Add a selection filter model

This model presents the selection of a GtkSelectionModel
as its own list model.

7 files changed, 443 insertions, 0 deletions

diff --git a/docs/reference/gtk/gtk4-docs.xml b/docs/reference/gtk/gtk4-docs.xml
index f6a46015cc..643fc0ebc1 100644
--- a/docs/reference/gtk/gtk4-docs.xml
+++ b/docs/reference/gtk/gtk4-docs.xml
@@ -74,6 +74,7 @@
         <xi:include href="xml/gtksingleselection.xml" />
         <xi:include href="xml/gtkmultiselection.xml" />
       </section>
+      <xi:include href="xml/gtkselectionfiltermodel.xml" />
       <xi:include href="xml/gtkbookmarklist.xml" />
       <xi:include href="xml/gtkdirectorylist.xml" />
       <xi:include href="xml/gtkstringlist.xml" />
diff --git a/docs/reference/gtk/gtk4-sections.txt b/docs/reference/gtk/gtk4-sections.txt
index 8ec00d44e6..208151976c 100644
--- a/docs/reference/gtk/gtk4-sections.txt
+++ b/docs/reference/gtk/gtk4-sections.txt
@@ -7613,3 +7613,13 @@ gtk_string_list_get_string
 GtkStringObject
 gtk_string_object_get_string
 </SECTION>
+
+<SECTION>
+<FILE>gtkselectionfiltermodel</FILE>
+<TITLE>GtkSelectionFilterModel</TITLE>
+GtkSelectionFilterModel
+gtk_selection_filter_model_new
+gtk_selection_filter_model_new_for_type
+gtk_selection_filter_model_set_model
+gtk_selection_filter_model_get_model
+</SECTION>
diff --git a/docs/reference/gtk/gtk4.types.in b/docs/reference/gtk/gtk4.types.in
index d61305ae2e..a890a5167b 100644
--- a/docs/reference/gtk/gtk4.types.in
+++ b/docs/reference/gtk/gtk4.types.in
@@ -184,6 +184,7 @@ gtk_scrollbar_get_type
 gtk_scrolled_window_get_type
 gtk_search_bar_get_type
 gtk_search_entry_get_type
+gtk_selection_filter_model_get_type
 gtk_selection_model_get_type
 gtk_separator_get_type
 gtk_settings_get_type
diff --git a/gtk/gtk.h b/gtk/gtk.h
index ed85587d73..50c23caf26 100644
--- a/gtk/gtk.h
+++ b/gtk/gtk.h
@@ -213,6 +213,7 @@
 #include <gtk/gtkscrolledwindow.h>
 #include <gtk/gtksearchbar.h>
 #include <gtk/gtksearchentry.h>
+#include <gtk/gtkselectionfiltermodel.h>
 #include <gtk/gtkselectionmodel.h>
 #include <gtk/gtkseparator.h>
 #include <gtk/gtksettings.h>
diff --git a/gtk/gtkselectionfiltermodel.c b/gtk/gtkselectionfiltermodel.c
new file mode 100644
index 0000000000..5cf094e1a3
--- /dev/null
+++ b/gtk/gtkselectionfiltermodel.c
@@ -0,0 +1,376 @@
+/*
+ * Copyright © 2020 Red Hat, Inc.
+ *
+ * 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 2.1 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: Matthias Clasen
+ */
+
+#include "config.h"
+
+#include "gtkselectionfiltermodel.h"
+#include "gtkbitset.h"
+
+#include "gtkintl.h"
+#include "gtkprivate.h"
+
+/**
+ * SECTION:gtkselectionfiltermodel
+ * @title: GtkSelectionFilterModel
+ * @short_description: A list model that turns a selection in a model
+ * @see_also: #GtkSelectionModel
+ *
+ * #GtkSelectionFilterModel is a list model that presents the
+ * selected items in a #GtkSelectionModel as its own list model.
