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