gio/gmemorysettingsbackend.c

   1 /*
   2  * Copyright © 2010 Codethink Limited
   3  *
   4  * SPDX-License-Identifier: LGPL-2.1-or-later
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  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-priv.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_modules_ensure_extension_points_registered ();
  45                          g_io_extension_point_implement (G_SETTINGS_BACKEND_EXTENSION_POINT_NAME,
  46                                                          g_define_type_id, "memory", 10))
  47
  48 static GVariant *
  49 g_memory_settings_backend_read (GSettingsBackend   *backend,
  50                                 const gchar        *key,
  51                                 const GVariantType *expected_type,
  52                                 gboolean            default_value)
  53 {
  54   GMemorySettingsBackend *memory = G_MEMORY_SETTINGS_BACKEND (backend);
  55   GVariant *value;
  56
  57   if (default_value)
  58     return NULL;
  59
  60   value = g_hash_table_lookup (memory->table, key);
  61
  62   if (value != NULL)
  63     g_variant_ref (value);
  64
  65   return value;
  66 }
  67
  68 static gboolean
  69 g_memory_settings_backend_write (GSettingsBackend *backend,
  70                                  const gchar      *key,
  71                                  GVariant         *value,
  72                                  gpointer          origin_tag)
  73 {
  74   GMemorySettingsBackend *memory = G_MEMORY_SETTINGS_BACKEND (backend);
  75   GVariant *old_value;
  76
  77   old_value = g_hash_table_lookup (memory->table, key);
  78   g_variant_ref_sink (value);
  79
  80   if (old_value == NULL || !g_variant_equal (value, old_value))
  81     {
  82       g_hash_table_insert (memory->table, g_strdup (key), value);
  83       g_settings_backend_changed (backend, key, origin_tag);
  84     }
  85   else
  86     g_variant_unref (value);
  87
  88   return TRUE;
  89 }
  90
  91 static gboolean
  92 g_memory_settings_backend_write_one (gpointer key,
  93                                      gpointer value,
  94                                      gpointer data)
  95 {
  96   GMemorySettingsBackend *memory = data;
  97
  98   if (value != NULL)
  99     g_hash_table_insert (memory->table, g_strdup (key), g_variant_ref (value));
 100   else
 101     g_hash_table_remove (memory->table, key);
 102
 103   return FALSE;
 104 }
 105
 106 static gboolean
 107 g_memory_settings_backend_write_tree (GSettingsBackend *backend,
 108                                       GTree            *tree,
 109                                       gpointer          origin_tag)
 110 {
 111   g_tree_foreach (tree, g_memory_settings_backend_write_one, backend);
 112   g_settings_backend_changed_tree (backend, tree, origin_tag);
 113
 114   return TRUE;
 115 }
 116
 117 static void
 118 g_memory_settings_backend_reset (GSettingsBackend *backend,
 119                                  const gchar      *key,
 120                                  gpointer          origin_tag)
 121 {
 122   GMemorySettingsBackend *memory = G_MEMORY_SETTINGS_BACKEND (backend);
 123
 124   if (g_hash_table_lookup (memory->table, key))
 125     {
 126       g_hash_table_remove (memory->table, key);
 127       g_settings_backend_changed (backend, key, origin_tag);
 128     }
 129 }
 130
 131 static gboolean
 132 g_memory_settings_backend_get_writable (GSettingsBackend *backend,
 133                                         const gchar      *name)
 134 {
 135   return TRUE;
 136 }
 137
 138 static GPermission *
 139 g_memory_settings_backend_get_permission (GSettingsBackend *backend,
 140                                           const gchar      *path)
 141 {
 142   return g_simple_permission_new (TRUE);
 143 }
 144
 145 static void
 146 g_memory_settings_backend_finalize (GObject *object)
 147 {
 148   GMemorySettingsBackend *memory = G_MEMORY_SETTINGS_BACKEND (object);
 149
 150   g_hash_table_unref (memory->table);
 151
 152   G_OBJECT_CLASS (g_memory_settings_backend_parent_class)
 153     ->finalize (object);
 154 }
 155
 156 static void
 157 g_memory_settings_backend_init (GMemorySettingsBackend *memory)
 158 {
 159   memory->table = g_hash_table_new_full (g_str_hash, g_str_equal, g_free,
 160                                          (GDestroyNotify) g_variant_unref);
 161 }
 162
 163 static void
 164 g_memory_settings_backend_class_init (GMemorySettingsBackendClass *class)
 165 {
 166   GSettingsBackendClass *backend_class = G_SETTINGS_BACKEND_CLASS (class);
 167   GObjectClass *object_class = G_OBJECT_CLASS (class);
 168
 169   backend_class->read = g_memory_settings_backend_read;
 170   backend_class->write = g_memory_settings_backend_write;
 171   backend_class->write_tree = g_memory_settings_backend_write_tree;
 172   backend_class->reset = g_memory_settings_backend_reset;
 173   backend_class->get_writable = g_memory_settings_backend_get_writable;
 174   backend_class->get_permission = g_memory_settings_backend_get_permission;
 175   object_class->finalize = g_memory_settings_backend_finalize;
 176 }
 177
 178 /**
 179  * g_memory_settings_backend_new:
 180  *
 181  * Creates a memory-backed #GSettingsBackend.
 182  *
 183  * This backend allows changes to settings, but does not write them
 184  * to any backing storage, so the next time you run your application,
 185  * the memory backend will start out with the default values again.
 186  *
 187  * Returns: (transfer full): a newly created #GSettingsBackend
 188  *
 189  * Since: 2.28
 190  */
 191 GSettingsBackend *
 192 g_memory_settings_backend_new (void)
 193 {
 194   return g_object_new (G_TYPE_MEMORY_SETTINGS_BACKEND, NULL);
 195 }