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# 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
#
import sys
def is_persistent(item):
prop = item[1]
return type(prop) is property and \
hasattr(prop.fget, 'decorator') and \
prop.fget.decorator is PersistentProperty
class Persistent(type):
def __init__(cls, name, bases, dct):
# is_dirty
setattr(cls, '__dirty__', False)
# properties
setattr(cls, '__properties__', filter(is_persistent, dct.iteritems()))
super(Persistent, cls).__init__(name, bases, dct)
def PersistentProperty(function):
function.decorator = PersistentProperty
keys = 'fset', 'fdel'
func_locals = {'doc':function.__doc__}
def fgetter(obj, name, getter, fdef):
attr_name = '_' + obj.__class__.__name__ + '__' + name
if not hasattr(obj, attr_name):
setattr(obj, attr_name, fdef(obj))
return getter(obj)
def fsetter(obj, name, setter, value):
setattr(obj, '__dirty__', True)
return setter(obj, value)
def probe_function(frame, event, arg):
if event == 'return':
locals = frame.f_locals
func_locals.update(dict((k,locals.get(k)) for k in keys))
if locals.has_key('fset'):
func_locals['fset'] = lambda obj, value : fsetter(obj, function.__name__, locals['fset'], value)
if locals.has_key('fdef'):
f = lambda obj : fgetter(obj, function.__name__, locals['fget'], locals['fdef'])
else:
f = lambda obj : fgetter(obj, function.__name__, locals['fget'], lambda x : None)
f.decorator = PersistentProperty # tag the getter
func_locals['fget'] = f
sys.settrace(None)
return probe_function
sys.settrace(probe_function)
function()
return property(**func_locals)
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