Marc-André Lureau <marcandre.lur...@redhat.com> writes:
> Add helpers to wrap generated code with #if/#endif lines.
>
> Add a function decorator that will be used to wrap visitor methods.
> The decorator will check if code was generated before adding #if/#endif
> lines. Used in the following patches.
>
> Signed-off-by: Marc-André Lureau <marcandre.lur...@redhat.com>
> ---
> scripts/qapi.py | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 55 insertions(+)
>
> diff --git a/scripts/qapi.py b/scripts/qapi.py
> index 2a8e60e975..94b735d8d6 100644
> --- a/scripts/qapi.py
> +++ b/scripts/qapi.py
> @@ -1897,6 +1897,61 @@ def guardend(name):
> name=guardname(name))
>
>
> +def gen_if(ifcond):
> + if not ifcond:
> + return ''
> + if isinstance(ifcond, str):
> + ifcond = [ifcond]
Perhaps we should take this normalization step in the QAPISchema
constructors.
> + ret = ''
> + for ifc in ifcond:
> + ret += mcgen('''
> +#if %(cond)s
> +''', cond=ifc)
> + return ret
> +
> +
> +def gen_endif(ifcond):
> + if not ifcond:
> + return ''
> + if isinstance(ifcond, str):
> + ifcond = [ifcond]
> + ret = ''
> + for ifc in reversed(ifcond):
> + ret += mcgen('''
> +#endif /* %(cond)s */
> +''', cond=ifc)
> + return ret
> +
> +
> +# Wrap a method to add #if / #endif to generated code, only if some
> +# code was generated. The method must have an 'ifcond' argument.
> +# self must have 'if_members' listing the attributes to wrap.
> +def ifcond_decorator(func):
> +
> + def func_wrapper(self, *args, **kwargs):
> + import inspect
Is hiding imports in function a good idea?
> + idx = inspect.getargspec(func).args.index('ifcond')
> + ifcond = args[idx - 1]
> + save = {}
> + for mem in self.if_members:
> + save[mem] = getattr(self, mem)
> + func(self, *args, **kwargs)
> + for mem, val in save.items():
> + newval = getattr(self, mem)
> + if newval != val:
> + assert newval.startswith(val)
> + newval = newval[len(val):]
> + if newval[0] == '\n':
> + val += '\n'
> + newval = newval[1:]
> + val += gen_if(ifcond)
> + val += newval
> + val += gen_endif(ifcond)
> + setattr(self, mem, val)
> +
> + return func_wrapper
> +
> +
> def gen_enum_lookup(name, values, prefix=None):
> ret = mcgen('''
My gut feeling is still "too clever by half", but i'm reserving
judgement until after review of its use, and exploration of
alternatives.
