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########################## LICENCE ###############################
##
## Copyright (c) 2005, Michele Simionato
## All rights reserved.
##
## Redistributions of source code must retain the above copyright
## notice, this list of conditions and the following disclaimer.
## Redistributions in bytecode form must reproduce the above copyright
## notice, this list of conditions and the following disclaimer in
## the documentation and/or other materials provided with the
## distribution.
## THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
## "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
## LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
## A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
## HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
## INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
## BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
## OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
## ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
## TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
## USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
## DAMAGE.
"""
Decorator module, see http://pypi.python.org/pypi/decorator
for the documentation.
"""
from __future__ import print_function
__all__ = [
"decorator",
"FunctionMaker",
"partial",
"deprecated",
"getinfo",
"new_wrapper",
]
import os, sys, re, inspect, warnings
try:
from functools import partial
except ImportError: # for Python version < 2.5
class partial(object):
"A simple replacement of functools.partial"
def __init__(self, func, *args, **kw):
self.func = func
self.args = args
self.keywords = kw
def __call__(self, *otherargs, **otherkw):
kw = self.keywords.copy()
kw.update(otherkw)
return self.func(*(self.args + otherargs), **kw)
DEF = re.compile("\s*def\s*([_\w][_\w\d]*)\s*\(")
# basic functionality
class FunctionMaker(object):
"""
An object with the ability to create functions with a given signature.
It has attributes name, doc, module, signature, defaults, dict and
methods update and make.
"""
def __init__(
self,
func=None,
name=None,
signature=None,
defaults=None,
doc=None,
module=None,
funcdict=None,
):
if func:
# func can also be a class or a callable, but not an instance method
self.name = func.__name__
if self.name == "<lambda>": # small hack for lambda functions
self.name = "_lambda_"
self.doc = func.__doc__
self.module = func.__module__
if inspect.isfunction(func):
self.signature = inspect.formatargspec(
formatvalue=lambda val: "", *inspect.getargspec(func)
)[1:-1]
self.defaults = func.__defaults__
self.dict = func.__dict__.copy()
if name:
self.name = name
if signature is not None:
self.signature = signature
if defaults:
self.defaults = defaults
if doc:
self.doc = doc
if module:
self.module = module
if funcdict:
self.dict = funcdict
# check existence required attributes
assert hasattr(self, "name")
if not hasattr(self, "signature"):
raise TypeError("You are decorating a non function: %s" % func)
def update(self, func, **kw):
"Update the signature of func with the data in self"
func.__name__ = self.name
func.__doc__ = getattr(self, "doc", None)
func.__dict__ = getattr(self, "dict", {})
func.__defaults__ = getattr(self, "defaults", ())
callermodule = sys._getframe(3).f_globals.get("__name__", "?")
func.__module__ = getattr(self, "module", callermodule)
func.__dict__.update(kw)
def make(self, src_templ, evaldict=None, addsource=False, **attrs):
"Make a new function from a given template and update the signature"
src = src_templ % vars(self) # expand name and signature
evaldict = evaldict or {}
mo = DEF.match(src)
if mo is None:
raise SyntaxError("not a valid function template\n%s" % src)
name = mo.group(1) # extract the function name
reserved_names = set(
[name] + [arg.strip(" *") for arg in self.signature.split(",")]
)
for n, v in evaldict.items():
if n in reserved_names:
raise NameError("%s is overridden in\n%s" % (n, src))
if not src.endswith("\n"): # add a newline just for safety
src += "\n"
try:
code = compile(src, "<string>", "single")
exec(code, evaldict)
except:
print("Error in generated code:", file=sys.stderr)
print(src, file=sys.stderr)
raise
func = evaldict[name]
if addsource:
attrs["__source__"] = src
self.update(func, **attrs)
return func
@classmethod
def create(cls, obj, body, evaldict, defaults=None, addsource=True, **attrs):
"""
Create a function from the strings name, signature and body.
evaldict is the evaluation dictionary. If addsource is true an attribute
__source__ is added to the result. The attributes attrs are added,
if any.
