257 lines
7.8 KiB
Python
257 lines
7.8 KiB
Python
__all__ = ['coroutine',
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'iscoroutinefunction', 'iscoroutine']
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import functools
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import inspect
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import opcode
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import os
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import sys
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import traceback
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import types
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from . import events
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from . import futures
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from .log import logger
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_PY35 = sys.version_info >= (3, 5)
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# Opcode of "yield from" instruction
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_YIELD_FROM = opcode.opmap['YIELD_FROM']
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# If you set _DEBUG to true, @coroutine will wrap the resulting
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# generator objects in a CoroWrapper instance (defined below). That
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# instance will log a message when the generator is never iterated
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# over, which may happen when you forget to use "yield from" with a
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# coroutine call. Note that the value of the _DEBUG flag is taken
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# when the decorator is used, so to be of any use it must be set
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# before you define your coroutines. A downside of using this feature
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# is that tracebacks show entries for the CoroWrapper.__next__ method
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# when _DEBUG is true.
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_DEBUG = (not sys.flags.ignore_environment
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and bool(os.environ.get('PYTHONASYNCIODEBUG')))
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try:
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types.coroutine
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except AttributeError:
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native_coroutine_support = False
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else:
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native_coroutine_support = True
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try:
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_iscoroutinefunction = inspect.iscoroutinefunction
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except AttributeError:
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_iscoroutinefunction = lambda func: False
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try:
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inspect.CO_COROUTINE
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except AttributeError:
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_is_native_coro_code = lambda code: False
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else:
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_is_native_coro_code = lambda code: (code.co_flags &
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inspect.CO_COROUTINE)
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# Check for CPython issue #21209
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def has_yield_from_bug():
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class MyGen:
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def __init__(self):
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self.send_args = None
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def __iter__(self):
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return self
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def __next__(self):
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return 42
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def send(self, *what):
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self.send_args = what
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return None
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def yield_from_gen(gen):
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yield from gen
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value = (1, 2, 3)
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gen = MyGen()
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coro = yield_from_gen(gen)
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next(coro)
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coro.send(value)
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return gen.send_args != (value,)
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_YIELD_FROM_BUG = has_yield_from_bug()
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del has_yield_from_bug
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def debug_wrapper(gen):
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# This function is called from 'sys.set_coroutine_wrapper'.
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# We only wrap here coroutines defined via 'async def' syntax.
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# Generator-based coroutines are wrapped in @coroutine
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# decorator.
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if _is_native_coro_code(gen.gi_code):
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return CoroWrapper(gen, None)
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else:
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return gen
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class CoroWrapper:
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# Wrapper for coroutine object in _DEBUG mode.
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def __init__(self, gen, func=None):
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assert inspect.isgenerator(gen) or inspect.iscoroutine(gen), gen
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self.gen = gen
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self.func = func # Used to unwrap @coroutine decorator
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self._source_traceback = traceback.extract_stack(sys._getframe(1))
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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 __repr__(self):
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coro_repr = _format_coroutine(self)
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if self._source_traceback:
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frame = self._source_traceback[-1]
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coro_repr += ', created at %s:%s' % (frame[0], frame[1])
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return '<%s %s>' % (self.__class__.__name__, coro_repr)
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def __iter__(self):
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return self
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if _PY35:
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__await__ = __iter__ # make compatible with 'await' expression
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def __next__(self):
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return next(self.gen)
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if _YIELD_FROM_BUG:
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# For for CPython issue #21209: using "yield from" and a custom
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# generator, generator.send(tuple) unpacks the tuple instead of passing
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# the tuple unchanged. Check if the caller is a generator using "yield
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# from" to decide if the parameter should be unpacked or not.
