41 lines
1.5 KiB
Python
41 lines
1.5 KiB
Python
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"""
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Implements signals based on blinker if available, otherwise
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falls silently back to a noop. Shamelessly stolen from flask.signals:
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https://github.com/mitsuhiko/flask/blob/master/flask/signals.py
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"""
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signals_available = False
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try:
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from blinker import Namespace
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signals_available = True
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except ImportError: # noqa
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class Namespace:
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def signal(self, name, doc=None):
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return _FakeSignal(name, doc)
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class _FakeSignal:
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"""If blinker is unavailable, create a fake class with the same
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interface that allows sending of signals but will fail with an
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error on anything else. Instead of doing anything on send, it
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will just ignore the arguments and do nothing instead.
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"""
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def __init__(self, name, doc=None):
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self.name = name
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self.__doc__ = doc
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def _fail(self, *args, **kwargs):
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raise RuntimeError('signalling support is unavailable '
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'because the blinker library is '
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'not installed.')
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send = lambda *a, **kw: None
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connect = disconnect = has_receivers_for = receivers_for = \
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temporarily_connected_to = connected_to = _fail
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del _fail
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# The namespace for code signals. If you are not oauthlib code, do
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# not put signals in here. Create your own namespace instead.
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_signals = Namespace()
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# Core signals.
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scope_changed = _signals.signal('scope-changed')
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