1  # #########################     LICENSE     ############################ #
   2  
   3  # Copyright (c) 2005-2025, Michele Simionato
   4  # All rights reserved.
   5  
   6  # Redistribution and use in source and binary forms, with or without
   7  # modification, are permitted provided that the following conditions are
   8  # met:
   9  
  10  #   Redistributions of source code must retain the above copyright
  11  #   notice, this list of conditions and the following disclaimer.
  12  #   Redistributions in bytecode form must reproduce the above copyright
  13  #   notice, this list of conditions and the following disclaimer in
  14  #   the documentation and/or other materials provided with the
  15  #   distribution.
  16  
  17  # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  18  # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  19  # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  20  # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  21  # HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  22  # INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  23  # BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
  24  # OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  25  # ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
  26  # TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
  27  # USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
  28  # DAMAGE.
  29  
  30  """
  31  Decorator module, see
  32  https://github.com/micheles/decorator/blob/master/docs/documentation.md
  33  for the documentation.
  34  """
  35  import re
  36  import sys
  37  import inspect
  38  import operator
  39  import itertools
  40  import functools
  41  from contextlib import _GeneratorContextManager
  42  from inspect import getfullargspec, iscoroutinefunction, isgeneratorfunction
  43  
  44  __version__ = '5.2.1'
  45  
  46  DEF = re.compile(r'\s*def\s*([_\w][_\w\d]*)\s*\(')
  47  POS = inspect.Parameter.POSITIONAL_OR_KEYWORD
  48  EMPTY = inspect.Parameter.empty
  49  
  50  
  51  # this is not used anymore in the core, but kept for backward compatibility
  52  class FunctionMaker(object):
  53      """
  54      An object with the ability to create functions with a given signature.
  55      It has attributes name, doc, module, signature, defaults, dict and
  56      methods update and make.
  57      """
  58  
  59      # Atomic get-and-increment provided by the GIL
  60      _compile_count = itertools.count()
  61  
  62      # make pylint happy
  63      args = varargs = varkw = defaults = kwonlyargs = kwonlydefaults = ()
  64  
  65      def __init__(self, func=None, name=None, signature=None,
  66                   defaults=None, doc=None, module=None, funcdict=None):
  67          self.shortsignature = signature
  68          if func:
  69              # func can be a class or a callable, but not an instance method
  70              self.name = func.__name__
  71              if self.name == '<lambda>':  # small hack for lambda functions
  72                  self.name = '_lambda_'
  73              self.doc = func.__doc__
  74              self.module = func.__module__
  75              if inspect.isroutine(func) or isinstance(func, functools.partial):
  76                  argspec = getfullargspec(func)
  77                  self.annotations = getattr(func, '__annotations__', {})
  78                  for a in ('args', 'varargs', 'varkw', 'defaults', 'kwonlyargs',
  79                            'kwonlydefaults'):
  80                      setattr(self, a, getattr(argspec, a))
  81                  for i, arg in enumerate(self.args):
  82                      setattr(self, 'arg%d' % i, arg)
  83                  allargs = list(self.args)
  84                  allshortargs = list(self.args)
  85                  if self.varargs:
  86                      allargs.append('*' + self.varargs)
  87                      allshortargs.append('*' + self.varargs)
  88                  elif self.kwonlyargs:
  89                      allargs.append('*')  # single star syntax
  90                  for a in self.kwonlyargs:
  91                      allargs.append('%s=None' % a)
  92                      allshortargs.append('%s=%s' % (a, a))
  93                  if self.varkw:
  94                      allargs.append('**' + self.varkw)
  95                      allshortargs.append('**' + self.varkw)
  96                  self.signature = ', '.join(allargs)
  97                  self.shortsignature = ', '.join(allshortargs)
  98                  self.dict = func.__dict__.copy()
  99          # func=None happens when decorating a caller
 100          if name:
 101              self.name = name
 102          if signature is not None:
 103              self.signature = signature
 104          if defaults:
 105              self.defaults = defaults
 106          if doc:
 107              self.doc = doc
 108          if module:
 109              self.module = module
 110          if funcdict:
 111              self.dict = funcdict
 112          # check existence required attributes
 113          assert hasattr(self, 'name')
 114          if not hasattr(self, 'signature'):
 115              raise TypeError('You are decorating a non function: %s' % func)
 116  
 117      def update(self, func, **kw):
 118          """
 119          Update the signature of func with the data in self
 120          """
 121          func.__name__ = self.name
 122          func.__doc__ = getattr(self, 'doc', None)
 123          func.__dict__ = getattr(self, 'dict', {})
 124          func.__defaults__ = self.defaults
 125          func.__kwdefaults__ = self.kwonlydefaults or None
 126          func.__annotations__ = getattr(self, 'annotations', None)
 127          try:
 128              frame = sys._getframe(3)
 129          except AttributeError:  # for IronPython and similar implementations
 130              callermodule = '?'
