atk/atkregistry.c

   1 /* ATK - Accessibility Toolkit
   2  * Copyright 2001 Sun Microsystems Inc.
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Library General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 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  * Library General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Library 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
  20 #include "atkregistry.h"
  21 #include "atknoopobjectfactory.h"
  22
  23 static AtkRegistry *default_registry = NULL;
  24
  25 static void              atk_registry_init           (AtkRegistry      *instance,
  26                                                       AtkRegistryClass *klass);
  27 static void              atk_registry_finalize       (GObject          *instance);
  28 static void              atk_registry_class_init     (AtkRegistryClass *klass);
  29 static AtkRegistry*      atk_registry_new            (void);
  30
  31 static gpointer parent_class = NULL;
  32
  33 GType
  34 atk_registry_get_type (void)
  35 {
  36   static GType type = 0;
  37
  38   if (!type)
  39     {
  40       static const GTypeInfo info =
  41       {
  42         sizeof (AtkRegistryClass),
  43         (GBaseInitFunc) NULL,                             /* base_init */
  44         (GBaseFinalizeFunc) NULL,                         /* base_finalize */
  45         (GClassInitFunc) atk_registry_class_init,         /* class_init */
  46         (GClassFinalizeFunc) NULL,                        /* class_finalize */
  47         NULL,                                             /* class_data */
  48         sizeof (AtkRegistry),                             /* instance size */
  49         0,                                                /* n_preallocs */
  50         (GInstanceInitFunc) atk_registry_init,            /* instance init */
  51         NULL                                              /* value table */
  52       };
  53
  54       type = g_type_register_static (G_TYPE_OBJECT, "AtkRegistry", &info, 0);
  55     }
  56
  57   return type;
  58 }
  59
  60 static void
  61 atk_registry_class_init (AtkRegistryClass *klass)
  62 {
  63   GObjectClass *object_class = (GObjectClass *) klass;
  64
  65   parent_class = g_type_class_peek_parent (klass);
  66
  67   object_class->finalize = atk_registry_finalize;
  68 }
  69
  70 #if 0
  71 /*
  72  * Cannot define a class_finalize function when calling
  73  * g_type_register_static()
  74  */
  75 static void
  76 atk_registry_class_finalize (GObjectClass *klass)
  77 {
  78   g_return_if_fail (ATK_IS_REGISTRY_CLASS (klass));
  79
  80   g_object_unref (G_OBJECT (default_registry));
  81 }
  82 #endif
  83
  84 static void
  85 atk_registry_init (AtkRegistry *instance, AtkRegistryClass *klass)
  86 {
  87   instance->factory_type_registry = g_hash_table_new ((GHashFunc) NULL,
  88                                                       (GEqualFunc) NULL);
  89   instance->factory_singleton_cache = g_hash_table_new ((GHashFunc) NULL,
  90                                                         (GEqualFunc) NULL);
  91 }
  92
  93 static AtkRegistry *
  94 atk_registry_new (void)
  95 {
  96   GObject *object;
  97
  98   object = g_object_new (ATK_TYPE_REGISTRY, NULL);
  99
 100   g_return_val_if_fail (ATK_IS_REGISTRY (object), NULL);
 101
 102   return (AtkRegistry *) object;
 103 }
 104
 105 static void
 106 atk_registry_finalize (GObject *object)
 107 {
 108   AtkRegistry *registry = ATK_REGISTRY (object);
 109
 110   g_hash_table_destroy (registry->factory_type_registry);
 111   g_hash_table_destroy (registry->factory_singleton_cache);
 112
 113   G_OBJECT_CLASS (parent_class)->finalize (object);
 114 }
 115
 116 /**
 117  * atk_registry_set_factory_type:
 118  * @registry: the #AtkRegistry in which to register the type association
 119  * @type: an #AtkObject type
 120  * @factory_type: an #AtkObjectFactory type to associate with @type.  Must
 121  * implement AtkObject appropriate for @type.
 122  *
 123  * Associate an #AtkObjectFactory subclass with a #GType. Note:
 124  * The associated @factory_type will thereafter be responsible for
 125  * the creation of new #AtkObject implementations for instances
 126  * appropriate for @type.
