Re: value_copy in sfiglue.c (Re: Optimizations)

[Stefan Westerfeld <stefan space twc de>]

   Hi!

On Tue, Feb 03, 2004 at 08:18:36PM +0100, Tim Janik wrote:
> On Tue, 3 Feb 2004, Stefan Westerfeld wrote:
> > * Patch #1: removes redundant value copy, by appending an empty value and
> > filling it directly.
> >
> > Index: sfiglue.c
> > ===================================================================
> > RCS file: /cvs/gnome/beast/sfi/sfiglue.c,v
> > retrieving revision 1.9
> > diff -u -p -r1.9 sfiglue.c
> > --- sfiglue.c	23 Dec 2003 04:50:55 -0000	1.9
> > +++ sfiglue.c	2 Feb 2004 20:57:02 -0000
> > @@ -339,14 +339,8 @@ sfi_glue_call_valist (const gchar *proc_
> >  	error = g_strdup_printf ("%s: invalid category_type (%u)", G_STRLOC, arg_type);
> >        else
> >  	{
> > -	  GValue value = { 0, };
> > -	  g_value_init (&value, collect_type);
> > -	  G_VALUE_COLLECT (&value, var_args, 0, &error);
> > -	  if (!error)
> > -	    {
> > -	      sfi_seq_append (seq, &value);
> > -	      g_value_unset (&value);
> > -	    }
> > +	  GValue *value = sfi_seq_append_empty (seq, collect_type);
> > +	  G_VALUE_COLLECT (value, var_args, 0, &error);
> >  	}
> >        if (error)
> >  	{
> 
> this change alters behaviour, in case of error, the original
> version doesn't append to the sequence while your version
> does (unconditionally).

But in case of error, the sequence gets freed anyway: the whole source of
the patched version is:

  seq = sfi_seq_new ();
  while (arg_type)
    {
      gchar *error = NULL;
      GType collect_type = sfi_category_type (arg_type);
      if (!collect_type)
        error = g_strdup_printf ("%s: invalid category_type (%u)", G_STRLOC, arg_type);
      else
        {
          GValue *value = sfi_seq_append_empty (seq, collect_type);
          G_VALUE_COLLECT (value, var_args, 0, &error);
        }
      if (error)
        {
          sfi_warn ("%s: %s", G_STRLOC, error);
          g_free (error);
          sfi_seq_unref (seq);
          return NULL;
        }
      arg_type = va_arg (var_args, guint);
    }

So if an error occurs, the new version appends unconditionally, but it also
frees the resulting sequence if an error occured.

   Cu... Stefan
-- 
  -* Stefan Westerfeld, stefan@space.twc.de (PGP!), Hamburg/Germany
     KDE Developer, project infos at http://space.twc.de/~stefan/kde *-