27 lines
868 B
Python
27 lines
868 B
Python
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patched = {}
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def patch(namespace, name, value):
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""" rebind the 'name' on the 'namespace' to the 'value',
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possibly and remember the original value. Multiple
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invocations to the same namespace/name pair will
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remember a list of old values.
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"""
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nref = (namespace, name)
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orig = getattr(namespace, name)
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patched.setdefault(nref, []).append(orig)
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setattr(namespace, name, value)
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return orig
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def revert(namespace, name):
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""" revert to the orginal value the last patch modified.
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Raise ValueError if no such original value exists.
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"""
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nref = (namespace, name)
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if nref not in patched or not patched[nref]:
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raise ValueError, "No original value stored for %s.%s" % nref
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current = getattr(namespace, name)
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orig = patched[nref].pop()
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setattr(namespace, name, orig)
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return current
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