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 #include "gioalias.h"
  32
  33 static gboolean g_poll_file_monitor_cancel (GFileMonitor* monitor);
  34 static void schedule_poll_timeout (GPollFileMonitor* poll_monitor);
  35
  36 struct _GPollFileMonitor
  37 {
  38   GFileMonitor parent_instance;
  39   GFile *file;
  40   GFileInfo *last_info;
  41   guint timeout;
  42 };
  43
  44 #define POLL_TIME_SECS 5
  45
  46 #define g_poll_file_monitor_get_type _g_poll_file_monitor_get_type
  47 G_DEFINE_TYPE (GPollFileMonitor, g_poll_file_monitor, G_TYPE_FILE_MONITOR)
  48
  49 static void
  50 g_poll_file_monitor_finalize (GObject* object)
  51 {
  52   GPollFileMonitor* poll_monitor;
  53
  54   poll_monitor = G_POLL_FILE_MONITOR (object);
  55
  56   g_object_unref (poll_monitor->file);
  57
  58   G_OBJECT_CLASS (g_poll_file_monitor_parent_class)->finalize (object);
  59 }
  60
  61
  62 static void
  63 g_poll_file_monitor_class_init (GPollFileMonitorClass* klass)
  64 {
  65   GObjectClass* gobject_class = G_OBJECT_CLASS (klass);
  66   GFileMonitorClass *file_monitor_class = G_FILE_MONITOR_CLASS (klass);
  67
  68   gobject_class->finalize = g_poll_file_monitor_finalize;
  69
  70   file_monitor_class->cancel = g_poll_file_monitor_cancel;
  71 }
  72
  73 static void
  74 g_poll_file_monitor_init (GPollFileMonitor* poll_monitor)
  75 {
  76 }
  77
  78 static int
  79 safe_strcmp (const char *a,
  80              const char *b)
  81 {
  82   if (a == NULL && b == NULL)
  83     return 0;
  84   if (a == NULL)
  85     return -1;
  86   if (b == NULL)
  87     return 1;
  88
  89   return strcmp (a, b);
  90 }
  91
  92 static int
  93 calc_event_type (GFileInfo *last,
  94                  GFileInfo *new)
  95 {
  96   if (last == NULL && new == NULL)
  97     return -1;
  98
  99   if (last == NULL && new != NULL)
 100     return G_FILE_MONITOR_EVENT_CREATED;
 101
 102   if (last != NULL && new == NULL)
 103     return G_FILE_MONITOR_EVENT_DELETED;
 104
 105   if (safe_strcmp (g_file_info_get_etag (last),
 106                    g_file_info_get_etag (new)))
 107     return G_FILE_MONITOR_EVENT_CHANGED;
 108
 109   if (g_file_info_get_size (last) !=
 110       g_file_info_get_size (new))
 111     return G_FILE_MONITOR_EVENT_CHANGED;
 112
 113   return -1;
 114 }
 115
 116 static void
 117 got_new_info (GObject      *source_object,
 118               GAsyncResult *res,
 119               gpointer      user_data)
 120 {
 121   GPollFileMonitor* poll_monitor = user_data;
 122   GFileInfo *info;
 123   int event;
 124
 125   info = g_file_query_info_finish (poll_monitor->file, res, NULL);
 126
 127   if (!g_file_monitor_is_cancelled (G_FILE_MONITOR (poll_monitor)))
 128     {
 129       event = calc_event_type (poll_monitor->last_info, info);
 130
 131       if (event != -1)
 132         {
 133           g_file_monitor_emit_event (G_FILE_MONITOR (poll_monitor),
 134                                      poll_monitor->file,
 135                                      NULL, event);
 136           /* We're polling so slowly anyway, so always emit the done hint */
 137           if (event == G_FILE_MONITOR_EVENT_CHANGED)
 138             g_file_monitor_emit_event (G_FILE_MONITOR (poll_monitor),
 139                                        poll_monitor->file,
 140                                        NULL, G_FILE_MONITOR_EVENT_CHANGES_DONE_HINT);
 141         }
 142
 143       if (poll_monitor->last_info)
 144         {
 145           g_object_unref (poll_monitor->last_info);
 146           poll_monitor->last_info = NULL;
 147         }
 148
 149       if (info)
 150         poll_monitor->last_info = g_object_ref (info);
 151
 152       schedule_poll_timeout (poll_monitor);
 153     }
 154
 155   if (info)
 156     g_object_unref (info);
 157
 158   g_object_unref (poll_monitor);
 159 }
 160
 161 static gboolean
 162 poll_file_timeout (gpointer data)
 163 {
 164   GPollFileMonitor* poll_monitor = data;
 165
 166   poll_monitor->timeout = FALSE;
 167
 168   g_file_query_info_async (poll_monitor->file, G_FILE_ATTRIBUTE_ETAG_VALUE "," G_FILE_ATTRIBUTE_STANDARD_SIZE,
 169                          0, 0, NULL, got_new_info, g_object_ref (poll_monitor));
 170
 171   return FALSE;
 172 }
 173
 174 static void
 175 schedule_poll_timeout (GPollFileMonitor* poll_monitor)
 176 {
 177   poll_monitor->timeout = g_timeout_add_seconds (POLL_TIME_SECS, poll_file_timeout, poll_monitor);
 178  }
 179
 180 static void
 181 got_initial_info (GObject      *source_object,
 182                   GAsyncResult *res,
 183                   gpointer      user_data)
 184 {
 185   GPollFileMonitor* poll_monitor = user_data;
 186   GFileInfo *info;
 187
 188   info = g_file_query_info_finish (poll_monitor->file, res, NULL);
 189
 190   poll_monitor->last_info = info;
 191
 192   if (!g_file_monitor_is_cancelled (G_FILE_MONITOR (poll_monitor)))
 193     schedule_poll_timeout (poll_monitor);
 194
 195   g_object_unref (poll_monitor);
 196 }
 197
 198 /**
 199  * g_poll_file_monitor_new:
 200  * @file: a #GFile.
 201  *
 202  * Polls @file for changes.
 203  *
 204  * Returns: a new #GFileMonitor for the given #GFile.
 205  **/
 206 GFileMonitor*
 207 _g_poll_file_monitor_new (GFile *file)
 208 {
 209   GPollFileMonitor* poll_monitor;
 210
 211   poll_monitor = g_object_new (G_TYPE_POLL_FILE_MONITOR, NULL);
 212
 213   poll_monitor->file = g_object_ref (file);
 214
 215   g_file_query_info_async (file, G_FILE_ATTRIBUTE_ETAG_VALUE "," G_FILE_ATTRIBUTE_STANDARD_SIZE,
 216                            0, 0, NULL, got_initial_info, g_object_ref (poll_monitor));
 217
 218   return G_FILE_MONITOR (poll_monitor);
 219 }
 220
 221 static gboolean
 222 g_poll_file_monitor_cancel (GFileMonitor* monitor)
 223 {
 224   GPollFileMonitor *poll_monitor = G_POLL_FILE_MONITOR (monitor);
 225
 226   if (poll_monitor->timeout)
 227     {
 228       g_source_remove (poll_monitor->timeout);
 229       poll_monitor->timeout = 0;
 230     }
 231
 232   return TRUE;
 233 }