2a6420a3ed
Change-Id: I2518e0cf928210acf9cfb2e5f4c19f973df64485 Signed-off-by: Stephen Finucane <stephenfin@redhat.com>
71 lines
2.2 KiB
Python
71 lines
2.2 KiB
Python
# Copyright (C) 2014 Yahoo! Inc. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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import threading
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class Timeout:
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"""An object which represents a timeout.
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This object has the ability to be interrupted before the actual timeout
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is reached.
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"""
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def __init__(self, value, event_factory=threading.Event):
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if value < 0:
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raise ValueError(
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"Timeout value must be greater or"
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" equal to zero and not '%s'" % (value)
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)
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self._value = value
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self._event = event_factory()
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@property
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def value(self):
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"""Immutable value of the internally used timeout."""
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return self._value
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def interrupt(self):
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"""Forcefully set the timeout (releases any waiters)."""
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self._event.set()
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def is_stopped(self):
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"""Returns if the timeout has been interrupted."""
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return self._event.is_set()
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def wait(self):
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"""Block current thread (up to timeout) and wait until interrupted."""
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self._event.wait(self._value)
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def reset(self):
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"""Reset so that interruption (and waiting) can happen again."""
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self._event.clear()
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def convert_to_timeout(
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value=None, default_value=None, event_factory=threading.Event
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):
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"""Converts a given value to a timeout instance (and returns it).
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Does nothing if the value provided is already a timeout instance.
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"""
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if value is None:
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value = default_value
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if isinstance(value, (int, float, str)):
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return Timeout(float(value), event_factory=event_factory)
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elif isinstance(value, Timeout):
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return value
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else:
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raise ValueError("Invalid timeout literal '%s'" % (value))
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