wip: Add GtkSelectionMonitor

This is a list model that turns a GtkSelectionModel
into a model containing just the selected items.
This is currently only implemented for GtkSingleSelection.

5 files changed, 459 insertions, 0 deletions

diff --git a/gtk/gtk.h b/gtk/gtk.h
index 78f971db05..325234cbfb 100644
--- a/gtk/gtk.h
+++ b/gtk/gtk.h
@@ -219,6 +219,7 @@
 #include <gtk/gtksearchentry.h>
 #include <gtk/gtkselection.h>
 #include <gtk/gtkselectionmodel.h>
+#include <gtk/gtkselectionmonitor.h>
 #include <gtk/gtkseparator.h>
 #include <gtk/gtkseparatormenuitem.h>
 #include <gtk/gtkseparatortoolitem.h>
diff --git a/gtk/gtkselectionmonitor.c b/gtk/gtkselectionmonitor.c
new file mode 100644
index 0000000000..fc9101a00c
--- /dev/null
+++ b/gtk/gtkselectionmonitor.c
@@ -0,0 +1,388 @@
+/*
+ * Copyright © 2019 Matthias Clasen
+ *
+ * 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 <mclasen@redhat.com>
+ */
+
+#include "config.h"
+
+#include "gtkselectionmonitor.h"
+
+#include "gtkintl.h"
+#include "gtkselectionmodel.h"
+#include "gtksingleselection.h"
+
+struct _GtkSelectionMonitor
+{
+  GObject parent_instance;
+
+  guint n_selected;
+  GtkSelectionModel *model;
+
+  /* Keep an internal iter to speed up the case where
+   * we iterate over all items in the model from 0 to n.
+   */
+  guint last_in;
+  guint last_out;
+  guint start_range;
+  guint n_items;
+  guint n_before;
+};
+
+struct _GtkSelectionMonitorClass
+{
+  GObjectClass parent_class;
+};
+
+enum {
+  PROP_0,
+  PROP_MODEL,
+  N_PROPS
+};
+
+static GParamSpec *properties[N_PROPS] = { NULL, };
+
+static GType
+gtk_selection_monitor_get_item_type (GListModel *list)
+{
+  GtkSelectionMonitor *self = GTK_SELECTION_MONITOR (list);
+
+  return g_list_model_get_item_type (G_LIST_MODEL (self->model));
+}
+
+static guint
+gtk_selection_monitor_get_n_items (GListModel *list)
+{
+  GtkSelectionMonitor *self = GTK_SELECTION_MONITOR (list);
+
+  return self->n_selected;
+}
+
+static gpointer
+gtk_selection_monitor_get_item (GListModel *list,
+                                guint       position)
+{
+  GtkSelectionMonitor *self = GTK_SELECTION_MONITOR (list);
+
+  if (GTK_IS_SINGLE_SELECTION (self->model))
+    {
+      gpointer item;
+
+      if (position != 0)
+        return NULL;
+
+      item = gtk_single_selection_get_selected_item (GTK_SINGLE_SELECTION (self->model));
+      if (item == NULL)
+        return NULL;
+
+      return g_object_ref (item);
+    }
+  else
+    {
+      guint n_before;
+      guint pos;
+
+      if (self->last_in != GTK_INVALID_LIST_POSITION && position > self->last_in)
+        {
+          if (self->last_out + (position - self->last_in) < self->start_range + self->n_items)
+            {
+              /* still inside the last queried range */
+              self->last_out = self->last_out + (position - self->last_in);
+              self->last_in = position;
+
+              return g_list_model_get_item (G_LIST_MODEL (self->model), self->last_out);
+            }
+          else
+            {
+              /* query the next range */
+              pos = self->start_range + self->n_items;
+              n_before = self->n_before + self->n_items;
+            }
+        }
+      else
+        {
+          /* query from the beginning */
+          pos = 0;
+          n_before = 0;
+        }
+
+      while (TRUE)
+        {
+          guint start_range;
+          guint n_items;
+          gboolean selected;
+
