# Copyright 1999-2006 Gentoo Foundation
# Distributed under the terms of the GNU General Public License v2
# $Header: $

import template
from metadata_overlay import database as db_module

class database(db_module):

	def __init__(self, location, label, auxdbkeys, **config):
		super(database, self).__init__(location, label, auxdbkeys, **config)
		self._db_cache = {}

	def __getitem__(self, cpv):
		"""Each item will remain cached in memory until reset() is called."""
		try:
			return self._db_cache[cpv].copy()
		except KeyError:
			pass

		# This raises a KeyError if necessary.
		data = self._copy_dict(super(database, self).__getitem__(cpv))
		self._db_cache[cpv] = data
		return data.copy()

	def _setitem(self, name, values):
		my_values = self._copy_dict(values)
		self._db_cache[name] = my_values
		super(database, self)._setitem(name, my_values)

	def _delitem(self, cpv):
		super(database, self)._delitem(cpv)
		try:
			del self._db_cache[cpv]
		except KeyError:
			pass

	def has_key(self, cpv):
		return cpv in self._db_cache or super(database, self).has_key(cpv)

	def reset(self):
		self._db_cache = {}

	def _copy_dict(self, d):
		"""For mappings that don't support the copy() method"""
		data = {}
		data.update(d)
		return data