[ PARENT ]

EDIT :: decorator.py

# ######################### LICENSE ############################ # # Copyright (c) 2005-2018, 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. """ from __future__ import print_function import re import sys import inspect import operator import itertools import collections __version__ = '4.2.1' if sys.version >= '3': from inspect import getfullargspec def get_init(cls): return cls.__init__ else: FullArgSpec = collections.namedtuple( 'FullArgSpec', 'args varargs varkw defaults ' 'kwonlyargs kwonlydefaults') def getfullargspec(f): "A quick and dirty replacement for getfullargspec for Python 2.X" return FullArgSpec._make(inspect.getargspec(f) + ([], None)) def get_init(cls): return cls.__init__.__func__ try: iscoroutinefunction = inspect.iscoroutinefunction except AttributeError: # let's assume there are no coroutine functions in old Python def iscoroutinefunction(f): return False # getargspec has been deprecated in Python 3.5 ArgSpec = collections.namedtuple( 'ArgSpec', 'args varargs varkw defaults') def getargspec(f): """A replacement for inspect.getargspec""" spec = getfullargspec(f) return ArgSpec(spec.args, spec.varargs, spec.varkw, spec.defaults) DEF = re.compile(r'\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. """ # 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.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) 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: 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 decorate(func, caller, extras=()): """ decorate(func, caller) decorates a function using a caller. """ evaldict = dict(_call_=caller, _func_=func) es = '' for i, extra in enumerate(extras): ex = '_e%d_' % i evaldict[ex] = extra es += ex + ', ' fun = FunctionMaker.create( func, "return _call_(_func_, %s%%(shortsignature)s)" % es, evaldict, __wrapped__=func) if hasattr(func, '__qualname__'): fun.__qualname__ = func.__qualname__ return fun def decorator(caller, _func=None): """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) # else return a decorator function defaultargs, defaults = '', () if inspect.isclass(caller): name = caller.__name__.lower() doc = 'decorator(%s) converts functions/generators into ' \ 'factories of %s objects' % (caller.__name__, caller.__name__) elif inspect.isfunction(caller): if caller.__name__ == '<lambda>': name = '_lambda_' else: name = caller.__name__ doc = caller.__doc__ nargs = caller.__code__.co_argcount ndefs = len(caller.__defaults__ or ()) defaultargs = ', '.join(caller.__code__.co_varnames[nargs-ndefs:nargs]) if defaultargs: defaultargs += ',' defaults = caller.__defaults__ else: # assume caller is an object with a __call__ method name = caller.__class__.__name__.lower() doc = caller.__call__.__doc__ evaldict = dict(_call=caller, _decorate_=decorate) dec = FunctionMaker.create( '%s(func, %s)' % (name, defaultargs), 'if func is None: return lambda func: _decorate_(func, _call, (%s))\n' 'return _decorate_(func, _call, (%s))' % (defaultargs, defaultargs), evaldict, doc=doc, module=caller.__module__, __wrapped__=caller) if defaults: dec.__defaults__ = (None,) + defaults return dec # ####################### contextmanager ####################### # try: # Python >= 3.2 from contextlib import _GeneratorContextManager except ImportError: # Python >= 2.5 from contextlib import GeneratorContextManager as _GeneratorContextManager class ContextManager(_GeneratorContextManager): def __call__(self, func): """Context manager decorator""" return FunctionMaker.create( func, "with _self_: return _func_(%(shortsignature)s)", dict(_self_=self, _func_=func), __wrapped__=func) init = getfullargspec(_GeneratorContextManager.__init__) n_args = len(init.args) if n_args == 2 and not init.varargs: # (self, genobj) Python 2.7 def __init__(self, g, *a, **k): return _GeneratorContextManager.__init__(self, g(*a, **k)) ContextManager.__init__ = __init__ elif n_args == 2 and init.varargs: # (self, gen, *a, **k) Python 3.4 pass elif n_args == 4: # (self, gen, args, kwds) Python 3.5 def __init__(self, g, *a, **k): return _GeneratorContextManager.__init__(self, g, a, k) ContextManager.__init__ = __init__ _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

SAVE CANCEL