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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) 2006-2010 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
from UserDict import DictMixin
from ConfigParser import SafeConfigParser, NoSectionError, NoOptionError
from .constants import SESSION_DIR
from .helper import debug, info
from .odict import OrderedDict
NoSuchThing = (NoSectionError, NoOptionError)
sessionlist = []
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, name="", oldfiles = [], register = True):
"""
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.
@param oldfiles: old file names for the same file
@param name: short name describing the type of session
@param register: register in the global sessionlist, which is closed at the end
"""
self._cfg = SafeConfigParser({}, OrderedDict)
self._handlers = []
self._name = name if name else "MAIN"
self._file = os.path.join(SESSION_DIR, file)
if not (os.path.exists(SESSION_DIR) and os.path.isdir(SESSION_DIR)):
os.mkdir(SESSION_DIR)
oldfiles = [os.path.join(SESSION_DIR, x) for x in oldfiles]
if not os.path.exists(self._file):
for o in oldfiles:
if os.path.exists(o):
debug("Moving old session file '%s' to '%s'." % (o, file))
os.rename(o,self._file)
break
self._cfg.read([self._file])
if name:
i = _("Loading '%s' session from %s.") % (name, self._file)
else:
i = _("Loading session from %s.") % self._file
info(i)
# register
if register: sessionlist.append(self)
# 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
"""
convert = lambda (x,y): (y.upper(), x.lower())
options = map(lambda x: (self._name, x.lower()) if not hasattr(x, "__iter__") else convert(x), options)
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 NoSuchThing: # 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 necessary
if not hasattr(vals, "__iter__"):
vals = [vals]
debug("Saving %s with values %s", options, vals)
for value, (section, option) in zip(vals, options):
self.set(option, str(value), section)
with open(self._file, "w") as f:
self._cfg.write(f)
@classmethod
def close (cls):
for s in sessionlist:
if s._name != "MAIN":
info(_("Saving '%s' session to %s.") % (s._name, s._file))
else:
info(_("Saving session to %s.") % s._file)
s.save()
def set (self, key, value, section = None):
if section is None: section = self._name
section = section.upper()
try:
self._cfg.set(section, key, value)
except NoSectionError:
self._cfg.add_section(section)
self._cfg.set(section, key, value)
def get (self, key, section = None):
if section is None: section = self._name
section = section.upper()
try:
return self._cfg.get(section, key)
except NoSuchThing:
return None
def remove (self, key, section = None):
if section is None: section = self._name
section = section.upper()
self._cfg.remove_option(section, key)
def remove_section (self, section):
section = section.upper()
self._cfg.remove_section(section)
def rename (self, old, new, section = None):
if section is None: section = self._name
section = section.upper()
val = self.get(old, section)
if val is not None:
self.remove(old, section)
self.set(new, val, section)
def rename_section (self, old, new):
new = new.upper()
values = self._cfg.items(old)
self.remove_section(old)
for k,v in values:
self.set(k,v,new)
def check_version (self, vers):
pass # do nothing atm
class SectionDict (DictMixin):
"""A class, which maps a specific section of a session to a dictionary."""
def __init__ (self, session, section):
self._section = section.upper()
self._session = session
def __getitem__ (self, name):
item = self._session.get(name, section = self._section)
if item is None:
raise KeyError, "%s not in section %s" % (name, self._section)
return item
def __setitem__ (self, name, value):
self._session.set(name, value, section = self._section)
def __delitem__ (self, name):
self._session.remove(name, self._section)
def keys (self):
return self._session._cfg.options(self._section)
def __contains__ (self, name):
return self._session._cfg.has_option(self._section, name)
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