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EDIT :: coroutines.py

__all__ = ['coroutine', 'iscoroutinefunction', 'iscoroutine'] import functools import inspect import opcode import os import sys import traceback import types from . import compat from . import constants from . import events from . import base_futures from .log import logger # Opcode of "yield from" instruction _YIELD_FROM = opcode.opmap['YIELD_FROM'] # 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 "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. _DEBUG = (not sys.flags.ignore_environment and bool(os.environ.get('PYTHONASYNCIODEBUG'))) try: _types_coroutine = types.coroutine _types_CoroutineType = types.CoroutineType except AttributeError: # Python 3.4 _types_coroutine = None _types_CoroutineType = None try: _inspect_iscoroutinefunction = inspect.iscoroutinefunction except AttributeError: # Python 3.4 _inspect_iscoroutinefunction = lambda func: False try: from collections.abc import Coroutine as _CoroutineABC, \ Awaitable as _AwaitableABC except ImportError: _CoroutineABC = _AwaitableABC = None # Check for CPython issue #21209 def has_yield_from_bug(): class MyGen: def __init__(self): self.send_args = None def __iter__(self): return self def __next__(self): return 42 def send(self, *what): self.send_args = what return None def yield_from_gen(gen): yield from gen value = (1, 2, 3) gen = MyGen() coro = yield_from_gen(gen) next(coro) coro.send(value) return gen.send_args != (value,) _YIELD_FROM_BUG = has_yield_from_bug() del has_yield_from_bug def debug_wrapper(gen): # This function is called from 'sys.set_coroutine_wrapper'. # We only wrap here coroutines defined via 'async def' syntax. # Generator-based coroutines are wrapped in @coroutine # decorator. return CoroWrapper(gen, None) 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 = events.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 += ', created at %s:%s' % (frame[0], frame[1]) return '<%s %s>' % (self.__class__.__name__, coro_repr) def __iter__(self): return self def __next__(self): return self.gen.send(None) if _YIELD_FROM_BUG: # For for CPython issue #21209: using "yield from" and a custom # generator, generator.send(tuple) unpacks the tuple instead of passing # the tuple unchanged. Check if the caller is a generator using "yield # from" to decide if the parameter should be unpacked or not. def send(self, *value): frame = sys._getframe() caller = frame.f_back assert caller.f_lasti >= 0 if caller.f_code.co_code[caller.f_lasti] != _YIELD_FROM: value = value[0] return self.gen.send(value) else: 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 if compat.PY35: def __await__(self): cr_await = getattr(self.gen, 'cr_await', None) if cr_await is not None: raise RuntimeError( "Cannot await on coroutine {!r} while it's " "awaiting for {!r}".format(self.gen, cr_await)) return self @property def gi_yieldfrom(self): return self.gen.gi_yieldfrom @property def cr_await(self): return self.gen.cr_await @property def cr_running(self): return self.gen.cr_running @property def cr_code(self): return self.gen.cr_code @property def cr_frame(self): return self.gen.cr_frame 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 None: frame = getattr(gen, 'cr_frame', None) if frame is not None and frame.f_lasti == -1: msg = '%r was never yielded from' % self 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. """ if _inspect_iscoroutinefunction(func): # In Python 3.5 that's all we need to do for coroutines # defined with "async def". # Wrapping in CoroWrapper will happen via # 'sys.set_coroutine_wrapper' function. 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 elif _AwaitableABC is not None: # If 'func' returns an Awaitable (new in 3.5) we # want to run it. try: await_meth = res.__await__ except AttributeError: pass else: if isinstance(res, _AwaitableABC): res = yield from await_meth() return res if not _DEBUG: if _types_coroutine is None: wrapper = coro else: wrapper = _types_coroutine(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 (getattr(func, '_is_coroutine', None) is _is_coroutine or _inspect_iscoroutinefunction(func)) _COROUTINE_TYPES = (types.GeneratorType, CoroWrapper) if _CoroutineABC is not None: _COROUTINE_TYPES += (_CoroutineABC,) if _types_CoroutineType is not None: # Prioritize native coroutine check to speed-up # asyncio.iscoroutine. _COROUTINE_TYPES = (_types_CoroutineType,) + _COROUTINE_TYPES def iscoroutine(obj): """Return True if obj is a coroutine object.""" return isinstance(obj, _COROUTINE_TYPES) def _format_coroutine(coro): assert iscoroutine(coro) if not hasattr(coro, 'cr_code') and not hasattr(coro, 'gi_code'): # Most likely a built-in type or a Cython coroutine. # Built-in types might not have __qualname__ or __name__. coro_name = getattr( coro, '__qualname__', getattr(coro, '__name__', type(coro).__name__)) coro_name = '{}()'.format(coro_name) running = False try: running = coro.cr_running except AttributeError: try: running = coro.gi_running except AttributeError: pass if running: return '{} running'.format(coro_name) else: return coro_name coro_name = None if isinstance(coro, CoroWrapper): func = coro.func coro_name = coro.__qualname__ if coro_name is not None: coro_name = '{}()'.format(coro_name) else: func = coro if coro_name is None: coro_name = events._format_callback(func, (), {}) 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_frame = None if hasattr(coro, 'cr_frame') and coro.cr_frame: coro_frame = coro.cr_frame elif hasattr(coro, 'gi_frame') and coro.gi_frame: coro_frame = coro.gi_frame filename = '<empty co_filename>' if coro_code and coro_code.co_filename: filename = coro_code.co_filename lineno = 0 coro_repr = coro_name if (isinstance(coro, CoroWrapper) and not inspect.isgeneratorfunction(coro.func) and coro.func is not None): source = events._get_function_source(coro.func) if source is not None: filename, lineno = source if coro_frame is None: coro_repr = ('%s done, defined at %s:%s' % (coro_name, filename, lineno)) else: coro_repr = ('%s running, defined at %s:%s' % (coro_name, filename, lineno)) elif coro_frame is not None: lineno = coro_frame.f_lineno coro_repr = ('%s running at %s:%s' % (coro_name, filename, lineno)) elif coro_code: lineno = coro_code.co_firstlineno coro_repr = ('%s done, defined at %s:%s' % (coro_name, filename, lineno)) return coro_repr

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