64 lines
1.9 KiB
Python
64 lines
1.9 KiB
Python
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""" A signal/slot implementation
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File: signal.py
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Author: Thiago Marcos P. Santos
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Author: Christopher S. Case
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Author: David H. Bronke
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Created: August 28, 2008
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Updated: December 12, 2011
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License: MIT
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"""
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import inspect
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from weakref import WeakKeyDictionary
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class Signal(object):
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def __init__(self):
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# The original implementation used WeakSet to store functions,
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# but that causes lambdas without any other reference to be
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# garbage collected. So we use a normal set to avoid that.
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self._functions = set()
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self._methods = WeakKeyDictionary()
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# The original implementation used __call__, so one would just call the signal itself:
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#
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# my_signal("foo")
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#
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# This has been changed to the emit() method to both be more consistent with how signals/slots
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# work in Qt & GTK and to make it more easily apparent that a signal is being triggered.
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# The correct way to trigger a signal is therefore:
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#
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# my_signal.emit("foo")
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def emit(self, *args, **kargs):
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# Call handler functions
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for func in self._functions.copy():
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func(*args, **kargs)
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# Call handler methods
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for obj, funcs in self._methods.copy().items():
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for func in funcs.copy():
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func(obj, *args, **kargs)
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def connect(self, slot):
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if inspect.ismethod(slot):
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if slot.__self__ not in self._methods:
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self._methods[slot.__self__] = set()
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self._methods[slot.__self__].add(slot.__func__)
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else:
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self._functions.add(slot)
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def disconnect(self, slot):
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if inspect.ismethod(slot):
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if slot.__self__ in self._methods:
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self._methods[slot.__self__].discard(slot.__func__)
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else:
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if slot in self._functions:
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self._functions.discard(slot)
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def clear(self):
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self._functions.clear()
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self._methods.clear()
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