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Edit File: coroutines.py
__all__ = 'coroutine', 'iscoroutinefunction', 'iscoroutine' import collections.abc import functools import inspect import os import sys import traceback import types import warnings from . import base_futures from . import constants from . import format_helpers from .log import logger def _is_debug_mode(): # If you set _DEBUG to true, @coroutine will wrap the resulting # generator objects in a CoroWrapper instance (defined below). That # instance will log a message when the generator is never iterated # over, which may happen when you forget to use "await" or "yield from" # with a coroutine call. # Note that the value of the _DEBUG flag is taken # when the decorator is used, so to be of any use it must be set # before you define your coroutines. A downside of using this feature # is that tracebacks show entries for the CoroWrapper.__next__ method # when _DEBUG is true. return sys.flags.dev_mode or (not sys.flags.ignore_environment and bool(os.environ.get('PYTHONASYNCIODEBUG'))) _DEBUG = _is_debug_mode() class CoroWrapper: # Wrapper for coroutine object in _DEBUG mode. def __init__(self, gen, func=None): assert inspect.isgenerator(gen) or inspect.iscoroutine(gen), gen self.gen = gen self.func = func # Used to unwrap @coroutine decorator self._source_traceback = format_helpers.extract_stack(sys._getframe(1)) self.__name__ = getattr(gen, '__name__', None) self.__qualname__ = getattr(gen, '__qualname__', None) def __repr__(self): coro_repr = _format_coroutine(self) if self._source_traceback: frame = self._source_traceback[-1] coro_repr += f', created at {frame[0]}:{frame[1]}' return f'<{self.__class__.__name__} {coro_repr}>' def __iter__(self): return self def __next__(self): return self.gen.send(None) def send(self, value): return self.gen.send(value) def throw(self, type, value=None, traceback=None): return self.gen.throw(type, value, traceback) def close(self): return self.gen.close() @property def gi_frame(self): return self.gen.gi_frame @property def gi_running(self): return self.gen.gi_running @property def gi_code(self): return self.gen.gi_code def __await__(self): return self @property def gi_yieldfrom(self): return self.gen.gi_yieldfrom def __del__(self): # Be careful accessing self.gen.frame -- self.gen might not exist. gen = getattr(self, 'gen', None) frame = getattr(gen, 'gi_frame', None) if frame is not None and frame.f_lasti == -1: msg = f'{self!r} was never yielded from' tb = getattr(self, '_source_traceback', ()) if tb: tb = ''.join(traceback.format_list(tb)) msg += (f'\nCoroutine object created at ' f'(most recent call last, truncated to ' f'{constants.DEBUG_STACK_DEPTH} last lines):\n') msg += tb.rstrip() logger.error(msg) def coroutine(func): """Decorator to mark coroutines. If the coroutine is not yielded from before it is destroyed, an error message is logged. """ warnings.warn('"@coroutine" decorator is deprecated since Python 3.8, use "async def" instead', DeprecationWarning, stacklevel=2) if inspect.iscoroutinefunction(func): # In Python 3.5 that's all we need to do for coroutines # defined with "async def". return func if inspect.isgeneratorfunction(func): coro = func else: @functools.wraps(func) def coro(*args, **kw): res = func(*args, **kw) if (base_futures.isfuture(res) or inspect.isgenerator(res) or isinstance(res, CoroWrapper)): res = yield from res else: # If 'res' is an awaitable, run it. try: await_meth = res.__await__ except AttributeError: pass else: if isinstance(res, collections.abc.Awaitable): res = yield from await_meth() return res coro = types.coroutine(coro) if not _DEBUG: wrapper = coro else: @functools.wraps(func) def wrapper(*args, **kwds): w = CoroWrapper(coro(*args, **kwds), func=func) if w._source_traceback: del w._source_traceback[-1] # Python < 3.5 does not implement __qualname__ # on generator objects, so we set it manually. # We use getattr as some callables (such as # functools.partial may lack __qualname__). w.__name__ = getattr(func, '__name__', None) w.__qualname__ = getattr(func, '__qualname__', None) return w wrapper._is_coroutine = _is_coroutine # For iscoroutinefunction(). return wrapper # A marker for iscoroutinefunction. _is_coroutine = object() def iscoroutinefunction(func): """Return True if func is a decorated coroutine function.""" return (inspect.iscoroutinefunction(func) or getattr(func, '_is_coroutine', None) is _is_coroutine) # Prioritize native coroutine check to speed-up # asyncio.iscoroutine. _COROUTINE_TYPES = (types.CoroutineType, types.GeneratorType, collections.abc.Coroutine, CoroWrapper) _iscoroutine_typecache = set() def iscoroutine(obj): """Return True if obj is a coroutine object.""" if type(obj) in _iscoroutine_typecache: return True if isinstance(obj, _COROUTINE_TYPES): # Just in case we don't want to cache more than 100 # positive types. That shouldn't ever happen, unless # someone stressing the system on purpose. if len(_iscoroutine_typecache) < 100: _iscoroutine_typecache.add(type(obj)) return True else: return False def _format_coroutine(coro): assert iscoroutine(coro) is_corowrapper = isinstance(coro, CoroWrapper) def get_name(coro): # Coroutines compiled with Cython sometimes don't have # proper __qualname__ or __name__. While that is a bug # in Cython, asyncio shouldn't crash with an AttributeError # in its __repr__ functions. if is_corowrapper: return format_helpers._format_callback(coro.func, (), {}) if hasattr(coro, '__qualname__') and coro.__qualname__: coro_name = coro.__qualname__ elif hasattr(coro, '__name__') and coro.__name__: coro_name = coro.__name__ else: # Stop masking Cython bugs, expose them in a friendly way. coro_name = f'<{type(coro).__name__} without __name__>' return f'{coro_name}()' def is_running(coro): try: return coro.cr_running except AttributeError: try: return coro.gi_running except AttributeError: return False coro_code = None if hasattr(coro, 'cr_code') and coro.cr_code: coro_code = coro.cr_code elif hasattr(coro, 'gi_code') and coro.gi_code: coro_code = coro.gi_code coro_name = get_name(coro) if not coro_code: # Built-in types might not have __qualname__ or __name__. if is_running(coro): return f'{coro_name} running' else: return coro_name coro_frame = None if hasattr(coro, 'gi_frame') and coro.gi_frame: coro_frame = coro.gi_frame elif hasattr(coro, 'cr_frame') and coro.cr_frame: coro_frame = coro.cr_frame # If Cython's coroutine has a fake code object without proper # co_filename -- expose that. filename = coro_code.co_filename or '<empty co_filename>' lineno = 0 if (is_corowrapper and coro.func is not None and not inspect.isgeneratorfunction(coro.func)): source = format_helpers._get_function_source(coro.func) if source is not None: filename, lineno = source if coro_frame is None: coro_repr = f'{coro_name} done, defined at {filename}:{lineno}' else: coro_repr = f'{coro_name} running, defined at {filename}:{lineno}' elif coro_frame is not None: lineno = coro_frame.f_lineno coro_repr = f'{coro_name} running at {filename}:{lineno}' else: lineno = coro_code.co_firstlineno coro_repr = f'{coro_name} done, defined at {filename}:{lineno}' return coro_repr