adg/adg-model.c

   1 /* ADG - Automatic Drawing Generation
   2  * Copyright (C) 2007,2008,2009 Nicola Fontana <ntd at entidi.it>
   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 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, write to the
  16  * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  17  * Boston, MA  02110-1301, USA.
  18  */
  19
  20
  21 /**
  22  * SECTION:adg-model
  23  * @short_description: The base class of the ADG model infrastructure
  24  *
  25  * A model is a conceptual representation of something. From an ADG
  26  * user point of view, it is a collection of data and rules that
  27  * defines how an object should be represented on a drawing.
  28  *
  29  * Because #AdgModel instances are only a conceptual idea, they are
  30  * not renderable (that is, #AdgModel is not derived from #AdgEntity).
  31  * Instead, it must be passed as subject to entities such as #AdgStroke
  32  * or #AdgHatch.
  33  **/
  34
  35 /**
  36  * AdgModel:
  37  *
  38  * All fields are private and should not be used directly.
  39  * Use its public methods instead.
  40  **/
  41
  42
  43 #include "adg-model.h"
  44 #include "adg-model-private.h"
  45 #include "adg-marshal.h"
  46 #include "adg-intl.h"
  47
  48 #define PARENT_OBJECT_CLASS  ((GObjectClass *) adg_model_parent_class)
  49
  50
  51 enum {
  52     PROP_0,
  53     PROP_DEPENDENCY
  54 };
  55
  56 enum {
  57     ADD_DEPENDENCY,
  58     REMOVE_DEPENDENCY,
  59     CHANGED,
  60     LAST_SIGNAL
  61 };
  62
  63
  64 static void     dispose                 (GObject        *object);
  65 static void     set_property            (GObject        *object,
  66                                          guint           prop_id,
  67                                          const GValue   *value,
  68                                          GParamSpec     *pspec);
  69
  70 static GSList * get_dependencies        (AdgModel       *model);
  71 static void     add_dependency          (AdgModel       *model,
  72                                          AdgEntity      *entity);
  73 static void     remove_dependency       (AdgModel       *model,
  74                                          AdgEntity      *entity);
  75 static void     changed                 (AdgModel       *model);
  76
  77 static guint signals[LAST_SIGNAL] = { 0 };
  78
  79
  80 G_DEFINE_ABSTRACT_TYPE(AdgModel, adg_model, G_TYPE_OBJECT);
  81
  82
  83 static void
  84 adg_model_class_init(AdgModelClass *klass)
  85 {
  86     GObjectClass *gobject_class;
  87     GParamSpec *param;
  88
  89     gobject_class = (GObjectClass *) klass;
  90
  91     g_type_class_add_private(klass, sizeof(AdgModelPrivate));
  92
  93     gobject_class->dispose = dispose;
  94     gobject_class->set_property = set_property;
  95
  96     klass->get_dependencies = get_dependencies;
  97     klass->add_dependency = add_dependency;
  98     klass->remove_dependency = remove_dependency;
  99     klass->changed = changed;
 100
 101     param = g_param_spec_object("dependency",
 102                                 P_("Dependency"),
 103                                 P_("Can be used to add a new dependency from this model (this entity will be invalidated on model changed)"),
 104                                 ADG_TYPE_ENTITY, G_PARAM_WRITABLE);
 105     g_object_class_install_property(gobject_class, PROP_DEPENDENCY, param);
 106
 107     /**
 108      * AdgModel::add-dependency:
 109      * @model: an #AdgModel
 110      * @entity: an #AdgEntity that depends on @model
 111      *
 112      * Adds @entity to @model. After that @entity will depend on @model,
 113      * that is #AdgModel::changed on @model will invalidate @entity.
 114      **/
 115     signals[ADD_DEPENDENCY] = g_signal_new("add-dependency",
 116                                            G_OBJECT_CLASS_TYPE(gobject_class),
 117                                            G_SIGNAL_RUN_FIRST,
 118                                            G_STRUCT_OFFSET(AdgModelClass, add_dependency),
 119                                            NULL, NULL,
 120                                            adg_marshal_VOID__OBJECT,
 121                                            G_TYPE_NONE, 1, ADG_TYPE_ENTITY);
 122
 123     /**
 124      * AdgModel::remove-dependency:
 125      * @model: an #AdgModel
 126      * @entity: the #AdgEntity that does not depend on @model anymore
 127      *
 128      * Removes the @entity from @model, that is @entity will not depend
 129      * on @model anymore.
