[gtk/stack-fixes: 1/12] gtk: Add GtkSelectionModel

[Matthias Clasen <matthiasc src gnome org>]

commit 31961e211e537c24f64702231dd74c4b68273be5
Author: Benjamin Otte <otte redhat com>
Date:   Wed Oct 3 18:49:48 2018 +0200

    gtk: Add GtkSelectionModel
    
    The selection model is a list model interface that takes care of
    selections and is to be used by the list model widgets to manage their
    selections.

 docs/reference/gtk/gtk4-docs.xml     |   1 +
 docs/reference/gtk/gtk4-sections.txt |  41 +++++
 docs/reference/gtk/gtk4.types.in     |   2 +
 gtk/gtk.h                            |   1 +
 gtk/gtkselectionmodel.c              | 296 +++++++++++++++++++++++++++++++++++
 gtk/gtkselectionmodel.h              | 120 ++++++++++++++
 gtk/meson.build                      |   2 +
 7 files changed, 463 insertions(+)
---
diff --git a/docs/reference/gtk/gtk4-docs.xml b/docs/reference/gtk/gtk4-docs.xml
index a5e25803fa..d841e608b8 100644
--- a/docs/reference/gtk/gtk4-docs.xml
+++ b/docs/reference/gtk/gtk4-docs.xml
@@ -49,6 +49,7 @@
       <xi:include href="xml/gtkslicelistmodel.xml" />
       <xi:include href="xml/gtksortlistmodel.xml" />
       <xi:include href="xml/gtktreelistmodel.xml" />
+      <xi:include href="xml/gtkselectionmodel.xml" />
     </chapter>
 
     <chapter id="Application">
diff --git a/docs/reference/gtk/gtk4-sections.txt b/docs/reference/gtk/gtk4-sections.txt
index 1929eaf4a1..fd93df5a50 100644
--- a/docs/reference/gtk/gtk4-sections.txt
+++ b/docs/reference/gtk/gtk4-sections.txt
@@ -414,6 +414,47 @@ gtk_list_box_get_type
 gtk_list_box_row_get_type
 </SECTION>
 
+<SECTION>
+<FILE>gtkselectionmodel</FILE>
+<TITLE>GtkSelectionModel</TITLE>
+GtkSelectionModel
+gtk_selection_model_is_selected
+gtk_selection_model_select_item
+gtk_selection_model_unselect_item
+gtk_selection_model_select_range
+gtk_selection_model_unselect_range
+gtk_selection_model_select_all
+gtk_selection_model_unselect_all
+<SUBSECTION>
+gtk_selection_model_selection_changed
+<SUBSECTION Standard>
+GTK_SELECTION_MODEL
+GTK_SELECTION_MODEL_CLASS
+GTK_SELECTION_MODEL_GET_CLASS
+GTK_IS_SELECTION_MODEL
+GTK_IS_SELECTION_MODEL_CLASS
+GTK_TYPE_SELECTION_MODEL
+<SUBSECTION Private>
+gtk_selection_model_get_type
+</SECTION>
+
+<SECTION>
+<FILE>gtksingleselection</FILE>
+<TITLE>GtkSingleSelection</TITLE>
+GtkSingleSelection
+GTK_INVALID_LIST_POSITION
+gtk_single_selection_new
+gtk_single_selection_get_selected
+gtk_single_selection_set_selected
+gtk_single_selection_get_selected_item
+gtk_single_selection_get_autoselect
+gtk_single_selection_set_autoselect
+gtk_single_selection_get_can_unselect
+gtk_single_selection_set_can_unselect
+<SUBSECTION Private>
+gtk_single_selection_get_type
+</SECTION>
+
 <SECTION>
 <FILE>gtkbuildable</FILE>
 GtkBuildable
diff --git a/docs/reference/gtk/gtk4.types.in b/docs/reference/gtk/gtk4.types.in
index ecb383d45b..79d73c04a4 100644
--- a/docs/reference/gtk/gtk4.types.in
+++ b/docs/reference/gtk/gtk4.types.in
@@ -142,6 +142,7 @@ gtk_scrollbar_get_type
 gtk_scrolled_window_get_type
 gtk_search_bar_get_type
 gtk_search_entry_get_type
+gtk_selection_model_get_type
 gtk_separator_get_type
 gtk_separator_menu_item_get_type
