def callable_info(cls, f):
'''Info about a callable.
The results are cached for efficiency.
:param f:
:type f: callable
:rtype: frozendict
'''
if not callable(f):
return None
if isinstance(f, FunctionType):
# in case of ensure_va_kwa
try:
f = f.wrapped_func
except AttributeError:
pass
cache_key = callable_cache_key(f)
try:
return cls._info_cache[cache_key]
except KeyError:
pass
is_method, args, varargs, varkw, defaults = cls.getargspec(f)
_args = []
args_len = len(args)
defaults_len = 0
if defaults is not None:
defaults_len = len(defaults)
for i,n in enumerate(args):
default_index = i-(args_len-defaults_len)
v = Undefined
if default_index > -1:
v = defaults[default_index]
_args.append((n, v))
info = frozendict({
'name':f.func_name,
'args':tuple(_args),
'varargs':bool(varargs),
'varkw':bool(varkw),
'method':is_method
})
cls._info_cache[cache_key] = info
return info
def ensure_va_kwa(cls, f, parent=None):
'''Ensures `f` accepts both ``*varargs`` and ``**kwargs``.
If `f` does not support ``*args``, it will be wrapped with a
function which cuts away extra arguments in ``*args``.
If `f` does not support ``*args``, it will be wrapped with a
function which discards the ``**kwargs``.
:param f:
:type f: callable
:param parent: The parent on which `f` is defined. If specified, we will perform
``parent.<name of f> = wrapper`` in the case we needed to wrap `f`.
:type parent: object
:returns: A callable which is guaranteed to accept both ``*args`` and ``**kwargs``.
:rtype: callable
'''
is_method, args, varargs, varkw, defaults = cls.getargspec(f)
va_kwa_wrapper = None
if varargs is None and varkw is None:
if args:
def va_kwa_wrapper(*va, **kw):
kws = kw.copy()
for k in kw:
if k not in args:
del kws[k]
return f(*va[:len(args)], **kws)
else:
def va_kwa_wrapper(*va, **kw):
return f()
elif varargs is None:
if args:
def va_kwa_wrapper(*va, **kw):
return f(*va[:len(args)], **kw)
else:
def va_kwa_wrapper(*va, **kw):
return f(**kw)
elif varkw is None:
if args:
def va_kwa_wrapper(*va, **kw):
kws = kw.copy()
for k in kw:
if k not in args:
del kws[k]
return f(*va, **kw)
else:
def va_kwa_wrapper(*va, **kw):
return f(*va)
if va_kwa_wrapper:
va_kwa_wrapper.info = frozendict(cls.callable_info(f).update({
'varargs': True,
'varkw': True
}))
cls._info_cache[callable_cache_key(f)] = va_kwa_wrapper.info
va_kwa_wrapper.wrapped_func = f
va_kwa_wrapper.im_func = f
va_kwa_wrapper.__name__ = f.__name__
try:
va_kwa_wrapper.im_class = f.im_class
except AttributeError:
pass
for k in dir(f):
if k[0] != '_' or k in ('__name__'):
setattr(va_kwa_wrapper, k, getattr(f, k))
if parent is not None:
setattr(parent, info['name'], va_kwa_wrapper)
return va_kwa_wrapper
return f
