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from typing import Any, Iterable, Optional, TypeVar
from reactivex import Observable, abc
from reactivex.disposable import (
CompositeDisposable,
Disposable,
SerialDisposable,
SingleAssignmentDisposable,
)
from reactivex.scheduler import CurrentThreadScheduler
_T = TypeVar("_T")
def catch_with_iterable_(sources: Iterable[Observable[_T]]) -> Observable[_T]:
"""Continues an observable sequence that is terminated by an
exception with the next observable sequence.
Examples:
>>> res = catch([xs, ys, zs])
>>> res = reactivex.catch(src for src in [xs, ys, zs])
Args:
sources: an Iterable of observables. Thus a generator is accepted.
Returns:
An observable sequence containing elements from consecutive
source sequences until a source sequence terminates
successfully.
"""
sources_ = iter(sources)
def subscribe(
observer: abc.ObserverBase[_T], scheduler_: Optional[abc.SchedulerBase] = None
) -> abc.DisposableBase:
_scheduler = scheduler_ or CurrentThreadScheduler.singleton()
subscription = SerialDisposable()
cancelable = SerialDisposable()
last_exception = None
is_disposed = False
def action(scheduler: abc.SchedulerBase, state: Any = None) -> None:
def on_error(exn: Exception) -> None:
nonlocal last_exception
last_exception = exn
cancelable.disposable = _scheduler.schedule(action)
if is_disposed:
return
try:
current = next(sources_)
except StopIteration:
if last_exception:
observer.on_error(last_exception)
else:
observer.on_completed()
except Exception as ex: # pylint: disable=broad-except
observer.on_error(ex)
else:
d = SingleAssignmentDisposable()
subscription.disposable = d
d.disposable = current.subscribe(
observer.on_next,
on_error,
observer.on_completed,
scheduler=scheduler_,
)
cancelable.disposable = _scheduler.schedule(action)
def dispose() -> None:
nonlocal is_disposed
is_disposed = True
return CompositeDisposable(subscription, cancelable, Disposable(dispose))
return Observable(subscribe)
__all__ = ["catch_with_iterable_"]
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