452 lines
16 KiB
Python
452 lines
16 KiB
Python
# ######################### LICENSE ############################ #
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# Copyright (c) 2005-2021, Michele Simionato
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# All rights reserved.
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# Redistribution and use in source and binary forms, with or without
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# modification, are permitted provided that the following conditions are
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# met:
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# Redistributions of source code must retain the above copyright
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# notice, this list of conditions and the following disclaimer.
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# Redistributions in bytecode form must reproduce the above copyright
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# notice, this list of conditions and the following disclaimer in
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# the documentation and/or other materials provided with the
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# distribution.
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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# HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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# OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
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# TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
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# USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
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# DAMAGE.
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"""
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Decorator module, see
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https://github.com/micheles/decorator/blob/master/docs/documentation.md
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for the documentation.
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"""
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import re
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import sys
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import inspect
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import operator
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import itertools
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from contextlib import _GeneratorContextManager
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from inspect import getfullargspec, iscoroutinefunction, isgeneratorfunction
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__version__ = '5.1.1'
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DEF = re.compile(r'\s*def\s*([_\w][_\w\d]*)\s*\(')
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POS = inspect.Parameter.POSITIONAL_OR_KEYWORD
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EMPTY = inspect.Parameter.empty
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# this is not used anymore in the core, but kept for backward compatibility
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class FunctionMaker(object):
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"""
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An object with the ability to create functions with a given signature.
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It has attributes name, doc, module, signature, defaults, dict and
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methods update and make.
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"""
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# Atomic get-and-increment provided by the GIL
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_compile_count = itertools.count()
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# make pylint happy
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args = varargs = varkw = defaults = kwonlyargs = kwonlydefaults = ()
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def __init__(self, func=None, name=None, signature=None,
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defaults=None, doc=None, module=None, funcdict=None):
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self.shortsignature = signature
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if func:
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# func can be a class or a callable, but not an instance method
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self.name = func.__name__
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if self.name == '<lambda>': # small hack for lambda functions
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self.name = '_lambda_'
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self.doc = func.__doc__
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self.module = func.__module__
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if inspect.isroutine(func):
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argspec = getfullargspec(func)
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self.annotations = getattr(func, '__annotations__', {})
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for a in ('args', 'varargs', 'varkw', 'defaults', 'kwonlyargs',
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'kwonlydefaults'):
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setattr(self, a, getattr(argspec, a))
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for i, arg in enumerate(self.args):
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setattr(self, 'arg%d' % i, arg)
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allargs = list(self.args)
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allshortargs = list(self.args)
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if self.varargs:
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allargs.append('*' + self.varargs)
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allshortargs.append('*' + self.varargs)
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elif self.kwonlyargs:
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allargs.append('*') # single star syntax
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for a in self.kwonlyargs:
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allargs.append('%s=None' % a)
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allshortargs.append('%s=%s' % (a, a))
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if self.varkw:
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allargs.append('**' + self.varkw)
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allshortargs.append('**' + self.varkw)
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self.signature = ', '.join(allargs)
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self.shortsignature = ', '.join(allshortargs)
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self.dict = func.__dict__.copy()
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# func=None happens when decorating a caller
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if name:
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self.name = name
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if signature is not None:
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self.signature = signature
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if defaults:
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self.defaults = defaults
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if doc:
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self.doc = doc
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if module:
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self.module = module
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if funcdict:
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self.dict = funcdict
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# check existence required attributes
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assert hasattr(self, 'name')
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if not hasattr(self, 'signature'):
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raise TypeError('You are decorating a non function: %s' % func)
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def update(self, func, **kw):
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"""
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Update the signature of func with the data in self
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"""
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func.__name__ = self.name
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func.__doc__ = getattr(self, 'doc', None)
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func.__dict__ = getattr(self, 'dict', {})
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func.__defaults__ = self.defaults
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func.__kwdefaults__ = self.kwonlydefaults or None
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func.__annotations__ = getattr(self, 'annotations', None)
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try:
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frame = sys._getframe(3)
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except AttributeError: # for IronPython and similar implementations
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callermodule = '?'
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else:
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callermodule = frame.f_globals.get('__name__', '?')
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func.__module__ = getattr(self, 'module', callermodule)
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func.__dict__.update(kw)
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def make(self, src_templ, evaldict=None, addsource=False, **attrs):
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"""
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Make a new function from a given template and update the signature
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"""
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src = src_templ % vars(self) # expand name and signature
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evaldict = evaldict or {}
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mo = DEF.search(src)
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if mo is None:
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raise SyntaxError('not a valid function template\n%s' % src)
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name = mo.group(1) # extract the function name
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names = set([name] + [arg.strip(' *') for arg in
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self.shortsignature.split(',')])
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for n in names:
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if n in ('_func_', '_call_'):
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raise NameError('%s is overridden in\n%s' % (n, src))
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if not src.endswith('\n'): # add a newline for old Pythons
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src += '\n'
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# Ensure each generated function has a unique filename for profilers
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# (such as cProfile) that depend on the tuple of (<filename>,
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# <definition line>, <function name>) being unique.
