#!/usr/bin/env python
#
# Compresses old rdiff-backup increments.  See
# http://www.stanford.edu/~bescoto/rdiff-backup for information on
# rdiff-backup.

from __future__ import nested_scopes, generators
import os, sys, getopt

rdiff_backup_location = "/usr/bin/rdiff-backup"
no_compression_regexp_string = None
__no_execute__ = 1

def print_help():
	"""Print usage, exit"""
	print """
Usage: compress-rdiff-backup-increments [options] mirror_directory

This script will compress the old rdiff-backup increments under
mirror_directory, in a format compatible with rdiff-backup version
0.7.1 and later.  So for instance if you were using an old version
of rdiff-backup like this:

rdiff-backup /foo /backup

and now you want to take advantage of v0.7.1's space saving
compression, you can run:

compress-rdiff-backup-increments /backup


Options:

--rdiff-backup-location location
    This script reads your rdiff-backup executable.  The default
    is "/usr/bin/rdiff-backup", so if your rdiff-backup is in a
    different location, you must use this switch.

--no-compression-regexp regexp
    Any increments whose base name match this regular expression
    won't be compressed.  This is generally used to avoid
    compressing already compressed files.  See the rdiff-backup
    man page for the default.
"""
	sys.exit(1)
	
def parse_args(arglist):
	"""Check and evaluate command line arguments, return dirname"""
	global rdiff_backup_location
	global no_compression_regexp_string
	try: optlist, args = getopt.getopt(arglist, "v:",
									   ["rdiff-backup-location=",
										"no-compression-regexp="])
	except getopt.error: print_help()

	for opt, arg in optlist:
		if opt == "--no-compression-regexp":
			no_compression_regexp_string = arg
		elif opt == "--rdiff-backup-location": rdiff_backup_location = arg
		else:
			print "Bad option: ", opt
			print_help()

	if len(args) != 1:
		print "Wrong number of arguments"
		print_help()
	return args[0]

def exec_rdiff_backup():
	"""Execs rdiff-backup"""
	try: execfile(rdiff_backup_location, globals())
	except IOError:
		print "Unable to read", rdiff_backup_location
		print "You may need to use the --rdiff-backup-location argument"
		sys.exit(1)

	if not map(int, Globals.version.split(".")) >= [0, 7, 1]:
		print "This script requires rdiff-backup version 0.7.1 or later,",
		print "found version", Globals.version
		sys.exit(1)

def gzip_file(rp):
	"""gzip rp, adding .gz to path and deleting original"""
	newrp = RPath(rp.conn, rp.base, rp.index[:-1] + (rp.index[-1]+".gz",))
	if newrp.lstat():
		print "Warning: %s already exists, skipping" % newrp.path
		return

	print "gzipping ", rp.path
	newrp.write_from_fileobj(rp.open("rb"), compress = 1)
	RPath.copy_attribs(rp, newrp)
	rp.delete()

def Main():
	dirname = parse_args(sys.argv[1:])
	exec_rdiff_backup()
	if no_compression_regexp_string is not None:
		no_compression_regexp = re.compile(no_compression_regexp_string, re.I)
	else: no_compression_regexp = \
		  re.compile(Globals.no_compression_regexp_string, re.I)
	Globals.change_source_perms = 1
	Globals.change_ownership = (os.getuid() == 0)

	# Check to make sure rbdir exists
	root_rp = RPath(Globals.local_connection, dirname)
	rbdir = root_rp.append("rdiff-backup-data")
	if not rbdir.lstat():
		print "Cannot find %s, exiting" % rbdir.path
		sys.exit(1)

	for dsrp in DestructiveStepping.Iterate_with_Finalizer(rbdir, 1):
		if (dsrp.isincfile() and dsrp.isreg() and
			not dsrp.isinccompressed() and
			(dsrp.getinctype() == "diff" or dsrp.getinctype() == "snapshot")
			and dsrp.getsize() != 0 and
			not no_compression_regexp.match(dsrp.getincbase_str())):
			gzip_file(dsrp)

Main()