 gtk_separator_tool_item_get_type
@@ -151,6 +152,7 @@ gtk_shortcuts_window_get_type
 gtk_shortcuts_section_get_type
 gtk_shortcuts_group_get_type
 gtk_shortcuts_shortcut_get_type
+gtk_single_selection_get_type
 gtk_size_group_get_type
 gtk_snapshot_get_type
 gtk_spin_button_get_type
diff --git a/gtk/gtk.h b/gtk/gtk.h
index e5e1995bc0..90ee2e8654 100644
--- a/gtk/gtk.h
+++ b/gtk/gtk.h
@@ -184,6 +184,7 @@
 #include <gtk/gtksearchbar.h>
 #include <gtk/gtksearchentry.h>
 #include <gtk/gtkselection.h>
+#include <gtk/gtkselectionmodel.h>
 #include <gtk/gtkseparator.h>
 #include <gtk/gtkseparatormenuitem.h>
 #include <gtk/gtkseparatortoolitem.h>
diff --git a/gtk/gtkselectionmodel.c b/gtk/gtkselectionmodel.c
new file mode 100644
index 0000000000..d004e3886d
--- /dev/null
+++ b/gtk/gtkselectionmodel.c
@@ -0,0 +1,296 @@
+/*
+ * Copyright © 2018 Benjamin Otte
+ *
+ * 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: Benjamin Otte <otte gnome org>
+ */
+
+#include "config.h"
+
+#include "gtkselectionmodel.h"
+
+#include "gtkintl.h"
+#include "gtkmarshalers.h"
+
+/**
+ * SECTION:gtkselectionmodel
+ * @Title: GtkSelectionModel
+ * @Short_description: An extension of the list model interface that handles selections
+ * @See_also: #GListModel, #GtkSingleSelection
+ *
+ * #GtkSelectionModel is an interface that extends the #GListModel interface by adding
+ * support for selections. This support is then used by widgets using list models to add
+ * the ability to select and unselect various items.
+ *
+ * GTK provides default implementations of the mode common selection modes such as
+ * #GtkSingleSelection, so you will only need to implement this interface if you want
+ * detailed control about how selections should be handled.
+ *
+ * A #GtkSelectionModel supports a single boolean per row indicating if a row is selected
+ * or not. This can be queried via gtk_selection_model_is_selected(). When the selected
+ * state of one or more rows changes, the model will emit the
+ * GtkSelectionModel::selection-changed signal by calling the
+ * gtk_selection_model_selection_changed() function. The positions given in that signal
+ * may have their selection state changed, though that is not a requirement.  
+ * If new items added to the model via the #GListModel::items-changed signal are selected
+ * or not is up to the implementation.
+ *
+ * Additionally, the interface can expose functionality to select and unselect items.
+ * If these functions are implemented, GTK's list widgets will allow users to select and
+ * unselect items. However, #GtkSelectionModels are free to only implement them
+ * partially or not at all. In that case the widgets will not support the unimplemented
+ * operations.
+ *
+ * When selecting or unselecting is supported by a model, the return values of the
+ * selection functions do NOT indicate if selection or unselection happened. They are
+ * only meant to indicate complete failure, like when this mode of selecting is not
+ * supported by the model.
+ * Selections may happen asynchronously, so the only reliable way to find out when an
+ * item was selected is to listen to the signals that indicate selection.