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def send(self, *value):
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frame = sys._getframe()
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caller = frame.f_back
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assert caller.f_lasti >= 0
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if caller.f_code.co_code[caller.f_lasti] != _YIELD_FROM:
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value = value[0]
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return self.gen.send(value)
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else:
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def send(self, value):
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return self.gen.send(value)
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def throw(self, exc):
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return self.gen.throw(exc)
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def close(self):
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return self.gen.close()
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@property
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def gi_frame(self):
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return self.gen.gi_frame
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@property
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def gi_running(self):
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return self.gen.gi_running
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@property
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def gi_code(self):
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return self.gen.gi_code
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def __del__(self):
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# Be careful accessing self.gen.frame -- self.gen might not exist.
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gen = getattr(self, 'gen', None)
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frame = getattr(gen, 'gi_frame', None)
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if frame is not None and frame.f_lasti == -1:
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msg = '%r was never yielded from' % self
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tb = getattr(self, '_source_traceback', ())
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if tb:
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tb = ''.join(traceback.format_list(tb))
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msg += ('\nCoroutine object created at '
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'(most recent call last):\n')
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msg += tb.rstrip()
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logger.error(msg)
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def coroutine(func):
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"""Decorator to mark coroutines.
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If the coroutine is not yielded from before it is destroyed,
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an error message is logged.
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"""
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is_coroutine = _iscoroutinefunction(func)
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if is_coroutine and _is_native_coro_code(func.__code__):
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# In Python 3.5 that's all we need to do for coroutines
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# defiend with "async def".
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# Wrapping in CoroWrapper will happen via
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# 'sys.set_coroutine_wrapper' function.
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return func
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if inspect.isgeneratorfunction(func):
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coro = func
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else:
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@functools.wraps(func)
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def coro(*args, **kw):
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res = func(*args, **kw)
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if isinstance(res, futures.Future) or inspect.isgenerator(res):
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res = yield from res
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return res
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if not _DEBUG:
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if native_coroutine_support:
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wrapper = types.coroutine(coro)
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else:
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wrapper = coro
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else:
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@functools.wraps(func)
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def wrapper(*args, **kwds):
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w = CoroWrapper(coro(*args, **kwds), func=func)
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if w._source_traceback:
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del w._source_traceback[-1]
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# Python < 3.5 does not implement __qualname__
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# on generator objects, so we set it manually.
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# We use getattr as some callables (such as
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# functools.partial may lack __qualname__).
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w.__name__ = getattr(func, '__name__', None)
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w.__qualname__ = getattr(func, '__qualname__', None)
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return w
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wrapper._is_coroutine = True # For iscoroutinefunction().
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return wrapper
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def iscoroutinefunction(func):
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"""Return True if func is a decorated coroutine function."""
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return (getattr(func, '_is_coroutine', False) or
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_iscoroutinefunction(func))
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_COROUTINE_TYPES = (types.GeneratorType, CoroWrapper)
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def iscoroutine(obj):
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"""Return True if obj is a coroutine object."""
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return isinstance(obj, _COROUTINE_TYPES)
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def _format_coroutine(coro):
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assert iscoroutine(coro)
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if isinstance(coro, CoroWrapper):
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func = coro.func
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else:
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func = coro
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coro_name = events._format_callback(func, ())
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filename = coro.gi_code.co_filename
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if (isinstance(coro, CoroWrapper)
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and not inspect.isgeneratorfunction(coro.func)):
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filename, lineno = events._get_function_source(coro.func)
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if coro.gi_frame is None:
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coro_repr = ('%s done, defined at %s:%s'
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% (coro_name, filename, lineno))
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else:
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coro_repr = ('%s running, defined at %s:%s'
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% (coro_name, filename, lineno))
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elif coro.gi_frame is not None:
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lineno = coro.gi_frame.f_lineno
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coro_repr = ('%s running at %s:%s'
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% (coro_name, filename, lineno))
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else:
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lineno = coro.gi_code.co_firstlineno
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coro_repr = ('%s done, defined at %s:%s'
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% (coro_name, filename, lineno))
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return coro_repr
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