bazarr/libs/tqdm/contrib/utils_worker.py

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"""
IO/concurrency helpers for `tqdm.contrib`.
"""
from __future__ import absolute_import
from collections import deque
from concurrent.futures import ThreadPoolExecutor
from ..auto import tqdm as tqdm_auto
__author__ = {"github.com/": ["casperdcl"]}
__all__ = ['MonoWorker']
class MonoWorker(object):
"""
Supports one running task and one waiting task.
The waiting task is the most recent submitted (others are discarded).
"""
def __init__(self):
self.pool = ThreadPoolExecutor(max_workers=1)
self.futures = deque([], 2)
def submit(self, func, *args, **kwargs):
"""`func(*args, **kwargs)` may replace currently waiting task."""
futures = self.futures
if len(futures) == futures.maxlen:
running = futures.popleft()
if not running.done():
if len(futures): # clear waiting
waiting = futures.pop()
waiting.cancel()
futures.appendleft(running) # re-insert running
try:
waiting = self.pool.submit(func, *args, **kwargs)
except Exception as e:
tqdm_auto.write(str(e))
else:
futures.append(waiting)
return waiting