gio/gliststore.c

   1 /*
   2  * Copyright 2015 Lars Uebernickel
   3  * Copyright 2015 Ryan Lortie
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General
  16  * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
  17  *
  18  * Authors:
  19  *     Lars Uebernickel <lars@uebernic.de>
  20  *     Ryan Lortie <desrt@desrt.ca>
  21  */
  22
  23 #include "config.h"
  24
  25 #include "gliststore.h"
  26 #include "glistmodel.h"
  27
  28 /**
  29  * SECTION:glistmodel
  30  * @title: GListStore
  31  * @short_description: A simple implementation of #GListModel
  32  * @include: gio/gio.h
  33  *
  34  * #GListStore is a simple implementation of #GListModel that stores all
  35  * items in memory.
  36  *
  37  * It provides insertions, deletions, and lookups in logarithmic time
  38  * with a fast path for the common case of iterating the list linearly.
  39  */
  40
  41 struct _GListStore
  42 {
  43   GObject parent_instance;
  44
  45   GType item_type;
  46   GSequence *items;
  47
  48   /* cache */
  49   guint last_position;
  50   GSequenceIter *last_iter;
  51 };
  52
  53 enum
  54 {
  55   PROP_0,
  56   PROP_ITEM_TYPE,
  57   N_PROPERTIES
  58 };
  59
  60 static void g_list_store_iface_init (GListModelInterface *iface);
  61
  62 G_DEFINE_TYPE_WITH_CODE (GListStore, g_list_store, G_TYPE_OBJECT,
  63                          G_IMPLEMENT_INTERFACE (G_TYPE_LIST_MODEL, g_list_store_iface_init));
  64
  65 static void
  66 g_list_store_items_changed (GListStore *store,
  67                             guint       position,
  68                             guint       removed,
  69                             guint       added)
  70 {
  71   /* check if the iter cache may have been invalidated */
  72   if (position <= store->last_position)
  73     {
  74       store->last_iter = NULL;
  75       store->last_position = -1u;
  76     }
  77
  78   g_list_model_items_changed (G_LIST_MODEL (store), position, removed, added);
  79 }
  80
  81 static void
  82 g_list_store_dispose (GObject *object)
  83 {
  84   GListStore *store = G_LIST_STORE (object);
  85
  86   g_clear_pointer (&store->items, g_sequence_free);
  87
  88   G_OBJECT_CLASS (g_list_store_parent_class)->dispose (object);
  89 }
  90
  91 static void
  92 g_list_store_get_property (GObject    *object,
  93                            guint       property_id,
  94                            GValue     *value,
  95                            GParamSpec *pspec)
  96 {
  97   GListStore *store = G_LIST_STORE (object);
  98
  99   switch (property_id)
 100     {
 101     case PROP_ITEM_TYPE:
 102       g_value_set_gtype (value, store->item_type);
 103       break;
 104
 105     default:
 106       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
 107     }
 108 }
 109
 110 static void
 111 g_list_store_set_property (GObject      *object,
 112                            guint         property_id,
 113                            const GValue *value,
 114                            GParamSpec   *pspec)
 115 {
 116   GListStore *store = G_LIST_STORE (object);
 117
 118   switch (property_id)
 119     {
 120     case PROP_ITEM_TYPE: /* construct-only */
 121       store->item_type = g_value_get_gtype (value);
 122       if (!g_type_is_a (store->item_type, G_TYPE_OBJECT))
 123         g_critical ("GListStore cannot store items of type '%s'. Items must be GObjects.",
 124                     g_type_name (store->item_type));
 125       break;
 126
 127     default:
 128       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
 129     }
 130 }
 131
 132 static void
 133 g_list_store_class_init (GListStoreClass *klass)
 134 {
 135   GObjectClass *object_class = G_OBJECT_CLASS (klass);
 136
 137   object_class->dispose = g_list_store_dispose;
 138   object_class->get_property = g_list_store_get_property;
 139   object_class->set_property = g_list_store_set_property;
 140
 141   /**
 142    * GListStore:item-type:
 143    *
 144    * The type of items contained in this list store. Items must be
 145    * subclasses of #GObject.
