, poll_monitor);
 175  }
 176
 177 static void
 178 got_initial_info (GObject      *source_object,
 179                   GAsyncResult *res,
 180                   gpointer      user_data)
 181 {
 182   GPollFileMonitor* poll_monitor = user_data;
 183   GFileInfo *info;
 184
 185   info = g_file_query_info_finish (poll_monitor->file, res, NULL);
 186
 187   poll_monitor->last_info = info;
 188
 189   if (!g_file_monitor_is_cancelled (G_FILE_MONITOR (poll_monitor)))
 190     schedule_poll_timeout (poll_monitor);
 191
 192   g_object_unref (poll_monitor);
 193 }
 194
 195 /**
 196  * g_poll_file_monitor_new:
 197  * @file: a #GFile.
 198  *
 199  * Polls @file for changes.
 200  *
 201  * Returns: a new #GFileMonitor for the given #GFile.
 202  **/
 203 GFileMonitor*
 204 _g_poll_file_monitor_new (GFile *file)
 205 {
 206   GPollFileMonitor* poll_monitor;
 207
 208   poll_monitor = g_object_new (G_TYPE_POLL_FILE_MONITOR, NULL);
 209
 210   poll_monitor->file = g_object_ref (file);
 211
 212   g_file_query_info_async (file, G_FILE_ATTRIBUTE_ETAG_VALUE "," G_FILE_ATTRIBUTE_STANDARD_SIZE,
 213                            0, 0, NULL, got_initial_info, g_object_ref (poll_monitor));
 214
 215   return G_FILE_MONITOR (poll_monitor);
 216 }
 217
 218 static gboolean
 219 g_poll_file_monitor_cancel (GFileMonitor* monitor)
 220 {
 221   GPollFileMonitor *poll_monitor = G_POLL_FILE_MONITOR (monitor);
 222
 223   if (poll_monitor->timeout)
 224     {
 225       g_source_remove (poll_monitor->timeout);
 226       poll_monitor->timeout = 0;
 227     }
 228
 229   return TRUE;
 230 }