########################## LICENCE ###############################
# Copyright (c) 2005-2012, Michele Simionato
# All rights reserved.
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
# 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.
"""
__version__ = '3.4.0'
__all__ = ["decorator", "FunctionMaker", "contextmanager"]
import sys, re, inspect
if sys.version >= '3':
from inspect import getfullargspec
def get_init(cls):
return cls.__init__
else:
class getfullargspec(object):
"A quick and dirty replacement for getfullargspec for Python 2.X"
def __init__(self, f):
self.args, self.varargs, self.varkw, self.defaults = \
inspect.getargspec(f)
self.kwonlyargs = []
self.kwonlydefaults = None
def __iter__(self):
yield self.args
yield self.varargs
yield self.varkw
yield self.defaults
def get_init(cls):
return cls.__init__.im_func
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):
self.shortsignature = signature
if func:
# func can 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):
argspec = getfullargspec(func)
self.annotations = getattr(func, '__annotations__', {})
for a in ('args', 'varargs', 'varkw', 'defaults', 'kwonlyargs',
'kwonlydefaults'):
setattr(self, a, getattr(argspec, a))
for i, arg in enumerate(self.args):
setattr(self, 'arg%d' % i, arg)
if sys.version < '3': # easy way
self.shortsignature = self.signature = \
inspect.formatargspec(
formatvalue=lambda val: "", *argspec)[1:-1]
else: # Python 3 way
allargs = list(self.args)
allshortargs = list(self.args)
if self.varargs:
allargs.append('*' + self.varargs)
allshortargs.append('*' + self.varargs)
elif self.kwonlyargs:
allargs.append('*') # single star syntax
for a in self.kwonlyargs:
allargs.append('%s=None' % a)
allshortargs.append('%s=%s' % (a, a))
if self.varkw:
allargs.append('**' + self.varkw)
allshortargs.append('**' + self.varkw)
self.signature = ', '.join(allargs)
self.shortsignature = ', '.join(allshortargs)
self.dict = func.__dict__.copy()
# func=None happens when decorating a caller
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.func_defaults = getattr(self, 'defaults', ())
func.__kwdefaults__ = getattr(self, 'kwonlydefaults', None)
func.__annotations__ = getattr(self, 'annotations', None)
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
names = set([name] + [arg.strip(' *') for arg in
self.shortsignature.split(',')])
for n in names:
if n in ('_func_', '_call_'):
raise NameError('%s is overridden in\n%s' % (n, src))
if not src.endswith('\n'): # add a newline just for safety
src += '\n' # this is needed in old versions of Python
try:
code = compile(src, '<string>', 'single')
# print >> sys.stderr, 'Compiling %s' % src
exec code in evaldict
except:
print >> sys.stderr, 'Error in generated code:'
print >> sys.stderr, src
raise
func = evaldict[name]
if addsource:
attrs['__source__'] = src
self.update(func, **attrs)
return func
@classmethod
def create(cls, obj, body, evaldict, defaults=None,
doc=None, module=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] #strip a right parens
func = None
else: # a function
name = None
signature = None
func = obj
self = cls(func, name, signature, defaults, doc, module)
ibody = '\n'.join(' ' + line for line in body.splitlines())
return self.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
evaldict = func.func_globals.copy()
evaldict['_call_'] = caller
evaldict['_func_'] = func
return FunctionMaker.create(
func, "return _call_(_func_, %(shortsignature)s)",
evaldict, undecorated=func, __wrapped__=func)
else: # returns a decorator
if inspect.isclass(caller):
name = caller.__name__.lower()
callerfunc = get_init(caller)
doc = 'decorator(%s) converts functions/generators into ' \
'factories of %s objects' % (caller.__name__, caller.__name__)
fun = getfullargspec(callerfunc).args[1] # second arg
elif inspect.isfunction(caller):
name = '_lambda_' if caller.__name__ == '<lambda>' \
else caller.__name__
callerfunc = caller
doc = caller.__doc__
fun = getfullargspec(callerfunc).args[0] # first arg
else: # assume caller is an object with a __call__ method
name = caller.__class__.__name__.lower()
callerfunc = caller.__call__.im_func
doc = caller.__call__.__doc__
fun = getfullargspec(callerfunc).args[1] # second arg
evaldict = callerfunc.func_globals.copy()
evaldict['_call_'] = caller
evaldict['decorator'] = decorator
return FunctionMaker.create(
'%s(%s)' % (name, fun),
'return decorator(_call_, %s)' % fun,
evaldict, undecorated=caller, __wrapped__=caller,
doc=doc, module=caller.__module__)
######################### contextmanager ########################
def __call__(self, func):
'Context manager decorator'
return FunctionMaker.create(
func, "with _self_: return _func_(%(shortsignature)s)",
dict(_self_=self, _func_=func), __wrapped__=func)
try: # Python >= 3.2
from contextlib import _GeneratorContextManager
ContextManager = type(
'ContextManager', (_GeneratorContextManager,), dict(__call__=__call__))
except ImportError: # Python >= 2.5
from contextlib import GeneratorContextManager
def __init__(self, f, *a, **k):
return GeneratorContextManager.__init__(self, f(*a, **k))
ContextManager = type(
'ContextManager', (GeneratorContextManager,),
dict(__call__=__call__, __init__=__init__))
contextmanager = decorator(ContextManager)