36 lines
999 B
Python
36 lines
999 B
Python
# Customized from https://github.com/open-telemetry/opentelemetry-python/blob/754fc36a408dd45e86d4a0f820f84e692f14b4c1/opentelemetry-api/src/opentelemetry/util/_once.py
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from threading import Lock
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from typing import Callable
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class Once:
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"""Execute a function exactly once and block all callers until the function returns"""
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def __init__(self) -> None:
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self.__lock = Lock()
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self.__done = False
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@property
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def done(self):
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with self.__lock:
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return self.__done
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@done.setter
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def done(self, value):
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with self.__lock:
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self.__done = value
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def do_once(self, func: Callable[[], None]):
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"""
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Execute ``func`` if it hasn't been executed or return.
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Will block until ``func`` has been called by one thread.
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"""
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if self.__done:
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return
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with self.__lock:
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if not self.__done:
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func()
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self.__done = True
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return
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