#!/usr/bin/python2

#
# Copyright 2004 Michael Kefeder (h.t.d@gmx.de)
# 
# Module to work with CNID databases of netatalk 2

# import bsddb3, for python <2.3 needed. don't know how to not require it for 2.3
# that's why it is here ;)
from bsddb3 import db
import os, struct, sys

class cnid_db:
	def __init__(self):
		self.numdevino = 0

	def open(self, DB_PATH):
		DB_PATH = os.path.abspath (DB_PATH)
		 
		if not os.path.isfile (DB_PATH + '/cnid2.db'):
			DB_PATH = os.path.join (DB_PATH, '.AppleDB')
			if not os.path.isfile (DB_PATH + '/cnid2.db'):
				e = "cannot find database file '%s'" % (DB_PATH + '/cnid2.db')
				raise NameError, e
		# preparation to support transactions
		#self.dbenv = db.DBEnv()
		#self.dbenv.open (DB_PATH, db.DB_INIT_TXN)
		#self.transaction = self.dbenv.txn_begin()
		self.cnid2_db = db.DB() # db.DB(self.dbenv)
		self.cnid2_db.set_get_returns_none(0)
		self.cnid2_db.open(DB_PATH + '/cnid2.db', 'cnid2.db', db.DB_BTREE)
		self.cnid_db = self.cnid2_db.cursor()
		self.didname2_db = db.DB()
		self.didname2_db.set_get_returns_none(0)
		self.didname2_db.open(DB_PATH + '/cnid2.db', 'didname.db', db.DB_BTREE)
		self.didname_db = self.didname2_db.cursor()
		self.devino2_db = db.DB()
		self.devino2_db.set_get_returns_none(0)
		self.devino2_db.open(DB_PATH + '/cnid2.db', 'devino.db', db.DB_BTREE, db.DB_RDONLY)
		# get number of entries in table devino
		self.numdevino = len(self.devino2_db)
		self.devino_db = self.devino2_db.cursor()
	
	def close(self):
		#self.transaction.commit()
		self.cnid2_db.close()
		self.didname2_db.close()
		self.devino2_db.close()
		#self.dbenv.close()

	def updateFilenameFromCNID (self, cnid, newname):
		"""
		updates filename in database based on CNID
		"""
		try:
			# update cnid_db
			old_data = self.cnid_db.set(struct.pack (">L", cnid), db.DB_SET)
			new_data = old_data[1][:28] + newname + '\0'
			self.cnid_db.put (struct.pack (">L", cnid), new_data, db.DB_CURRENT)
			# update didname_db
			old_did_data = self.didname_db.set(old_data[1][24:], db.DB_SET)
			new_did_key = old_did_data[0][:4] + newname + '\0'
			self.didname2_db.delete (old_did_data[0])
			self.didname2_db.put (new_did_key, old_did_data[1])
		except db.DBError, dbe:
			sys.stderr.write ("DBError: %i: %s\n" % (dbe[0], dbe[1]))
			sys.stderr.write ("CNID: %i Filename: '%s'" % (cnid, newname))

	def renameFromDEVINO (self, device, inode, newname):
		try:
			dev_inode = struct.pack (">QQ", device, inode)
			devino_data = self.devino_db.set(dev_inode, db.DB_SET)
		except db.DBError:
			#raise NameErrorm, "DEVICE and INODE combination not found."
			return -1
		self.updateFilenameFromCNID (struct.unpack(">L", devino_data[1])[0], newname)
		return 0

	def DEVINOexists (self, device, inode):
		try:
			dev_inode = struct.pack (">QQ", device, inode)
			devino_data = self.devino_db.set(dev_inode, db.DB_SET)
			cnid = struct.unpack(">L", devino_data[1])[0]
			cnid_data = self.cnid_db.set(struct.pack (">L", cnid), db.DB_SET)
			didname_data = self.didname_db.set(cnid_data[1][24:], db.DB_SET)
			return 0
		except db.DBError:
			return -1