gio/gpollfilemonitor.c

   1 /* GIO - GLib Input, Output and Streaming Library
   2  *
   3  * Copyright (C) 2006-2007 Red Hat, Inc.
   4  *
   5  * SPDX-License-Identifier: LGPL-2.1-or-later
   6  *
   7  * This library is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * This library is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General
  18  * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
  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   GSource *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_poll_file_monitor_cancel (G_FILE_MONITOR (poll_monitor));
  56   g_object_unref (poll_monitor->file);
  57   g_clear_object (&poll_monitor->last_info);
  58
  59   G_OBJECT_CLASS (g_poll_file_monitor_parent_class)->finalize (object);
  60 }
  61
  62
  63 static void
  64 g_poll_file_monitor_class_init (GPollFileMonitorClass* klass)
  65 {
  66   GObjectClass* gobject_class = G_OBJECT_CLASS (klass);
  67   GFileMonitorClass *file_monitor_class = G_FILE_MONITOR_CLASS (klass);
  68
  69   gobject_class->finalize = g_poll_file_monitor_finalize;
  70
  71   file_monitor_class->cancel = g_poll_file_monitor_cancel;
  72 }
  73
  74 static void
  75 g_poll_file_monitor_init (GPollFileMonitor* poll_monitor)
  76 {
  77 }
  78
  79 static int
  80 calc_event_type (GFileInfo *last,
  81                  GFileInfo *new)
  82 {
  83   if (last == NULL && new == NULL)
  84     return -1;
  85
  86   if (last == NULL && new != NULL)
  87     return G_FILE_MONITOR_EVENT_CREATED;
  88
  89   if (last != NULL && new == NULL)
  90     return G_FILE_MONITOR_EVENT_DELETED;
  91
  92   if (g_file_info_has_attribute (last, G_FILE_ATTRIBUTE_ETAG_VALUE) &&
  93       g_file_info_has_attribute (new, G_FILE_ATTRIBUTE_ETAG_VALUE) &&
  94       g_strcmp0 (g_file_info_get_etag (last), g_file_info_get_etag (new)) != 0)
  95     return G_FILE_MONITOR_EVENT_CHANGED;
  96
  97   if (g_file_info_has_attribute (last, G_FILE_ATTRIBUTE_STANDARD_SIZE) &&
  98       g_file_info_has_attribute (new, G_FILE_ATTRIBUTE_STANDARD_SIZE) &&
  99       g_file_info_get_size (last) != g_file_info_get_size (new))
 100     return G_FILE_MONITOR_EVENT_CHANGED;
 101
 102   return -1;
 103 }
 104
 105 static void
 106 got_new_info (GObject      *source_object,
 107               GAsyncResult *res,
 108               gpointer      user_data)
 109 {
 110   GPollFileMonitor* poll_monitor = user_data;
 111   GFileInfo *info;
 112   int event;
 113
 114   info = g_file_query_info_finish (poll_monitor->file, res, NULL);
 115
 116   if (!g_file_monitor_is_cancelled (G_FILE_MONITOR (poll_monitor)))
 117     {
 118       event = calc_event_type (poll_monitor->last_info, info);
 119
 120       if (event != -1)
 121         {
 122           g_file_monitor_emit_event (G_FILE_MONITOR (poll_monitor),
 123                                      poll_monitor->file,
 124                                      NULL, event);
 125           /* We're polling so slowly anyway, so always emit the done hint */
 126           if (!g_file_monitor_is_cancelled (G_FILE_MONITOR (poll_monitor)) &&
 127              (event == G_FILE_MONITOR_EVENT_CHANGED || event == G_FILE_MONITOR_EVENT_CREATED))
 128             g_file_monitor_emit_event (G_FILE_MONITOR (poll_monitor),
 129                                        poll_monitor->file,
 130                                        NULL, G_FILE_MONITOR_EVENT_CHANGES_DONE_HINT);
 131         }
 132
 133       if (poll_monitor->last_info)
 134         {
 135           g_object_unref (poll_monitor->last_info);
 136           poll_monitor->last_info = NULL;
 137         }
 138
 139       if (info)
 140         poll_monitor->last_info = g_object_ref (info);
 141
 142       schedule_poll_timeout (poll_monitor);
 143     }
 144
 145   if (info)
 146     g_object_unref (info);
 147
 148   g_object_unref (poll_monitor);
 149 }
 150
 151 static gboolean
 152 poll_file_timeout (gpointer data)
 153 {
 154   GPollFileMonitor* poll_monitor = data;
 155
 156   g_source_unref (poll_monitor->timeout);
 157   poll_monitor->timeout = NULL;
 158
 159   g_file_query_info_async (poll_monitor->file, G_FILE_ATTRIBUTE_ETAG_VALUE "," G_FILE_ATTRIBUTE_STANDARD_SIZE,
 160                          0, 0, NULL, got_new_info, g_object_ref (poll_monitor));
 161
 162   return G_SOURCE_REMOVE;
 163 }
 164
 165 static void
 166 schedule_poll_timeout (GPollFileMonitor* poll_monitor)
 167 {
 168   poll_monitor->timeout = g_timeout_source_new_seconds (POLL_TIME_SECS);
 169   g_source_set_callback (poll_monitor->timeout, poll_file_timeout, poll_monitor, NULL);
 170   g_source_attach (poll_monitor->timeout, g_main_context_get_thread_default ());
 171 }
 172
 173 static void
 174 got_initial_info (GObject      *source_object,
 175                   GAsyncResult *res,
 176                   gpointer      user_data)
 177 {
 178   GPollFileMonitor* poll_monitor = user_data;
 179   GFileInfo *info;
 180
 181   info = g_file_query_info_finish (poll_monitor->file, res, NULL);
 182
 183   poll_monitor->last_info = info;
 184
 185   if (!g_file_monitor_is_cancelled (G_FILE_MONITOR (poll_monitor)))
 186     schedule_poll_timeout (poll_monitor);
 187
 188   g_object_unref (poll_monitor);
 189 }
 190
 191 /**
 192  * _g_poll_file_monitor_new:
 193  * @file: a #GFile.
 194  *
 195  * Polls @file for changes.
 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_STANDARD_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_destroy (poll_monitor->timeout);
 222       g_source_unref (poll_monitor->timeout);
 223       poll_monitor->timeout = NULL;
 224     }
 225
 226   return TRUE;
 227 }