 130      **/
 131     signals[REMOVE_DEPENDENCY] = g_signal_new("remove-dependency",
 132                                               G_OBJECT_CLASS_TYPE(gobject_class),
 133                                               G_SIGNAL_RUN_FIRST,
 134                                               G_STRUCT_OFFSET(AdgModelClass, remove_dependency),
 135                                               NULL, NULL,
 136                                               adg_marshal_VOID__OBJECT,
 137                                               G_TYPE_NONE, 1, ADG_TYPE_ENTITY);
 138
 139     /**
 140      * AdgModel::changed:
 141      * @model: an #AdgModel
 142      *
 143      * Notificates that the model has changed. By default, the model
 144      * cache is invalidated.
 145      **/
 146     signals[CHANGED] = g_signal_new("changed", ADG_TYPE_MODEL,
 147                                      G_SIGNAL_RUN_LAST|G_SIGNAL_NO_RECURSE,
 148                                      G_STRUCT_OFFSET(AdgModelClass, changed),
 149                                      NULL, NULL,
 150                                      adg_marshal_VOID__VOID,
 151                                      G_TYPE_NONE, 0);
 152 }
 153
 154 static void
 155 adg_model_init(AdgModel *model)
 156 {
 157     AdgModelPrivate *data = G_TYPE_INSTANCE_GET_PRIVATE(model, ADG_TYPE_MODEL,
 158                                                         AdgModelPrivate);
 159
 160     data->dependencies = NULL;
 161
 162     model->data = data;
 163 }
 164
 165 static void
 166 dispose(GObject *object)
 167 {
 168     AdgModel *model;
 169     AdgModelPrivate *data;
 170
 171     model = (AdgModel *) object;
 172     data = model->data;
 173
 174     /* Remove all the dependencies from the model: this will emit
 175      * a "remove" signal for every dependency and will drop all the
 176      * references from those entities to this model */
 177     while (data->dependencies != NULL)
 178         adg_model_remove_dependency(model,
 179                                     (AdgEntity *) data->dependencies->data);
 180
 181     if (PARENT_OBJECT_CLASS->dispose != NULL)
 182         PARENT_OBJECT_CLASS->dispose(object);
 183 }
 184
 185 static void
 186 set_property(GObject *object,
 187              guint prop_id, const GValue *value, GParamSpec *pspec)
 188 {
 189     AdgModel *model = (AdgModel *) object;
 190
 191     switch (prop_id) {
 192     case PROP_DEPENDENCY:
 193         adg_model_add_dependency(model, g_value_get_object(value));
 194         break;
 195     default:
 196         G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
 197     }
 198 }
 199
 200
 201 /**
 202  * adg_model_add_dependency:
 203  * @model: an #AdgModel
 204  * @entity: an #AdgEntity
 205  *
 206  * <note><para>
 207  * This function is only useful in entity implementations.
 208  * </para></note>
 209  *
 210  * Emits a #AdgModel::add-dependency signal on @model passing @entity
 211  * as argument. This will add a reference to @entity owned by @model.
 212  **/
 213 void
 214 adg_model_add_dependency(AdgModel *model, AdgEntity *entity)
 215 {
 216     g_return_if_fail(ADG_IS_MODEL(model));
 217     g_return_if_fail(ADG_IS_ENTITY(entity));
 218
 219     g_signal_emit(model, signals[ADD_DEPENDENCY], 0, entity);
 220 }
 221
 222 /**
 223  * adg_model_remove_dependency:
 224  * @model: an #AdgModel
 225  * @entity: an #AdgEntity
 226  *
 227  * <note><para>
 228  * This function is only useful in entity implementations.
 229  * </para></note>
 230  *
 231  * Emits a #AdgModel::remove-dependency signal on @model passing
 232  * @entity as argument. @entity must be inside @model.
 233  *
 234  * Note that @model will own a reference to @entity and it
 235  * may be the last reference held: this means removing an entity
 236  * from the model can destroy it.
