[gtk/wip/otte/listview: 1011/1040] listitemwidget: Lazily create listitems

[Benjamin Otte <otte src gnome org>]

commit 5c7e574ed7d7e6e17ed1a73c185867e3d779fc9e
Author: Benjamin Otte <otte redhat com>
Date:   Sun Nov 3 03:59:04 2019 +0100

    listitemwidget: Lazily create listitems
    
    We only create them in root/unroot (they should be created in
    appear/disappear, but that vfunc doesn't exist yet), that way we can
    avoid expensive work while the widget isn't used for anything.

 gtk/gtklistitemwidget.c        | 133 +++++++++++++++++++++++++++++++++--------
 gtk/gtklistitemwidgetprivate.h |   2 +
 2 files changed, 110 insertions(+), 25 deletions(-)
---
diff --git a/gtk/gtklistitemwidget.c b/gtk/gtklistitemwidget.c
index 54f1eb0c96..60360288e2 100644
--- a/gtk/gtklistitemwidget.c
+++ b/gtk/gtklistitemwidget.c
@@ -45,6 +45,13 @@ struct _GtkListItemWidgetPrivate
   gboolean selected;
 };
 
+enum {
+  PROP_0,
+  PROP_FACTORY,
+
+  N_PROPS
+};
+
 enum
 {
   ACTIVATE_SIGNAL,
@@ -53,6 +60,7 @@ enum
 
 G_DEFINE_TYPE_WITH_PRIVATE (GtkListItemWidget, gtk_list_item_widget, GTK_TYPE_WIDGET)
 
+static GParamSpec *properties[N_PROPS] = { NULL, };
 static guint signals[LAST_SIGNAL] = { 0 };
 
 static void
@@ -110,23 +118,64 @@ gtk_list_item_widget_grab_focus (GtkWidget *widget)
   GtkListItemWidget *self = GTK_LIST_ITEM_WIDGET (widget);
   GtkListItemWidgetPrivate *priv = gtk_list_item_widget_get_instance_private (self);
 
-  if (priv->list_item->child && gtk_widget_grab_focus (priv->list_item->child))
+  if (priv->list_item && priv->list_item->child && gtk_widget_grab_focus (priv->list_item->child))
     return TRUE;
 
   return GTK_WIDGET_CLASS (gtk_list_item_widget_parent_class)->grab_focus (widget);
 }
 
 static void
-gtk_list_item_widget_dispose (GObject *object)
+gtk_list_item_widget_root (GtkWidget *widget)
 {
-  GtkListItemWidget *self = GTK_LIST_ITEM_WIDGET (object);
+  GtkListItemWidget *self = GTK_LIST_ITEM_WIDGET (widget);
   GtkListItemWidgetPrivate *priv = gtk_list_item_widget_get_instance_private (self);
 
+  GTK_WIDGET_CLASS (gtk_list_item_widget_parent_class)->root (widget);
+
+  if (priv->factory)
+    gtk_list_item_factory_setup (priv->factory, self);
+}
+
+static void
+gtk_list_item_widget_unroot (GtkWidget *widget)
+{
+  GtkListItemWidget *self = GTK_LIST_ITEM_WIDGET (widget);
+  GtkListItemWidgetPrivate *priv = gtk_list_item_widget_get_instance_private (self);
+
+  GTK_WIDGET_CLASS (gtk_list_item_widget_parent_class)->unroot (widget);
+
   if (priv->list_item)
-    {
       gtk_list_item_factory_teardown (priv->factory, self);
-      g_assert (priv->list_item == NULL);
+}
+
+static void
+gtk_list_item_widget_set_property (GObject      *object,
+                                   guint         property_id,
+                                   const GValue *value,
+                                   GParamSpec   *pspec)
+{
+  GtkListItemWidget *self = GTK_LIST_ITEM_WIDGET (object);
+
+  switch (property_id)
+    {
+    case PROP_FACTORY:
+      gtk_list_item_widget_set_factory (self, g_value_get_object (value));
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+      break;
     }
+}
+
+static void
+gtk_list_item_widget_dispose (GObject *object)
+{
+  GtkListItemWidget *self = GTK_LIST_ITEM_WIDGET (object);
+  GtkListItemWidgetPrivate *priv = gtk_list_item_widget_get_instance_private (self);
+
+  g_assert (priv->list_item == NULL);
+
   g_clear_object (&priv->item);
   g_clear_object (&priv->factory);
 
@@ -164,9 +213,21 @@ gtk_list_item_widget_class_init (GtkListItemWidgetClass *klass)
 
   widget_class->focus = gtk_list_item_widget_focus;
   widget_class->grab_focus = gtk_list_item_widget_grab_focus;
+  widget_class->root = gtk_list_item_widget_root;
+  widget_class->unroot = gtk_list_item_widget_unroot;
 
