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from collections import UserDict |
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from typing import Dict, Optional, Union |
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4
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import curio |
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6
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from ..protocol import Observable, Observer, Subscription |
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__all__ = ["rx_dict"] |
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10
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11
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class _RxDict(UserDict): |
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def __init__(self, dict: Union[Dict, "_RxDict"]): |
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self._event = curio.UniversalEvent() |
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self._subscribers = 0 |
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super().__init__(dict) |
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17
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View Code Duplication |
async def subscribe(self, an_observer: Observer) -> Subscription: |
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if self._subscribers > 0: |
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raise RuntimeError("Only one subscription is supported") |
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self._subscribers += 1 |
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_consumer_task = None |
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async def consumer(): |
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try: |
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while True: |
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await self._event.wait() |
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await an_observer.on_next(dict(self.data)) |
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self._event.clear() |
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except curio.TaskCancelled: |
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# it's time to finish |
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pass |
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async def _subscription(): |
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nonlocal _consumer_task |
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if _consumer_task: |
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await _consumer_task.cancel() |
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_consumer_task = None |
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self._subscribers -= 1 |
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_consumer_task = await curio.spawn(consumer()) |
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await an_observer.on_next(dict(self.data)) |
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return _subscription |
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def _set_event(self): |
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if not self._event.is_set() and self._subscribers: |
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self._event.set() |
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def __setitem__(self, key, item): |
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self.data[key] = item |
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self._set_event() |
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def __delitem__(self, key): |
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del self.data[key] |
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self._set_event() |
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def copy(self): |
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return _RxDict(super().copy()) |
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65
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def rx_dict(initial_value: Optional[Dict] = None) -> Observable: |
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"""Create an observable on dictionnary. |
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68
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The observer receive the current value of dictionnary on subscribe |
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and when a key change (added, updated or deleted). |
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This observable implements a UserDict, so you can use it as a classic dictionnary. |
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72
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Args: |
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initial_value (Optional[Dict]): intial value (default: {}) |
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Returns: |
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(Observable): observable instance |
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""" |
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return _RxDict(dict=initial_value if initial_value else {}) |
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geronimo-iia /
async-rx
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