Cours/venv/lib/python3.12/site-packages/watchdog/utils/delayed_queue.py

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2024-09-02 16:55:06 +00:00
""":module: watchdog.utils.delayed_queue
:author: thomas.amland@gmail.com (Thomas Amland)
:author: contact@tiger-222.fr (Mickaël Schoentgen)
"""
from __future__ import annotations
import threading
import time
from collections import deque
from typing import Callable, Generic, TypeVar
T = TypeVar("T")
class DelayedQueue(Generic[T]):
def __init__(self, delay: float) -> None:
self.delay_sec = delay
self._lock = threading.Lock()
self._not_empty = threading.Condition(self._lock)
self._queue: deque[tuple[T, float, bool]] = deque()
self._closed = False
def put(self, element: T, *, delay: bool = False) -> None:
"""Add element to queue."""
self._lock.acquire()
self._queue.append((element, time.time(), delay))
self._not_empty.notify()
self._lock.release()
def close(self) -> None:
"""Close queue, indicating no more items will be added."""
self._closed = True
# Interrupt the blocking _not_empty.wait() call in get
self._not_empty.acquire()
self._not_empty.notify()
self._not_empty.release()
def get(self) -> T | None:
"""Remove and return an element from the queue, or this queue has been
closed raise the Closed exception.
"""
while True:
# wait for element to be added to queue
self._not_empty.acquire()
while len(self._queue) == 0 and not self._closed:
self._not_empty.wait()
if self._closed:
self._not_empty.release()
return None
head, insert_time, delay = self._queue[0]
self._not_empty.release()
# wait for delay if required
if delay:
time_left = insert_time + self.delay_sec - time.time()
while time_left > 0:
time.sleep(time_left)
time_left = insert_time + self.delay_sec - time.time()
# return element if it's still in the queue
with self._lock:
if len(self._queue) > 0 and self._queue[0][0] is head:
self._queue.popleft()
return head
def remove(self, predicate: Callable[[T], bool]) -> T | None:
"""Remove and return the first items for which predicate is True,
ignoring delay.
"""
with self._lock:
for i, (elem, *_) in enumerate(self._queue):
if predicate(elem):
del self._queue[i]
return elem
return None