Re: [Vala] Unexpected behaviour when using interfaces.



On Wed, 2011-01-19 at 22:46 +0100, Jürg Billeter wrote:
On Wed, 2011-01-19 at 21:52 +0100, Sergej Reich wrote:
I know that calling interface methods is expensive and that it's a known issue
in GLib but there is another problem. When a class implements an interface,
calling methods is slow regardless whether you declare your objects as being
instances of the class or the interface.

[...]

So my question would be whether this is intentional, maybe I'm missing something?
If it is then interfaces have to be used even more carefully and you need to use
a dummy class in between the interface just to be able to use your class without
the extra overhead when the interface is not needed.

Vala follows common GLib practice where possible and in the case of
interface implementations, it's common practice to not export the method
implementations directly and always use the interface wrapper functions
instead.

I understand that this may be a performance issue, however, deviating
from common practice in that regard would work only with classes written
in Vala and require many annotations in bindings of GLib/C libraries as
they usually do not support direct calls. That's why I'd like to keep it
the way it is. The plan for the Dova profile is to allow direct access
to the method implementations for performance and other reasons.

Jürg

Thank you for the clarification, of course consistency with other GLib
code is more important.

My main concern then would be with libraries like Gee. Right now all the
classes are implemented through abstract classes so the mentioned
problem is not noticeable but if Gee would use the interfaces directly
this would probably change.

Regards, Sergej




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