+ */
+
+enum {
+  PROP_0,
+  PROP_ITEM_TYPE,
+  PROP_MODEL,
+  NUM_PROPERTIES
+};
+
+struct _GtkSelectionFilterModel
+{
+  GObject parent_instance;
+
+  GType item_type;
+  GtkSelectionModel *model;
+  GtkBitset *selection;
+};
+
+struct _GtkSelectionFilterModelClass
+{
+  GObjectClass parent_class;
+};
+
+static GParamSpec *properties[NUM_PROPERTIES] = { NULL, };
+
+static GType
+gtk_selection_filter_model_get_item_type (GListModel *list)
+{
+  GtkSelectionFilterModel *self = GTK_SELECTION_FILTER_MODEL (list);
+
+  return self->item_type;
+}
+
+static guint
+gtk_selection_filter_model_get_n_items (GListModel *list)
+{
+  GtkSelectionFilterModel *self = GTK_SELECTION_FILTER_MODEL (list);
+
+  if (self->selection)
+    return gtk_bitset_get_size (self->selection);
+
+  return 0;
+}
+
+static gpointer
+gtk_selection_filter_model_get_item (GListModel *list,
+                                     guint       position)
+{
+  GtkSelectionFilterModel *self = GTK_SELECTION_FILTER_MODEL (list);
+
+  position = gtk_bitset_get_nth (self->selection, position);
+
+  return g_list_model_get_item (G_LIST_MODEL (self->model), position);
+}
+
+static void
+gtk_selection_filter_model_list_model_init (GListModelInterface *iface)
+{
+  iface->get_item_type = gtk_selection_filter_model_get_item_type;
+  iface->get_n_items = gtk_selection_filter_model_get_n_items;
+  iface->get_item = gtk_selection_filter_model_get_item;
+}
+
+G_DEFINE_TYPE_WITH_CODE (GtkSelectionFilterModel, gtk_selection_filter_model, G_TYPE_OBJECT,
+                         G_IMPLEMENT_INTERFACE (G_TYPE_LIST_MODEL, gtk_selection_filter_model_list_model_init))
+
+static void
+gtk_selection_filter_model_items_changed_cb (GListModel *model,
+                                             guint       position,
+                                             guint       removed,
+                                             guint       added,
+                                             GtkSelectionFilterModel *self)
+{
+  GtkBitset *selection;
+  guint sel_position;
+  guint sel_removed;
+  guint sel_added;
+
+  selection = gtk_selection_model_get_selection (self->model);
+
+  sel_position = gtk_bitset_get_size_in_range (self->selection, 0, position - 1);
+  sel_removed = gtk_bitset_get_size_in_range (self->selection, position, position + removed);
+  sel_added = gtk_bitset_get_size_in_range (selection, position, position + added);
+
+  gtk_bitset_unref (self->selection);
+  self->selection = gtk_bitset_copy (selection);
+
+  gtk_bitset_unref (selection);
+
+  if (sel_removed > 0 || sel_added > 0)
+    g_list_model_items_changed (G_LIST_MODEL (self), sel_position, sel_removed, sel_added);
+}
+
+static void
+gtk_selection_filter_model_selection_changed_cb (GListModel *model,
+                                                 guint       position,
+                                                 guint       n_items,
+                                                 GtkSelectionFilterModel *self)
+{
+  GtkBitset *selection;
+  guint sel_position;
+  guint sel_removed;
+  guint sel_added;
+
+  selection = gtk_selection_model_get_selection (self->model);
+
+  sel_position = gtk_bitset_get_size_in_range (self->selection, 0, position - 1);
+  sel_removed = gtk_bitset_get_size_in_range (self->selection, position, position + n_items);
+  sel_added = gtk_bitset_get_size_in_range (selection, position, position + n_items);
+
+  gtk_bitset_unref (self->selection);
+  self->selection = gtk_bitset_copy (selection);
+
+  gtk_bitset_unref (selection);
+
+  if (sel_removed > 0 || sel_added > 0)
+    g_list_model_items_changed (G_LIST_MODEL (self), sel_position, sel_removed, sel_added);
+}
+
+static void
+gtk_selection_filter_model_set_property (GObject      *object,
+                                         guint         prop_id,
+                                         const GValue *value,
+                                         GParamSpec   *pspec)
+{
+  GtkSelectionFilterModel *self = GTK_SELECTION_FILTER_MODEL (object);
+
+  switch (prop_id)
+    {
+    case PROP_ITEM_TYPE:
+      self->item_type = g_value_get_gtype (value);
+      break;
+
+    case PROP_MODEL:
+      gtk_selection_filter_model_set_model (self, g_value_get_object (value));
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+static void
+gtk_selection_filter_model_get_property (GObject     *object,
