dosage/dosagelib/decorators.py

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# -*- coding: iso-8859-1 -*-
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# Copyright (C) 2012-2014 Bastian Kleineidam
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class memoized (object):
"""Decorator that caches a function's return value each time it is called.
If called later with the same arguments, the cached value is returned, and
not re-evaluated."""
def __init__(self, func):
"""Store function and initialize the cache."""
self.func = func
self.cache = {}
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def __call__(self, *args, **kwargs):
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"""Lookup and return cached result if found. Else call stored
function with given arguments."""
try:
return self.cache[args]
except KeyError:
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self.cache[args] = value = self.func(*args, **kwargs)
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return value
except TypeError:
# uncachable -- for instance, passing a list as an argument.
# Better to not cache than to blow up entirely.
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return self.func(*args, **kwargs)
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def __repr__(self):
"""Return the function's docstring."""
return self.func.__doc__