def errback(failure): 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, value, tb): if not self.running and not self.finished: self.future = Future() future_set_exc_info(self.future, (typ, value, tb)) self.run() return True else: return False
def handle_yield(self, yielded): # Lists containing YieldPoints require stack contexts; # other lists are handled in convert_yielded. if _contains_yieldpoint(yielded): yielded = multi(yielded) if isinstance(yielded, YieldPoint): # YieldPoints are too closely coupled to the Runner to go # through the generic convert_yielded mechanism. self.future = Future() def start_yield_point(): try: yielded.start(self) if yielded.is_ready(): future_set_result_unless_cancelled( self.future, yielded.get_result()) else: self.yield_point = yielded except Exception: self.future = Future() future_set_exc_info(self.future, sys.exc_info()) if self.stack_context_deactivate is None: # Start a stack context if this is the first # YieldPoint we've seen. with stack_context.ExceptionStackContext( self.handle_exception) as deactivate: self.stack_context_deactivate = deactivate def cb(): start_yield_point() self.run() self.io_loop.add_callback(cb) return False else: start_yield_point() else: 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 not self.future.done(): def inner(f): # Break a reference cycle to speed GC. f = None # noqa self.run() self.io_loop.add_future(self.future, inner) return False return True
def start_yield_point(): try: yielded.start(self) if yielded.is_ready(): future_set_result_unless_cancelled( self.future, yielded.get_result()) else: self.yield_point = yielded except Exception: self.future = Future() future_set_exc_info(self.future, sys.exc_info())
def set_result(self, key, result): """Sets the result for ``key`` and attempts to resume the generator.""" self.results[key] = result if self.yield_point is not None and self.yield_point.is_ready(): try: future_set_result_unless_cancelled( self.future, self.yield_point.get_result()) except: future_set_exc_info(self.future, sys.exc_info()) self.yield_point = None self.run()
def run(): try: result = func() if result is not None: from tornado_py2.gen import convert_yielded result = convert_yielded(result) except Exception: future_cell[0] = Future() future_set_exc_info(future_cell[0], sys.exc_info()) else: if is_future(result): future_cell[0] = result else: future_cell[0] = Future() future_cell[0].set_result(result) self.add_future(future_cell[0], lambda future: self.stop())
def callback(f): unfinished_children.remove(f) if not unfinished_children: result_list = [] for f in children: 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 handle_exception(typ, value, tb): if future.done(): return False else: future_set_exc_info(future, (typ, value, tb)) return True
def wrapper(*args, **kwargs): future = _create_future() if replace_callback and 'callback' in kwargs: warnings.warn( "callback arguments are deprecated, use the returned Future instead", DeprecationWarning, stacklevel=2) callback = kwargs.pop('callback') IOLoop.current().add_future( future, lambda future: callback(future.result())) try: result = 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 else: if isinstance(result, GeneratorType): # 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: orig_stack_contexts = stack_context._state.contexts yielded = next(result) if stack_context._state.contexts is not orig_stack_contexts: yielded = _create_future() yielded.set_exception( stack_context.StackContextInconsistentError( 'stack_context inconsistency (probably caused ' 'by yield within a "with StackContext" block)') ) 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(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 future_set_result_unless_cancelled(future, result) return future
def run(self): """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 not future.done(): return self.future = None try: orig_stack_contexts = stack_context._state.contexts exc_info = None try: value = future.result() except Exception: self.had_exception = True exc_info = sys.exc_info() future = None if exc_info is not None: try: yielded = self.gen.throw(*exc_info) finally: # Break up a reference to itself # for faster GC on CPython. exc_info = None else: yielded = self.gen.send(value) if stack_context._state.contexts is not orig_stack_contexts: self.gen.throw( stack_context.StackContextInconsistentError( 'stack_context inconsistency (probably caused ' 'by yield within a "with StackContext" block)') ) except (StopIteration, Return) as e: self.finished = True self.future = _null_future if self.pending_callbacks and not self.had_exception: # If we ran cleanly without waiting on all callbacks # raise an error (really more of a warning). If we # had an exception then some callbacks may have been # orphaned, so skip the check in that case. raise LeakedCallbackError( "finished without waiting for callbacks %r" % self.pending_callbacks) future_set_result_unless_cancelled( self.result_future, _value_from_stopiteration(e)) self.result_future = None self._deactivate_stack_context() return except Exception: self.finished = True self.future = _null_future future_set_exc_info(self.result_future, sys.exc_info()) self.result_future = None self._deactivate_stack_context() return if not self.handle_yield(yielded): return yielded = None finally: self.running = False