+                                         guint        prop_id,
+                                         GValue      *value,
+                                         GParamSpec  *pspec)
+{
+  GtkSelectionFilterModel *self = GTK_SELECTION_FILTER_MODEL (object);
+
+  switch (prop_id)
+    {
+    case PROP_ITEM_TYPE:
+      g_value_set_gtype (value, self->item_type);
+      break;
+
+    case PROP_MODEL:
+      g_value_set_object (value, self->model);
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+static void
+gtk_selection_filter_model_clear_model (GtkSelectionFilterModel *self)
+{
+  if (self->model == NULL)
+    return;
+
+  g_signal_handlers_disconnect_by_func (self->model, gtk_selection_filter_model_items_changed_cb, self);
+  g_signal_handlers_disconnect_by_func (self->model, gtk_selection_filter_model_selection_changed_cb, self);
+
+  g_clear_object (&self->model);
+  g_clear_pointer (&self->selection, gtk_bitset_unref);
+}
+
+static void
+gtk_selection_filter_model_dispose (GObject *object)
+{
+  GtkSelectionFilterModel *self = GTK_SELECTION_FILTER_MODEL (object);
+
+  gtk_selection_filter_model_clear_model (self);
+
+  G_OBJECT_CLASS (gtk_selection_filter_model_parent_class)->dispose (object);
+}
+
+static void
+gtk_selection_filter_model_class_init (GtkSelectionFilterModelClass *class)
+{
+  GObjectClass *gobject_class = G_OBJECT_CLASS (class);
+
+  gobject_class->set_property = gtk_selection_filter_model_set_property;
+  gobject_class->get_property = gtk_selection_filter_model_get_property;
+  gobject_class->dispose = gtk_selection_filter_model_dispose;
+
+  /**
+   * GtkSelectionFilterModel:item-type:
+   *
+   * The #GType for elements of this object
+   */
+  properties[PROP_ITEM_TYPE] =
+      g_param_spec_gtype ("item-type",
+                          P_("Item type"),
+                          P_("The type of elements of this object"),
+                          G_TYPE_OBJECT,
+                          GTK_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_EXPLICIT_NOTIFY);
+
+  /**
+   * GtkSelectionFilterModel:model:
+   *
+   * The model being filtered
+   */
+  properties[PROP_MODEL] =
+      g_param_spec_object ("model",
+                           P_("Model"),
+                           P_("The model being filtered"),
+                           GTK_TYPE_SELECTION_MODEL,
+                           GTK_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY);
+
+  g_object_class_install_properties (gobject_class, NUM_PROPERTIES, properties);
+}
+
+static void
+gtk_selection_filter_model_init (GtkSelectionFilterModel *self)
+{
+}
+
+/**
+ * gtk_selection_filter_model_new:
+ * @model: the selection model to filter
+ *
+ * Creates a new #GtkSelectionFilterModel that will include the
+ * selected items from the underlying selection model.
+ *
+ * Returns: a new #GtkSelectionFilterModel
+ **/
+GtkSelectionFilterModel *
+gtk_selection_filter_model_new (GtkSelectionModel *model)
+{
+  GtkSelectionFilterModel *result;
+
+  g_return_val_if_fail (GTK_IS_SELECTION_MODEL (model), NULL);
+
+  result = g_object_new (GTK_TYPE_SELECTION_FILTER_MODEL,
+                         "item-type", g_list_model_get_item_type (G_LIST_MODEL (model)),
+                         "model", model,
+                         NULL);
+
+  return result;
+}
+
+/**
+ * gtk_selection_filter_model_new_for_type:
+ * @item_type: the type of the items that will be returned
+ *
+ * Creates a new empty selection filter model set up to return items
+ * of type @item_type. It is up to the application to set a proper
+ * selection model to ensure the item type is matched.
+ *
+ * Returns: a new #GtkSelectionFilterModel
+ **/
+GtkSelectionFilterModel *
+gtk_selection_filter_model_new_for_type (GType item_type)
+{
+  g_return_val_if_fail (g_type_is_a (item_type, G_TYPE_OBJECT), NULL);
+
+  return g_object_new (GTK_TYPE_SELECTION_FILTER_MODEL,
+                       "item-type", item_type,
+                       NULL);
+}
+
+/**
+ * gtk_selection_filter_model_set_model:
+ * @self: a #GtkSelectionFilterModel
+ * @model: (allow-none): The model to be filtered
+ *
+ * Sets the model to be filtered.
+ *
+ * Note that GTK makes no effort to ensure that @model conforms to
+ * the item type of @self. It assumes that the caller knows what they
+ * are doing and have set up an appropriate filter to ensure that item
+ * types match.