 146    *
 147    * Since: 2.44
 148    **/
 149   g_object_class_install_property (object_class, PROP_ITEM_TYPE,
 150     g_param_spec_gtype ("item-type", "", "", G_TYPE_OBJECT,
 151                         G_PARAM_CONSTRUCT_ONLY | G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
 152 }
 153
 154 static GType
 155 g_list_store_get_item_type (GListModel *list)
 156 {
 157   GListStore *store = G_LIST_STORE (list);
 158
 159   return store->item_type;
 160 }
 161
 162 static guint
 163 g_list_store_get_n_items (GListModel *list)
 164 {
 165   GListStore *store = G_LIST_STORE (list);
 166
 167   return g_sequence_get_length (store->items);
 168 }
 169
 170 static gpointer
 171 g_list_store_get_item (GListModel *list,
 172                        guint       position)
 173 {
 174   GListStore *store = G_LIST_STORE (list);
 175   GSequenceIter *it = NULL;
 176
 177   if (store->last_position != -1u)
 178     {
 179       if (store->last_position == position + 1)
 180         it = g_sequence_iter_prev (store->last_iter);
 181       else if (store->last_position == position - 1)
 182         it = g_sequence_iter_next (store->last_iter);
 183       else if (store->last_position == position)
 184         it = store->last_iter;
 185     }
 186
 187   if (it == NULL)
 188     it = g_sequence_get_iter_at_pos (store->items, position);
 189
 190   store->last_iter = it;
 191   store->last_position = position;
 192
 193   if (g_sequence_iter_is_end (it))
 194     return NULL;
 195   else
 196     return g_object_ref (g_sequence_get (it));
 197 }
 198
 199 static void
 200 g_list_store_iface_init (GListModelInterface *iface)
 201 {
 202   iface->get_item_type = g_list_store_get_item_type;
 203   iface->get_n_items = g_list_store_get_n_items;
 204   iface->get_item = g_list_store_get_item;
 205 }
 206
 207 static void
 208 g_list_store_init (GListStore *store)
 209 {
 210   store->items = g_sequence_new (g_object_unref);
 211   store->last_position = -1u;
 212 }
 213
 214 /**
 215  * g_list_store_new:
 216  * @item_type: the #GType of items in the list
 217  *
 218  * Creates a new #GListStore with items of type @item_type. @item_type
 219  * must be a subclass of #GObject.
 220  *
 221  * Returns: a new #GListStore
 222  * Since: 2.44
 223  */
 224 GListStore *
 225 g_list_store_new (GType item_type)
 226 {
 227   /* We only allow GObjects as item types right now. This might change
 228    * in the future.
 229    */
 230   g_return_val_if_fail (g_type_is_a (item_type, G_TYPE_OBJECT), NULL);
 231
 232   return g_object_new (G_TYPE_LIST_STORE,
 233                        "item-type", item_type,
 234                        NULL);
 235 }
 236
 237 /**
 238  * g_list_store_insert:
 239  * @store: a #GListStore
 240  * @position: the position at which to insert the new item
 241  * @item: the new item
 242  *
 243  * Inserts @item into @store at @position. @item must be of type
 244  * #GListStore:item-type or derived from it. @position must be smaller
 245  * than the length of the list, or equal to it to append.
 246  *
 247  * This function takes a ref on @item.
 248  *
 249  * Use g_list_store_splice() to insert multiple items at the same time
 250  * efficiently.
 251  *
 252  * Since: 2.44
 253  */
 254 void
 255 g_list_store_insert (GListStore *store,
 256                      guint       position,
 257                      gpointer    item)
 258 {
 259   GSequenceIter *it;
 260
 261   g_return_if_fail (G_IS_LIST_STORE (store));
 262   g_return_if_fail (g_type_is_a (G_OBJECT_TYPE (item), store->item_type));
 263   g_return_if_fail (position <= g_sequence_get_length (store->items));
 264
 265   it = g_sequence_get_iter_at_pos (store->items, position);
 266   g_sequence_insert_before (it, g_object_ref (item));
 267
 268   g_list_store_items_changed (store, position, 0, 1);
 269 }
 270
 271 /**
 272  * g_list_store_append:
 273  * @store: a #GListStore
 274  * @item: the new item
 275  *
 276  * Appends @item to @store. @item must be of type #GListStore:item-type.
 277  *
 278  * This function takes a ref on @item.
 279  *
 280  * Use g_list_store_splice() to append multiple items at the same time
 281  * efficiently.
