gio/gmemorysettingsbackend.c

   1 /*
   2  * Copyright © 2010 Codethink Limited
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the licence, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the
  16  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17  * Boston, MA 02111-1307, USA.
  18  *
  19  * Author: Ryan Lortie <desrt@desrt.ca>
  20  */
  21
  22 #include "config.h"
  23
  24 #include "gsimplepermission.h"
  25 #include "gsettingsbackendinternal.h"
  26 #include "giomodule.h"
  27
  28
  29 #define G_TYPE_MEMORY_SETTINGS_BACKEND  (g_memory_settings_backend_get_type())
  30 #define G_MEMORY_SETTINGS_BACKEND(inst) (G_TYPE_CHECK_INSTANCE_CAST ((inst), \
  31                                          G_TYPE_MEMORY_SETTINGS_BACKEND,     \
  32                                          GMemorySettingsBackend))
  33
  34 typedef GSettingsBackendClass GMemorySettingsBackendClass;
  35 typedef struct
  36 {
  37   GSettingsBackend parent_instance;
  38   GHashTable *table;
  39 } GMemorySettingsBackend;
  40
  41 G_DEFINE_TYPE_WITH_CODE (GMemorySettingsBackend,
  42                          g_memory_settings_backend,
  43                          G_TYPE_SETTINGS_BACKEND,
  44                          g_io_extension_point_implement (G_SETTINGS_BACKEND_EXTENSION_POINT_NAME,
  45                                                          g_define_type_id, "memory", 10))
  46
  47 static GVariant *
  48 g_memory_settings_backend_read (GSettingsBackend   *backend,
  49                                 const gchar        *key,
  50                                 const GVariantType *expected_type,
  51                                 gboolean            default_value)
  52 {
  53   GMemorySettingsBackend *memory = G_MEMORY_SETTINGS_BACKEND (backend);
  54   GVariant *value;
  55
  56   if (default_value)
  57     return NULL;
  58
  59   value = g_hash_table_lookup (memory->table, key);
  60
  61   if (value != NULL)
  62     g_variant_ref (value);
  63
  64   return value;
  65 }
  66
  67 static gboolean
  68 g_memory_settings_backend_write (GSettingsBackend *backend,
  69                                  const gchar      *key,
  70                                  GVariant         *value,
  71                                  gpointer          origin_tag)
  72 {
  73   GMemorySettingsBackend *memory = G_MEMORY_SETTINGS_BACKEND (backend);
  74   GVariant *old_value;
  75
  76   old_value = g_hash_table_lookup (memory->table, key);
  77   g_variant_ref_sink (value);
  78
  79   if (old_value == NULL || !g_variant_equal (value, old_value))
  80     {
  81       g_hash_table_insert (memory->table, g_strdup (key), value);
  82       g_settings_backend_changed (backend, key, origin_tag);
  83     }
  84   else
  85     g_variant_unref (value);
  86
  87   return TRUE;
  88 }
  89
  90 static gboolean
  91 g_memory_settings_backend_write_one (gpointer key,
  92                                      gpointer value,
  93                                      gpointer data)
  94 {
  95   GMemorySettingsBackend *memory = data;
  96
  97   if (value != NULL)
  98     g_hash_table_insert (memory->table, g_strdup (key), g_variant_ref (value));
  99   else
 100     g_hash_table_remove (memory->table, key);
 101
 102   return FALSE;
 103 }
 104
 105 static gboolean
 106 g_memory_settings_backend_write_tree (GSettingsBackend *backend,
 107                                       GTree            *tree,
 108                                       gpointer          origin_tag)
 109 {
 110   g_tree_foreach (tree, g_memory_settings_backend_write_one, backend);
 111   g_settings_backend_changed_tree (backend, tree, origin_tag);
 112
 113   return TRUE;
 114 }
 115
 116 static void
 117 g_memory_settings_backend_reset (GSettingsBackend *backend,
 118                                  const gchar      *key,
 119                                  gpointer          origin_tag)
 120 {
 121   GMemorySettingsBackend *memory = G_MEMORY_SETTINGS_BACKEND (backend);
 122
 123   if (g_hash_table_lookup (memory->table, key))
 124     {
 125       g_hash_table_remove (memory->table, key);
 126       g_settings_backend_changed (backend, key, origin_tag);
 127     }
 128 }
 129
 130 static gboolean
 131 g_memory_settings_backend_get_writable (GSettingsBackend *backend,
 132                                         const gchar      *name)
 133 {
 134   return TRUE;
 135 }
 136
 137 static GPermission *
 138 g_memory_settings_backend_get_permission (GSettingsBackend *backend,
 139                                           const gchar      *path)
 140 {
 141   return g_simple_permission_new (TRUE);
 142 }
 143
 144 static void
 145 g_memory_settings_backend_finalize (GObject *object)
 146 {
 147   GMemorySettingsBackend *memory = G_MEMORY_SETTINGS_BACKEND (object);
 148
 149   g_hash_table_unref (memory->table);
 150
 151   G_OBJECT_CLASS (g_memory_settings_backend_parent_class)
 152     ->finalize (object);
 153 }
 154
 155 static void
 156 g_memory_settings_backend_init (GMemorySettingsBackend *memory)
 157 {
 158   memory->table = g_hash_table_new_full (g_str_hash, g_str_equal, g_free,
 159                                          (GDestroyNotify) g_variant_unref);
 160 }
 161
 162 static void
 163 g_memory_settings_backend_class_init (GMemorySettingsBackendClass *class)
 164 {
 165   GSettingsBackendClass *backend_class = G_SETTINGS_BACKEND_CLASS (class);
 166   GObjectClass *object_class = G_OBJECT_CLASS (class);
 167
 168   backend_class->read = g_memory_settings_backend_read;
 169   backend_class->write = g_memory_settings_backend_write;
 170   backend_class->write_tree = g_memory_settings_backend_write_tree;
 171   backend_class->reset = g_memory_settings_backend_reset;
 172   backend_class->get_writable = g_memory_settings_backend_get_writable;
 173   backend_class->get_permission = g_memory_settings_backend_get_permission;
 174   object_class->finalize = g_memory_settings_backend_finalize;
 175 }
 176
 177 /**
 178  * g_memory_settings_backend_new:
 179  *
 180  * Creates a memory-backed #GSettingsBackend.
 181  *
 182  * This backend allows changes to settings, but does not write them
 183  * to any backing storage, so the next time you run your application,
 184  * the memory backend will start out with the default values again.
 185  *
 186  * Returns: (transfer full): a newly created #GSettingsBackend
 187  *
 188  * Since: 2.28
 189  */
 190 GSettingsBackend *
 191 g_memory_settings_backend_new (void)
 192 {
 193   return g_object_new (G_TYPE_MEMORY_SETTINGS_BACKEND, NULL);
 194 }