A queue-style container that provides both sync and async interface. This is used to provide a compatible interface for janus.Queue.
| 362 | |
| 363 | |
| 364 | class AsyncQueue: |
| 365 | """ |
| 366 | A queue-style container that provides both sync and async interface. |
| 367 | This is used to provide a compatible interface for janus.Queue. |
| 368 | """ |
| 369 | |
| 370 | class EventLoopShutdownError(Exception): |
| 371 | pass |
| 372 | |
| 373 | class MixedSyncAsyncAPIError(Exception): |
| 374 | pass |
| 375 | |
| 376 | def __init__(self): |
| 377 | self._q = collections.deque() |
| 378 | self._event = asyncio.Event() |
| 379 | self._tainted = False |
| 380 | self._sync_q = _SyncQueue(self) |
| 381 | |
| 382 | @property |
| 383 | def sync_q(self): |
| 384 | return self._sync_q |
| 385 | |
| 386 | def full(self) -> bool: |
| 387 | return len(self._q) == self._q.maxlen |
| 388 | |
| 389 | def empty(self) -> bool: |
| 390 | return not self._q |
| 391 | |
| 392 | def put(self, item) -> None: |
| 393 | self._q.append(item) |
| 394 | self._event.set() |
| 395 | |
| 396 | # Decoupled put and notify. |
| 397 | # Deque is thread safe so we can put from outside the event loop. |
| 398 | # However, we have to schedule notify in event loop because it's not thread safe. |
| 399 | # In this case the notify part may get scheduled late, to the point that |
| 400 | # corresponding data in deque may have already been consumed. |
| 401 | # Avoid firing the event in this case. |
| 402 | def put_nowait(self, item) -> None: |
| 403 | self._q.append(item) |
| 404 | |
| 405 | def notify(self) -> None: |
| 406 | if self._q: |
| 407 | self._event.set() |
| 408 | |
| 409 | def unsafe_get(self): |
| 410 | # Unsafe get taints the queue, renders it unusable by async methods. |
| 411 | self._tainted = True |
| 412 | # Use exception to detect empty. Pre-check is not thread safe. |
| 413 | try: |
| 414 | return self._q.popleft() |
| 415 | except IndexError: |
| 416 | raise asyncio.QueueEmpty() from None |
| 417 | |
| 418 | async def get(self, timeout=None): |
| 419 | if self._tainted: |
| 420 | raise AsyncQueue.MixedSyncAsyncAPIError() |
| 421 |
no outgoing calls