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# shareddict.py, classes to aid activities in sharing a state
# Reinier Heeres, reinier@heeres.eu
#
# 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
#
# Change log:
# 2007-06-21: rwh, first version
import logging
_logger = logging.getLogger('sharinghelper')
from sharedobject import SharedObject
class SharedDict(SharedObject):
"""Shared dictionary object, generates key-based difference objects"""
def __init__(self, name, helper, opt={}):
SharedObject.__init__(self, name, helper, opt=opt)
self._value = {}
def __getitem__(self, key):
# _logger.debug('SharedDict.__getitem__(%s)', key)
return self.get_key(key)
def __setitem__(self, key, val):
# _logger.debug('SharedDict.__setitem__(%s, %s)', key, val)
return self.set_key(key, val)
def __delitem__(self, key):
self.delete_key(key)
def get_key(self, key, val):
return self._value[key]
def set_key(self, key, val):
if key in self._value:
d = {'change': {key: val}}
else:
d = {'add': {key: val}}
self._value[key] = val
self.changed(d, True)
def delete_key(self, key):
if key in self._value:
del self._value[key]
d = {'remove': key}
self.changed(d, True)
def _compatible_diffs(self, diffa, diffb):
for key in diffa:
if key in diffb:
return False
return True
def diff(self, cur, old):
ret = {'remove': [], 'add': {}, 'change': {}}
if old is None:
return ret
for key in set(old.keys()).difference(cur.keys()):
ret['remove'].append(key)
for key in set(cur.keys()).difference(old.keys()):
ret['add'][key] = cur[key]
for key in set(cur.keys()).intersection(old.keys()):
if cur[key] is not old[key]:
ret['change'][key] = cur[key]
return ret
def _apply_diff_to(self, obj, diffobj):
"""Apply a diff and return an object that describes the inverse diff"""
if diffobj is None:
return (None, None)
ret = {'add':{}, 'remove':[], 'change':{}}
if 'remove' in diffobj:
for key in diffobj['remove']:
ret['add'][key] = obj[key]
del self._value[key]
if 'add' in diffobj:
for key, val in diffobj['add'].iteritems():
ret['remove'].append(key)
obj[key] = val
if 'change' in diffobj:
for key, val in diffobj['change'].iteritems():
ret[key] = self._value[key]
obj[key] = val
return (obj, ret)
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