 131          else:
 132              callermodule = frame.f_globals.get('__name__', '?')
 133          func.__module__ = getattr(self, 'module', callermodule)
 134          func.__dict__.update(kw)
 135  
 136      def make(self, src_templ, evaldict=None, addsource=False, **attrs):
 137          """
 138          Make a new function from a given template and update the signature
 139          """
 140          src = src_templ % vars(self)  # expand name and signature
 141          evaldict = evaldict or {}
 142          mo = DEF.search(src)
 143          if mo is None:
 144              raise SyntaxError('not a valid function template\n%s' % src)
 145          name = mo.group(1)  # extract the function name
 146          names = set([name] + [arg.strip(' *') for arg in
 147                                self.shortsignature.split(',')])
 148          for n in names:
 149              if n in ('_func_', '_call_'):
 150                  raise NameError('%s is overridden in\n%s' % (n, src))
 151  
 152          if not src.endswith('\n'):  # add a newline for old Pythons
 153              src += '\n'
 154  
 155          # Ensure each generated function has a unique filename for profilers
 156          # (such as cProfile) that depend on the tuple of (<filename>,
 157          # <definition line>, <function name>) being unique.
 158          filename = '<decorator-gen-%d>' % next(self._compile_count)
 159          try:
 160              code = compile(src, filename, 'single')
 161              exec(code, evaldict)
 162          except Exception:
 163              print('Error in generated code:', file=sys.stderr)
 164              print(src, file=sys.stderr)
 165              raise
 166          func = evaldict[name]
 167          if addsource:
 168              attrs['__source__'] = src
 169          self.update(func, **attrs)
 170          return func
 171  
 172      @classmethod
 173      def create(cls, obj, body, evaldict, defaults=None,
 174                 doc=None, module=None, addsource=True, **attrs):
 175          """
 176          Create a function from the strings name, signature and body.
 177          evaldict is the evaluation dictionary. If addsource is true an
 178          attribute __source__ is added to the result. The attributes attrs
 179          are added, if any.
 180          """
 181          if isinstance(obj, str):  # "name(signature)"
 182              name, rest = obj.strip().split('(', 1)
 183              signature = rest[:-1]  # strip a right parens
 184              func = None
 185          else:  # a function
 186              name = None
 187              signature = None
 188              func = obj
 189          self = cls(func, name, signature, defaults, doc, module)
 190          ibody = '\n'.join('    ' + line for line in body.splitlines())
 191          caller = evaldict.get('_call_')  # when called from `decorate`
 192          if caller and iscoroutinefunction(caller):
 193              body = ('async def %(name)s(%(signature)s):\n' + ibody).replace(
 194                  'return', 'return await')
 195          else:
 196              body = 'def %(name)s(%(signature)s):\n' + ibody
 197          return self.make(body, evaldict, addsource, **attrs)
 198  
 199  
 200  def fix(args, kwargs, sig):
 201      """
 202      Fix args and kwargs to be consistent with the signature
 203      """
 204      ba = sig.bind(*args, **kwargs)
 205      ba.apply_defaults()  # needed for test_dan_schult
 206      return ba.args, ba.kwargs
 207  
 208  
 209  def decorate(func, caller, extras=(), kwsyntax=False):
 210      """
 211      Decorates a function/generator/coroutine using a caller.
 212      If kwsyntax is True calling the decorated functions with keyword
 213      syntax will pass the named arguments inside the ``kw`` dictionary,
 214      even if such argument are positional, similarly to what functools.wraps
 215      does. By default kwsyntax is False and the the arguments are untouched.
