# ######################### LICENSE ############################ #
# Copyright (c) 2005-2021, Michele Simionato
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# modification, are permitted provided that the following conditions are
# met:
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# 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
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
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# USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
# DAMAGE.
"""
Decorator module, see
https://github.com/micheles/decorator/blob/master/docs/documentation.md
for the documentation.
"""
import re
import sys
import inspect
import operator
import itertools
from contextlib import _GeneratorContextManager
from inspect import getfullargspec, iscoroutinefunction, isgeneratorfunction
__version__ = '5.1.1'
DEF = re.compile(r'\s*def\s*([_\w][_\w\d]*)\s*\(')
POS = inspect.Parameter.POSITIONAL_OR_KEYWORD
EMPTY = inspect.Parameter.empty
# this is not used anymore in the core, but kept for backward compatibility
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.
"""
# Atomic get-and-increment provided by the GIL
_compile_count = itertools.count()
# make pylint happy
args = varargs = varkw = defaults = kwonlyargs = kwonlydefaults = ()
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.isroutine(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)
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.__defaults__ = self.defaults
func.__kwdefaults__ = self.kwonlydefaults or None
func.__annotations__ = getattr(self, 'annotations', None)
try:
frame = sys._getframe(3)
except AttributeError: # for IronPython and similar implementations
callermodule = '?'
else:
callermodule = frame.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.search(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 for old Pythons
src += '\n'
# Ensure each generated function has a unique filename for profilers
# (such as cProfile) that depend on the tuple of (<filename>,
# <definition line>, <function name>) being unique.
filename = '<decorator-gen-%d>' % next(self._compile_count)
try:
code = compile(src, filename, 'single')
exec(code, evaldict)
except Exception:
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,
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())
caller = evaldict.get('_call_') # when called from `decorate`
if caller and iscoroutinefunction(caller):
body = ('async def %(name)s(%(signature)s):\n' + ibody).replace(
'return', 'return await')
else:
body = 'def %(name)s(%(signature)s):\n' + ibody
return self.make(body, evaldict, addsource, **attrs)
def fix(args, kwargs, sig):
"""
Fix args and kwargs to be consistent with the signature
"""
ba = sig.bind(*args, **kwargs)
ba.apply_defaults() # needed for test_dan_schult
return ba.args, ba.kwargs
def decorate(func, caller, extras=(), kwsyntax=False):
"""
Decorates a function/generator/coroutine using a caller.
If kwsyntax is True calling the decorated functions with keyword
syntax will pass the named arguments inside the ``kw`` dictionary,
even if such argument are positional, similarly to what functools.wraps
does. By default kwsyntax is False and the the arguments are untouched.
"""
sig = inspect.signature(func)
if iscoroutinefunction(caller):
async def fun(*args, **kw):
if not kwsyntax:
args, kw = fix(args, kw, sig)
return await caller(func, *(extras + args), **kw)
elif isgeneratorfunction(caller):
def fun(*args, **kw):
if not kwsyntax:
args, kw = fix(args, kw, sig)
for res in caller(func, *(extras + args), **kw):
yield res
else:
def fun(*args, **kw):
if not kwsyntax:
args, kw = fix(args, kw, sig)
return caller(func, *(extras + args), **kw)
fun.__name__ = func.__name__
fun.__doc__ = func.__doc__
fun.__wrapped__ = func
fun.__signature__ = sig
fun.__qualname__ = func.__qualname__
# builtin functions like defaultdict.__setitem__ lack many attributes
try:
fun.__defaults__ = func.__defaults__
except AttributeError:
pass
try:
fun.__kwdefaults__ = func.__kwdefaults__
except AttributeError:
pass
try:
fun.__annotations__ = func.__annotations__
except AttributeError:
pass
try:
fun.__module__ = func.__module__
except AttributeError:
pass
try:
fun.__dict__.update(func.__dict__)
except AttributeError:
pass
return fun
def decoratorx(caller):
"""
A version of "decorator" implemented via "exec" and not via the
Signature object. Use this if you are want to preserve the `.__code__`
object properties (https://github.com/micheles/decorator/issues/129).
