[Click] dynamic_cast ?

[Eddie Kohler]

Hi Harald,

Click elements don't know what element(s) are connected to a push input port, 
or a pull output port.  This is because it is valid for one or more elements 
to connect there.

So if e->input_is_push(i), then e->input(i).element() == 0.

To find the element or elements connected to a push input port, use
Router functions to traverse the element graph.  I've just checked in a rework 
of this functionality that should help you.  On current mainline, you could say:

#include <click/routervisitor.hh>
...
ElementNeighborTracker tracker(router());
router()->visit_upstream(this, 0, &tracker);
tracker.elements() // is a vector containing exactly those elements
                    // that are connected to [0]this

Does this make sense?

Eddie




Harald Schiöberg wrote:
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> Eddie Kohler wrote:
>> Hi Harald,
>>
>> Click already provides a cast() method on Element that should do what
>> you want.
> 
> Thanks a lot, apparently I'm to blind to see the obvious.
> 
> yet (completly off-topic) this segfaults:
> 
> int
> MultiFlowDispatcher::initialize(ErrorHandler * errh ) {
> 
>   int i;
>   for (i=0; i<=1; i++){
>     if ( input(i).element()->cast("MultiFlowDispatcher") ){
> 
> 
> and the debugger tells me that the input has no element
> 
> (gdb) p input(0)
> $1 = (const Element::Port &) @0x826d324: {_e = 0x0, _port = -1}
> 
> are the neighbors not known at initialization time?
> Is there anything better than this really ugly thing:
> 
> MultiFlowDispatcher::push( ) {
> 	if (!_neighbor_config)
> 		do_neighbor_config()
> }
> 
> 
> - --
> Harald Schiöberg
> Technische Universität Berlin | T-Laboratories | FG INET
> www: http://www.net.t-labs.tu-berlin.de
> Phone: +49-(0)30-8353-58476 | Fax: +49-(0)391 534 783 47
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