+          gtk_selection_model_query_range (self->model, pos, &start_range, &n_items, &selected);
+
+          if (selected)
+            {
+              if (position - n_before < n_items)
+                {
+                  self->last_in = position;
+                  self->last_out = start_range + (position - n_before);
+                  self->start_range = start_range;
+                  self->n_items = n_items;
+                  self->n_before = n_before;
+
+                  return g_list_model_get_item (G_LIST_MODEL (self->model), self->last_out);
+                }
+
+              n_before += n_items;
+            }
+
+          pos = start_range + n_items;
+
+          if (n_items == 0)
+            break;
+        }
+
+      self->last_in = GTK_INVALID_LIST_POSITION;
+      self->last_out = GTK_INVALID_LIST_POSITION;
+    }
+
+  return NULL;
+}
+
+static void
+gtk_selection_monitor_list_model_init (GListModelInterface *iface)
+{
+  iface->get_item_type = gtk_selection_monitor_get_item_type;
+  iface->get_n_items = gtk_selection_monitor_get_n_items;
+  iface->get_item = gtk_selection_monitor_get_item;
+}
+
+static gboolean
+gtk_selection_monitor_is_selected (GtkSelectionModel *model,
+                                   guint              position)
+{
+  return FALSE;
+}
+
+static void
+gtk_selection_monitor_query_range (GtkSelectionModel *model,
+                                   guint              position,
+                                   guint             *start_range,
+                                   guint             *n_range,
+                                   gboolean          *selected)
+{
+  GtkSelectionMonitor *self = GTK_SELECTION_MONITOR (model);
+
+  *start_range = 0;
+  *n_range = g_list_model_get_n_items (G_LIST_MODEL (self));
+  *selected = FALSE;
+}
+
+static void
+gtk_selection_monitor_selection_model_init (GtkSelectionModelInterface *iface)
+{
+  iface->is_selected = gtk_selection_monitor_is_selected; 
+  iface->query_range = gtk_selection_monitor_query_range;
+}
+
+G_DEFINE_TYPE_EXTENDED (GtkSelectionMonitor, gtk_selection_monitor, G_TYPE_OBJECT, 0,
+                        G_IMPLEMENT_INTERFACE (G_TYPE_LIST_MODEL,
+                                               gtk_selection_monitor_list_model_init)
+                        G_IMPLEMENT_INTERFACE (GTK_TYPE_SELECTION_MODEL,
+                                               gtk_selection_monitor_selection_model_init))
+
+static guint
+get_n_selected (GtkSelectionMonitor *self)
+{
+  if (GTK_IS_SINGLE_SELECTION (self->model))
+    {
+      if (gtk_single_selection_get_selected (GTK_SINGLE_SELECTION (self->model)) == GTK_INVALID_LIST_POSITION)
+        return 0;
+      else
+        return 1;
+    }
+  else
+    {
+      guint n_selected;
+      guint pos;
+
+      n_selected = 0;
+      pos = 0;
+      while (TRUE)
+        {
+          guint start_range;
+          guint n_items;
+          gboolean selected;
+
+          gtk_selection_model_query_range (self->model, pos, &start_range, &n_items, &selected);
+
+          if (selected)
+            n_selected += n_items;
+
+          pos = start_range + n_items;
+
+          if (n_items == 0)
+            break;
+        }
+
+      return n_selected;
+    }
+}
+
+static void
+selection_changed (GtkSelectionModel *selection,
+                   guint position,
+                   guint n_items,
+                   GtkSelectionMonitor *self)
+{
+  guint old_selected;
+
+  self->last_in = GTK_INVALID_LIST_POSITION;
+
+  old_selected = self->n_selected;
