mirror of
https://github.com/python/cpython.git
synced 2025-08-04 08:59:19 +00:00
5376ba9630
Summary of changes:
1. Coroutines now have a distinct, separate from generators
type at the C level: PyGen_Type, and a new typedef PyCoroObject.
PyCoroObject shares the initial segment of struct layout with
PyGenObject, making it possible to reuse existing generators
machinery. The new type is exposed as 'types.CoroutineType'.
As a consequence of having a new type, CO_GENERATOR flag is
no longer applied to coroutines.
2. Having a separate type for coroutines made it possible to add
an __await__ method to the type. Although it is not used by the
interpreter (see details on that below), it makes coroutines
naturally (without using __instancecheck__) conform to
collections.abc.Coroutine and collections.abc.Awaitable ABCs.
[The __instancecheck__ is still used for generator-based
coroutines, as we don't want to add __await__ for generators.]
3. Add new opcode: GET_YIELD_FROM_ITER. The opcode is needed to
allow passing native coroutines to the YIELD_FROM opcode.
Before this change, 'yield from o' expression was compiled to:
(o)
GET_ITER
LOAD_CONST
YIELD_FROM
Now, we use GET_YIELD_FROM_ITER instead of GET_ITER.
The reason for adding a new opcode is that GET_ITER is used
in some contexts (such as 'for .. in' loops) where passing
a coroutine object is invalid.
4. Add two new introspection functions to the inspec module:
getcoroutinestate(c) and getcoroutinelocals(c).
5. inspect.iscoroutine(o) is updated to test if 'o' is a native
coroutine object. Before this commit it used abc.Coroutine,
and it was requested to update inspect.isgenerator(o) to use
abc.Generator; it was decided, however, that inspect functions
should really be tailored for checking for native types.
6. sys.set_coroutine_wrapper(w) API is updated to work with only
native coroutines. Since types.coroutine decorator supports
any type of callables now, it would be confusing that it does
not work for all types of coroutines.
7. Exceptions logic in generators C implementation was updated
to raise clearer messages for coroutines:
Before: TypeError("generator raised StopIteration")
After: TypeError("coroutine raised StopIteration")
254 lines
8.5 KiB
Python
254 lines
8.5 KiB
Python
"""
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Define names for built-in types that aren't directly accessible as a builtin.
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"""
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import sys
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# Iterators in Python aren't a matter of type but of protocol. A large
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# and changing number of builtin types implement *some* flavor of
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# iterator. Don't check the type! Use hasattr to check for both
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# "__iter__" and "__next__" attributes instead.
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def _f(): pass
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FunctionType = type(_f)
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LambdaType = type(lambda: None) # Same as FunctionType
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CodeType = type(_f.__code__)
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MappingProxyType = type(type.__dict__)
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SimpleNamespace = type(sys.implementation)
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def _g():
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yield 1
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GeneratorType = type(_g())
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async def _c(): pass
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_c = _c()
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CoroutineType = type(_c)
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_c.close() # Prevent ResourceWarning
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class _C:
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def _m(self): pass
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MethodType = type(_C()._m)
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BuiltinFunctionType = type(len)
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BuiltinMethodType = type([].append) # Same as BuiltinFunctionType
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ModuleType = type(sys)
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try:
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raise TypeError
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except TypeError:
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tb = sys.exc_info()[2]
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TracebackType = type(tb)
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FrameType = type(tb.tb_frame)
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tb = None; del tb
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# For Jython, the following two types are identical
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GetSetDescriptorType = type(FunctionType.__code__)
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MemberDescriptorType = type(FunctionType.__globals__)
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del sys, _f, _g, _C, _c, # Not for export
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# Provide a PEP 3115 compliant mechanism for class creation
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def new_class(name, bases=(), kwds=None, exec_body=None):
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"""Create a class object dynamically using the appropriate metaclass."""
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meta, ns, kwds = prepare_class(name, bases, kwds)
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if exec_body is not None:
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exec_body(ns)
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return meta(name, bases, ns, **kwds)
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def prepare_class(name, bases=(), kwds=None):
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"""Call the __prepare__ method of the appropriate metaclass.
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Returns (metaclass, namespace, kwds) as a 3-tuple
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*metaclass* is the appropriate metaclass
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*namespace* is the prepared class namespace
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*kwds* is an updated copy of the passed in kwds argument with any
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'metaclass' entry removed. If no kwds argument is passed in, this will
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be an empty dict.
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"""
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if kwds is None:
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kwds = {}
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else:
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kwds = dict(kwds) # Don't alter the provided mapping
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if 'metaclass' in kwds:
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meta = kwds.pop('metaclass')
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else:
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if bases:
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meta = type(bases[0])
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else:
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meta = type
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if isinstance(meta, type):
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# when meta is a type, we first determine the most-derived metaclass
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# instead of invoking the initial candidate directly
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meta = _calculate_meta(meta, bases)
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if hasattr(meta, '__prepare__'):
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ns = meta.__prepare__(name, bases, **kwds)
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else:
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ns = {}
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return meta, ns, kwds
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def _calculate_meta(meta, bases):
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"""Calculate the most derived metaclass."""
