96 lines
3.1 KiB
Python
96 lines
3.1 KiB
Python
# Copyright (c) 2018, Neil Booth
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#
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# All rights reserved.
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#
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# The MIT License (MIT)
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#
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# Permission is hereby granted, free of charge, to any person obtaining
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# a copy of this software and associated documentation files (the
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# "Software"), to deal in the Software without restriction, including
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# without limitation the rights to use, copy, modify, merge, publish,
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# distribute, sublicense, and/or sell copies of the Software, and to
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# permit persons to whom the Software is furnished to do so, subject to
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# the following conditions:
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#
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# The above copyright notice and this permission notice shall be
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# included in all copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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__all__ = ()
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import asyncio
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from collections import namedtuple
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import inspect
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# other_params: None means cannot be called with keyword arguments only
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# any means any name is good
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SignatureInfo = namedtuple('SignatureInfo', 'min_args max_args '
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'required_names other_names')
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def signature_info(func):
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params = inspect.signature(func).parameters
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min_args = max_args = 0
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required_names = []
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other_names = []
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no_names = False
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for p in params.values():
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if p.kind == p.POSITIONAL_OR_KEYWORD:
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max_args += 1
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if p.default is p.empty:
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min_args += 1
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required_names.append(p.name)
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else:
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other_names.append(p.name)
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elif p.kind == p.KEYWORD_ONLY:
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other_names.append(p.name)
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elif p.kind == p.VAR_POSITIONAL:
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max_args = None
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elif p.kind == p.VAR_KEYWORD:
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other_names = any
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elif p.kind == p.POSITIONAL_ONLY:
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max_args += 1
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if p.default is p.empty:
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min_args += 1
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no_names = True
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if no_names:
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other_names = None
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return SignatureInfo(min_args, max_args, required_names, other_names)
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class Concurrency:
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def __init__(self, max_concurrent):
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self._require_non_negative(max_concurrent)
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self._max_concurrent = max_concurrent
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self.semaphore = asyncio.Semaphore(max_concurrent)
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def _require_non_negative(self, value):
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if not isinstance(value, int) or value < 0:
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raise RuntimeError('concurrency must be a natural number')
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@property
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def max_concurrent(self):
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return self._max_concurrent
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async def set_max_concurrent(self, value):
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self._require_non_negative(value)
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diff = value - self._max_concurrent
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self._max_concurrent = value
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if diff >= 0:
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for _ in range(diff):
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self.semaphore.release()
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else:
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for _ in range(-diff):
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await self.semaphore.acquire()
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