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 "config.h"
  21
  22 #include "atkregistry.h"
  23 #include "atknoopobjectfactory.h"
  24
  25 /**
  26  * SECTION:atkregistry
  27  * @Short_description: An object used to store the GType of the
  28  * factories used to create an accessible object for an object of a
  29  * particular GType.
  30  * @Title:AtkRegistry
  31  *
  32  * The AtkRegistry is normally used to create appropriate ATK "peers"
  33  * for user interface components.  Application developers usually need
  34  * only interact with the AtkRegistry by associating appropriate ATK
  35  * implementation classes with GObject classes via the
  36  * atk_registry_set_factory_type call, passing the appropriate GType
  37  * for application custom widget classes.
  38  */
  39
  40 static AtkRegistry *default_registry = NULL;
  41
  42 static void              atk_registry_init           (AtkRegistry      *instance,
  43                                                       AtkRegistryClass *klass);
  44 static void              atk_registry_finalize       (GObject          *instance);
  45 static void              atk_registry_class_init     (AtkRegistryClass *klass);
  46 static AtkRegistry*      atk_registry_new            (void);
  47
  48 static gpointer parent_class = NULL;
  49
  50 GType
  51 atk_registry_get_type (void)
  52 {
  53   static GType type = 0;
  54
  55   if (!type)
  56     {
  57       static const GTypeInfo info =
  58       {
  59         sizeof (AtkRegistryClass),
  60         (GBaseInitFunc) NULL,                             /* base_init */
  61         (GBaseFinalizeFunc) NULL,                         /* base_finalize */
  62         (GClassInitFunc) atk_registry_class_init,         /* class_init */
  63         (GClassFinalizeFunc) NULL,                        /* class_finalize */
  64         NULL,                                             /* class_data */
  65         sizeof (AtkRegistry),                             /* instance size */
  66         0,                                                /* n_preallocs */
  67         (GInstanceInitFunc) atk_registry_init,            /* instance init */
  68         NULL                                              /* value table */
  69       };
  70
  71       type = g_type_register_static (G_TYPE_OBJECT, "AtkRegistry", &info, 0);
  72     }
  73
  74   return type;
  75 }
  76
  77 static void
  78 atk_registry_class_init (AtkRegistryClass *klass)
  79 {
  80   GObjectClass *object_class = (GObjectClass *) klass;
  81
  82   parent_class = g_type_class_peek_parent (klass);
  83
  84   object_class->finalize = atk_registry_finalize;
  85 }
  86
  87 #if 0
  88 /*
  89  * Cannot define a class_finalize function when calling
  90  * g_type_register_static()
  91  */
  92 static void
  93 atk_registry_class_finalize (GObjectClass *klass)
  94 {
  95   g_return_if_fail (ATK_IS_REGISTRY_CLASS (klass));
  96
  97   g_object_unref (G_OBJECT (default_registry));
  98 }
  99 #endif
 100
 101 static void
 102 atk_registry_init (AtkRegistry *instance, AtkRegistryClass *klass)
 103 {
 104   instance->factory_type_registry = g_hash_table_new ((GHashFunc) NULL,
 105                                                       (GEqualFunc) NULL);
 106   instance->factory_singleton_cache = g_hash_table_new ((GHashFunc) NULL,
 107                                                         (GEqualFunc) NULL);
 108 }
 109
 110 static AtkRegistry *
 111 atk_registry_new (void)
 112 {
 113   GObject *object;
 114
 115   object = g_object_new (ATK_TYPE_REGISTRY, NULL);
 116
 117   g_return_val_if_fail (ATK_IS_REGISTRY (object), NULL);
 118
 119   return (AtkRegistry *) object;
 120 }
 121
 122 static void
 123 atk_registry_finalize (GObject *object)
 124 {
 125   AtkRegistry *registry = ATK_REGISTRY (object);
 126
 127   g_hash_table_destroy (registry->factory_type_registry);
 128   g_hash_table_destroy (registry->factory_singleton_cache);
 129
 130   G_OBJECT_CLASS (parent_class)->finalize (object);
 131 }
 132
 133 /**
 134  * atk_registry_set_factory_type:
 135  * @registry: the #AtkRegistry in which to register the type association
 136  * @type: an #AtkObject type
 137  * @factory_type: an #AtkObjectFactory type to associate with @type.  Must
 138  * implement AtkObject appropriate for @type.
 139  *
 140  * Associate an #AtkObjectFactory subclass with a #GType. Note:
 141  * The associated @factory_type will thereafter be responsible for
 142  * the creation of new #AtkObject implementations for instances
 143  * appropriate for @type.