+  self->n_selected = get_n_selected (self);
+  g_list_model_items_changed (G_LIST_MODEL (self), 0, old_selected, self->n_selected);
+}
+
+static void
+gtk_selection_monitor_clear_model (GtkSelectionMonitor *self)
+{
+  if (self->model == NULL)
+    return;
+
+  self->last_in = GTK_INVALID_LIST_POSITION;
+
+  g_signal_handlers_disconnect_by_func (self->model, selection_changed, self);
+  g_clear_object (&self->model);
+}
+
+static void
+gtk_selection_monitor_set_property (GObject      *object,
+                                   guint         prop_id,
+                                   const GValue *value,
+                                   GParamSpec   *pspec)
+
+{
+  GtkSelectionMonitor *self = GTK_SELECTION_MONITOR (object);
+  guint old_selected;
+
+  switch (prop_id)
+    {
+    case PROP_MODEL:
+      gtk_selection_monitor_clear_model (self);
+      self->model = g_value_dup_object (value);
+      old_selected = self->n_selected;
+      self->n_selected = get_n_selected (self);
+      g_list_model_items_changed (G_LIST_MODEL (self), 0, old_selected, self->n_selected);
+      g_signal_connect (self->model, "selection-changed", G_CALLBACK (selection_changed), self);
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+static void
+gtk_selection_monitor_get_property (GObject    *object,
+                                    guint       prop_id,
+                                    GValue     *value,
+                                    GParamSpec *pspec)
+{
+  GtkSelectionMonitor *self = GTK_SELECTION_MONITOR (object);
+
+  switch (prop_id)
+    {
+    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_monitor_dispose (GObject *object)
+{
+  GtkSelectionMonitor *self = GTK_SELECTION_MONITOR (object);
+
+  gtk_selection_monitor_clear_model (self);
+
+  G_OBJECT_CLASS (gtk_selection_monitor_parent_class)->dispose (object);
+}
+
+static void
+gtk_selection_monitor_class_init (GtkSelectionMonitorClass *klass)
+{
+  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
+
+  gobject_class->get_property = gtk_selection_monitor_get_property;
+  gobject_class->set_property = gtk_selection_monitor_set_property;
+  gobject_class->dispose = gtk_selection_monitor_dispose;
+
+  /**
+   * GtkSelectionMonitor:model:
+   *
+   * The selection model
+   */
+  properties[PROP_MODEL] =
+    g_param_spec_object ("model",
+                       P_("The selection model"),
+                       P_("The selection model"),
+                       GTK_TYPE_SELECTION_MODEL,
+                       G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_STRINGS);
+
+  g_object_class_install_properties (gobject_class, N_PROPS, properties);
+}
+
+static void
+gtk_selection_monitor_init (GtkSelectionMonitor *self)
+{
+  self->last_in = GTK_INVALID_LIST_POSITION;
+}
+
+/**
+ * gtk_selection_monitor_new:
+ * @model: (transfer none): the #GtkSelectionModel to monitor
+ *
+ * Creates a new selection monitor to observe @model.
+ *
+ * Currently, only #GtkSingleSelection can be monitored
+ *
+ * Returns: (transfer full) (type GtkSelectionMonitor): a new #GtkSelectionMonitor
+ **/
+GtkSelectionMonitor *
+gtk_selection_monitor_new (GtkSelectionModel *model)
+{
+  g_return_val_if_fail (GTK_IS_SELECTION_MODEL (model), NULL);
+
+  return g_object_new (GTK_TYPE_SELECTION_MONITOR,
+                       "model", model,
+                       NULL);
+}
+
+/**
+ * gtk_selection_monitor_get_model:
+ * @self: a #GtkSelectionMonitor
+ *
+ * Gets the model that @self is wrapping.
