def wrapper(*args, **kwargs):
# type: (*Any, **Any) -> Future[_T]
# This function is type-annotated with a comment to work around
# https://bitbucket.org/pypy/pypy/issues/2868/segfault-with-args-type-annotation-in
future = _create_future()
if contextvars is not None:
ctx_run = contextvars.copy_context().run # type: Callable
else:
ctx_run = _fake_ctx_run
try:
result = ctx_run(func, *args, **kwargs)
except (Return, StopIteration) as e:
result = _value_from_stopiteration(e)
except Exception:
future_set_exc_info(future, sys.exc_info())
try:
return future
finally:
# Avoid circular references
future = None # type: ignore
else:
if isinstance(result, Generator):
# Inline the first iteration of Runner.run. This lets us
# avoid the cost of creating a Runner when the coroutine
# never actually yields, which in turn allows us to
# use "optional" coroutines in critical path code without
# performance penalty for the synchronous case.
try:
yielded = ctx_run(next, result)
except (StopIteration, Return) as e:
future_set_result_unless_cancelled(
future, _value_from_stopiteration(e))
except Exception:
future_set_exc_info(future, sys.exc_info())
else:
# Provide strong references to Runner objects as long
# as their result future objects also have strong
# references (typically from the parent coroutine's
# Runner). This keeps the coroutine's Runner alive.
# We do this by exploiting the public API
# add_done_callback() instead of putting a private
# attribute on the Future.
# (GitHub issues #1769, #2229).
runner = Runner(ctx_run, result, future, yielded)
future.add_done_callback(lambda _: runner)
yielded = None
try:
return future
finally:
# Subtle memory optimization: if next() raised an exception,
# the future's exc_info contains a traceback which
# includes this stack frame. This creates a cycle,
# which will be collected at the next full GC but has
# been shown to greatly increase memory usage of
# benchmarks (relative to the refcount-based scheme
# used in the absence of cycles). We can avoid the
# cycle by clearing the local variable after we return it.
future = None # type: ignore
future_set_result_unless_cancelled(future, result)
return future
def errback(failure: failure.Failure) -> None:
try:
failure.raiseException()
# Should never happen, but just in case
raise Exception("errback called without error")
except:
future_set_exc_info(f, sys.exc_info())
def handle_exception(self, typ: Type[Exception], value: Exception,
tb: types.TracebackType) -> bool:
if not self.running and not self.finished:
self.future = Future()
future_set_exc_info(self.future, (typ, value, tb))
self.ctx_run(self.run)
return True
else:
return False
def run(self) -> None:
"""Starts or resumes the generator, running until it reaches a
yield point that is not ready.
"""
if self.running or self.finished:
return
try:
self.running = True
while True:
future = self.future
if future is None:
raise Exception("No pending future")
if not future.done():
return
self.future = None
try:
exc_info = None
try:
value = future.result()
except Exception:
exc_info = sys.exc_info()
future = None
if exc_info is not None:
try:
yielded = self.gen.throw(*exc_info) # type: ignore
finally:
# Break up a reference to itself
# for faster GC on CPython.
exc_info = None
else:
yielded = self.gen.send(value)
except (StopIteration, Return) as e:
self.finished = True
self.future = _null_future
future_set_result_unless_cancelled(
self.result_future, _value_from_stopiteration(e)
)
self.result_future = None # type: ignore
return
except Exception:
self.finished = True
self.future = _null_future
future_set_exc_info(self.result_future, sys.exc_info())
self.result_future = None # type: ignore
return
if not self.handle_yield(yielded):
return
yielded = None
finally:
self.running = False
def callback(fut: Future) -> None:
unfinished_children.remove(fut)
if not unfinished_children:
result_list = []
for f in children_futs:
try:
result_list.append(f.result())
except Exception as e:
if future.done():
if not isinstance(e, quiet_exceptions):
app_log.error("Multiple exceptions in yield list",
exc_info=True)
else:
future_set_exc_info(future, sys.exc_info())
if not future.done():
if keys is not None:
future_set_result_unless_cancelled(
future, dict(zip(keys, result_list)))
else:
future_set_result_unless_cancelled(future, result_list)
def run() -> None:
try:
result = func()
if result is not None:
from tornado_py3.gen import convert_yielded
result = convert_yielded(result)
except Exception:
fut = Future() # type: Future[Any]
future_cell[0] = fut
future_set_exc_info(fut, sys.exc_info())
else:
if is_future(result):
future_cell[0] = result
else:
fut = Future()
future_cell[0] = fut
fut.set_result(result)
assert future_cell[0] is not None
self.add_future(future_cell[0], lambda future: self.stop())
def handle_yield(self, yielded: _Yieldable) -> bool:
try:
self.future = convert_yielded(yielded)
except BadYieldError:
self.future = Future()
future_set_exc_info(self.future, sys.exc_info())
if self.future is moment:
self.io_loop.add_callback(self.run)
return False
elif self.future is None:
raise Exception("no pending future")
elif not self.future.done():
def inner(f: Any) -> None:
# Break a reference cycle to speed GC.
f = None # noqa: F841
self.run()
self.io_loop.add_future(self.future, inner)
return False
return True