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 2.1 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   GSource *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 calc_event_type (GFileInfo *last,
  77                  GFileInfo *new)
  78 {
  79   if (last == NULL && new == NULL)
  80     return -1;
  81
  82   if (last == NULL && new != NULL)
  83     return G_FILE_MONITOR_EVENT_CREATED;
  84
  85   if (last != NULL && new == NULL)
  86     return G_FILE_MONITOR_EVENT_DELETED;
  87
  88   if (g_strcmp0 (g_file_info_get_etag (last), g_file_info_get_etag (new)))
  89     return G_FILE_MONITOR_EVENT_CHANGED;
  90
  91   if (g_file_info_get_size (last) != g_file_info_get_size (new))
  92     return G_FILE_MONITOR_EVENT_CHANGED;
  93
  94   return -1;
  95 }
  96
  97 static void
  98 got_new_info (GObject      *source_object,
  99               GAsyncResult *res,
 100               gpointer      user_data)
 101 {
 102   GPollFileMonitor* poll_monitor = user_data;
 103   GFileInfo *info;
 104   int event;
 105
 106   info = g_file_query_info_finish (poll_monitor->file, res, NULL);
 107
 108   if (!g_file_monitor_is_cancelled (G_FILE_MONITOR (poll_monitor)))
 109     {
 110       event = calc_event_type (poll_monitor->last_info, info);
 111
 112       if (event != -1)
 113         {
 114           g_file_monitor_emit_event (G_FILE_MONITOR (poll_monitor),
 115                                      poll_monitor->file,
 116                                      NULL, event);
 117           /* We're polling so slowly anyway, so always emit the done hint */
 118           if (!g_file_monitor_is_cancelled (G_FILE_MONITOR (poll_monitor)) &&
 119              (event == G_FILE_MONITOR_EVENT_CHANGED || event == G_FILE_MONITOR_EVENT_CREATED))
 120             g_file_monitor_emit_event (G_FILE_MONITOR (poll_monitor),
 121                                        poll_monitor->file,
 122                                        NULL, G_FILE_MONITOR_EVENT_CHANGES_DONE_HINT);
 123         }
 124
 125       if (poll_monitor->last_info)
 126         {
 127           g_object_unref (poll_monitor->last_info);
 128           poll_monitor->last_info = NULL;
 129         }
 130
 131       if (info)
 132         poll_monitor->last_info = g_object_ref (info);
 133
 134       schedule_poll_timeout (poll_monitor);
 135     }
 136
 137   if (info)
 138     g_object_unref (info);
 139
 140   g_object_unref (poll_monitor);
 141 }
 142
 143 static gboolean
 144 poll_file_timeout (gpointer data)
 145 {
 146   GPollFileMonitor* poll_monitor = data;
 147
 148   poll_monitor->timeout = FALSE;
 149
 150   g_file_query_info_async (poll_monitor->file, G_FILE_ATTRIBUTE_ETAG_VALUE "," G_FILE_ATTRIBUTE_STANDARD_SIZE,
 151                          0, 0, NULL, got_new_info, g_object_ref (poll_monitor));
 152
 153   return G_SOURCE_REMOVE;
 154 }
 155
 156 static void
 157 schedule_poll_timeout (GPollFileMonitor* poll_monitor)
 158 {
 159   poll_monitor->timeout = g_timeout_source_new_seconds (POLL_TIME_SECS);
 160   g_source_set_callback (poll_monitor->timeout, poll_file_timeout, poll_monitor, NULL);
 161   g_source_attach (poll_monitor->timeout, g_main_context_get_thread_default ());
 162 }
 163
 164 static void
 165 got_initial_info (GObject      *source_object,
 166                   GAsyncResult *res,
 167                   gpointer      user_data)
 168 {
 169   GPollFileMonitor* poll_monitor = user_data;
 170   GFileInfo *info;
 171
 172   info = g_file_query_info_finish (poll_monitor->file, res, NULL);
 173
 174   poll_monitor->last_info = info;
 175
 176   if (!g_file_monitor_is_cancelled (G_FILE_MONITOR (poll_monitor)))
 177     schedule_poll_timeout (poll_monitor);
 178
 179   g_object_unref (poll_monitor);
 180 }
 181
 182 /**
 183  * _g_poll_file_monitor_new:
 184  * @file: a #GFile.
 185  *
 186  * Polls @file for changes.
 187  *
 188  * Returns: a new #GFileMonitor for the given #GFile.
 189  **/
 190 GFileMonitor*
 191 _g_poll_file_monitor_new (GFile *file)
 192 {
 193   GPollFileMonitor* poll_monitor;
 194
 195   poll_monitor = g_object_new (G_TYPE_POLL_FILE_MONITOR, NULL);
 196
 197   poll_monitor->file = g_object_ref (file);
 198
 199   g_file_query_info_async (file, G_FILE_ATTRIBUTE_ETAG_VALUE "," G_FILE_ATTRIBUTE_STANDARD_SIZE,
 200                            0, 0, NULL, got_initial_info, g_object_ref (poll_monitor));
 201
 202   return G_FILE_MONITOR (poll_monitor);
 203 }
 204
 205 static gboolean
 206 g_poll_file_monitor_cancel (GFileMonitor* monitor)
 207 {
 208   GPollFileMonitor *poll_monitor = G_POLL_FILE_MONITOR (monitor);
 209
 210   if (poll_monitor->timeout)
 211     {
 212       g_source_destroy (poll_monitor->timeout);
 213       g_source_unref (poll_monitor->timeout);
 214       poll_monitor->timeout = NULL;
 215     }
 216
 217   return TRUE;
 218 }