+ *
+ * Returns: (transfer none): The model being wrapped
+ **/
+GtkSelectionModel *
+gtk_selection_monitor_get_model (GtkSelectionMonitor *self)
+{
+  g_return_val_if_fail (GTK_IS_SELECTION_MONITOR (self), NULL);
+
+  return self->model;
+}
+
diff --git a/gtk/gtkselectionmonitor.h b/gtk/gtkselectionmonitor.h
new file mode 100644
index 0000000000..0faee0bc23
--- /dev/null
+++ b/gtk/gtkselectionmonitor.h
@@ -0,0 +1,41 @@
+/*
+ * Copyright © 2019 Matthias Clasen
+ *
+ * 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 <mclasen@redhat.com>
+ */
+
+#ifndef __GTK_SELECTION_MONITOR_H__
+#define __GTK_SELECTION_MONITOR_H__
+
+#include <gtk/gtktypes.h>
+#include <gtk/gtkselectionmodel.h>
+
+G_BEGIN_DECLS
+
+#define GTK_TYPE_SELECTION_MONITOR (gtk_selection_monitor_get_type ())
+
+GDK_AVAILABLE_IN_ALL
+G_DECLARE_FINAL_TYPE (GtkSelectionMonitor, gtk_selection_monitor, GTK, SELECTION_MONITOR, GObject)
+
+GDK_AVAILABLE_IN_ALL
+GtkSelectionMonitor *   gtk_selection_monitor_new       (GtkSelectionModel   *model);
+
+GDK_AVAILABLE_IN_ALL
+GtkSelectionModel *     gtk_selection_monitor_get_model (GtkSelectionMonitor *self);
+
+G_END_DECLS
+
+#endif /* __GTK_SELECTION_MONITOR_H__ */
diff --git a/gtk/meson.build b/gtk/meson.build
index d546efbc50..1f73829c0c 100644
--- a/gtk/meson.build
+++ b/gtk/meson.build
@@ -366,6 +366,7 @@ gtk_public_sources = files([
   'gtksearchentry.c',
   'gtkselection.c',
   'gtkselectionmodel.c',
+  'gtkselectionmonitor.c',
   'gtkseparator.c',
   'gtkseparatormenuitem.c',
   'gtkseparatortoolitem.c',
@@ -640,6 +641,7 @@ gtk_public_headers = files([
   'gtksearchentry.h',
   'gtkselection.h',
   'gtkselectionmodel.h',
+  'gtkselectionmonitor.h',
   'gtkseparator.h',
   'gtkseparatormenuitem.h',
   'gtkseparatortoolitem.h',
diff --git a/testsuite/gtk/singleselection.c b/testsuite/gtk/singleselection.c
index 24de458e1c..7dbd49278f 100644
--- a/testsuite/gtk/singleselection.c
+++ b/testsuite/gtk/singleselection.c
@@ -642,6 +642,32 @@ test_query_range (void)
   g_object_unref (selection);
 }
 
+static void
+test_monitor (void)
+{
+  GtkSelectionModel *selection;
+  GtkSelectionMonitor *monitor;
+  GListStore *store;
+
+  store = new_store (1, 20, 1);
+  selection = new_model (store, TRUE, TRUE);
+  monitor = gtk_selection_monitor_new (selection);
+
+  assert_selection (selection, "1");
+  assert_model (monitor, "1");
+
+  gtk_selection_model_select_item (selection, 2, TRUE);  
+
+  assert_selection (selection, "3");
+  assert_model (monitor, "3");
+
+  ignore_selection_changes (selection);
+
+  g_object_unref (store);
+  g_object_unref (selection);
+  g_object_unref (monitor);
+}
+
 int
 main (int argc, char *argv[])
 {
@@ -660,6 +686,7 @@ main (int argc, char *argv[])
   g_test_add_func ("/singleselection/persistence", test_persistence);
   g_test_add_func ("/singleselection/query-range", test_query_range);
   g_test_add_func ("/singleselection/changes", test_changes);
+  g_test_add_func ("/singleselection/monitor", test_monitor);
 
   return g_test_run ();
 }