 216      """
 217      sig = inspect.signature(func)
 218      if isinstance(func, functools.partial):
 219          func = functools.update_wrapper(func, func.func)
 220      if iscoroutinefunction(caller):
 221          async def fun(*args, **kw):
 222              if not kwsyntax:
 223                  args, kw = fix(args, kw, sig)
 224              return await caller(func, *(extras + args), **kw)
 225      elif isgeneratorfunction(caller):
 226          def fun(*args, **kw):
 227              if not kwsyntax:
 228                  args, kw = fix(args, kw, sig)
 229              for res in caller(func, *(extras + args), **kw):
 230                  yield res
 231      else:
 232          def fun(*args, **kw):
 233              if not kwsyntax:
 234                  args, kw = fix(args, kw, sig)
 235              return caller(func, *(extras + args), **kw)
 236  
 237      fun.__name__ = func.__name__
 238      fun.__doc__ = func.__doc__
 239      fun.__wrapped__ = func
 240      fun.__signature__ = sig
 241      fun.__qualname__ = func.__qualname__
 242      # builtin functions like defaultdict.__setitem__ lack many attributes
 243      try:
 244          fun.__defaults__ = func.__defaults__
 245      except AttributeError:
 246          pass
 247      try:
 248          fun.__kwdefaults__ = func.__kwdefaults__
 249      except AttributeError:
 250          pass
 251      try:
 252          fun.__annotations__ = func.__annotations__
 253      except AttributeError:
 254          pass
 255      try:
 256          fun.__module__ = func.__module__
 257      except AttributeError:
 258          pass
 259      try:
 260          fun.__name__ = func.__name__
 261      except AttributeError:  # happens with old versions of numpy.vectorize
 262          func.__name__ == 'noname'
 263      try:
 264          fun.__dict__.update(func.__dict__)
 265      except AttributeError:
 266          pass
 267      return fun
 268  
 269  
 270  def decoratorx(caller):
 271      """
 272      A version of "decorator" implemented via "exec" and not via the
 273      Signature object. Use this if you are want to preserve the `.__code__`
 274      object properties (https://github.com/micheles/decorator/issues/129).
 275      """
 276      def dec(func):
 277          return FunctionMaker.create(
 278              func,
 279              "return _call_(_func_, %(shortsignature)s)",
 280              dict(_call_=caller, _func_=func),
 281              __wrapped__=func, __qualname__=func.__qualname__)
 282      return dec
 283  
 284  
 285  def decorator(caller, _func=None, kwsyntax=False):
 286      """
 287      decorator(caller) converts a caller function into a decorator
 288      """
 289      if _func is not None:  # return a decorated function
 290          # this is obsolete behavior; you should use decorate instead
 291          return decorate(_func, caller, (), kwsyntax)
 292      # else return a decorator function
 293      sig = inspect.signature(caller)
 294      dec_params = [p for p in sig.parameters.values() if p.kind is POS]
 295  
 296      def dec(func=None, *args, **kw):
 297          na = len(args) + 1
 298          extras = args + tuple(kw.get(p.name, p.default)
 299                                for p in dec_params[na:]
 300                                if p.default is not EMPTY)
 301          if func is None:
 302              return lambda func: decorate(func, caller, extras, kwsyntax)
 303          else:
 304              return decorate(func, caller, extras, kwsyntax)
 305      dec.__signature__ = sig.replace(parameters=dec_params)
 306      dec.__name__ = caller.__name__
 307      dec.__doc__ = caller.__doc__
 308      dec.__wrapped__ = caller
 309      dec.__qualname__ = caller.__qualname__
 310      dec.__kwdefaults__ = getattr(caller, '__kwdefaults__', None)
 311      dec.__dict__.update(caller.__dict__)
 312      return dec
 313  
 314  
 315  # ####################### contextmanager ####################### #
 316  
 317  
 318  class ContextManager(_GeneratorContextManager):
 319      def __init__(self, g, *a, **k):
 320          _GeneratorContextManager.__init__(self, g, a, k)
 321  
 322      def __call__(self, func):
 323          def caller(f, *a, **k):
 324              with self.__class__(self.func, *self.args, **self.kwds):
 325                  return f(*a, **k)
 326          return decorate(func, caller)
 327  
 328  
 329  _contextmanager = decorator(ContextManager)
 330  
 331  
 332  def contextmanager(func):
 333      # Enable Pylint config: contextmanager-decorators=decorator.contextmanager
 334      return _contextmanager(func)
 335  
 336  
 337  # ############################ dispatch_on ############################ #
 338  
 339  def append(a, vancestors):
 340      """
 341      Append ``a`` to the list of the virtual ancestors, unless it is already
 342      included.
