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'''
This file is part of ConfigShell Community Edition.
Copyright (c) 2011 by RisingTide Systems LLC
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as
published by the Free Software Foundation, version 3 (AGPLv3).
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 Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
'''
import cPickle
class Prefs(object):
'''
This is a preferences backend object used to:
- Hold the ConfigShell preferences
- Handle persistent storage and retrieval of these preferences
- Share the preferences between the ConfigShell and ConfigNode objects
As it is inherently destined to be shared between objects, this is a Borg.
'''
_prefs = {}
filename = None
autosave = False
__borg_state = {}
def __init__(self, filename=None):
'''
Instanciates the ConfigShell preferences object.
@param filename: File to store the preferencces to.
@type filename: str
'''
self.__dict__ = self.__borg_state
if filename is not None:
self.filename = filename
def __getitem__(self, key):
'''
Proxies dict-like references to prefs.
One specific behavior, though, is that if the key does not exists,
we will return None instead of raising an exception.
@param key: The preferences dictionnary key to get.
@type key: any valid dict key
@return: The key value
@rtype: n/a
'''
if key in self._prefs:
return self._prefs[key]
else:
return None
def __setitem__(self, key, value):
'''
Proxies dict-like references to prefs.
@param key: The preferences dictionnary key to set.
@type key: any valid dict key
'''
self._prefs[key] = value
if self.autosave:
self.save()
def __contains__(self, key):
'''
Do the preferences contain key ?
@param key: The preferences dictionnary key to check.
@type key: any valid dict key
'''
if key in self._prefs:
return True
else:
return False
def __delitem__(self, key):
'''
Deletes a preference key.
@param key: The preference to delete.
@type key: any valid dict key
'''
del self._prefs[key]
if self.autosave:
self.save()
def __iter__(self):
'''
Generic iterator for the preferences.
'''
return self._prefs.__iter__()
# Public methods
def keys(self):
'''
@return: Returns the list of keys in preferences.
@rtype: list
'''
return self._prefs.keys()
def items(self):
'''
@return: Returns the list of items in preferences.
@rtype: list of (key, value) tuples
'''
return self._prefs.items()
def iteritems(self):
'''
@return: Iterates on the items in preferences.
@rtype: yields items that are (key, value) pairs
'''
return self._prefs.iteritems()
def save(self, filename=None):
'''
Saves the preferences to disk. If filename is not specified,
use the default one if it is set, else do nothing.
@param filename: Optional alternate file to use.
@type filename: str
'''
if filename is None:
filename = self.filename
if filename is not None:
fsock = open(filename, 'wb')
try:
cPickle.dump(self._prefs, fsock, 2)
finally:
fsock.close()
def load(self, filename=None):
'''
Loads the preferences from file. Use either the supplied filename,
or the default one if set. Else, do nothing.
'''
if filename is None:
filename = self.filename
if filename is not None:
fsock = open(filename, 'rb')
try:
self._prefs = cPickle.load(fsock)
finally:
fsock.close()
|
