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94 lines
1.9 KiB
Python
94 lines
1.9 KiB
Python
from typing import TypeVar
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from abc import ABCMeta, abstractmethod
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from ..error import PatternLockedError
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T = TypeVar('T', bound='Lockable')
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I = TypeVar('I', bound='LockableImpl')
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class Lockable(metaclass=ABCMeta):
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"""
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Abstract class for all lockable entities
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"""
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__slots__ = ()
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'''
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---- Methods
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'''
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@abstractmethod
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def lock(self: T) -> T:
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"""
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Lock the object, disallowing further changes
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Returns:
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self
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"""
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pass
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@abstractmethod
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def unlock(self: T) -> T:
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"""
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Unlock the object, reallowing changes
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Returns:
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self
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"""
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pass
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@abstractmethod
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def is_locked(self) -> bool:
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"""
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Returns:
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True if the object is locked
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"""
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pass
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def set_locked(self: T, locked: bool) -> T:
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"""
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Locks or unlocks based on the argument.
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No action if already in the requested state.
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Args:
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locked: State to set.
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Returns:
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self
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"""
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if locked != self.is_locked():
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if locked:
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self.lock()
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else:
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self.unlock()
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return self
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class LockableImpl(Lockable, metaclass=ABCMeta):
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"""
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Simple implementation of Lockable
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"""
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__slots__ = ()
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locked: bool
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""" If `True`, disallows changes to the object """
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'''
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---- Non-abstract methods
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'''
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def __setattr__(self, name, value):
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if self.locked and name != 'locked':
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raise PatternLockedError()
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object.__setattr__(self, name, value)
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def lock(self: I) -> I:
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object.__setattr__(self, 'locked', True)
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return self
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def unlock(self: I) -> I:
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object.__setattr__(self, 'locked', False)
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return self
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def is_locked(self) -> bool:
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return self.locked
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