sh_cpl/src/cpl_reactive_extensions/observable.py

82 lines
2.5 KiB
Python

from typing import Callable, Union, Any, Optional
from cpl_reactive_extensions.abc.operator import Operator
from cpl_reactive_extensions.abc.subscribable import Subscribable
from cpl_reactive_extensions.subscriber import Observer, Subscriber
from cpl_reactive_extensions.subscription import Subscription
class Observable(Subscribable):
def __init__(self, subscribe: Callable = None):
Subscribable.__init__(self)
if subscribe is not None:
self._subscribe = subscribe
self._source: Optional[Observable] = None
self._operator: Optional[Operator] = None
@staticmethod
def from_list(values: list):
i = 0
def callback(x: Subscriber):
nonlocal i
if i == len(values):
i = 0
x.complete()
else:
x.next(values[i])
i += 1
if not x.closed:
callback(x)
observable = Observable(callback)
return observable
@staticmethod
def _is_observer(value: Any) -> bool:
return isinstance(value, Observer)
@staticmethod
def _is_subscription(value: Any) -> bool:
return isinstance(value, Subscription)
@staticmethod
def _is_subscriber(value: Any) -> bool:
return isinstance(value, Subscriber) or Observable._is_observer(value) and Observable._is_subscription(value)
def _subscribe(self, subscriber: Subscriber) -> Subscription:
return self._source.subscribe(subscriber)
def subscribe(
self, observer_or_next: Union[Callable, Observer], on_error: Callable = None, on_complete: Callable = None
) -> Subscription:
subscriber = (
observer_or_next
if Observable._is_subscriber(observer_or_next)
else Subscriber(observer_or_next, on_error, on_complete)
)
subscriber.add(
self._operator.call(subscriber, self._source)
if self._operator is not None
else self._subscribe(subscriber)
if self._source is not None
else self._try_subscribe(subscriber)
)
return subscriber
def _try_subscribe(self, subscriber: Subscriber):
try:
return self._subscribe(subscriber)
except Exception as e:
subscriber.error(e)
def _call(self, observer: Observer):
try:
self._subscribe(observer)
except Exception as e:
observer.error(e)