Add GListModel

GListModel is an interface that represents a dynamic list of GObjects.

Also add GListStore, a simple implementation of GListModel that stores
all objects in memory, using a GSequence.

https://bugzilla.gnome.org/show_bug.cgi?id=729351

1 files changed, 421 insertions, 0 deletions

diff --git a/gio/gliststore.c b/gio/gliststore.c
new file mode 100644
index 000000000..407dcbf67
--- /dev/null
+++ b/gio/gliststore.c
@@ -0,0 +1,421 @@
+/*
+ * Copyright 2015 Lars Uebernickel
+ * Copyright 2015 Ryan Lortie
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General
+ * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors:
+ *     Lars Uebernickel <lars@uebernic.de>
+ *     Ryan Lortie <desrt@desrt.ca>
+ */
+
+#include "config.h"
+
+#include "gliststore.h"
+#include "glistmodel.h"
+
+/**
+ * SECTION:glistmodel
+ * @title: GListStore
+ * @short_description: A simple implementation of #GListModel
+ * @include: gio/gio.h
+ *
+ * #GListStore is a simple implementation of #GListModel that stores all
+ * items in memory.
+ *
+ * It provides insertions, deletions, and lookups in logarithmic time
+ * with a fast path for the common case of iterating the list linearly.
+ */
+
+struct _GListStore
+{
+  GObject parent_instance;
+
+  GType item_type;
+  GSequence *items;
+
+  /* cache */
+  guint last_position;
+  GSequenceIter *last_iter;
+};
+
+enum
+{
+  PROP_0,
+  PROP_ITEM_TYPE,
+  N_PROPERTIES
+};
+
+static void g_list_store_iface_init (GListModelInterface *iface);
+
+G_DEFINE_TYPE_WITH_CODE (GListStore, g_list_store, G_TYPE_OBJECT,
+                         G_IMPLEMENT_INTERFACE (G_TYPE_LIST_MODEL, g_list_store_iface_init));
+
+static void
+g_list_store_items_changed (GListStore *store,
+                            guint       position,
+                            guint       removed,
+                            guint       added)
+{
+  /* check if the iter cache may have been invalidated */
+  if (position <= store->last_position)
+    {
+      store->last_iter = NULL;
+      store->last_position = -1u;
+    }
+
+  g_list_model_items_changed (G_LIST_MODEL (store), position, removed, added);
+}
+
+static void
+g_list_store_dispose (GObject *object)
+{
+  GListStore *store = G_LIST_STORE (object);
+
+  g_clear_pointer (&store->items, g_sequence_free);
+
+  G_OBJECT_CLASS (g_list_store_parent_class)->dispose (object);
+}
+
+static void
+g_list_store_get_property (GObject    *object,
+                           guint       property_id,
+                           GValue     *value,
+                           GParamSpec *pspec)
+{
+  GListStore *store = G_LIST_STORE (object);
+
+  switch (property_id)
+    {
+    case PROP_ITEM_TYPE:
+      g_value_set_gtype (value, store->item_type);
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+    }
+}
+
+static void
+g_list_store_set_property (GObject      *object,
+                           guint         property_id,
+                           const GValue *value,
+                           GParamSpec   *pspec)
+{
+  GListStore *store = G_LIST_STORE (object);
+
+  switch (property_id)
+    {
+    case PROP_ITEM_TYPE: /* construct-only */
+      store->item_type = g_value_get_gtype (value);
+      if (!g_type_is_a (store->item_type, G_TYPE_OBJECT))
+        g_critical ("GListStore cannot store items of type '%s'. Items must be GObjects.",
+                    g_type_name (store->item_type));
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+    }
+}
+
+static void
+g_list_store_class_init (GListStoreClass *klass)
+{
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
+
+  object_class->dispose = g_list_store_dispose;
+  object_class->get_property = g_list_store_get_property;
+  object_class->set_property = g_list_store_set_property;
+
+  /**
+   * GListStore:item-type:
+   *
+   * The type of items contained in this list store. Items must be
