Wireshark · Wireshark-dev: Re: [Wireshark-dev] proto_tree_get_parent()

[wsgd <wsgd@xxxxxxx>]

If I well understand the current Wireshark design on this point :

1) the parent of an item is the tree which contains this item
And a tree is an item.
-> proto_item_get_parent

2) the parent of a tree is an item which is the tree itself
proto_item and  proto_tree are both proto_node.
-> proto_tree_get_parent



Olivier


Maynard, Chris a écrit :
> ... and if we really want to retain a function call for whatever reason, then at the very least it should be renamed to something like proto_tree_cast_tree_to_item() for clarity, since that's all the function does.
>
> - Chris
>
>
> -----Original Message-----
> From: wireshark-dev-bounces@xxxxxxxxxxxxx [mailto:wireshark-dev-bounces@xxxxxxxxxxxxx] On Behalf Of Maynard, Chris
> Sent: Monday, March 29, 2010 10:21 AM
> To: 'Developer support list for Wireshark'
> Subject: Re: [Wireshark-dev] proto_tree_get_parent()
>
> I still don't get it.  Compare proto_item_get_parent() with proto_tree_get_parent():
>
> proto_item*
> proto_item_get_parent(proto_item *ti) {
>         if (!ti)
>                 return (NULL);
>         return ti->parent;
> }
>
> proto_item*
> proto_tree_get_parent(proto_tree *tree) {
>         if (!tree)
>                 return (NULL);
>         return (proto_item*) tree;
> }
>
> The former returns a pointer to the parent whereas the latter simply casts the tree to an item.  If a cast is all that's needed, then that can be very easily accomplished without a confusing and misleading function call.
>
> - Chris
>
>
> -----Original Message-----
> From: wireshark-dev-bounces@xxxxxxxxxxxxx [mailto:wireshark-dev-bounces@xxxxxxxxxxxxx] On Behalf Of Kukosa, Tomas
> Sent: Monday, March 29, 2010 2:26 AM
> To: Developer support list for Wireshark
> Subject: Re: [Wireshark-dev] proto_tree_get_parent()
>
> Hi, 
> I guess the function works well and as expected.
> It returns parent proto_item of the proto_tree and in our internal representation the item and its subtree are the same object only casted either to proto_item or proto_tree.
>
> Regards,
>   Tomas
>
>
> -----Original Message-----
> From: wireshark-dev-bounces@xxxxxxxxxxxxx [mailto:wireshark-dev-bounces@xxxxxxxxxxxxx] On Behalf Of Maynard, Chris
> Sent: Sunday, March 28, 2010 1:46 AM
> To: 'Developer support list for Wireshark'
> Subject: Re: [Wireshark-dev] proto_tree_get_parent()
>
> This sure looks like a bug to me.  A quick search shows at least these 18 dissectors calling it:
> $ grep -l proto_tree_get_parent packet-*.c
> packet-amr.c
> packet-assa_r3.c
> packet-dcerpc.c
> packet-h264.c
> packet-h450-ros.c
> packet-h450.c
> packet-h460.c
> packet-iax2.c
> packet-isakmp.c
> packet-mikey.c
> packet-mp4ves.c
> packet-q931.c
> packet-q932-ros.c
> packet-qsig.c
> packet-rtp.c
> packet-smb2.c
> packet-ssl.c
> packet-tcp.c
>
> If things are working correctly in those dissectors, then I think it's by pure luck and the function call can simply be omitted.  Either way, I think the function should be changed to implement what its proto_item_get_parent() peer implements.  I would suggest filing a bug report about.
>
> Good catch.
> - Chris
>
>
> -----Original Message-----
> From: wireshark-dev-bounces@xxxxxxxxxxxxx [mailto:wireshark-dev-bounces@xxxxxxxxxxxxx] On Behalf Of Eloy Paris
> Sent: Thursday, March 25, 2010 8:49 PM
> To: Developer support list for Wireshark
> Subject: [Wireshark-dev] proto_tree_get_parent()
>
> Is this right (from epan/proto.c):
>
> proto_item*
> proto_tree_get_parent(proto_tree *tree) {
> 	if (!tree)
> 		return (NULL);
> 	return (proto_item*) tree;
> }
>
> This basically returns the same thing that is received as a parameter. 
> Shouldn't tree->parent be returned instead, just as 
> proto_item_get_parent() (a few lines above in the same file) does?
>
> The weird thing is that there is code using this seemingly broken 
> proto_tree_get_parent(). I don't know how things are working given that 
> proto_tree_get_parent() is not really providing the parent node.
>
> Confused,
>
> Eloy Paris.-
> netexpect.org
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