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# -*- coding: utf-8 -*-
#
# File: portato/session.py
# This file is part of the Portato-Project, a graphical portage-frontend.
#
# Copyright (C) 2007 René 'Necoro' Neumann
# This is free software. You may redistribute copies of it under the terms of
# the GNU General Public License version 2.
# There is NO WARRANTY, to the extent permitted by law.
#
# Written by René 'Necoro' Neumann <necoro@necoro.net>
from __future__ import absolute_import, with_statement
import os, os.path
from .config_parser import ConfigParser, SectionNotFoundException
from .constants import SESSION_DIR
from .helper import debug, info
class Session (object):
"""
A small class allowing to save certain states of a program.
This class works in a quite abstract manner, as it works with handlers, which
define what options to use out of the config file and how to apply them to the program.
Note: This class currently does not work with boolean config options. If you
want to define boolean values, use 0 and 1. This is future proof.
"""
# the current session format version
VERSION = 1
def __init__ (self, file):
"""
Initialize a session with a certain file inside L{SESSION_DIR}.
@param file: the file in L{SESSION_DIR}, where the options will be saved.
"""
self._cfg = None
self._handlers = []
if not (os.path.exists(SESSION_DIR) and os.path.isdir(SESSION_DIR)):
os.mkdir(SESSION_DIR)
self._cfg = ConfigParser(os.path.join(SESSION_DIR, file))
info(_("Loading session from '%s'.") % self._cfg.file)
try:
self._cfg.parse()
except IOError, e:
if e.errno == 2: pass
else: raise
# add version check
self.add_handler(([("version", "session")], self.check_version, lambda: self.VERSION))
def add_handler (self, (options, load_fn, save_fn), default = None):
"""
Adds a handler to this session. A handler is a three-tuple consisting of:
- a list of (key,section) values
- a function getting number of option arguments and applying them to the program
- a function returning the number of option return values - getting them out of the program
"""
self._handlers.append((options, load_fn, save_fn, default))
def load (self, defaults_only = False):
"""
Loads and applies all values of the session.
"""
def ldefault (options, lfn, default):
if not default: return
debug("Loading %s with defaults %s.", options, default)
lfn(*default)
for options, lfn, sfn, default in self._handlers:
if defaults_only:
ldefault(options, lfn, default)
else:
try:
loaded = [self._cfg.get(*x) for x in options]
except KeyError: # does not exist -> ignore
debug("No values for %s.", options)
ldefault(options, lfn, default)
else:
debug("Loading %s with values %s.", options, loaded)
lfn(*loaded)
def save (self):
"""
Saves all options into the file.
"""
for options, lfn, sfn, default in self._handlers:
vals = sfn()
# map into list if necessairy
if not hasattr(vals, "__iter__"):
vals = [vals]
debug("Saving %s with values %s", options, vals)
for value, (option, section) in zip(vals, options):
self.set(option, str(value), section)
self._cfg.write()
def set (self, key, value, section):
try:
self._cfg.add(key, value, section, with_blankline = False)
except SectionNotFoundException:
self._cfg.add_section(section)
self._cfg.add(key, value, section, with_blankline = False)
def get (self, key, section):
try:
return self._cfg.get(key, section)
except KeyError:
return None
def get_boolean (self, key, section):
try:
return self._cfg.get_boolean(key, section)
except KeyError:
return None
def check_version (self, vers):
pass # do nothing atm
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