+ */
+
+G_DEFINE_INTERFACE (GtkSelectionModel, gtk_selection_model, G_TYPE_LIST_MODEL)
+
+enum {
+  SELECTION_CHANGED,
+  LAST_SIGNAL
+};
+
+static guint signals[LAST_SIGNAL] = { 0 };
+
+static gboolean
+gtk_selection_model_default_is_selected (GtkSelectionModel *model,
+                                         guint              position)
+{
+  return FALSE;
+}
+
+static gboolean
+gtk_selection_model_default_select_item (GtkSelectionModel *model,
+                                         guint              position,
+                                         gboolean           exclusive)
+{
+  return FALSE;
+}
+static gboolean
+gtk_selection_model_default_unselect_item (GtkSelectionModel *model,
+                                           guint              position)
+{
+  return FALSE;
+}
+
+static gboolean
+gtk_selection_model_default_select_range (GtkSelectionModel *model,
+                                          guint              position,
+                                          guint              n_items,
+                                          gboolean           exclusive)
+{
+  return FALSE;
+}
+
+static gboolean
+gtk_selection_model_default_unselect_range (GtkSelectionModel *model,
+                                            guint              position,
+                                            guint              n_items)
+{
+  return FALSE;
+}
+
+static gboolean
+gtk_selection_model_default_select_all (GtkSelectionModel *model)
+{
+  return gtk_selection_model_select_range (model, 0, g_list_model_get_n_items (G_LIST_MODEL (model)), FALSE);
+}
+
+static gboolean
+gtk_selection_model_default_unselect_all (GtkSelectionModel *model)
+{
+  return gtk_selection_model_unselect_range (model, 0, g_list_model_get_n_items (G_LIST_MODEL (model)));;
+}
+
+static void
+gtk_selection_model_default_init (GtkSelectionModelInterface *iface)
+{
+  iface->is_selected = gtk_selection_model_default_is_selected; 
+  iface->select_item = gtk_selection_model_default_select_item; 
+  iface->unselect_item = gtk_selection_model_default_unselect_item; 
+  iface->select_range = gtk_selection_model_default_select_range; 
+  iface->unselect_range = gtk_selection_model_default_unselect_range; 
+  iface->select_all = gtk_selection_model_default_select_all; 
+  iface->unselect_all = gtk_selection_model_default_unselect_all; 
+
+  /**
+   * GtkSelectionModel::selection-changed
+   * @model: a #GtkSelectionModel
+   * @position: The first item that may have changed
+   * @n_items: number of items with changes
+   *
+   * Emitted when the selection state of some of the items in @model changes.
+   *
+   * Note that this signal does not specify the new selection state of the items,
+   * they need to be queried manually.  
+   * It is also not necessary for a model to change the selection state of any of
+   * the items in the selection model, though it would be rather useless to emit
+   * such a signal.
+   */
+  signals[SELECTION_CHANGED] =
+    g_signal_new ("selection-changed",
+                  GTK_TYPE_SELECTION_MODEL,
+                  G_SIGNAL_RUN_LAST,
+                  0,
+                  NULL, NULL,
+                  _gtk_marshal_VOID__UINT_UINT,
+                  G_TYPE_NONE, 2, G_TYPE_UINT, G_TYPE_UINT);
+  g_signal_set_va_marshaller (signals[SELECTION_CHANGED],
+                              GTK_TYPE_SELECTION_MODEL,
+                              _gtk_marshal_VOID__UINT_UINTv);
+
+  g_object_interface_install_property (iface,
+    g_param_spec_object ("model",
+                         P_("Model"),
+                         P_("List managed by this selection"),
+                         G_TYPE_LIST_MODEL,
+                         G_PARAM_READWRITE
+                         | G_PARAM_CONSTRUCT_ONLY
+                         | G_PARAM_EXPLICIT_NOTIFY
+                         | G_PARAM_STATIC_STRINGS));
+
+}
+
+/**
+ * gtk_selection_model_is_selected:
+ * @model: a #GtkSelectionModel
+ * @position: the position of the item to query
+ *
+ * Checks if the given item is selected.