 282  *
 283  * Since: 2.44
 284  */
 285 void
 286 g_list_store_append (GListStore *store,
 287                      gpointer    item)
 288 {
 289   guint n_items;
 290
 291   g_return_if_fail (G_IS_LIST_STORE (store));
 292   g_return_if_fail (g_type_is_a (G_OBJECT_TYPE (item), store->item_type));
 293
 294   n_items = g_sequence_get_length (store->items);
 295   g_sequence_append (store->items, g_object_ref (item));
 296
 297   g_list_store_items_changed (store, n_items, 0, 1);
 298 }
 299
 300 /**
 301  * g_list_store_remove:
 302  * @store: a #GListStore
 303  * @position: the position of the item that is to be removed
 304  *
 305  * Removes the item from @store that is at @position. @position must be
 306  * smaller than the current length of the list.
 307  *
 308  * Use g_list_store_splice() to remove multiple items at the same time
 309  * efficiently.
 310  *
 311  * Since: 2.44
 312  */
 313 void
 314 g_list_store_remove (GListStore *store,
 315                      guint       position)
 316 {
 317   GSequenceIter *it;
 318
 319   g_return_if_fail (G_IS_LIST_STORE (store));
 320
 321   it = g_sequence_get_iter_at_pos (store->items, position);
 322   g_return_if_fail (!g_sequence_iter_is_end (it));
 323
 324   g_sequence_remove (it);
 325   g_list_store_items_changed (store, position, 1, 0);
 326 }
 327
 328 /**
 329  * g_list_store_remove_all:
 330  * @store: a #GListStore
 331  *
 332  * Removes all items from @store.
 333  *
 334  * Since: 2.44
 335  */
 336 void
 337 g_list_store_remove_all (GListStore *store)
 338 {
 339   guint n_items;
 340
 341   g_return_if_fail (G_IS_LIST_STORE (store));
 342
 343   n_items = g_sequence_get_length (store->items);
 344   g_sequence_remove_range (g_sequence_get_begin_iter (store->items),
 345                            g_sequence_get_end_iter (store->items));
 346
 347   g_list_store_items_changed (store, 0, n_items, 0);
 348 }
 349
 350 /**
 351  * g_list_store_splice:
 352  * @store: a #GListStore
 353  * @position: the position at which to make the change
 354  * @n_removals: the number of items to remove
 355  * @additions: (array length=n_additions): the items to add
 356  * @n_additions: the number of items to add
 357  *
 358  * Changes @store by removing @n_removals items and adding @n_additions
 359  * items to it. @additions must contain @n_additions items of type
 360  * #GListStore:item-type.  %NULL is not permitted.
 361  *
 362  * This function is more efficient than g_list_store_insert() and
 363  * g_list_store_remove(), because it only emits
 364  * #GListModel::items-changed once for the change.
 365  *
 366  * This function takes a ref on each item in @additions.
 367  *
 368  * The parameters @position and @n_removals must be correct (ie:
 369  * @position + @n_removals must be less than or equal to the length of
 370  * the list at the time this function is called).
 371  *
 372  * Since: 2.44
 373  */
 374 void
 375 g_list_store_splice (GListStore *store,
 376                      guint       position,
 377                      guint       n_removals,
 378                      gpointer   *additions,
 379                      guint       n_additions)
 380 {
 381   GSequenceIter *it;
 382   guint n_items;
 383
 384   g_return_if_fail (G_IS_LIST_STORE (store));
 385   g_return_if_fail (position + n_removals >= position); /* overflow */
 386
 387   n_items = g_sequence_get_length (store->items);
 388   g_return_if_fail (position + n_removals <= n_items);
 389
 390   it = g_sequence_get_iter_at_pos (store->items, position);
 391
 392   if (n_removals)
 393     {
 394       GSequenceIter *end;
 395
 396       end = g_sequence_iter_move (it, n_removals);
 397       g_sequence_remove_range (it, end);
 398
 399       it = end;
 400     }
 401
 402   if (n_additions)
 403     {
 404       gint i;
 405
 406       it = g_sequence_iter_next (it);
 407       for (i = 0; i < n_additions; i++)
 408         {
 409           if G_UNLIKELY (!g_type_is_a (G_OBJECT_TYPE (additions[i]), store->item_type))
 410             {
 411               g_critical ("%s: item %d is a %s instead of a %s.  GListStore is now in an undefined state.",
 412                           G_STRFUNC, i, G_OBJECT_TYPE_NAME (additions[i]), g_type_name (store->item_type));
 413               return;
 414             }
 415
 416           it = g_sequence_insert_before (it, g_object_ref (additions[i]));
 417         }
 418     }
 419
 420   g_list_store_items_changed (store, position, n_removals, n_additions);
 421 }