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 2.1 of the License, 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 *
g_memory_settings_backend_read(GSettingsBackend * backend,const gchar * key,const GVariantType * expected_type,gboolean default_value)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
g_memory_settings_backend_write(GSettingsBackend * backend,const gchar * key,GVariant * value,gpointer origin_tag)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
g_memory_settings_backend_write_one(gpointer key,gpointer value,gpointer data)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
g_memory_settings_backend_write_tree(GSettingsBackend * backend,GTree * tree,gpointer origin_tag)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
g_memory_settings_backend_reset(GSettingsBackend * backend,const gchar * key,gpointer origin_tag)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
g_memory_settings_backend_get_writable(GSettingsBackend * backend,const gchar * name)129 g_memory_settings_backend_get_writable (GSettingsBackend *backend,
130                                         const gchar      *name)
131 {
132   return TRUE;
133 }
134 
135 static GPermission *
g_memory_settings_backend_get_permission(GSettingsBackend * backend,const gchar * path)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
g_memory_settings_backend_finalize(GObject * object)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
g_memory_settings_backend_init(GMemorySettingsBackend * memory)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
g_memory_settings_backend_class_init(GMemorySettingsBackendClass * class)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 *
g_memory_settings_backend_new(void)189 g_memory_settings_backend_new (void)
190 {
191   return g_object_new (G_TYPE_MEMORY_SETTINGS_BACKEND, NULL);
192 }
193