+ *
+ * Returns: %TRUE if the item is selected
+ **/
+gboolean
+gtk_selection_model_is_selected (GtkSelectionModel *model,
+                                 guint              position)
+{
+  GtkSelectionModelInterface *iface;
+
+  g_return_val_if_fail (GTK_IS_SELECTION_MODEL (model), 0);
+
+  iface = GTK_SELECTION_MODEL_GET_IFACE (model);
+  return iface->is_selected (model, position);
+}
+
+gboolean
+gtk_selection_model_select_item (GtkSelectionModel *model,
+                                 guint              position,
+                                 gboolean           exclusive)
+{
+  GtkSelectionModelInterface *iface;
+
+  g_return_val_if_fail (GTK_IS_SELECTION_MODEL (model), 0);
+
+  iface = GTK_SELECTION_MODEL_GET_IFACE (model);
+  return iface->select_item (model, position, exclusive);
+}
+
+gboolean
+gtk_selection_model_unselect_item (GtkSelectionModel *model,
+                                   guint              position)
+{
+  GtkSelectionModelInterface *iface;
+
+  g_return_val_if_fail (GTK_IS_SELECTION_MODEL (model), 0);
+
+  iface = GTK_SELECTION_MODEL_GET_IFACE (model);
+  return iface->unselect_item (model, position);
+}
+
+gboolean
+gtk_selection_model_select_range (GtkSelectionModel *model,
+                                  guint              position,
+                                  guint              n_items,
+                                  gboolean           exclusive)
+{
+  GtkSelectionModelInterface *iface;
+
+  g_return_val_if_fail (GTK_IS_SELECTION_MODEL (model), 0);
+
+  iface = GTK_SELECTION_MODEL_GET_IFACE (model);
+  return iface->select_range (model, position, n_items, exclusive);
+}
+
+gboolean
+gtk_selection_model_unselect_range (GtkSelectionModel *model,
+                                    guint              position,
+                                    guint              n_items)
+{
+  GtkSelectionModelInterface *iface;
+
+  g_return_val_if_fail (GTK_IS_SELECTION_MODEL (model), 0);
+
+  iface = GTK_SELECTION_MODEL_GET_IFACE (model);
+  return iface->unselect_range (model, position, n_items);
+}
+
+gboolean
+gtk_selection_model_select_all (GtkSelectionModel *model)
+{
+  GtkSelectionModelInterface *iface;
+
+  g_return_val_if_fail (GTK_IS_SELECTION_MODEL (model), 0);
+
+  iface = GTK_SELECTION_MODEL_GET_IFACE (model);
+  return iface->select_all (model);
+}
+
+gboolean
+gtk_selection_model_unselect_all (GtkSelectionModel *model)
+{
+  GtkSelectionModelInterface *iface;
+
+  g_return_val_if_fail (GTK_IS_SELECTION_MODEL (model), 0);
+
+  iface = GTK_SELECTION_MODEL_GET_IFACE (model);
+  return iface->unselect_all (model);
+}
+
+/**
+ * gtk_selection_model_get_model:
+ * @model: a #GtkSelectionModel
+ *
+ * Gets the underlying model of @model.
+ *
+ * Returns: (transfer none): the underlying model
+ */
+GListModel *
+gtk_selection_model_get_model (GtkSelectionModel *model)
+{
+  GListModel *child;
+
+  g_object_get (model, "model", &child, NULL);
+  if (child)
+    g_object_unref (child);
+
+  return child;
+}
+
+void
+gtk_selection_model_selection_changed (GtkSelectionModel *model,
+                                       guint              position,
+                                       guint              n_items)
+{
+  g_return_if_fail (GTK_IS_SELECTION_MODEL (model));
+
+  g_signal_emit (model, signals[SELECTION_CHANGED], 0, position, n_items);
+}
+
diff --git a/gtk/gtkselectionmodel.h b/gtk/gtkselectionmodel.h
new file mode 100644
index 0000000000..c3add80f0a
--- /dev/null
+++ b/gtk/gtkselectionmodel.h
@@ -0,0 +1,120 @@
+/*
+ * Copyright © 2018 Benjamin Otte
+ *
+ * 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: Benjamin Otte <otte gnome org>
+ */
+
+#ifndef __GTK_SELECTION_MODEL_H__
+#define __GTK_SELECTION_MODEL_H__
+
+#if !defined (__GTK_H_INSIDE__) && !defined (GTK_COMPILATION)
+#error "Only <gtk/gtk.h> can be included directly."
+#endif
+
+#include <gdk/gdk.h>
+
+G_BEGIN_DECLS
+
+#define GTK_TYPE_SELECTION_MODEL       (gtk_selection_model_get_type ())
+                                                      
+GDK_AVAILABLE_IN_ALL
+G_DECLARE_INTERFACE (GtkSelectionModel, gtk_selection_model, GTK, SELECTION_MODEL, GListModel)
+
+/**
+ * GtkSelectionModelInterface:
+ * @is_selected: Return if the item at the given position is selected.
+ * @select_item: Select the item in the given position. If the operation
+ *     is known to fail, return %FALSE.
+ * @unselect_item: Unselect the item in the given position. If the
+ *     operation is known to fail, return %FALSE.
+ * @select_range: Select all items in the given range. If the operation
+ *     is unsupported or known to fail for all items, return %FALSE.