 343      """
 344      add = True
 345      for j, va in enumerate(vancestors):
 346          if issubclass(va, a):
 347              add = False
 348              break
 349          if issubclass(a, va):
 350              vancestors[j] = a
 351              add = False
 352      if add:
 353          vancestors.append(a)
 354  
 355  
 356  # inspired from simplegeneric by P.J. Eby and functools.singledispatch
 357  def dispatch_on(*dispatch_args):
 358      """
 359      Factory of decorators turning a function into a generic function
 360      dispatching on the given arguments.
 361      """
 362      assert dispatch_args, 'No dispatch args passed'
 363      dispatch_str = '(%s,)' % ', '.join(dispatch_args)
 364  
 365      def check(arguments, wrong=operator.ne, msg=''):
 366          """Make sure one passes the expected number of arguments"""
 367          if wrong(len(arguments), len(dispatch_args)):
 368              raise TypeError('Expected %d arguments, got %d%s' %
 369                              (len(dispatch_args), len(arguments), msg))
 370  
 371      def gen_func_dec(func):
 372          """Decorator turning a function into a generic function"""
 373  
 374          # first check the dispatch arguments
 375          argset = set(getfullargspec(func).args)
 376          if not set(dispatch_args) <= argset:
 377              raise NameError('Unknown dispatch arguments %s' % dispatch_str)
 378  
 379          typemap = {}
 380  
 381          def vancestors(*types):
 382              """
 383              Get a list of sets of virtual ancestors for the given types
 384              """
 385              check(types)
 386              ras = [[] for _ in range(len(dispatch_args))]
 387              for types_ in typemap:
 388                  for t, type_, ra in zip(types, types_, ras):
 389                      if issubclass(t, type_) and type_ not in t.mro():
 390                          append(type_, ra)
 391              return [set(ra) for ra in ras]
 392  
 393          def ancestors(*types):
 394              """
 395              Get a list of virtual MROs, one for each type
 396              """
 397              check(types)
 398              lists = []
 399              for t, vas in zip(types, vancestors(*types)):
 400                  n_vas = len(vas)
 401                  if n_vas > 1:
 402                      raise RuntimeError(
 403                          'Ambiguous dispatch for %s: %s' % (t, vas))
 404                  elif n_vas == 1:
 405                      va, = vas
 406                      mro = type('t', (t, va), {}).mro()[1:]
 407                  else:
 408                      mro = t.mro()
 409                  lists.append(mro[:-1])  # discard t and object
 410              return lists
 411  
 412          def register(*types):
 413              """
 414              Decorator to register an implementation for the given types
 415              """
 416              check(types)
 417  
 418              def dec(f):
 419                  check(getfullargspec(f).args, operator.lt, ' in ' + f.__name__)
 420                  typemap[types] = f
 421                  return f
 422              return dec
 423  
 424          def dispatch_info(*types):
 425              """
 426              An utility to introspect the dispatch algorithm
 427              """
 428              check(types)
 429              lst = []
 430              for ancs in itertools.product(*ancestors(*types)):
 431                  lst.append(tuple(a.__name__ for a in ancs))
 432              return lst
 433  
 434          def _dispatch(dispatch_args, *args, **kw):
 435              types = tuple(type(arg) for arg in dispatch_args)
 436              try:  # fast path
 437                  f = typemap[types]
 438              except KeyError:
 439                  pass
 440              else:
 441                  return f(*args, **kw)
 442              combinations = itertools.product(*ancestors(*types))
 443              next(combinations)  # the first one has been already tried
 444              for types_ in combinations:
 445                  f = typemap.get(types_)
 446                  if f is not None:
 447                      return f(*args, **kw)
 448  
 449              # else call the default implementation
 450              return func(*args, **kw)
 451  
 452          return FunctionMaker.create(
 453              func, 'return _f_(%s, %%(shortsignature)s)' % dispatch_str,
 454              dict(_f_=_dispatch), register=register, default=func,
 455              typemap=typemap, vancestors=vancestors, ancestors=ancestors,
 456              dispatch_info=dispatch_info, __wrapped__=func)
 457  
 458      gen_func_dec.__name__ = 'dispatch_on' + dispatch_str
 459      return gen_func_dec
 460