"""
if isinstance(obj, str): # "name(signature)"
name, rest = obj.strip().split("(", 1)
signature = rest[:-1]
func = None
else: # a function
name = None
signature = None
func = obj
fun = cls(func, name, signature, defaults)
ibody = "\n".join(" " + line for line in body.splitlines())
return fun.make(
"def %(name)s(%(signature)s):\n" + ibody, evaldict, addsource, **attrs
)
def decorator(caller, func=None):
"""
decorator(caller) converts a caller function into a decorator;
decorator(caller, func) decorates a function using a caller.
"""
if func is not None: # returns a decorated function
return FunctionMaker.create(
func,
"return _call_(_func_, %(signature)s)",
dict(_call_=caller, _func_=func),
undecorated=func,
)
else: # returns a decorator
if isinstance(caller, partial):
return partial(decorator, caller)
# otherwise assume caller is a function
f = inspect.getargspec(caller)[0][0] # first arg
return FunctionMaker.create(
"%s(%s)" % (caller.__name__, f),
"return decorator(_call_, %s)" % f,
dict(_call_=caller, decorator=decorator),
undecorated=caller,
)
###################### deprecated functionality #########################
@decorator
def deprecated(func, *args, **kw):
"A decorator for deprecated functions"
warnings.warn(
(
"Calling the deprecated function %r\n"
"Downgrade to decorator 2.3 if you want to use this functionality"
)
% func.__name__,
DeprecationWarning,
stacklevel=3,
)
return func(*args, **kw)
@deprecated
def getinfo(func):
"""
Returns an info dictionary containing:
- name (the name of the function : str)
- argnames (the names of the arguments : list)
- defaults (the values of the default arguments : tuple)
- signature (the signature : str)
- doc (the docstring : str)
- module (the module name : str)
- dict (the function __dict__ : str)
>>> def f(self, x=1, y=2, *args, **kw): pass
>>> info = getinfo(f)
>>> info["name"]
'f'
>>> info["argnames"]
['self', 'x', 'y', 'args', 'kw']
>>> info["defaults"]
(1, 2)
>>> info["signature"]
'self, x, y, *args, **kw'
"""
assert inspect.ismethod(func) or inspect.isfunction(func)
regargs, varargs, varkwargs, defaults = inspect.getargspec(func)
argnames = list(regargs)
if varargs:
argnames.append(varargs)
if varkwargs:
argnames.append(varkwargs)
signature = inspect.formatargspec(
regargs, varargs, varkwargs, defaults, formatvalue=lambda value: ""
)[1:-1]
return dict(
name=func.__name__,
argnames=argnames,
signature=signature,
defaults=func.__defaults__,
doc=func.__doc__,
module=func.__module__,
dict=func.__dict__,
globals=func.__globals__,
closure=func.__closure__,
)
@deprecated
def update_wrapper(wrapper, model, infodict=None):
"A replacement for functools.update_wrapper"
infodict = infodict or getinfo(model)
wrapper.__name__ = infodict["name"]
wrapper.__doc__ = infodict["doc"]
wrapper.__module__ = infodict["module"]
wrapper.__dict__.update(infodict["dict"])
wrapper.__defaults__ = infodict["defaults"]
wrapper.undecorated = model
return wrapper
@deprecated
def new_wrapper(wrapper, model):
"""
An improvement over functools.update_wrapper. The wrapper is a generic
callable object. It works by generating a copy of the wrapper with the
right signature and by updating the copy, not the original.
Moreovoer, 'model' can be a dictionary with keys 'name', 'doc', 'module',
'dict', 'defaults'.
"""
if isinstance(model, dict):
infodict = model
else: # assume model is a function
infodict = getinfo(model)
assert (
not "_wrapper_" in infodict["argnames"]
), '"_wrapper_" is a reserved argument name!'
src = "lambda %(signature)s: _wrapper_(%(signature)s)" % infodict
funcopy = eval(src, dict(_wrapper_=wrapper))
return update_wrapper(funcopy, model, infodict)