[Spice-devel] [PATCH] codegen: Add a --generate-wireshark-dissector option

[Jonathon Jongsma]

The wireshark protocol dissector is a bit out-of-date. Several new channel types
and enums have been added.  It would be nice if these values (and the
translation between the value and the name) could be automatically generated so
that updating the dissector was a slightly less manual process.  This patch adds
a commandline switch which generates both the enums and value-name lists in the
format that wireshark expects.
---
 python_modules/ptypes.py |  17 ++++++++
 spice_codegen.py         | 105 +++++++++++++++++++++++++++++++----------------
 2 files changed, 86 insertions(+), 36 deletions(-)

diff --git a/python_modules/ptypes.py b/python_modules/ptypes.py
index d9fbfe2..2bfbf0d 100644
--- a/python_modules/ptypes.py
+++ b/python_modules/ptypes.py
@@ -247,6 +247,23 @@ class EnumBaseType(Type):
     def get_fixed_nw_size(self):
         return self.bits / 8
 
+    # generates a value-name table suitable for use with the wireshark protocol
+    # dissector
+    def c_describe(self, writer):
+        writer.write("static const value_string %s_vs[] = " % codegen.prefix_underscore_lower(self.name))
+        writer.begin_block()
+        values = self.names.keys()
+        values.sort()
+        for i in values:
+            writer.write("{ ")
+            writer.write(self.c_enumname(i))
+            writer.write(", \"%s\" }," % self.names[i])
+            writer.newline()
+        writer.write("{ 0, NULL }")
+        writer.end_block(semicolon=True)
+        writer.newline()
+
+
 class EnumType(EnumBaseType):
     def __init__(self, bits, name, enums, attribute_list):
         Type.__init__(self)
diff --git a/spice_codegen.py b/spice_codegen.py
index e9e64c0..de1f87b 100755
--- a/spice_codegen.py
+++ b/spice_codegen.py
@@ -10,38 +10,73 @@ from python_modules import codegen
 from python_modules import demarshal
 from python_modules import marshal
 
-def write_channel_enums(writer, channel, client):
+def write_channel_enums(writer, channel, client, describe):
     messages = filter(lambda m : m.channel == channel, \
                           channel.client_messages if client else channel.server_messages)
     if len(messages) == 0:
         return
-    writer.begin_block("enum")
-    i = 0
     if client:
-        prefix = [ "MSGC" ]
+        prefix = [ "msgc" ]
     else:
-        prefix = [ "MSG" ]
+        prefix = [ "msg" ]
     if channel.member_name:
-        prefix.append(channel.member_name.upper())
+        prefix.append(channel.member_name)
+    if not describe:
+        writer.begin_block("enum")
+    else:
+        writer.begin_block("static const value_string %s_vs[] = " % (codegen.prefix_underscore_lower(*prefix)))
+    i = 0
     prefix.append(None) # To be replaced with name
     for m in messages:
-        prefix[-1] = m.name.upper()
+        prefix[-1] = m.name
         enum = codegen.prefix_underscore_upper(*prefix)
-        if m.value == i:
-            writer.writeln("%s," % enum)
-            i = i + 1
+        if describe:
+            writer.writeln("{ %s, \"%s %s\" }," % (enum, "Client" if client else "Server", m.name.upper()))
         else:
-            writer.writeln("%s = %s," % (enum, m.value))
-            i = m.value + 1
-    if channel.member_name:
-        prefix[-1] = prefix[-2]
-        prefix[-2] = "END"
-        writer.newline()
-        writer.writeln("%s" % (codegen.prefix_underscore_upper(*prefix)))
+            if m.value == i:
+                writer.writeln("%s," % enum)
+                i = i + 1
+            else:
+                writer.writeln("%s = %s," % (enum, m.value))
+                i = m.value + 1
+    if describe:
+        writer.writeln("{ 0, NULL }");
+    else:
+        if channel.member_name:
+            prefix[-1] = prefix[-2]
+            prefix[-2] = "END"
+            writer.newline()
+            writer.writeln("%s" % (codegen.prefix_underscore_upper(*prefix)))
     writer.end_block(semicolon=True)
     writer.newline()
 
-def write_enums(writer):
+def write_channel_type_enum(writer, describe=False):
+    i = 0
+    if describe:
+        writer.begin_block("static const value_string channel_types_vs[] =")
+    else:
+        writer.begin_block("enum")
+    for c in proto.channels:
+        enum = codegen.prefix_underscore_upper("CHANNEL", c.name.upper())
+        if describe:
+            writer.writeln("{ %s, \"%s\" }," % (enum, c.name.upper()))
+        else:
+            if c.value == i:
+                writer.writeln("%s," % enum)
+                i = i + 1
+            else:
+                writer.writeln("%s = %s," % (enum, c.value))
+                i = c.value + 1
+    writer.newline()
+    if describe:
+        writer.writeln("{ 0, NULL }")
+    else:
+        writer.writeln("SPICE_END_CHANNEL")
+    writer.end_block(semicolon=True)
+    writer.newline()
+
+
+def write_enums(writer, describe=False):
     writer.writeln("#ifndef _H_SPICE_ENUMS")
     writer.writeln("#define _H_SPICE_ENUMS")
     writer.newline()
@@ -52,27 +87,22 @@ def write_enums(writer):
     for t in ptypes.get_named_types():
         if isinstance(t, ptypes.EnumBaseType):
             t.c_define(writer)
+            if describe:
+                t.c_describe(writer)
 
-    i = 0
-    writer.begin_block("enum")
-    for c in proto.channels:
-        enum = codegen.prefix_underscore_upper("CHANNEL", c.name.upper())
-        if c.value == i:
-            writer.writeln("%s," % enum)
-            i = i + 1
-        else:
-            writer.writeln("%s = %s," % (enum, c.value))
-            i = c.value + 1
-    writer.newline()
-    writer.writeln("SPICE_END_CHANNEL")
-    writer.end_block(semicolon=True)
-    writer.newline()
+    write_channel_type_enum(writer)
+    if (describe):
+        write_channel_type_enum(writer, True)
 
     for c in ptypes.get_named_types():
         if not isinstance(c, ptypes.ChannelType):
             continue
-        write_channel_enums(writer, c, False)
-        write_channel_enums(writer, c, True)
+        write_channel_enums(writer, c, False, False)
+        if describe:
+            write_channel_enums(writer, c, False, describe)
+        write_channel_enums(writer, c, True, False)
+        if describe:
+            write_channel_enums(writer, c, True, describe)
 
     writer.writeln("#endif /* _H_SPICE_ENUMS */")
 
@@ -80,6 +110,9 @@ parser = OptionParser(usage="usage: %prog [options] <protocol_file> <destination
 parser.add_option("-e", "--generate-enums",
                   action="store_true", dest="generate_enums", default=False,
                   help="Generate enums")
+parser.add_option("-w", "--generate-wireshark-dissector",
+                  action="store_true", dest="generate_dissector", default=False,
+                  help="Generate Wireshark dissector definitions")
 parser.add_option("-d", "--generate-demarshallers",
                   action="store_true", dest="generate_demarshallers", default=False,
                   help="Generate demarshallers")
@@ -160,8 +193,8 @@ if options.includes:
         writer.header.writeln('#include "%s"' % i)
         writer.writeln('#include "%s"' % i)
 
-if options.generate_enums:
-    write_enums(writer)
+if options.generate_enums or options.generate_dissector:
+    write_enums(writer, options.generate_dissector)
 
 if options.generate_demarshallers:
     if not options.server and not options.client:
-- 
1.8.3.1