+ * @unselect_range: Unselect all items in the given range. If the
+ *     operation is unsupported or known to fail for all items, return
+ *     %FALSE.
+ * @select_all: Select all items in the model. If the operation is
+ *     unsupported or known to fail for all items, return %FALSE.
+ * @unselect_all: Unselect all items in the model. If the operation is
+ *     unsupported or known to fail for all items, return %FALSE.
+ *
+ * The list of virtual functions for the #GtkSelectionModel interface.
+ * All getter functions are mandatory to implement, but the model does
+ * not need to implement any functions to support selecting or unselecting
+ * items. Of course, if the model does not do that, it means that users
+ * cannot select or unselect items in a list widgets using the model.
+ */
+struct _GtkSelectionModelInterface
+{
+  /*< private >*/
+  GTypeInterface g_iface;
+
+  /*< public >*/
+  gboolean              (* is_selected)                         (GtkSelectionModel      *model,
+                                                                 guint                   position);
+
+  gboolean              (* select_item)                         (GtkSelectionModel      *model,
+                                                                 guint                   position,
+                                                                 gboolean                exclusive);
+  gboolean              (* unselect_item)                       (GtkSelectionModel      *model,
+                                                                 guint                   position);
+  gboolean              (* select_range)                        (GtkSelectionModel      *model,
+                                                                 guint                   position,
+                                                                 guint                   n_items,
+                                                                 gboolean                exclusive);
+  gboolean              (* unselect_range)                      (GtkSelectionModel      *model,
+                                                                 guint                   position,
+                                                                 guint                   n_items);
+  gboolean              (* select_all)                          (GtkSelectionModel      *model);
+  gboolean              (* unselect_all)                        (GtkSelectionModel      *model);
+};
+
+GDK_AVAILABLE_IN_ALL
+gboolean                gtk_selection_model_is_selected         (GtkSelectionModel      *model,
+                                                                 guint                   position);
+
+GDK_AVAILABLE_IN_ALL
+gboolean                gtk_selection_model_select_item         (GtkSelectionModel      *model,
+                                                                 guint                   position,
+                                                                 gboolean                exclusive);
+GDK_AVAILABLE_IN_ALL
+gboolean                gtk_selection_model_unselect_item       (GtkSelectionModel      *model,
+                                                                 guint                   position);
+GDK_AVAILABLE_IN_ALL
+gboolean                gtk_selection_model_select_range        (GtkSelectionModel      *model,
+                                                                 guint                   position,
+                                                                 guint                   n_items,
+                                                                 gboolean                exclusive);
+GDK_AVAILABLE_IN_ALL
+gboolean                gtk_selection_model_unselect_range      (GtkSelectionModel      *model,
+                                                                 guint                   position,
+                                                                 guint                   n_items);
+GDK_AVAILABLE_IN_ALL
+gboolean                gtk_selection_model_select_all          (GtkSelectionModel      *model);
+GDK_AVAILABLE_IN_ALL
+gboolean                gtk_selection_model_unselect_all        (GtkSelectionModel      *model);
+
+GDK_AVAILABLE_IN_ALL
+GListModel *            gtk_selection_model_get_model           (GtkSelectionModel      *model);
+
+/* for implementations only */
+GDK_AVAILABLE_IN_ALL
+void                    gtk_selection_model_selection_changed   (GtkSelectionModel      *model,
+                                                                 guint                   position,
+                                                                 guint                   n_items);
+
+G_END_DECLS
+
+#endif /* __GTK_SELECTION_MODEL_H__ */
diff --git a/gtk/meson.build b/gtk/meson.build
index c700b37289..f6fd1023ca 100644
--- a/gtk/meson.build
+++ b/gtk/meson.build
@@ -323,6 +323,7 @@ gtk_public_sources = files([
   'gtksearchbar.c',
   'gtksearchentry.c',
   'gtkselection.c',
+  'gtkselectionmodel.c',
   'gtkseparator.c',
   'gtkseparatormenuitem.c',
   'gtkseparatortoolitem.c',
@@ -557,6 +558,7 @@ gtk_public_headers = files([
   'gtksearchbar.h',
   'gtksearchentry.h',
   'gtkselection.h',
+  'gtkselectionmodel.h',
   'gtkseparator.h',
   'gtkseparatormenuitem.h',
   'gtkseparatortoolitem.h',