[Spice-devel] [PATCH spice-common] codegen: Define identity macros for enum types

[Frediano Ziglio]

> 
> Hey,
> 
> Some concrete examples of what you are going to do with it would be
> useful ;)
> 
> Christophe
> 
> On Mon, Nov 13, 2017 at 01:16:32PM +0000, Frediano Ziglio wrote:
> > An identity macro in C is a macro defined as
> > 
> >   #define SOME_NAME SOME_NAME
> > 
> > They are often used to make possible to use preprocessor to check
> > for values existence like
> > 
> >   #ifdef SOME_NAME
> >   ... use SOME_NAME ...
> >   #endif

This IMO is a concrete example. A more concrete would be another
commit but looks weird putting a hash to a not merged commit.
Or should I inline the commit here?

> > 
> > Defining these macro for each enumeration value allows to do finer
> > check in the code that uses spice-protocol.
> > 
> > Signed-off-by: Frediano Ziglio <fziglio at redhat.com>
> > ---
> >  python_modules/codegen.py | 10 ++++++++++
> >  python_modules/ptypes.py  |  2 ++
> >  spice_codegen.py          |  2 ++
> >  3 files changed, 14 insertions(+)
> > 
> > diff --git a/python_modules/codegen.py b/python_modules/codegen.py
> > index f7a2048..6143905 100644
> > --- a/python_modules/codegen.py
> > +++ b/python_modules/codegen.py
> > @@ -327,6 +327,16 @@ class CodeWriter:
> >      def macro(self, name, args, define):
> >          self.write("#define %s(%s) %s" % (name, args, define)).newline()
> >  
> > +    def identity_macro(self, name):
> > +        """Define a preprocessor macro with same name as value.
> > +        This helps writing conditional code using preprocessor defines.
> > +        """
> > +        assert(self.at_line_start)
> > +        indentation = self.indentation
> > +        self.indentation = 0
> > +        self.writeln("#define %s %s" % (name, name))
> > +        self.indentation = indentation
> > +
> >      def ifdef(self, name):
> >          indentation = self.indentation
> >          self.indentation = 0;
> > diff --git a/python_modules/ptypes.py b/python_modules/ptypes.py
> > index 63a7a2f..47b32b5 100644
> > --- a/python_modules/ptypes.py
> > +++ b/python_modules/ptypes.py
> > @@ -381,6 +381,7 @@ class EnumType(EnumBaseType):
> >                  writer.write(" = %d" % (i))
> >              writer.write(",")
> >              writer.newline()
> > +            writer.identity_macro(self.c_enumname(i))
> >              current_default = i + 1
> >          writer.newline()
> >          writer.write(codegen.prefix_underscore_upper(self.name.upper(),
> >          "ENUM_END"))
> > @@ -434,6 +435,7 @@ class FlagsType(EnumBaseType):
> >              writer.write(" = (1 << %d)" % (i))
> >              writer.write(",")
> >              writer.newline()
> > +            writer.identity_macro(self.c_enumname(i))
> >              current_default = i + 1
> >          writer.newline()
> >          writer.write(codegen.prefix_underscore_upper(self.name.upper(),
> >          "MASK"))
> > diff --git a/spice_codegen.py b/spice_codegen.py
> > index 76d7c5e..bb50f31 100755
> > --- a/spice_codegen.py
> > +++ b/spice_codegen.py
> > @@ -40,6 +40,7 @@ def write_channel_enums(writer, channel, client,
> > describe):
> >              else:
> >                  writer.writeln("%s = %s," % (enum, m.value))
> >                  i = m.value + 1
> > +            writer.identity_macro(enum)
> >      if describe:
> >          writer.writeln("{ 0, NULL }");
> >      else:
> > @@ -68,6 +69,7 @@ def write_channel_type_enum(writer, describe=False):
> >              else:
> >                  writer.writeln("%s = %s," % (enum, c.value))
> >                  i = c.value + 1
> > +            writer.identity_macro(enum)
> >      writer.newline()
> >      if describe:
> >          writer.writeln("{ 0, NULL }")

Frediano