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import inspect
class DecoratableObject(object):
MODE_OVERRIDE = 0
MODE_PARAMS = 1
MODE_RESULT = 2
def __init__(self, fn, is_method=False):
self._callable = fn
self.is_method = is_method
self._params_decoration = None
self._result_decoration = None
def _decorate(self, fn, mode, **kwargs):
if mode == self.MODE_OVERRIDE:
self._decorate_full(fn, **kwargs)
elif mode == self.MODE_PARAMS:
self._decorate_params(fn)
elif mode == self.MODE_RESULT:
self._decorate_result(fn, **kwargs)
def _decorate_full(self, fn, needs_origin=True):
origin = self._callable
if needs_origin:
if self.is_method:
self._callable = lambda inst, *args, **kwargs: fn(inst, origin, *args, **kwargs)
else:
self._callable = lambda *args, **kwargs: fn(origin, *args, **kwargs)
else:
self._callable = fn
def _decorate_params(self, fn):
if not self._params_decoration:
self._params_decoration = []
self._params_decoration.append(fn)
def _decorate_result(self, fn, needs_params=False):
if not self._result_decoration:
self._result_decoration = []
fn._needs_params = needs_params
self._result_decoration.append(fn)
def __call__(self, *args, **kwargs):
if self._params_decoration:
for dec in self._params_decoration:
try:
args, kwargs = dec(*args, **kwargs)
except ReturnImediatelyException, e:
return e.ret
res = self._callable(*args, **kwargs)
if self._result_decoration:
for dec in self._result_decoration:
if dec._needs_params:
res = dec(res, *args, **kwargs)
else:
res = dec(res)
return res
class ReturnImediatelyException(Exception):
def __init__(self, ret):
super(Exception, self).__init__()
self.ret = ret
def _check_decoratable(origin, install=True):
if not hasattr(origin, '_decoratable_obj'):
if inspect.ismethod(origin) and not hasattr(origin, '_decoratable_obj'):
decoratable = DecoratableObject(origin)
def decoratable_method(self, *args, **kwargs):
return decoratable(self, *args, **kwargs)
decoratable_method._decoratable_obj = decoratable
def decoratable_decorate(fn, mode, **kwargs):
decoratable._decorate(fn, mode, **kwargs)
decoratable_method._decorate = decoratable_decorate
if install:
setattr(origin.im_class, origin.__name__, decoratable_method)
return decoratable_method
elif inspect.isfunction(origin):
decoratable = DecoratableObject(origin)
def decorated(*args, **kwargs):
return decoratable(*args, **kwargs)
decorated._decoratable_obj = decoratable
if install:
setattr(inspect.getmodule(origin), origin.__name__, decorated)
decorated.__name__ = origin.__name__
decorated.__module__ = origin.__module__
return decorated
return origin
def decorate(origin, needs_origin=True):
origin = _check_decoratable(origin)
def decorator(fn):
origin._decoratable_obj._decorate(fn, DecoratableObject.MODE_OVERRIDE, needs_origin=needs_origin)
return decorator
def _decorate_params(origin):
origin = _check_decoratable(origin)
def decorator(fn):
origin._decoratable_obj._decorate(fn, DecoratableObject.MODE_PARAMS)
return decorator
decorate.params = _decorate_params
def _decorate_result(origin, needs_params=False):
origin = _check_decoratable(origin)
def decorator(fn):
origin._decoratable_obj._decorate(fn, DecoratableObject.MODE_RESULT, needs_params=needs_params)
return decorator
decorate.result = _decorate_result
def _decorate_with(fn):
def decorator(origin):
origin = _check_decoratable(origin)
origin._decoratable_obj._decorate(fn, DecoratableObject.MODE_OVERRIDE, needs_origin=True)
return origin
return decorator
decorate.withfn = _decorate_with
def _decorate_result_with(fn, needs_params=False):
def decorator(origin):
origin = _check_decoratable(origin)
origin._decoratable_obj._decorate(fn, DecoratableObject.MODE_RESULT, needs_params=needs_params)
return origin
return decorator
decorate.result.withfn = _decorate_result_with
def _decorate_params_with(fn):
def decorator(origin):
origin = _check_decoratable(origin)
origin._decoratable_obj._decorate(fn, DecoratableObject.MODE_PARAMS)
return origin
return decorator
decorate.params.withfn = _decorate_params_with