+ **/
+void
+gtk_selection_filter_model_set_model (GtkSelectionFilterModel *self,
+                                      GtkSelectionModel       *model)
+{
+  guint removed, added;
+
+  g_return_if_fail (GTK_IS_SELECTION_FILTER_MODEL (self));
+  g_return_if_fail (model == NULL || GTK_IS_SELECTION_MODEL (model));
+  g_return_if_fail (model == NULL || g_type_is_a (g_list_model_get_item_type (G_LIST_MODEL (model)),
+                                                  self->item_type));
+
+  if (self->model == model)
+    return;
+
+  removed = g_list_model_get_n_items (G_LIST_MODEL (self));
+  gtk_selection_filter_model_clear_model (self);
+
+  if (model)
+    {
+      GtkBitset *selection;
+
+      self->model = g_object_ref (model);
+
+      selection = gtk_selection_model_get_selection (self->model);
+      self->selection = gtk_bitset_copy (selection);
+      gtk_bitset_unref (selection);
+
+      g_signal_connect (model, "items-changed", G_CALLBACK (gtk_selection_filter_model_items_changed_cb), self);
+      g_signal_connect (model, "selection-changed", G_CALLBACK (gtk_selection_filter_model_selection_changed_cb), self);
+    }
+
+  added = g_list_model_get_n_items (G_LIST_MODEL (self));
+
+  if (removed > 0 || added > 0)
+    g_list_model_items_changed (G_LIST_MODEL (self), 0, removed, added);
+
+  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_MODEL]);
+}
+
+/**
+ * gtk_selection_filter_model_get_model:
+ * @self: a #GtkSelectionFilterModel
+ *
+ * Gets the model currently filtered or %NULL if none.
+ *
+ * Returns: (nullable) (transfer none): The model that gets filtered
+ **/
+GtkSelectionModel *
+gtk_selection_filter_model_get_model (GtkSelectionFilterModel *self)
+{
+  g_return_val_if_fail (GTK_IS_SELECTION_FILTER_MODEL (self), NULL);
+
+  return self->model;
+}
diff --git a/gtk/gtkselectionfiltermodel.h b/gtk/gtkselectionfiltermodel.h
new file mode 100644
index 0000000000..69ab1df37f
--- /dev/null
+++ b/gtk/gtkselectionfiltermodel.h
@@ -0,0 +1,52 @@
+/*
+ * Copyright © 2020 Red Hat, Inc.
+ *
+ * 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 2.1 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: Matthias Clasen
+ */
+
+#ifndef __GTK_SELECTION_FILTER_MODEL_H__
+#define __GTK_SELECTION_FILTER_MODEL_H__
+
+
+#if !defined (__GTK_H_INSIDE__) && !defined (GTK_COMPILATION)
+#error "Only <gtk/gtk.h> can be included directly."
+#endif
+
+#include <gio/gio.h>
+#include <gtk/gtkselectionmodel.h>
+
+G_BEGIN_DECLS
+
+#define GTK_TYPE_SELECTION_FILTER_MODEL (gtk_selection_filter_model_get_type ())
+
+GDK_AVAILABLE_IN_ALL
+G_DECLARE_FINAL_TYPE (GtkSelectionFilterModel, gtk_selection_filter_model, GTK, SELECTION_FILTER_MODEL, GObject)
+
+GDK_AVAILABLE_IN_ALL
+GtkSelectionFilterModel * gtk_selection_filter_model_new          (GtkSelectionModel           *model);
+
+GDK_AVAILABLE_IN_ALL
+GtkSelectionFilterModel * gtk_selection_filter_model_new_for_type (GType                        item_type);
+
+GDK_AVAILABLE_IN_ALL
+void                      gtk_selection_filter_model_set_model    (GtkSelectionFilterModel     *self,
+                                                                   GtkSelectionModel           *model);
+GDK_AVAILABLE_IN_ALL
+GtkSelectionModel *       gtk_selection_filter_model_get_model    (GtkSelectionFilterModel     *self);
+
+G_END_DECLS
+
+#endif /* __GTK_SELECTION_FILTER_MODEL_H__ */
diff --git a/gtk/meson.build b/gtk/meson.build
index 22b274cba0..02ba60a842 100644
--- a/gtk/meson.build
+++ b/gtk/meson.build
@@ -348,6 +348,7 @@ gtk_public_sources = files([
   'gtkscrolledwindow.c',
   'gtksearchbar.c',
   'gtksearchentry.c',
+  'gtkselectionfiltermodel.c',
   'gtkselectionmodel.c',
   'gtkseparator.c',
   'gtksettings.c',
@@ -617,6 +618,7 @@ gtk_public_headers = files([
   'gtkscrolledwindow.h',
   'gtksearchbar.h',
   'gtksearchentry.h',
+  'gtkselectionfiltermodel.h',
   'gtkselectionmodel.h',
   'gtkseparator.h',
   'gtksettings.h',