 237  **/
 238 void
 239 adg_model_remove_dependency(AdgModel *model, AdgEntity *entity)
 240 {
 241     g_return_if_fail(ADG_IS_MODEL(model));
 242     g_return_if_fail(ADG_IS_ENTITY(entity));
 243
 244     g_signal_emit(model, signals[REMOVE_DEPENDENCY], 0, entity);
 245 }
 246
 247 /**
 248  * adg_model_get_dependencies:
 249  * @model: an #AdgModel
 250  *
 251  * Gets a list of entities dependent on @model.
 252  * This list must be freed with g_slist_free() when no longer user.
 253  *
 254  * Returns: a newly allocated #GSList or %NULL on error
 255  **/
 256 GSList *
 257 adg_model_get_dependencies(AdgModel *model)
 258 {
 259     g_return_val_if_fail(ADG_IS_MODEL(model), NULL);
 260
 261     return ADG_MODEL_GET_CLASS(model)->get_dependencies(model);
 262 }
 263
 264 /**
 265  * adg_model_foreach_dependency:
 266  * @model: an #AdgModel
 267  * @callback: a callback
 268  * @user_data: callback user data
 269  *
 270  * Invokes @callback on each entity linked to @model.
 271  * The callback should be declared as:
 272  *
 273  * |[
 274  * void callback(AdgEntity *entity, gpointer user_data);
 275  * ]|
 276  **/
 277 void
 278 adg_model_foreach_dependency(AdgModel *model, GCallback callback,
 279                              gpointer user_data)
 280 {
 281     GSList *dependencies;
 282
 283     g_return_if_fail(ADG_IS_MODEL(model));
 284     g_return_if_fail(callback != NULL);
 285
 286     dependencies = adg_model_get_dependencies(model);
 287
 288     while (dependencies) {
 289         if (dependencies->data)
 290             ((void (*) (gpointer, gpointer)) callback) (dependencies->data,
 291                                                         user_data);
 292
 293         dependencies = g_slist_delete_link(dependencies, dependencies);
 294     }
 295 }
 296
 297 /**
 298  * adg_model_changed:
 299  * @model: an #AdgModel
 300  *
 301  * <note><para>
 302  * This function is only useful in entity implementations.
 303  * </para></note>
 304  *
 305  * Emits the #AdgModel::changed signal on @model.
 306  **/
 307 void
 308 adg_model_changed(AdgModel *model)
 309 {
 310     g_return_if_fail(ADG_IS_MODEL(model));
 311
 312     g_signal_emit(model, signals[CHANGED], 0);
 313 }
 314
 315
 316 static void
 317 add_dependency(AdgModel *model, AdgEntity *entity)
 318 {
 319     AdgModelPrivate *data = model->data;
 320
 321     /* The prepend operation is more efficient */
 322     data->dependencies = g_slist_prepend(data->dependencies, entity);
 323
 324     g_object_ref(entity);
 325 }
 326
 327 static void
 328 remove_dependency(AdgModel *model, AdgEntity *entity)
 329 {
 330     AdgModelPrivate *data;
 331     GSList *node;
 332
 333     data = model->data;
 334     node = g_slist_find(data->dependencies, entity);
 335
 336     if (node == NULL) {
 337         g_warning("Attempting to remove an entity with type %s from a "
 338                   "model of type %s, but the entity is not present.",
 339                   g_type_name(G_OBJECT_TYPE(entity)),
 340                   g_type_name(G_OBJECT_TYPE(model)));
 341         return;
 342     }
 343
 344     data->dependencies = g_slist_delete_link(data->dependencies, node);
 345     g_object_unref(entity);
 346 }
 347
 348 static GSList *
 349 get_dependencies(AdgModel *model)
 350 {
 351     AdgModelPrivate *data = model->data;
 352
 353     /* The NULL case is yet managed by GLib */
 354     return g_slist_copy(data->dependencies);
 355 }
 356
 357 static void
 358 changed(AdgModel *model)
 359 {
 360     /* Invalidate all the entities dependent on this model */
 361     adg_model_foreach_dependency(model,
 362                                  G_CALLBACK(adg_entity_invalidate), NULL);
 363 }