74 lines
1.8 KiB
Python
74 lines
1.8 KiB
Python
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"""
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Module defining the Slot class.
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"""
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import types
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import weakref
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import sys
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from .signal import BaseSlot
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# We cannot test a branch for Python >= 3.4 in Python < 3.4.
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if sys.version_info < (3, 4): # pragma: no cover
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from weakrefmethod import WeakMethod
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else: # pragma: no cover
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from weakref import WeakMethod
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class Slot(BaseSlot):
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"""
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A slot is a callable object that manages a connection to a signal.
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If weak is true or the slot is a subclass of weakref.ref, the slot
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is automatically de-referenced to the called function.
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"""
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def __init__(self, slot, weak=False):
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self._weak = weak or isinstance(slot, weakref.ref)
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if weak and not isinstance(slot, weakref.ref):
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if isinstance(slot, types.MethodType):
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slot = WeakMethod(slot)
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else:
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slot = weakref.ref(slot)
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self._slot = slot
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@property
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def is_alive(self):
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"""
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Return True if this slot is "alive".
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"""
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return (not self._weak) or (self._slot() is not None)
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@property
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def func(self):
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"""
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Return the function that is called by this slot.
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"""
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if self._weak:
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return self._slot()
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else:
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return self._slot
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def __call__(self, **kwargs):
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"""
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Execute this slot.
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"""
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func = self.func
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if func is not None:
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return func(**kwargs)
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def __eq__(self, other):
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"""
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Compare this slot to another.
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"""
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if isinstance(other, BaseSlot):
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return self.func == other.func
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else:
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return self.func == other
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def __repr__(self):
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fn = self.func
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if fn is None:
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fn = 'dead'
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else:
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fn = repr(fn)
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return '<signalslot.Slot: %s>' % fn
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