+  gobject_class->set_property = gtk_list_item_widget_set_property;
   gobject_class->dispose = gtk_list_item_widget_dispose;
 
+  properties[PROP_FACTORY] =
+    g_param_spec_object ("factory",
+                         "Factory",
+                         "Factory managing this list item",
+                         GTK_TYPE_LIST_ITEM_FACTORY,
+                         G_PARAM_WRITABLE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
+
+  g_object_class_install_properties (gobject_class, N_PROPS, properties);
+
   signals[ACTIVATE_SIGNAL] =
     g_signal_new (I_("activate-keybinding"),
                   G_OBJECT_CLASS_TYPE (gobject_class),
@@ -351,24 +412,12 @@ GtkWidget *
 gtk_list_item_widget_new (GtkListItemFactory *factory,
                           const char         *css_name)
 {
-  GtkListItemWidget *result;
-
   g_return_val_if_fail (css_name != NULL, NULL);
 
-  result = g_object_new (GTK_TYPE_LIST_ITEM_WIDGET,
-                         "css-name", css_name,
-                         NULL);
-  if (factory)
-    {
-      GtkListItemWidgetPrivate *priv = gtk_list_item_widget_get_instance_private (result);
-
-      priv->factory = g_object_ref (factory);
-
-      gtk_list_item_factory_setup (factory, result);
-      g_assert (priv->list_item != NULL);
-    }
-
-  return GTK_WIDGET (result);
+  return g_object_new (GTK_TYPE_LIST_ITEM_WIDGET,
+                       "css-name", css_name,
+                       "factory", factory,
+                       NULL);
 }
 
 void
@@ -379,8 +428,10 @@ gtk_list_item_widget_update (GtkListItemWidget *self,
 {
   GtkListItemWidgetPrivate *priv = gtk_list_item_widget_get_instance_private (self);
 
-  if (priv->factory)
+  if (priv->list_item)
     gtk_list_item_factory_update (priv->factory, self, position, item, selected);
+  else
+    gtk_list_item_widget_default_update (self, NULL, position, item, selected);
 
   if (selected)
     gtk_widget_set_state_flags (GTK_WIDGET (self), GTK_STATE_FLAG_SELECTED, FALSE);
@@ -442,19 +493,51 @@ gtk_list_item_widget_default_update (GtkListItemWidget *self,
   /* FIXME: It's kinda evil to notify external objects from here... */
   
   if (g_set_object (&priv->item, item))
-    g_object_notify (G_OBJECT (list_item), "item");
+    {
+      if (list_item)
+        g_object_notify (G_OBJECT (list_item), "item");
+    }
 
   if (priv->position != position)
     {
       priv->position = position;
-      g_object_notify (G_OBJECT (list_item), "position");
+      if (list_item)
+        g_object_notify (G_OBJECT (list_item), "position");
     }
 
   if (priv->selected != selected)
     {
       priv->selected = selected;
-      g_object_notify (G_OBJECT (list_item), "selected");
+      if (list_item)
+        g_object_notify (G_OBJECT (list_item), "selected");
+    }
+}
+
+void
+gtk_list_item_widget_set_factory (GtkListItemWidget  *self,
+                                  GtkListItemFactory *factory)
+{
+  GtkListItemWidgetPrivate *priv = gtk_list_item_widget_get_instance_private (self);
+
+  if (priv->factory == factory)
+    return;
+
+  if (priv->factory)
+    {
+      if (priv->list_item)
+        gtk_list_item_factory_teardown (factory, self);
+      g_clear_object (&priv->factory);
+    }
+
+  if (factory)
+    {
+      priv->factory = g_object_ref (factory);
+
+      if (gtk_widget_get_root (GTK_WIDGET (self)))
+        gtk_list_item_factory_setup (factory, self);
     }
+
+  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_FACTORY]);
 }
 
 void
diff --git a/gtk/gtklistitemwidgetprivate.h b/gtk/gtklistitemwidgetprivate.h
index 0d74ee8ed2..b5f2ec7393 100644
--- a/gtk/gtklistitemwidgetprivate.h
+++ b/gtk/gtklistitemwidgetprivate.h
@@ -68,6 +68,8 @@ void                    gtk_list_item_widget_default_update     (GtkListItemWidg
                                                                  gpointer                item,
                                                                  gboolean                selected);
 
+void                    gtk_list_item_widget_set_factory        (GtkListItemWidget      *self,
+                                                                 GtkListItemFactory     *factory);
 void                    gtk_list_item_widget_add_child          (GtkListItemWidget      *self,
                                                                  GtkWidget              *child);
 void                    gtk_list_item_widget_remove_child       (GtkListItemWidget      *self,