"""
def dec(func):
return FunctionMaker.create(
func,
"return _call_(_func_, %(shortsignature)s)",
dict(_call_=caller, _func_=func),
__wrapped__=func, __qualname__=func.__qualname__)
return dec
def decorator(caller, _func=None, kwsyntax=False):
"""
decorator(caller) converts a caller function into a decorator
"""
if _func is not None: # return a decorated function
# this is obsolete behavior; you should use decorate instead
return decorate(_func, caller, (), kwsyntax)
# else return a decorator function
sig = inspect.signature(caller)
dec_params = [p for p in sig.parameters.values() if p.kind is POS]
def dec(func=None, *args, **kw):
na = len(args) + 1
extras = args + tuple(kw.get(p.name, p.default)
for p in dec_params[na:]
if p.default is not EMPTY)
if func is None:
return lambda func: decorate(func, caller, extras, kwsyntax)
else:
return decorate(func, caller, extras, kwsyntax)
dec.__signature__ = sig.replace(parameters=dec_params)
dec.__name__ = caller.__name__
dec.__doc__ = caller.__doc__
dec.__wrapped__ = caller
dec.__qualname__ = caller.__qualname__
dec.__kwdefaults__ = getattr(caller, '__kwdefaults__', None)
dec.__dict__.update(caller.__dict__)
return dec
# ####################### contextmanager ####################### #
class ContextManager(_GeneratorContextManager):
def __init__(self, g, *a, **k):
_GeneratorContextManager.__init__(self, g, a, k)
def __call__(self, func):
def caller(f, *a, **k):
with self.__class__(self.func, *self.args, **self.kwds):
return f(*a, **k)
return decorate(func, caller)
_contextmanager = decorator(ContextManager)
def contextmanager(func):
# Enable Pylint config: contextmanager-decorators=decorator.contextmanager
return _contextmanager(func)
# ############################ dispatch_on ############################ #
def append(a, vancestors):
"""
Append ``a`` to the list of the virtual ancestors, unless it is already
included.
"""
add = True
for j, va in enumerate(vancestors):
if issubclass(va, a):
add = False
break
if issubclass(a, va):
vancestors[j] = a
add = False
if add:
vancestors.append(a)
# inspired from simplegeneric by P.J. Eby and functools.singledispatch
def dispatch_on(*dispatch_args):
"""
Factory of decorators turning a function into a generic function
dispatching on the given arguments.
"""
assert dispatch_args, 'No dispatch args passed'
dispatch_str = '(%s,)' % ', '.join(dispatch_args)
def check(arguments, wrong=operator.ne, msg=''):
"""Make sure one passes the expected number of arguments"""
if wrong(len(arguments), len(dispatch_args)):
raise TypeError('Expected %d arguments, got %d%s' %
(len(dispatch_args), len(arguments), msg))
def gen_func_dec(func):
"""Decorator turning a function into a generic function"""
# first check the dispatch arguments
argset = set(getfullargspec(func).args)
if not set(dispatch_args) <= argset:
raise NameError('Unknown dispatch arguments %s' % dispatch_str)
typemap = {}
def vancestors(*types):
"""
Get a list of sets of virtual ancestors for the given types
"""
check(types)
ras = [[] for _ in range(len(dispatch_args))]
for types_ in typemap:
for t, type_, ra in zip(types, types_, ras):
if issubclass(t, type_) and type_ not in t.mro():
append(type_, ra)
return [set(ra) for ra in ras]
def ancestors(*types):
"""
Get a list of virtual MROs, one for each type
"""
check(types)
lists = []
for t, vas in zip(types, vancestors(*types)):
n_vas = len(vas)
if n_vas > 1:
raise RuntimeError(
'Ambiguous dispatch for %s: %s' % (t, vas))
elif n_vas == 1:
va, = vas
mro = type('t', (t, va), {}).mro()[1:]
else:
mro = t.mro()
lists.append(mro[:-1]) # discard t and object
return lists
def register(*types):
"""
Decorator to register an implementation for the given types
"""
check(types)
def dec(f):
check(getfullargspec(f).args, operator.lt, ' in ' + f.__name__)
typemap[types] = f
return f
return dec
def dispatch_info(*types):
"""
An utility to introspect the dispatch algorithm
"""
check(types)
lst = []
for anc in itertools.product(*ancestors(*types)):
lst.append(tuple(a.__name__ for a in anc))
return lst
def _dispatch(dispatch_args, *args, **kw):
types = tuple(type(arg) for arg in dispatch_args)
try: # fast path
f = typemap[types]
except KeyError:
pass
else:
return f(*args, **kw)
combinations = itertools.product(*ancestors(*types))
next(combinations) # the first one has been already tried
for types_ in combinations:
f = typemap.get(types_)
if f is not None:
return f(*args, **kw)
# else call the default implementation
return func(*args, **kw)
return FunctionMaker.create(
func, 'return _f_(%s, %%(shortsignature)s)' % dispatch_str,
dict(_f_=_dispatch), register=register, default=func,
typemap=typemap, vancestors=vancestors, ancestors=ancestors,
dispatch_info=dispatch_info, __wrapped__=func)
gen_func_dec.__name__ = 'dispatch_on' + dispatch_str
return gen_func_dec