#!/usr/bin/env python3

"""
Synopsis: %(prog)s [-h|-b|-g|-r|-a|-d] [ picklefile ] dbfile

Read the given picklefile as a series of key/value pairs and write to a new
database.  If the database already exists, any contents are deleted.  The
optional flags indicate the type of the output database:

    -a - open using dbm (open any supported format)
    -b - open as bsddb btree file
    -d - open as dbm.ndbm file
    -g - open as dbm.gnu file
    -h - open as bsddb hash file
    -r - open as bsddb recno file

The default is hash.  If a pickle file is named it is opened for read
access.  If no pickle file is named, the pickle input is read from standard
input.

Note that recno databases can only contain integer keys, so you can't dump a
hash or btree database using db2pickle.py and reconstitute it to a recno
database with %(prog)s unless your keys are integers.

"""

import getopt
try:
    import bsddb
except ImportError:
    bsddb = None
try:
    import dbm.ndbm as dbm
except ImportError:
    dbm = None
try:
    import dbm.gnu as gdbm
except ImportError:
    gdbm = None
try:
    import dbm.ndbm as anydbm
except ImportError:
    anydbm = None
import sys
try:
    import pickle as pickle
except ImportError:
    import pickle

prog = sys.argv[0]

def usage():
    sys.stderr.write(__doc__ % globals())

def main(args):
    try:
        opts, args = getopt.getopt(args, "hbrdag",
                                   ["hash", "btree", "recno", "dbm", "anydbm",
                                    "gdbm"])
    except getopt.error:
        usage()
        return 1

    if len(args) == 0 or len(args) > 2:
        usage()
        return 1
    elif len(args) == 1:
        pfile = sys.stdin
        dbfile = args[0]
    else:
        try:
            pfile = open(args[0], 'rb')
        except IOError:
            sys.stderr.write("Unable to open %s\n" % args[0])
            return 1
        dbfile = args[1]

    dbopen = None
    for opt, arg in opts:
        if opt in ("-h", "--hash"):
            try:
                dbopen = bsddb.hashopen
            except AttributeError:
                sys.stderr.write("bsddb module unavailable.\n")
                return 1
        elif opt in ("-b", "--btree"):
            try:
                dbopen = bsddb.btopen
            except AttributeError:
                sys.stderr.write("bsddb module unavailable.\n")
                return 1
        elif opt in ("-r", "--recno"):
            try:
                dbopen = bsddb.rnopen
            except AttributeError:
                sys.stderr.write("bsddb module unavailable.\n")
                return 1
        elif opt in ("-a", "--anydbm"):
            try:
                dbopen = anydbm.open
            except AttributeError:
                sys.stderr.write("dbm module unavailable.\n")
                return 1
        elif opt in ("-g", "--gdbm"):
            try:
                dbopen = gdbm.open
            except AttributeError:
                sys.stderr.write("dbm.gnu module unavailable.\n")
                return 1
        elif opt in ("-d", "--dbm"):
            try:
                dbopen = dbm.open
            except AttributeError:
                sys.stderr.write("dbm.ndbm module unavailable.\n")
                return 1
    if dbopen is None:
        if bsddb is None:
            sys.stderr.write("bsddb module unavailable - ")
            sys.stderr.write("must specify dbtype.\n")
            return 1
        else:
            dbopen = bsddb.hashopen

    try:
        db = dbopen(dbfile, 'c')
    except bsddb.error:
        sys.stderr.write("Unable to open %s.  " % dbfile)
        sys.stderr.write("Check for format or version mismatch.\n")
        return 1
    else:
        for k in list(db.keys()):
            del db[k]

    while 1:
        try:
            (key, val) = pickle.load(pfile)
        except EOFError:
            break
        db[key] = val

    db.close()
    pfile.close()

    return 0

if __name__ == "__main__":
    sys.exit(main(sys.argv[1:]))