 144  **/
 145 void
 146 atk_registry_set_factory_type (AtkRegistry *registry,
 147                                GType type,
 148                                GType factory_type)
 149 {
 150   GType old_type;
 151   gpointer value;
 152   AtkObjectFactory *old_factory;
 153
 154   g_return_if_fail (ATK_IS_REGISTRY (registry));
 155
 156   value = g_hash_table_lookup (registry->factory_type_registry,
 157                                   (gpointer) type);
 158   old_type = (GType) value;
 159   if (old_type && old_type != factory_type)
 160     {
 161       g_hash_table_remove (registry->factory_type_registry,
 162                            (gpointer) type);
 163       /*
 164        * If the old factory was created, notify it that it has
 165        * been replaced, then free it.
 166        */
 167       old_factory = g_hash_table_lookup (registry->factory_singleton_cache,
 168                                          (gpointer) old_type);
 169       if (old_factory)
 170         {
 171           atk_object_factory_invalidate (old_factory);
 172           g_type_free_instance ((GTypeInstance *) old_factory);
 173         }
 174     }
 175   g_hash_table_insert (registry->factory_type_registry,
 176                        (gpointer) type,
 177                        (gpointer) factory_type);
 178 }
 179
 180 /**
 181  * atk_registry_get_factory_type:
 182  * @registry: an #AtkRegistry
 183  * @type: a #GType with which to look up the associated #AtkObjectFactory
 184  * subclass
 185  *
 186  * Provides a #GType indicating the #AtkObjectFactory subclass
 187  * associated with @type.
 188  *
 189  * Returns: a #GType associated with type @type
 190  **/
 191 GType
 192 atk_registry_get_factory_type (AtkRegistry *registry,
 193                                GType type)
 194 {
 195   GType factory_type;
 196   gpointer value;
 197
 198   /*
 199    * look up factory type in first hash;
 200    * if there isn't an explicitly registered factory type,
 201    * try inheriting one...
 202    */
 203   do {
 204     value =
 205         g_hash_table_lookup (registry->factory_type_registry,
 206                              (gpointer) type);
 207     type = g_type_parent (type);
 208     if (type == G_TYPE_INVALID)
 209       {
 210         break;
 211       }
 212   } while (value == NULL);
 213
 214   factory_type = (GType) value;
 215   return factory_type;
 216 }
 217
 218 /**
 219  * atk_registry_get_factory:
 220  * @registry: an #AtkRegistry
 221  * @type: a #GType with which to look up the associated #AtkObjectFactory
 222  *
 223  * Gets an #AtkObjectFactory appropriate for creating #AtkObjects
 224  * appropriate for @type.
 225  *
 226  * Returns: (transfer none): an #AtkObjectFactory appropriate for creating
 227  * #AtkObjects appropriate for @type.
 228  **/
 229 AtkObjectFactory*
 230 atk_registry_get_factory (AtkRegistry *registry,
 231                           GType type)
 232 {
 233   gpointer factory_pointer = NULL;
 234   GType factory_type;
 235
 236   factory_type = atk_registry_get_factory_type (registry, type);
 237
 238   if (factory_type == G_TYPE_INVALID)
 239   {
 240   /* Factory type has not been specified for this object type */
 241     static AtkObjectFactory* default_factory = NULL;
 242
 243     if (!default_factory)
 244       default_factory = atk_no_op_object_factory_new ();
 245
 246     return default_factory;
 247   }
 248
 249   /* ask second hashtable for instance of factory type */
 250   factory_pointer =
 251         g_hash_table_lookup (registry->factory_singleton_cache,
 252         (gpointer) factory_type);
 253
 254   /* if there isn't one already, create one and save it */
 255   if (factory_pointer == NULL)
 256     {
 257       factory_pointer = g_type_create_instance (factory_type);
 258       g_hash_table_insert (registry->factory_singleton_cache,
 259                            (gpointer) factory_type,
 260                            factory_pointer);
 261     }
 262
 263   return ATK_OBJECT_FACTORY (factory_pointer);
 264 }
 265
 266 /**
 267  * atk_get_default_registry:
 268  *
 269  * Gets a default implementation of the #AtkObjectFactory/type
 270  * registry.
 271  * Note: For most toolkit maintainers, this will be the correct
 272  * registry for registering new #AtkObject factories. Following
 273  * a call to this function, maintainers may call atk_registry_set_factory_type()
 274  * to associate an #AtkObjectFactory subclass with the GType of objects
 275  * for whom accessibility information will be provided.
 276  *
 277  * Returns: (transfer full): a default implementation of the
 278  * #AtkObjectFactory/type registry
 279  **/
 280 AtkRegistry*
 281 atk_get_default_registry (void)
 282 {
 283   if (!default_registry)
 284     {
 285       default_registry = atk_registry_new ();
 286     }
 287   return default_registry;
 288 }