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, see <http://www.gnu.org/licenses/>.
  16  *
  17  * Author: Ryan Lortie <desrt@desrt.ca>
  18  */
  19
  20 #include "config.h"
  21
  22 #include "gsimplepermission.h"
  23 #include "gsettingsbackendinternal.h"
  24 #include "giomodule.h"
  25
  26
  27 #define G_TYPE_MEMORY_SETTINGS_BACKEND  (g_memory_settings_backend_get_type())
  28 #define G_MEMORY_SETTINGS_BACKEND(inst) (G_TYPE_CHECK_INSTANCE_CAST ((inst), \
  29                                          G_TYPE_MEMORY_SETTINGS_BACKEND,     \
  30                                          GMemorySettingsBackend))
  31
  32 typedef GSettingsBackendClass GMemorySettingsBackendClass;
  33 typedef struct
  34 {
  35   GSettingsBackend parent_instance;
  36   GHashTable *table;
  37 } GMemorySettingsBackend;
  38
  39 G_DEFINE_TYPE_WITH_CODE (GMemorySettingsBackend,
  40                          g_memory_settings_backend,
  41                          G_TYPE_SETTINGS_BACKEND,
  42                          g_io_extension_point_implement (G_SETTINGS_BACKEND_EXTENSION_POINT_NAME,
  43                                                          g_define_type_id, "memory", 10))
  44
  45 static GVariant *
  46 g_memory_settings_backend_read (GSettingsBackend   *backend,
  47                                 const gchar        *key,
  48                                 const GVariantType *expected_type,
  49                                 gboolean            default_value)
  50 {
  51   GMemorySettingsBackend *memory = G_MEMORY_SETTINGS_BACKEND (backend);
  52   GVariant *value;
  53
  54   if (default_value)
  55     return NULL;
  56
  57   value = g_hash_table_lookup (memory->table, key);
  58
  59   if (value != NULL)
  60     g_variant_ref (value);
  61
  62   return value;
  63 }
  64
  65 static gboolean
  66 g_memory_settings_backend_write (GSettingsBackend *backend,
  67                                  const gchar      *key,
  68                                  GVariant         *value,
  69                                  gpointer          origin_tag)
  70 {
  71   GMemorySettingsBackend *memory = G_MEMORY_SETTINGS_BACKEND (backend);
  72   GVariant *old_value;
  73
  74   old_value = g_hash_table_lookup (memory->table, key);
  75   g_variant_ref_sink (value);
  76
  77   if (old_value == NULL || !g_variant_equal (value, old_value))
  78     {
  79       g_hash_table_insert (memory->table, g_strdup (key), value);
  80       g_settings_backend_changed (backend, key, origin_tag);
  81     }
  82   else
  83     g_variant_unref (value);
  84
  85   return TRUE;
  86 }
  87
  88 static gboolean
  89 g_memory_settings_backend_write_one (gpointer key,
  90                                      gpointer value,
  91                                      gpointer data)
  92 {
  93   GMemorySettingsBackend *memory = data;
  94
  95   if (value != NULL)
  96     g_hash_table_insert (memory->table, g_strdup (key), g_variant_ref (value));
  97   else
  98     g_hash_table_remove (memory->table, key);
  99
 100   return FALSE;
 101 }
 102
 103 static gboolean
 104 g_memory_settings_backend_write_tree (GSettingsBackend *backend,
 105                                       GTree            *tree,
 106                                       gpointer          origin_tag)
 107 {
 108   g_tree_foreach (tree, g_memory_settings_backend_write_one, backend);
 109   g_settings_backend_changed_tree (backend, tree, origin_tag);
 110
 111   return TRUE;
 112 }
 113
 114 static void
 115 g_memory_settings_backend_reset (GSettingsBackend *backend,
 116                                  const gchar      *key,
 117                                  gpointer          origin_tag)
 118 {
 119   GMemorySettingsBackend *memory = G_MEMORY_SETTINGS_BACKEND (backend);
 120
 121   if (g_hash_table_lookup (memory->table, key))
 122     {
 123       g_hash_table_remove (memory->table, key);
 124       g_settings_backend_changed (backend, key, origin_tag);
 125     }
 126 }
 127
 128 static gboolean
 129 g_memory_settings_backend_get_writable (GSettingsBackend *backend,
 130                                         const gchar      *name)
 131 {
 132   return TRUE;
 133 }
 134
 135 static GPermission *
 136 g_memory_settings_backend_get_permission (GSettingsBackend *backend,
 137                                           const gchar      *path)
 138 {
 139   return g_simple_permission_new (TRUE);
 140 }
 141
 142 static void
 143 g_memory_settings_backend_finalize (GObject *object)
 144 {
 145   GMemorySettingsBackend *memory = G_MEMORY_SETTINGS_BACKEND (object);
 146
 147   g_hash_table_unref (memory->table);
 148
 149   G_OBJECT_CLASS (g_memory_settings_backend_parent_class)
 150     ->finalize (object);
 151 }
 152
 153 static void
 154 g_memory_settings_backend_init (GMemorySettingsBackend *memory)
 155 {
 156   memory->table = g_hash_table_new_full (g_str_hash, g_str_equal, g_free,
 157                                          (GDestroyNotify) g_variant_unref);
 158 }
 159
 160 static void
 161 g_memory_settings_backend_class_init (GMemorySettingsBackendClass *class)
 162 {
 163   GSettingsBackendClass *backend_class = G_SETTINGS_BACKEND_CLASS (class);
 164   GObjectClass *object_class = G_OBJECT_CLASS (class);
 165
 166   backend_class->read = g_memory_settings_backend_read;
 167   backend_class->write = g_memory_settings_backend_write;
 168   backend_class->write_tree = g_memory_settings_backend_write_tree;
 169   backend_class->reset = g_memory_settings_backend_reset;
 170   backend_class->get_writable = g_memory_settings_backend_get_writable;
 171   backend_class->get_permission = g_memory_settings_backend_get_permission;
 172   object_class->finalize = g_memory_settings_backend_finalize;
 173 }
 174
 175 /**
 176  * g_memory_settings_backend_new:
 177  *
 178  * Creates a memory-backed #GSettingsBackend.
 179  *
 180  * This backend allows changes to settings, but does not write them
 181  * to any backing storage, so the next time you run your application,
 182  * the memory backend will start out with the default values again.
 183  *
 184  * Returns: (transfer full): a newly created #GSettingsBackend
 185  *
 186  * Since: 2.28
 187  */
 188 GSettingsBackend *
 189 g_memory_settings_backend_new (void)
 190 {
 191   return g_object_new (G_TYPE_MEMORY_SETTINGS_BACKEND, NULL);
 192 }