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# Copyright (c) 2006-2007 LOGILAB S.A. (Paris, FRANCE).
# http://www.logilab.fr/ -- mailto:contact@logilab.fr
#
# This program is free software; you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free Software
# Foundation; either version 2 of the License, or (at your option) any later
# version.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along with
# this program; if not, write to the Free Software Foundation, Inc.,
# 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
"""this module contains some function/method decorators"""
# XXX rewrite so we can use the decorator syntax when keyarg has to be specified
def cached(callableobj, keyarg=None):
"""simple decorator to cache result of method call"""
#print callableobj, keyarg, callableobj.func_code.co_argcount
if callableobj.func_code.co_argcount == 1 or keyarg == 0:
def cache_wrapper1(self, *args):
cache = '_%s_cache_' % callableobj.__name__
#print 'cache1?', cache
try:
return self.__dict__[cache]
except KeyError:
#print 'miss'
value = callableobj(self, *args)
setattr(self, cache, value)
return value
return cache_wrapper1
elif keyarg:
def cache_wrapper2(self, *args, **kwargs):
cache = '_%s_cache_' % callableobj.__name__
key = args[keyarg-1]
#print 'cache2?', cache, self, key
try:
_cache = self.__dict__[cache]
except KeyError:
#print 'init'
_cache = {}
setattr(self, cache, _cache)
try:
return _cache[key]
except KeyError:
#print 'miss', self, cache, key
_cache[key] = callableobj(self, *args, **kwargs)
return _cache[key]
return cache_wrapper2
def cache_wrapper3(self, *args):
cache = '_%s_cache_' % callableobj.__name__
#print 'cache3?', cache, self, args
try:
_cache = self.__dict__[cache]
except KeyError:
#print 'init'
_cache = {}
setattr(self, cache, _cache)
try:
return _cache[args]
except KeyError:
#print 'miss'
_cache[args] = callableobj(self, *args)
return _cache[args]
return cache_wrapper3
def clear_cache(obj, funcname):
"""function to clear a cache handled by the cached decorator"""
try:
del obj.__dict__['_%s_cache_' % funcname]
except KeyError:
pass
def copy_cache(obj, funcname, cacheobj):
"""copy cache for <funcname> from cacheobj to obj"""
cache = '_%s_cache_' % funcname
try:
setattr(obj, cache, cacheobj.__dict__[cache])
except KeyError:
pass
class wproperty(object):
"""simple descriptor expecting to take a modifier function as first argument
and looking for a _<function name> to retreive the attribute
"""
def __init__(self, setfunc):
self.setfunc = setfunc
self.attrname = '_%s' % setfunc.__name__
def __set__(self, obj, value):
self.setfunc(obj, value)
def __get__(self, obj, cls):
assert obj is not None
return getattr(obj, self.attrname)
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