# Copyright 2002 Ben Escoto
#
# This file is part of rdiff-backup.
#
# rdiff-backup is free software; you can redistribute it and/or modify
# under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 2 of the License, or (at your
# option) any later version.
#
# rdiff-backup is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with rdiff-backup; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
# USA

"""Coordinate corresponding files with different names

For instance, some source filenames may contain characters not allowed
on the mirror end.  Also, if a source filename is very long (say 240
characters), the extra characters added to related increments may put
them over the usual 255 character limit.

"""

import re
import Globals, log

max_filename_length = 255

# If true, enable character quoting, and set characters making
# regex-style range.
chars_to_quote = None

# These compiled regular expressions are used in quoting and unquoting
chars_to_quote_regexp = None
unquoting_regexp = None

# Use given char to quote.  Default is set in Globals.
quoting_char = None


def set_init_quote_vals():
	"""Set quoting value from Globals on all conns"""
	for conn in Globals.connections:
		conn.FilenameMapping.set_init_quote_vals_local()

def set_init_quote_vals_local():
	"""Set value on local connection, initialize regexps"""
	global chars_to_quote, quoting_char
	chars_to_quote = Globals.chars_to_quote
	if len(Globals.quoting_char) != 1:
		log.Log.FatalError("Expected single character for quoting char,"
						   "got '%s' instead" % (Globals.quoting_char,))
	quoting_char = Globals.quoting_char
	init_quoting_regexps()

def init_quoting_regexps():
	"""Compile quoting regular expressions"""
	global chars_to_quote_regexp, unquoting_regexp
	try:
		chars_to_quote_regexp = \
				 re.compile("[%s%s]" % (chars_to_quote, quoting_char), re.S)
		unquoting_regexp = re.compile("%s[0-9]{3}" % quoting_char, re.S)
	except re.error:
		log.Log.FatalError("Error '%s' when processing char quote list %s" %
						   (re.error, chars_to_quote))

def quote(path):
	"""Return quoted version of given path

	Any characters quoted will be replaced by the quoting char and
	the ascii number of the character.  For instance, "10:11:12"
	would go to "10;05811;05812" if ":" were quoted and ";" were
	the quoting character.

	"""
	return chars_to_quote_regexp.sub(quote_single, path)

def quote_single(match):
	"""Return replacement for a single character"""
	return "%s%03d" % (quoting_char, ord(match.group()))

def unquote(path):
	"""Return original version of quoted filename"""
	return unquoting_regexp.sub(unquote_single, path)

def unquote_single(match):
	"""Unquote a single quoted character"""
	assert len(match.group()) == 4
	return chr(int(match.group()[1:]))