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# -*- coding: utf-8 -*-
#
# File: portato/db/__init__.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 collections import namedtuple
from . import database as db
from .exceptions import UnknownDatabaseTypeError, DatabaseInstantiationError, DatabaseInitError
from ..session import Session, SectionDict
from ..helper import debug, warning, error, info
from ..odict import OrderedDict
DBType = namedtuple("DBType", "name descr module cls alt")
types = [
("eixsql",
DBType(
_("eix + SQLite"),
_("Similar to SQLite, but now uses the eix database to get the package information.\nThis should be much faster on startup, but requires that your eix database is always up-to-date.\nAdditionally, this is the only database allowing searching in descriptions."),
"eix_sql", "EixSQLDatabase",
"sql")),
("sql",
DBType(
_("SQLite"),
_("Uses an SQLite-database to store package information.\nMay take longer to generate at the first time, but has advantages if portato is re-started with an unchanged portage tree. Additionally it allows to use fast SQL expressions for fetching the data."),
"sql", "SQLDatabase",
"dict")),
("dict",
DBType(
_("Hashmap"),
_("Uses an in-memory hashmap to store package information.\nHas been used since at least version 0.3.3, but all information has to be regenerated on each startup."),
"hash", "HashDatabase",
None))
]
types = OrderedDict(types)
class Database(db.Database):
DEFAULT = "dict"
def __new__ (cls, type = None):
try:
if not '_the_instance' in cls.__dict__:
dbcls = cls._generate(type)
cls._the_instance = dbcls(cls._get_session())
elif type is not None:
raise DatabaseInstantiationError("Database instantiation called with 'type' argument multiple times.")
except (ImportError, DatabaseInitError) as e:
db = types[cls.DB_TYPE]
error(_("Cannot load %s."), db.cls)
error(_("Error: %s"), e)
if db.alt is not None:
return cls.__new__(cls, db.alt)
else:
error(_("No alternative database given. Aborting."))
raise DatabaseInstantiationError("Cannot load database.")
return cls._the_instance
@classmethod
def _generate(cls, type):
if type is None:
warning("No database type specified! Falling back to default.")
type = cls.DEFAULT
try:
db = types[type]
except KeyError:
error(_("Unknown database type: %s"), type)
raise UnknownDatabaseTypeError(type)
cls.DB_TYPE = type
info(_("Using database type '%s'"), db.cls)
mod = __import__(db.module, globals(), locals(), [db.cls])
return getattr(mod, db.cls)
@classmethod
def _get_session(cls):
return SectionDict(Session("db.cfg", name = "DB"), cls.DB_TYPE)
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