Wireshark · Wireshark-dev: Re: [Wireshark-dev] Regenerating packet-parlay.c

[Luke Mewburn <luke@xxxxxxxxxxx>]

On 20-04-30 20:30, Jaap Keuter wrote:
  | On 4/30/20 2:41 AM, Luke Mewburn wrote:
  | > On 20-04-30 10:35, Luke Mewburn wrote:
  | >   | As to the problem; looking at the use of .keys() in wireshark_gen.py,
  | >   | there's a couple of places where the code is either:
  | >   | - get_intlist(), sorted:
  | >   | 	ret = list(ex_hash.keys())
  | >   | 	ret.sort()
  | >   | 	return ret
  | >   | - get_exceptionList(), unsorted:
  | >   | 	ret = list(ex_hash.keys())
  | >   | 	return ret
  | >   | 
  | >   | Both could be simplified to an ordered result using sorted():
  | >   | 	ret = sorted(ex_hash.keys())
  | >   | 	return ret
  | > 
  | > I actually meant:
  | > 	ret = sorted(ex_hash)
  | > 	return ret
  | > 
  | > Because sorted() takes an iterable.
  | > That seems to work in both python2 and python3.
  | > 
  | > 
  | > Luke.
  | 
  | Hi,
  | 
  | tried this, but: in get_exceptionList
  | ret = sorted(ex_hash.keys())
  | TypeError: '<' not supported between instances of 'Exception' and 'Exception'

I've reproduced the problem; the correct invocation is:
	ret = sorted(ex_hash, key=lambda ex: ex.identifier())
	return ret


However, looking at the code some more, it appears that generally
wireshark_gen.py generates code in the order the operations are defined;
the exception (hah!) is the user exceptions.

If I instead add at the top
	import collections
and change get_exceptionList() from
	ex_hash = {}  # holds a hash of unique exceptions.
to
	ex_hash = collections.OrderedDict()  # holds a hash of unique exceptions.

This results in consistent generated code with both python 2.7 (CentOS 7)
and python 3.7 (Fedora 31).

I've also fixed a whitespace issue in the generated code by indenting
the break in template_helper_switch_msgtype_default_end, so that it
matches the epan/dissectors code and other default statements.


Here's a patch with my suggested fixes.
Or would you prefer a commit/pull request (etc)?


regards,
Luke.

From 034db92a2119250c6f278b55f2f223ea1ace9d1a Mon Sep 17 00:00:00 2001
From: Luke Mewburn <luke@xxxxxxxxxxx>
Date: Fri, 1 May 2020 11:22:03 +1000
Subject: [PATCH] idl2wrs: generation improvements

Consistent user exception ordering.
Fix switch msgtype default indenting.

Change-Id: Id345013d558bb458f5476b3225dc91a0b6afeb42
---
 tools/wireshark_gen.py | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/tools/wireshark_gen.py b/tools/wireshark_gen.py
index f58470f1f6..f28f7edffe 100755
--- a/tools/wireshark_gen.py
+++ b/tools/wireshark_gen.py
@@ -54,6 +54,7 @@
 
 from __future__ import print_function
 
+import collections
 import tempfile
 
 from omniidl import idlast, idltype, idlutil, output
@@ -1747,7 +1748,7 @@ class wireshark_gen_C:
         to generate dissect_exception_XXX functions.
         """
 
-        ex_hash = {}  # holds a hash of unique exceptions.
+        ex_hash = collections.OrderedDict()  # holds a hash of unique exceptions.
         for op in oplist:
             for ex in op.raises():
                 if ex not in ex_hash:
@@ -1945,7 +1946,7 @@ default:
     expert_add_info_format(pinfo, item, &ei_@dissector_name@_unknown_giop_msg, "Unknown GIOP message %d", header->message_type);"""
 
     template_helper_switch_msgtype_default_end = """\
-break;"""
+    break;"""
 
     template_helper_switch_msgtype_end = """\
 } /* switch(header->message_type) */"""
-- 
2.24.2 (Apple Git-127)

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