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filename = '<decorator-gen-%d>' % next(self._compile_count)
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try:
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code = compile(src, filename, 'single')
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exec(code, evaldict)
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except Exception:
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print('Error in generated code:', file=sys.stderr)
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print(src, file=sys.stderr)
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raise
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func = evaldict[name]
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if addsource:
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attrs['__source__'] = src
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self.update(func, **attrs)
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return func
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@classmethod
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def create(cls, obj, body, evaldict, defaults=None,
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doc=None, module=None, addsource=True, **attrs):
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"""
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Create a function from the strings name, signature and body.
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evaldict is the evaluation dictionary. If addsource is true an
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attribute __source__ is added to the result. The attributes attrs
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are added, if any.
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"""
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if isinstance(obj, str): # "name(signature)"
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name, rest = obj.strip().split('(', 1)
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signature = rest[:-1] # strip a right parens
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func = None
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else: # a function
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name = None
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signature = None
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func = obj
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self = cls(func, name, signature, defaults, doc, module)
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ibody = '\n'.join(' ' + line for line in body.splitlines())
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caller = evaldict.get('_call_') # when called from `decorate`
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if caller and iscoroutinefunction(caller):
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body = ('async def %(name)s(%(signature)s):\n' + ibody).replace(
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'return', 'return await')
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else:
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body = 'def %(name)s(%(signature)s):\n' + ibody
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return self.make(body, evaldict, addsource, **attrs)
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def fix(args, kwargs, sig):
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"""
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Fix args and kwargs to be consistent with the signature
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"""
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ba = sig.bind(*args, **kwargs)
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ba.apply_defaults() # needed for test_dan_schult
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return ba.args, ba.kwargs
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def decorate(func, caller, extras=(), kwsyntax=False):
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"""
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Decorates a function/generator/coroutine using a caller.
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If kwsyntax is True calling the decorated functions with keyword
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syntax will pass the named arguments inside the ``kw`` dictionary,
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even if such argument are positional, similarly to what functools.wraps
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does. By default kwsyntax is False and the the arguments are untouched.
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"""
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sig = inspect.signature(func)
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if iscoroutinefunction(caller):
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async def fun(*args, **kw):
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if not kwsyntax:
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args, kw = fix(args, kw, sig)
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return await caller(func, *(extras + args), **kw)
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elif isgeneratorfunction(caller):
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def fun(*args, **kw):
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if not kwsyntax:
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args, kw = fix(args, kw, sig)
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for res in caller(func, *(extras + args), **kw):
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yield res
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else:
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def fun(*args, **kw):
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if not kwsyntax:
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args, kw = fix(args, kw, sig)
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return caller(func, *(extras + args), **kw)
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fun.__name__ = func.__name__
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fun.__doc__ = func.__doc__
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fun.__wrapped__ = func
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fun.__signature__ = sig
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fun.__qualname__ = func.__qualname__
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# builtin functions like defaultdict.__setitem__ lack many attributes
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try:
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fun.__defaults__ = func.__defaults__
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except AttributeError:
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pass
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try:
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fun.__kwdefaults__ = func.__kwdefaults__
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except AttributeError:
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pass
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try:
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fun.__annotations__ = func.__annotations__
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except AttributeError:
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pass
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try:
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fun.__module__ = func.__module__
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except AttributeError:
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pass
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try:
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fun.__dict__.update(func.__dict__)
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except AttributeError:
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pass
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return fun
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def decoratorx(caller):
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"""
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A version of "decorator" implemented via "exec" and not via the
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Signature object. Use this if you are want to preserve the `.__code__`
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object properties (https://github.com/micheles/decorator/issues/129).
