51 lines
1.5 KiB
Python
51 lines
1.5 KiB
Python
from concurrent.futures import Future, Executor
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import sys
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from typing import Any, Callable, Optional, TypeVar, TYPE_CHECKING
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from ..compat import ParamSpec
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_P = ParamSpec('_P')
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_T = TypeVar('_T')
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# https://stackoverflow.com/a/10436851/706389
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class DummyExecutor(Executor):
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"""
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This is useful if you're already using Executor for parallelising,
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but also want to provide an option to run the code serially (e.g. for debugging)
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"""
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def __init__(self, max_workers: Optional[int] = 1) -> None:
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self._shutdown = False
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self._max_workers = max_workers
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if TYPE_CHECKING:
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if sys.version_info[:2] <= (3, 8):
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# 3.8 doesn't support ParamSpec as Callable arg :(
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# and any attempt to type results in incompatible supertype.. so whatever
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def submit(self, fn, *args, **kwargs): ...
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else:
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def submit(self, fn: Callable[_P, _T], /, *args: _P.args, **kwargs: _P.kwargs) -> Future[_T]: ...
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else:
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def submit(self, fn, *args, **kwargs):
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if self._shutdown:
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raise RuntimeError('cannot schedule new futures after shutdown')
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f: Future[Any] = Future()
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try:
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result = fn(*args, **kwargs)
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except KeyboardInterrupt:
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raise
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except BaseException as e:
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f.set_exception(e)
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else:
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f.set_result(result)
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return f
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def shutdown(self, wait: bool = True, **kwargs) -> None:
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self._shutdown = True
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