+   * subclasses of #GObject.
+   *
+   * Since: 2.44
+   **/
+  g_object_class_install_property (object_class, PROP_ITEM_TYPE,
+    g_param_spec_gtype ("item-type", "", "", G_TYPE_OBJECT,
+                        G_PARAM_CONSTRUCT_ONLY | G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
+}
+
+static GType
+g_list_store_get_item_type (GListModel *list)
+{
+  GListStore *store = G_LIST_STORE (list);
+
+  return store->item_type;
+}
+
+static guint
+g_list_store_get_n_items (GListModel *list)
+{
+  GListStore *store = G_LIST_STORE (list);
+
+  return g_sequence_get_length (store->items);
+}
+
+static gpointer
+g_list_store_get_item (GListModel *list,
+                       guint       position)
+{
+  GListStore *store = G_LIST_STORE (list);
+  GSequenceIter *it = NULL;
+
+  if (store->last_position != -1u)
+    {
+      if (store->last_position == position + 1)
+        it = g_sequence_iter_prev (store->last_iter);
+      else if (store->last_position == position - 1)
+        it = g_sequence_iter_next (store->last_iter);
+      else if (store->last_position == position)
+        it = store->last_iter;
+    }
+
+  if (it == NULL)
+    it = g_sequence_get_iter_at_pos (store->items, position);
+
+  store->last_iter = it;
+  store->last_position = position;
+
+  if (g_sequence_iter_is_end (it))
+    return NULL;
+  else
+    return g_object_ref (g_sequence_get (it));
+}
+
+static void
+g_list_store_iface_init (GListModelInterface *iface)
+{
+  iface->get_item_type = g_list_store_get_item_type;
+  iface->get_n_items = g_list_store_get_n_items;
+  iface->get_item = g_list_store_get_item;
+}
+
+static void
+g_list_store_init (GListStore *store)
+{
+  store->items = g_sequence_new (g_object_unref);
+  store->last_position = -1u;
+}
+
+/**
+ * g_list_store_new:
+ * @item_type: the #GType of items in the list
+ *
+ * Creates a new #GListStore with items of type @item_type. @item_type
+ * must be a subclass of #GObject.
+ *
+ * Returns: a new #GListStore
+ * Since: 2.44
+ */
+GListStore *
+g_list_store_new (GType item_type)
+{
+  /* We only allow GObjects as item types right now. This might change
+   * in the future.
+   */
+  g_return_val_if_fail (g_type_is_a (item_type, G_TYPE_OBJECT), NULL);
+
+  return g_object_new (G_TYPE_LIST_STORE,
+                       "item-type", item_type,
+                       NULL);
+}
+
+/**
+ * g_list_store_insert:
+ * @store: a #GListStore
+ * @position: the position at which to insert the new item
+ * @item: the new item
+ *
+ * Inserts @item into @store at @position. @item must be of type
+ * #GListStore:item-type or derived from it. @position must be smaller
+ * than the length of the list, or equal to it to append.
+ *
+ * This function takes a ref on @item.
+ *
+ * Use g_list_store_splice() to insert multiple items at the same time
+ * efficiently.
+ *
+ * Since: 2.44
+ */
+void
+g_list_store_insert (GListStore *store,
+                     guint       position,
+                     gpointer    item)
+{
+  GSequenceIter *it;
+
+  g_return_if_fail (G_IS_LIST_STORE (store));
+  g_return_if_fail (g_type_is_a (G_OBJECT_TYPE (item), store->item_type));
+  g_return_if_fail (position <= g_sequence_get_length (store->items));
+
+  it = g_sequence_get_iter_at_pos (store->items, position);
+  g_sequence_insert_before (it, g_object_ref (item));
+
+  g_list_store_items_changed (store, position, 0, 1);
+}
+
+/**
+ * g_list_store_append:
+ * @store: a #GListStore
+ * @item: the new item
+ *
+ * Appends @item to @store. @item must be of type #GListStore:item-type.
+ *
+ * This function takes a ref on @item.
+ *
+ * Use g_list_store_splice() to append multiple items at the same time
+ * efficiently.
+ *
+ * Since: 2.44
+ */
+void
+g_list_store_append (GListStore *store,
+                     gpointer    item)
+{
+  guint n_items;
+
