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