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from typing import Any, List, Optional, Tuple
from reactivex import Observable, abc
from reactivex.disposable import CompositeDisposable, SingleAssignmentDisposable
def combine_latest_(*sources: Observable[Any]) -> Observable[Tuple[Any, ...]]:
"""Merges the specified observable sequences into one observable
sequence by creating a tuple whenever any of the
observable sequences produces an element.
Examples:
>>> obs = combine_latest(obs1, obs2, obs3)
Returns:
An observable sequence containing the result of combining
elements of the sources into a tuple.
"""
parent = sources[0]
def subscribe(
observer: abc.ObserverBase[Any], scheduler: Optional[abc.SchedulerBase] = None
) -> CompositeDisposable:
n = len(sources)
has_value = [False] * n
has_value_all = [False]
is_done = [False] * n
values = [None] * n
def _next(i: Any) -> None:
has_value[i] = True
if has_value_all[0] or all(has_value):
res = tuple(values)
observer.on_next(res)
elif all([x for j, x in enumerate(is_done) if j != i]):
observer.on_completed()
has_value_all[0] = all(has_value)
def done(i: Any) -> None:
is_done[i] = True
if all(is_done):
observer.on_completed()
subscriptions: List[Optional[SingleAssignmentDisposable]] = [None] * n
def func(i: int) -> None:
subscriptions[i] = SingleAssignmentDisposable()
def on_next(x: Any) -> None:
with parent.lock:
values[i] = x
_next(i)
def on_completed() -> None:
with parent.lock:
done(i)
subscription = subscriptions[i]
assert subscription
subscription.disposable = sources[i].subscribe(
on_next, observer.on_error, on_completed, scheduler=scheduler
)
for idx in range(n):
func(idx)
return CompositeDisposable(subscriptions)
return Observable(subscribe)
__all__ = ["combine_latest_"]
|