+  g_return_if_fail (G_IS_LIST_STORE (store));
+  g_return_if_fail (g_type_is_a (G_OBJECT_TYPE (item), store->item_type));
+
+  n_items = g_sequence_get_length (store->items);
+  g_sequence_append (store->items, g_object_ref (item));
+
+  g_list_store_items_changed (store, n_items, 0, 1);
+}
+
+/**
+ * g_list_store_remove:
+ * @store: a #GListStore
+ * @position: the position of the item that is to be removed
+ *
+ * Removes the item from @store that is at @position. @position must be
+ * smaller than the current length of the list.
+ *
+ * Use g_list_store_splice() to remove multiple items at the same time
+ * efficiently.
+ *
+ * Since: 2.44
+ */
+void
+g_list_store_remove (GListStore *store,
+                     guint       position)
+{
+  GSequenceIter *it;
+
+  g_return_if_fail (G_IS_LIST_STORE (store));
+
+  it = g_sequence_get_iter_at_pos (store->items, position);
+  g_return_if_fail (!g_sequence_iter_is_end (it));
+
+  g_sequence_remove (it);
+  g_list_store_items_changed (store, position, 1, 0);
+}
+
+/**
+ * g_list_store_remove_all:
+ * @store: a #GListStore
+ *
+ * Removes all items from @store.
+ *
+ * Since: 2.44
+ */
+void
+g_list_store_remove_all (GListStore *store)
+{
+  guint n_items;
+
+  g_return_if_fail (G_IS_LIST_STORE (store));
+
+  n_items = g_sequence_get_length (store->items);
+  g_sequence_remove_range (g_sequence_get_begin_iter (store->items),
+                           g_sequence_get_end_iter (store->items));
+
+  g_list_store_items_changed (store, 0, n_items, 0);
+}
+
+/**
+ * g_list_store_splice:
+ * @store: a #GListStore
+ * @position: the position at which to make the change
+ * @n_removals: the number of items to remove
+ * @additions: (array length=n_additions): the items to add
+ * @n_additions: the number of items to add
+ *
+ * Changes @store by removing @n_removals items and adding @n_additions
+ * items to it. @additions must contain @n_additions items of type
+ * #GListStore:item-type.  %NULL is not permitted.
+ *
+ * This function is more efficient than g_list_store_insert() and
+ * g_list_store_remove(), because it only emits
+ * #GListModel::items-changed once for the change.
+ *
+ * This function takes a ref on each item in @additions.
+ *
+ * The parameters @position and @n_removals must be correct (ie:
+ * @position + @n_removals must be less than or equal to the length of
+ * the list at the time this function is called).
+ *
+ * Since: 2.44
+ */
+void
+g_list_store_splice (GListStore *store,
+                     guint       position,
+                     guint       n_removals,
+                     gpointer   *additions,
+                     guint       n_additions)
+{
+  GSequenceIter *it;
+  guint n_items;
+
+  g_return_if_fail (G_IS_LIST_STORE (store));
+  g_return_if_fail (position + n_removals >= position); /* overflow */
+
+  n_items = g_sequence_get_length (store->items);
+  g_return_if_fail (position + n_removals <= n_items);
+
+  it = g_sequence_get_iter_at_pos (store->items, position);
+
+  if (n_removals)
+    {
+      GSequenceIter *end;
+
+      end = g_sequence_iter_move (it, n_removals);
+      g_sequence_remove_range (it, end);
+
+      it = end;
+    }
+
+  if (n_additions)
+    {
+      gint i;
+
+      it = g_sequence_iter_next (it);
+      for (i = 0; i < n_additions; i++)
+        {
+          if G_UNLIKELY (!g_type_is_a (G_OBJECT_TYPE (additions[i]), store->item_type))
+            {
+              g_critical ("%s: item %d is a %s instead of a %s.  GListStore is now in an undefined state.",
+                          G_STRFUNC, i, G_OBJECT_TYPE_NAME (additions[i]), g_type_name (store->item_type));
+              return;
+            }
+
+          it = g_sequence_insert_before (it, g_object_ref (additions[i]));
+        }
+    }
+
+  g_list_store_items_changed (store, position, n_removals, n_additions);
+}