Re: GdkPixbuf leaks memory (continuation)

[Paolo Molaro <lupus ximian com>]

On 05/04/01 Dov Grobgeld wrote:
> In continuation to my previous mail, there seems to be a problem with
> the GdkPixbufTypemap. According to the perlxs tutorial a pointer
> type with a destructor should be defined:
>
>    TYPEMAP
>    Foo *T_PTROBJ   
>
> but in build/GdkPixbufTypemap we have
>
>    Gtk::Gdk::Pixbuf        T_SimpleVal
>
> Is there any documentation that describes how gendefs work that could
> help me in figuring out how this works?

Most of the meat is in Gtk/gtk-0.99.typemap. There you will find that
types labelled with T_SimpleVal will be handled by this snippet when
used as a return value in an XS function:

$arg = sv_2mortal(newSV {[grep {s/://g,s/^GtkGdk/Gdk/,1} $ntype]}($var));

This means that in this case we get (have a look at the generated C files):

ST(0) = sv_2mortal(newSVGdkPixbuf(RETVAL));

newSVGdkPixbuf() is defined in GdkPixbuf/build/GdkPixbufDefs.c
(this file is automatically generated by gendefs):

SV * newSVGdkPixbuf(GdkPixbuf * value) {
        int n = 0;
        SV * result = newSVMiscRef(value, "Gtk::Gdk::Pixbuf", &n);
        if (n)
                gdk_pixbuf_ref(value);
        return result;
}

newSVMiscRef() will insert the C pointer in a hash table and
return a perl hash reference blessed in the "Gtk::Gdk::Pixbuf"
package. If this C pointer was not already in the hash table (n)
we increase the reference count. As I explained in another mail
this is not needed if the C object was created by the binding
(basically when the C object is returned by constructors such as
Gtk::Gdk::Pixbuf::new_from_file).

> In any case, this probably only takes care of the automatic calling
> of the DESTROY function, but doesn't help wit the reference count
> problem.

The problem is fixed in cvs as noted in another email.

lupus

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