Created attachment 255528 [details] [review]
GtkTextView: add create_buffer virtual method pointer

gtk_text_view_get_buffer() returns its priv->buffer. If priv->buffer is
NULL, a GtkTextBuffer is created and returned.

With a GtkSourceView (subclass of GtkTextView) and GtkSourceBuffer
(subclass of GtkTextBuffer), the gtk_text_view_get_buffer() function is
a problem. When we call gtk_text_view_get_buffer() when the priv->buffer
is NULL, we want a GtkSourceBuffer, not a GtkTextBuffer.

Why not make the get_buffer() function virtual, and override it in
GtkSourceView? It would not be a clean solution, because when
get_buffer() creates a new buffer, gtk_text_view_set_buffer() is called,
which indirectly call get_buffer(), etc. So there is an infinite loop.
And a hack is needed to avoid it.

On the other hand, the create_buffer() virtual function always creates a
buffer. It doesn't depend on priv->buffer.

Review of attachment 255528 [details] [review]:

I don't like the commit message at all - it completely breaks scanning to see what was done because you are talking about things not in GTK+ and approaches you didn't take. (Too me, making get_buffer() virtual is obviously completely horribly the wrong thing, so discussing why you didn't do it is a waste of space :-)

A commit mesage like

 This allows subclasses of GtkTextView that require a corresponding subclass of
 GtkTextBuffer to automatically do the right thing when constructed with a NULL
 buffer. An example of this is GtkSourceView which requires a GtkSourceBuffer.

would be fine.

::: gtk/gtktextview.h
@@ +107,3 @@
   void (* toggle_overwrite) (GtkTextView *text_view);
 
+  GtkTextBuffer * (* create_buffer) (void);

This definitely needs to take the text_view as the argument. A) it's conventional B) it is very useful C) you'll break language bindings if you have a virtual function without a self method.

Thank you for the review. Second patch iteration is coming soon.

Created attachment 255856 [details] [review]
GtkTextView: add create_buffer virtual method pointer

This allows subclasses of GtkTextView that require a corresponding
subclass of GtkTextBuffer to automatically do the right thing when
constructed with a NULL buffer. An example of this is GtkSourceView
which requires a GtkSourceBuffer.

Review of attachment 255856 [details] [review]:

Seems OK to me

Pushed.