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

From: wsgd <wsgd@xxxxxxx>
Date: Tue, 30 Mar 2010 21:06:16 +0200
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 �crit :
... 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
___________________________________________________________________________
Sent via:    Wireshark-dev mailing list <wireshark-dev@xxxxxxxxxxxxx>
Archives:    http://www.wireshark.org/lists/wireshark-dev
Unsubscribe: https://wireshark.org/mailman/options/wireshark-dev
             mailto:wireshark-dev-request@xxxxxxxxxxxxx?subject=unsubscribe
CONFIDENTIALITY NOTICE: The contents of this email are confidential
and for the exclusive use of the intended recipient. If you receive this
email in error, please delete it from your system immediately and notify us either by email, telephone or fax. You should not copy,
forward, or otherwise disclose the content of the email.

___________________________________________________________________________
Sent via:    Wireshark-dev mailing list <wireshark-dev@xxxxxxxxxxxxx>
Archives:    http://www.wireshark.org/lists/wireshark-dev
Unsubscribe: https://wireshark.org/mailman/options/wireshark-dev
             mailto:wireshark-dev-request@xxxxxxxxxxxxx?subject=unsubscribe
___________________________________________________________________________
Sent via:    Wireshark-dev mailing list <wireshark-dev@xxxxxxxxxxxxx>
Archives:    http://www.wireshark.org/lists/wireshark-dev
Unsubscribe: https://wireshark.org/mailman/options/wireshark-dev
             mailto:wireshark-dev-request@xxxxxxxxxxxxx?subject=unsubscribe
CONFIDENTIALITY NOTICE: The contents of this email are confidential
and for the exclusive use of the intended recipient. If you receive this
email in error, please delete it from your system immediately and notify us either by email, telephone or fax. You should not copy,
forward, or otherwise disclose the content of the email.

___________________________________________________________________________
Sent via:    Wireshark-dev mailing list <wireshark-dev@xxxxxxxxxxxxx>
Archives:    http://www.wireshark.org/lists/wireshark-dev
Unsubscribe: https://wireshark.org/mailman/options/wireshark-dev
             mailto:wireshark-dev-request@xxxxxxxxxxxxx?subject=unsubscribe
CONFIDENTIALITY NOTICE: The contents of this email are confidential
and for the exclusive use of the intended recipient. If you receive this
email in error, please delete it from your system immediately and notify us either by email, telephone or fax. You should not copy,
forward, or otherwise disclose the content of the email.

___________________________________________________________________________
Sent via:    Wireshark-dev mailing list <wireshark-dev@xxxxxxxxxxxxx>
Archives:    http://www.wireshark.org/lists/wireshark-dev
Unsubscribe: https://wireshark.org/mailman/options/wireshark-dev
             mailto:wireshark-dev-request@xxxxxxxxxxxxx?subject=unsubscribe




--
Wireshark Generic Dissector http://wsgd.free.fr