How to use the bsddb3.hashopen function in bsddb3

def perform(args):
    domain_db = bsddb3.hashopen(args.domain_db, 'c', 0o600)
    if args.get:
        print(unutf8(domain_db[utf8(args.get)], 'illegal'))
    elif args.put:
        domain_db[utf8(args.put[0])] = args.put[1]
    elif args.delete:
        del domain_db[utf8(args.delete)]
    elif args.unload:
        for k in list(domain_db.keys()):
            print('%s\t%s' % (unutf8(k, 'illegal'), unutf8(domain_db[k], 'illegal')))
        # Should work according to documentation, but doesn't
        # for k, v in DOMAIN_DB.iteritems():
        #     print k, '\t', v
    elif args.load:
        for line in sys.stdin:
            k, v = line.rstrip('\r\n').split('\t', 1)
            domain_db[utf8(k)] = v

authdomain TEXT,
                      regcontact TEXT,
                      regfirst   TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
                      reglatest  TIMESTAMP DEFAULT CURRENT_TIMESTAMP)''')
        except sqlite3.OperationalError as e:
            logging.warning('Cannot create `domains` table; maybe multiple processes started in parallel? %s' % str(e))
            # Try to get out of the way of a parallel updater
            time.sleep(1)
            # Someone else already created the table; he probably also
            # migrated it
            return
        try:
            if olddb is None:
                return
            elif isinstance(olddb, str):
                db = bsddb3.hashopen(olddb, 'r')
            else: # dict
                db = olddb
            for k,v in db.items():
                k = unutf8(k, 'illegal')
                v = unutf8(v, 'illegal')
                try:
                    (authsecret, authurl, authdomain, extra) = v.split("\t", 3)
                except ValueError:
                    (authsecret, authurl, authdomain) = v.split("\t", 2)
                    extra = None
                self.conn.execute('''INSERT INTO domains (xmppdomain, authsecret, authurl, authdomain) VALUES (?, ?, ?, ?)''', (k, authsecret, authurl, authdomain))
            if isinstance(olddb, str):
                db.close()
        except bsddb3.db.DBError as e:
            logging.error('Trouble converting %s: %s' % (olddb, e))

def db_upgrade_cache(self, olddb):
        logging.debug('Upgrading cache from %s' % olddb)
        try:
            if olddb is None:
                return
            elif isinstance(olddb, str):
                db = bsddb3.hashopen(olddb, 'r')
            else: # dict
                db = olddb
            for k,v in db.items():
                k = unutf8(k, 'illegal').replace(':', '@')
                v = unutf8(v, 'illegal')
                (pwhash, ts1, tsv, tsa, rest) = v.split("\t", 4)
                ts1 = datetime.utcfromtimestamp(int(ts1))
                tsv = datetime.utcfromtimestamp(int(tsv))
                tsa = datetime.utcfromtimestamp(int(tsa))
                # First import goes into persistent database
                self.conn.execute('''INSERT INTO authcache (jid, pwhash, firstauth, remoteauth, anyauth)
                     VALUES (?, ?, ?, ?, ?)''', (k, pwhash, ts1, tsv, tsa))
            if isinstance(olddb, str):
                db.close()
        except bsddb3.db.DBError as e:
            logging.error('Trouble converting %s: %s' % (olddb, e))

'''
    
    db = ctx.parent.params['db']
    newdb = db + '.new'
    
    if dbtype == 'gdbm':
        import gdbm
        new_d = gdbm.open(newdb, 'n')
    elif dbtype == 'dbm':
        import dbm
        new_d = dbm.open(newdb, 'n')
    elif dbtype == 'dbhash':
        import dbhash
        new_d = dbhash.open(newdb, 'n')
    elif dbtype == 'bsddb':
        new_d = bsddb.hashopen(newdb, 'n')
    elif dbtype == 'dumbdbm':
        import dumbdbm
        new_d = dumbdbm.open(newdb, 'n')
    else:
        raise click.ClickException("Invalid type %s" % dbtype)
    
    new_data = shelve.Shelf(new_d, protocol=exaile_pickle_protocol)
    
    for k, v in data.iteritems():
        new_data[k] = v
    
    new_data.sync()
    new_data.close()

def open_db3hash(*args):
    """Open a bsddb3 hash."""
    import bsddb3
    return bsddb3.hashopen(*args)

# We do this because BDB is generally considered more performant,
    # and because gdbm currently doesn't work at all in MSYS2.

    # Some DBM modules don't use the path we give them, but rather they have
    # multiple filenames. If the specified path doesn't exist, double check
    # to see if whichdb returns a result before trying to open it with bsddb
    force_migrate = False
    if not os.path.exists(path):
        from whichdb import whichdb

        if whichdb(path) is not None:
            force_migrate = True

    if not force_migrate:
        try:
            db = bsddb.hashopen(path, 'c')
            return shelve.BsdDbShelf(db, protocol=PICKLE_PROTOCOL)
        except bsddb.db.DBInvalidArgError:
            logger.warning("%s was created with an old backend, migrating it", path)
        except Exception:
            raise

    # special case: zero-length file
    if not force_migrate and os.path.getsize(path) == 0:
        os.unlink(path)
    else:
        from xl.migrations.database.to_bsddb import migrate

        migrate(path)

    db = bsddb.hashopen(path, 'c')
    return shelve.BsdDbShelf(db, protocol=PICKLE_PROTOCOL)

# Try to get out of the way of a parallel updater
            time.sleep(1)
            # Someone else already created the table; he probably also
            # migrated it
            return

        rosterinfo_fn = {}
        rosterinfo_rh = {}
        rosterinfo_lg = {}
        rosterusers = set([])
        rostergroups = {}
        try:
            if olddb is None:
                return
            elif isinstance(olddb, str):
                db = bsddb3.hashopen(olddb, 'r')
            else: # dict
                db = olddb
            for k,v in db.items():
                k = unutf8(k, 'illegal')
                v = unutf8(v, 'illegal')
                if k.startswith('FNC:'): # Full name (cache only)
                    jid = k[4:].replace(':', '@')
                    rosterusers.add(jid)
                    if '@' in jid: # Do not copy malformed (old buggy) entries
                        rosterinfo_fn[jid] = v
                if k.startswith('LIG:'): # Login In Group (state information)
                    jid = k[4:].replace(':', '@')
                    rosterusers.add(jid)
                    rosterinfo_lg[jid] = v
                if k.startswith('RGC:'): # Reverse Group Cache (state information)
                    gid = k[4:].replace(':', '@')

def __init__(self, filename, flag='c', protocol=2, writeback=False):
        db = bsddb3.hashopen(filename, flag)
        args = [self, db, protocol, writeback]
        if sys.version_info[0] == 3:
            args.append('utf8')
        shelve.Shelf.__init__(*args)