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"""
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def dec(func):
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return FunctionMaker.create(
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func,
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"return _call_(_func_, %(shortsignature)s)",
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dict(_call_=caller, _func_=func),
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__wrapped__=func, __qualname__=func.__qualname__)
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return dec
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def decorator(caller, _func=None, kwsyntax=False):
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"""
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decorator(caller) converts a caller function into a decorator
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"""
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if _func is not None: # return a decorated function
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# this is obsolete behavior; you should use decorate instead
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return decorate(_func, caller, (), kwsyntax)
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# else return a decorator function
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sig = inspect.signature(caller)
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dec_params = [p for p in sig.parameters.values() if p.kind is POS]
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def dec(func=None, *args, **kw):
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na = len(args) + 1
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extras = args + tuple(kw.get(p.name, p.default)
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for p in dec_params[na:]
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if p.default is not EMPTY)
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if func is None:
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return lambda func: decorate(func, caller, extras, kwsyntax)
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else:
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return decorate(func, caller, extras, kwsyntax)
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dec.__signature__ = sig.replace(parameters=dec_params)
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dec.__name__ = caller.__name__
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dec.__doc__ = caller.__doc__
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dec.__wrapped__ = caller
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dec.__qualname__ = caller.__qualname__
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dec.__kwdefaults__ = getattr(caller, '__kwdefaults__', None)
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dec.__dict__.update(caller.__dict__)
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return dec
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# ####################### contextmanager ####################### #
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class ContextManager(_GeneratorContextManager):
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def __init__(self, g, *a, **k):
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_GeneratorContextManager.__init__(self, g, a, k)
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def __call__(self, func):
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def caller(f, *a, **k):
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with self.__class__(self.func, *self.args, **self.kwds):
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return f(*a, **k)
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return decorate(func, caller)
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_contextmanager = decorator(ContextManager)
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def contextmanager(func):
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# Enable Pylint config: contextmanager-decorators=decorator.contextmanager
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return _contextmanager(func)
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# ############################ dispatch_on ############################ #
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def append(a, vancestors):
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"""
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Append ``a`` to the list of the virtual ancestors, unless it is already
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included.
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"""
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add = True
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for j, va in enumerate(vancestors):
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if issubclass(va, a):
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add = False
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break
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if issubclass(a, va):
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vancestors[j] = a
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add = False
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if add:
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vancestors.append(a)
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# inspired from simplegeneric by P.J. Eby and functools.singledispatch
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def dispatch_on(*dispatch_args):
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"""
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Factory of decorators turning a function into a generic function
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dispatching on the given arguments.
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"""
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assert dispatch_args, 'No dispatch args passed'
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dispatch_str = '(%s,)' % ', '.join(dispatch_args)
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def check(arguments, wrong=operator.ne, msg=''):
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"""Make sure one passes the expected number of arguments"""
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if wrong(len(arguments), len(dispatch_args)):
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raise TypeError('Expected %d arguments, got %d%s' %
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(len(dispatch_args), len(arguments), msg))
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def gen_func_dec(func):
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"""Decorator turning a function into a generic function"""
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# first check the dispatch arguments
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argset = set(getfullargspec(func).args)
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if not set(dispatch_args) <= argset:
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raise NameError('Unknown dispatch arguments %s' % dispatch_str)
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typemap = {}
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def vancestors(*types):
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"""
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Get a list of sets of virtual ancestors for the given types
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"""
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check(types)
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ras = [[] for _ in range(len(dispatch_args))]
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for types_ in typemap:
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for t, type_, ra in zip(types, types_, ras):
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if issubclass(t, type_) and type_ not in t.mro():
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append(type_, ra)
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return [set(ra) for ra in ras]
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def ancestors(*types):
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"""
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Get a list of virtual MROs, one for each type
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"""
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check(types)
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lists = []
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for t, vas in zip(types, vancestors(*types)):
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n_vas = len(vas)
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if n_vas > 1:
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raise RuntimeError(
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'Ambiguous dispatch for %s: %s' % (t, vas))
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elif n_vas == 1:
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va, = vas
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mro = type('t', (t, va), {}).mro()[1:]
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else:
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mro = t.mro()
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lists.append(mro[:-1]) # discard t and object
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return lists
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def register(*types):
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"""
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Decorator to register an implementation for the given types
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"""
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check(types)
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def dec(f):
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check(getfullargspec(f).args, operator.lt, ' in ' + f.__name__)
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typemap[types] = f
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return f
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return dec
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def dispatch_info(*types):
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"""
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An utility to introspect the dispatch algorithm
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"""
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check(types)
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lst = []
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for anc in itertools.product(*ancestors(*types)):
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lst.append(tuple(a.__name__ for a in anc))
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return lst
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def _dispatch(dispatch_args, *args, **kw):
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types = tuple(type(arg) for arg in dispatch_args)
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try: # fast path
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f = typemap[types]
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except KeyError:
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pass
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else:
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return f(*args, **kw)
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combinations = itertools.product(*ancestors(*types))
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next(combinations) # the first one has been already tried
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for types_ in combinations:
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f = typemap.get(types_)
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if f is not None:
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return f(*args, **kw)
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# else call the default implementation
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return func(*args, **kw)
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return FunctionMaker.create(
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func, 'return _f_(%s, %%(shortsignature)s)' % dispatch_str,
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dict(_f_=_dispatch), register=register, default=func,
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typemap=typemap, vancestors=vancestors, ancestors=ancestors,
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dispatch_info=dispatch_info, __wrapped__=func)
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gen_func_dec.__name__ = 'dispatch_on' + dispatch_str
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return gen_func_dec
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