[Spice-devel] [PATCH v3 38/51] Use a class to register wireshark fields

[Frediano Ziglio]

> 
> On Tue, Jul 21, 2015 at 05:46:08PM +0100, Frediano Ziglio wrote:
> > Allow to reuse code and check better if field was already registered
> > 
> > Signed-off-by: Frediano Ziglio <fziglio at redhat.com>
> > ---
> >  python_modules/dissector.py | 58
> >  +++++++++++++++++++++++++++++++++++++--------
> >  1 file changed, 48 insertions(+), 10 deletions(-)
> > 
> > diff --git a/python_modules/dissector.py b/python_modules/dissector.py
> > index 5639baa..c88118f 100644
> > --- a/python_modules/dissector.py
> > +++ b/python_modules/dissector.py
> > @@ -21,8 +21,49 @@ def new_ett(writer):
> >      return name
> >  
> >  
> > +# handle registration of wireshark flags
> >  hf_writer = None
> >  hf_defs = None
> > +class HF:
> 
> Just curious about the naming here, is 'HF' something which is used in
> wireshark? I'd prefer a longer, more expressive name for a class name
> 

Yes, wireshark thing. All fields have this hf prefix. The "f" surely stand for field... about "h" I don't exactly know.

Frediano

> > +    fields = {}
> > +
> > +    def __init__(self, hf_name, desc=''):
> > +        self.hf_name = hf_name
> > +        self.desc = desc
> > +        self.mask = '0'
> > +
> > +    def __str__(self):
> > +        x = []
> > +        for f in 'hf_name desc ws_name f_type base vals mask'.split():
> > +            x.append(f + ':' + self.__dict__[f])
> > +        return ' '.join(x)
> > +
> > +    # declare a field identifier
> > +    def add_wireshark_field(self):
> > +        if hf_writer.variable_defined(self.hf_name):
> > +            raise Exception('HF field %s already defined' % self.hf_name)
> > +        hf_writer.variable_def("static int", "%s = -1" % self.hf_name)
> > +
> > +    def create(self):
> > +        other = self.fields.get(self.ws_name)
> > +        if other:
> > +            for f in 'hf_name desc ws_name base vals mask'.split():
> > +                if other.__dict__[f] != self.__dict__[f]:
> > +                    raise Exception('HF Field different from previous
> > for\n\t%s\n\t%s' % (other, self))
> > +            if other.f_type != self.f_type:
> > +                if other.f_type[:7] != 'FT_UINT' or self.f_type[:7] !=
> > 'FT_UINT':
> > +                    raise Exception('HF Field different from previous
> > for\n\t%s\n\t%s' % (other, self))
> > +            return
> > +
> > +        self.fields[self.ws_name] = self
> > +
> > +        self.add_wireshark_field()
> > +
> > +        hf_defs.writeln('{ &%s,' % self.hf_name)
> > +        hf_defs.writeln('  { "%s", "spice2.%s",' % (self.desc,
> > self.ws_name))
> > +        hf_defs.writeln('    %s, %s, %s, %s,' % (self.f_type, self.base,
> > self.vals, self.mask))
> > +        hf_defs.writeln('    NULL, HFILL }')
> > +        hf_defs.writeln('},')
> >  
> >  
> >  # handle wireshark attributes
> > @@ -306,16 +347,13 @@ def write_wireshark_field(writer, container, member,
> > t, ws, tree, size, encoding
> >      writer.statement("%sproto_tree_add_item(%s, %s, glb->tvb, offset, %s,
> >      %s)" %
> >              (prefix, tree, hf_name, size, encoding))
> >  
> > -    # TODO handle better duplications
> > -    if hf_writer.variable_defined(hf_name):
> > -        return
> > -    hf_writer.variable_def("static int", "%s = -1" % hf_name)
> > -
> > -    hf_defs.writeln('{ &%s,' % hf_name)
> > -    hf_defs.writeln('  { "%s", "spice2.%s",' % (desc, ws_name))
> > -    hf_defs.writeln('    %s, %s, %s, 0,' % (f_type, base, vals))
> > -    hf_defs.writeln('    NULL, HFILL }')
> > -    hf_defs.writeln('},')
> > +    # write definition
> > +    hf = HF(hf_name, desc)
> > +    hf.ws_name = ws_name
> > +    hf.f_type = f_type
> > +    hf.base = base
> > +    hf.vals = vals
> > +    hf.create()
> >  
> >  
> >  # Note: during parsing, byte_size types have been converted to count
> >  during validation
> > --
> > 2.1.0
> > 
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>