A sample patch that illustrates how to do virtual methods

[Philip Van Hoof <spam pvanhoof be>]

On Mon, 2006-11-06 at 15:49 +0100, Philip Van Hoof wrote:

> For example making most methods virtual (which isn't easy in GObject,
> but I can teach you --it's not as easy as putting "virtual" in front of
> the method name, no. You need to store the function pointer
> somewhere--).

This patch illustrates how to transform normal methods into virtual
ones.

I would be very very interested in patches like this coming from people
on this mailing list ;-).

As far as I'm concerned, all implementation-methods of the tinymail
framework can be virtual ones (that's a lot, indeed).


-- 
Philip Van Hoof, software developer at x-tend 
home: me at pvanhoof dot be 
gnome: pvanhoof at gnome dot org 
work: vanhoof at x-tend dot be 
http://www.pvanhoof.be - http://www.x-tend.be

Index: tny-gtk-header-view.c
===================================================================
--- tny-gtk-header-view.c	(revision 1096)
+++ tny-gtk-header-view.c	(working copy)
@@ -57,10 +57,16 @@
 	return g_strdup (readable_date);
 }
 
-
 static void 
 tny_gtk_header_view_set_header (TnyHeaderView *self, TnyHeader *header)
 {
+	TNY_GTK_HEADER_VIEW_GET_CLASS (self)->set_header_func (self, header);
+	return;
+}
+
+static void 
+tny_gtk_header_view_set_header_default (TnyHeaderView *self, TnyHeader *header)
+{
 	TnyGtkHeaderViewPriv *priv = TNY_GTK_HEADER_VIEW_GET_PRIVATE (self);
 
 	if (G_LIKELY (priv->header))
@@ -69,7 +75,7 @@
 
 	if (header && G_IS_OBJECT (header))
 	{
-	    	gchar *str;
+		gchar *str;
 		g_object_ref (G_OBJECT (header)); 
 		priv->header = header;
 
@@ -81,29 +87,36 @@
 		gtk_label_set_text (GTK_LABEL (priv->date_label), (const gchar*)str);
 		g_free (str);
 	}
-    
+
 	return;
 }
 
-
 static void 
 tny_gtk_header_view_clear (TnyHeaderView *self)
 {
+	TNY_GTK_HEADER_VIEW_GET_CLASS (self)->clear_func (self);
+	return;
+}
+
+static void 
+tny_gtk_header_view_clear_default (TnyHeaderView *self)
+{
 	TnyGtkHeaderViewPriv *priv = TNY_GTK_HEADER_VIEW_GET_PRIVATE (self);
 
 	if (G_LIKELY (priv->header))
 		g_object_unref (G_OBJECT (priv->header));
 	priv->header = NULL;
-    
+
 	gtk_label_set_text (GTK_LABEL (priv->to_label), "");
 	gtk_label_set_text (GTK_LABEL (priv->from_label), "");
 	gtk_label_set_text (GTK_LABEL (priv->subject_label), "");
 	gtk_label_set_text (GTK_LABEL (priv->date_label), "");
-    
+
 	return;
 }
 
 
+
 /**
  * tny_gtk_header_view_new:
  *
@@ -203,7 +216,7 @@
 	if (G_LIKELY (priv->header))
 		g_object_unref (G_OBJECT (priv->header));
 	priv->header = NULL;
-    
+
 	(*parent_class->finalize) (object);
 
 	return;
@@ -216,7 +229,7 @@
 
 	klass->set_header_func = tny_gtk_header_view_set_header;
 	klass->clear_func = tny_gtk_header_view_clear;
-    
+
 	return;
 }
 
@@ -228,6 +241,9 @@
 	parent_class = g_type_class_peek_parent (class);
 	object_class = (GObjectClass*) class;
 
+	class->set_header_func = tny_gtk_header_view_set_header_default;
+	class->clear_func = tny_gtk_header_view_clear_default;
+
 	object_class->finalize = tny_gtk_header_view_finalize;
 
 	g_type_class_add_private (object_class, sizeof (TnyGtkHeaderViewPriv));
Index: tny-gtk-header-view.h
===================================================================
--- tny-gtk-header-view.h	(revision 1096)
+++ tny-gtk-header-view.h	(working copy)
@@ -46,6 +46,10 @@
 struct _TnyGtkHeaderViewClass
 {
 	GtkTableClass parent_class;
+
+	/* virtual methods */
+	void (*set_header_func) (TnyHeaderView *self, TnyHeader *header);
+	void (*clear_func) (TnyHeaderView *self);   
 };
 
 GType tny_gtk_header_view_get_type (void);