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winner = meta
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for base in bases:
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base_meta = type(base)
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if issubclass(winner, base_meta):
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continue
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if issubclass(base_meta, winner):
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winner = base_meta
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continue
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# else:
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raise TypeError("metaclass conflict: "
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"the metaclass of a derived class "
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"must be a (non-strict) subclass "
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"of the metaclasses of all its bases")
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return winner
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class DynamicClassAttribute:
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"""Route attribute access on a class to __getattr__.
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This is a descriptor, used to define attributes that act differently when
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accessed through an instance and through a class. Instance access remains
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normal, but access to an attribute through a class will be routed to the
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class's __getattr__ method; this is done by raising AttributeError.
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This allows one to have properties active on an instance, and have virtual
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attributes on the class with the same name (see Enum for an example).
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"""
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def __init__(self, fget=None, fset=None, fdel=None, doc=None):
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self.fget = fget
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self.fset = fset
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self.fdel = fdel
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# next two lines make DynamicClassAttribute act the same as property
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self.__doc__ = doc or fget.__doc__
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self.overwrite_doc = doc is None
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# support for abstract methods
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self.__isabstractmethod__ = bool(getattr(fget, '__isabstractmethod__', False))
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def __get__(self, instance, ownerclass=None):
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if instance is None:
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if self.__isabstractmethod__:
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return self
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raise AttributeError()
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elif self.fget is None:
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raise AttributeError("unreadable attribute")
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return self.fget(instance)
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def __set__(self, instance, value):
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if self.fset is None:
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raise AttributeError("can't set attribute")
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self.fset(instance, value)
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def __delete__(self, instance):
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if self.fdel is None:
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raise AttributeError("can't delete attribute")
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self.fdel(instance)
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def getter(self, fget):
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fdoc = fget.__doc__ if self.overwrite_doc else None
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result = type(self)(fget, self.fset, self.fdel, fdoc or self.__doc__)
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result.overwrite_doc = self.overwrite_doc
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return result
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def setter(self, fset):
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result = type(self)(self.fget, fset, self.fdel, self.__doc__)
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result.overwrite_doc = self.overwrite_doc
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return result
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def deleter(self, fdel):
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result = type(self)(self.fget, self.fset, fdel, self.__doc__)
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result.overwrite_doc = self.overwrite_doc
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return result
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import functools as _functools
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import collections.abc as _collections_abc
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def coroutine(func):
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"""Convert regular generator function to a coroutine."""
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if not callable(func):
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raise TypeError('types.coroutine() expects a callable')
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if (func.__class__ is FunctionType and
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getattr(func, '__code__', None).__class__ is CodeType):
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co_flags = func.__code__.co_flags
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# Check if 'func' is a coroutine function.
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# (0x180 == CO_COROUTINE | CO_ITERABLE_COROUTINE)
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if co_flags & 0x180:
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return func
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# Check if 'func' is a generator function.
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# (0x20 == CO_GENERATOR)
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if co_flags & 0x20:
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# TODO: Implement this in C.
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co = func.__code__
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func.__code__ = CodeType(
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co.co_argcount, co.co_kwonlyargcount, co.co_nlocals,
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co.co_stacksize,
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co.co_flags | 0x100, # 0x100 == CO_ITERABLE_COROUTINE
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co.co_code,
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co.co_consts, co.co_names, co.co_varnames, co.co_filename,
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co.co_name, co.co_firstlineno, co.co_lnotab, co.co_freevars,
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co.co_cellvars)
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return func
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# The following code is primarily to support functions that
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# return generator-like objects (for instance generators
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# compiled with Cython).
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class GeneratorWrapper:
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def __init__(self, gen):
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self.__wrapped__ = gen
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self.__name__ = getattr(gen, '__name__', None)
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self.__qualname__ = getattr(gen, '__qualname__', None)
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def send(self, val):
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return self.__wrapped__.send(val)
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def throw(self, *args):
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return self.__wrapped__.throw(*args)
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def close(self):
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return self.__wrapped__.close()
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@property
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def gi_code(self):
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return self.__wrapped__.gi_code
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@property
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def gi_frame(self):
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return self.__wrapped__.gi_frame
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@property
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def gi_running(self):
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return self.__wrapped__.gi_running
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cr_code = gi_code
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cr_frame = gi_frame
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cr_running = gi_running
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def __next__(self):
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return next(self.__wrapped__)
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def __iter__(self):
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return self.__wrapped__
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def __await__(self):
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return self.__wrapped__
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@_functools.wraps(func)
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def wrapped(*args, **kwargs):
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coro = func(*args, **kwargs)
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if coro.__class__ is CoroutineType:
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# 'coro' is a native coroutine object.
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return coro
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if (coro.__class__ is GeneratorType or
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(isinstance(coro, _collections_abc.Generator) and
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not isinstance(coro, _collections_abc.Coroutine))):
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# 'coro' is either a pure Python generator iterator, or it
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# implements collections.abc.Generator (and does not implement
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# collections.abc.Coroutine).
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return GeneratorWrapper(coro)
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# 'coro' is either an instance of collections.abc.Coroutine or
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# some other object -- pass it through.
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return coro
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return wrapped
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__all__ = [n for n in globals() if n[:1] != '_']
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