 127  **/
 128 void
 129 atk_registry_set_factory_type (AtkRegistry *registry,
 130                                GType type,
 131                                GType factory_type)
 132 {
 133   GType old_type;
 134   gpointer value;
 135   AtkObjectFactory *old_factory;
 136
 137   g_return_if_fail (ATK_IS_REGISTRY (registry));
 138
 139   value = g_hash_table_lookup (registry->factory_type_registry,
 140                                   (gpointer) type);
 141   old_type = (GType) value;
 142   if (old_type && old_type != factory_type)
 143     {
 144       g_hash_table_remove (registry->factory_type_registry,
 145                            (gpointer) type);
 146       /*
 147        * If the old factory was created, notify it that it has
 148        * been replaced, then free it.
 149        */
 150       old_factory = g_hash_table_lookup (registry->factory_singleton_cache,
 151                                          (gpointer) old_type);
 152       if (old_factory)
 153         {
 154           atk_object_factory_invalidate (old_factory);
 155           g_type_free_instance ((GTypeInstance *) old_factory);
 156         }
 157     }
 158   g_hash_table_insert (registry->factory_type_registry,
 159                        (gpointer) type,
 160                        (gpointer) factory_type);
 161 }
 162
 163 /**
 164  * atk_registry_get_factory_type:
 165  * @registry: an #AtkRegistry
 166  * @type: a #GType with which to look up the associated #AtkObjectFactory
 167  * subclass
 168  *
 169  * Provides a #GType indicating the #AtkObjectFactory subclass
 170  * associated with @type.
 171  *
 172  * Returns: a #GType associated with type @type
 173  **/
 174 GType
 175 atk_registry_get_factory_type (AtkRegistry *registry,
 176                                GType type)
 177 {
 178   GType factory_type;
 179   gpointer value;
 180
 181   /*
 182    * look up factory type in first hash;
 183    * if there isn't an explicitly registered factory type,
 184    * try inheriting one...
 185    */
 186   do {
 187     value =
 188         g_hash_table_lookup (registry->factory_type_registry,
 189                              (gpointer) type);
 190     type = g_type_parent (type);
 191     if (type == G_TYPE_INVALID)
 192       {
 193         break;
 194       }
 195   } while (value == NULL);
 196
 197   factory_type = (GType) value;
 198   return factory_type;
 199 }
 200
 201 /**
 202  * atk_registry_get_factory:
 203  * @registry: an #AtkRegistry
 204  * @type: a #GType with which to look up the associated #AtkObjectFactory
 205  *
 206  * Gets an #AtkObjectFactory appropriate for creating #AtkObjects
 207  * appropriate for @type.
 208  *
 209  * Returns: (transfer none): an #AtkObjectFactory appropriate for creating
 210  * #AtkObjects appropriate for @type.
 211  **/
 212 AtkObjectFactory*
 213 atk_registry_get_factory (AtkRegistry *registry,
 214                           GType type)
 215 {
 216   gpointer factory_pointer = NULL;
 217   GType factory_type;
 218
 219   factory_type = atk_registry_get_factory_type (registry, type);
 220
 221   if (factory_type == G_TYPE_INVALID)
 222   {
 223   /* Factory type has not been specified for this object type */
 224     static AtkObjectFactory* default_factory = NULL;
 225
 226     if (!default_factory)
 227       default_factory = atk_no_op_object_factory_new ();
 228
 229     return default_factory;
 230   }
 231
 232   /* ask second hashtable for instance of factory type */
 233   factory_pointer =
 234         g_hash_table_lookup (registry->factory_singleton_cache,
 235         (gpointer) factory_type);
 236
 237   /* if there isn't one already, create one and save it */
 238   if (factory_pointer == NULL)
 239     {
 240       factory_pointer = g_type_create_instance (factory_type);
 241       g_hash_table_insert (registry->factory_singleton_cache,
 242                            (gpointer) factory_type,
 243                            factory_pointer);
 244     }
 245
 246   return ATK_OBJECT_FACTORY (factory_pointer);
 247 }
 248
 249 /**
 250  * atk_get_default_registry:
 251  *
 252  * Gets a default implementation of the #AtkObjectFactory/type
 253  * registry.
 254  * Note: For most toolkit maintainers, this will be the correct
 255  * registry for registering new #AtkObject factories. Following
 256  * a call to this function, maintainers may call atk_registry_set_factory_type()
 257  * to associate an #AtkObjectFactory subclass with the GType of objects
 258  * for whom accessibility information will be provided.
 259  *
 260  * Returns: (transfer full): a default implementation of the
 261  * #AtkObjectFactory/type registry
 262  **/
 263 AtkRegistry*
 264 atk_get_default_registry (void)
 265 {
 266   if (!default_registry)
 267     {
 268       default_registry = atk_registry_new ();
 269     }
 270   return default_registry;
 271 }