diffconfig

#! /usr/bin/env python3
'''\
Show differences between two configuration files (config1 - config2)

$Id$
'''
from __future__ import print_function

import sys
import io
import argparse
import package_info
import re
from feedback import die

from configobj import Section
from expconfig import ConfigObj


# recursively removes differences between two config objects c1 and c2 
def subConfig(c1, c2):
    for k in c1:
        if (type(c1[k]) is Section) and (k in c2):
            subConfig(c1[k],c2[k])
            if not c1[k].keys():
                del c1[k]
        else:
            if (k in c2) and c2[k]==c1[k]:
                del c1[k]
        
#
# Main routine
#

# Check command line

command_line = argparse.ArgumentParser(description=__doc__.split('\n', 1)[0])
# TODO: print differences option,  ...
command_line.add_argument('--indent-string', default='  ', help='set indent string [%(default)s]')
command_line.add_argument('--inline-comments' , '-c', action='store_true',
                          help='compact white space before inline comments'
                               ' (BETA)')
command_line.add_argument('--trailing-space' , '-t', action='store_true',
                          help='remove white space at end of lines')
command_line.add_argument('config1', help='original configuration file name of minuend')
command_line.add_argument('config2', help='original configuration file name of subtrahend')
command_line.add_argument('-V', '--version', action='version',
                          version=package_info.version)
args = command_line.parse_args()


# File handling

try:
    config_file1 = args.config1
    config_file2 = args.config2
    config_data1 = ConfigObj(config_file1, 
                file_error=True,write_empty_values=True)
    config_data2 = ConfigObj(config_file2, 
                file_error=True)
except IOError as error:
    die(error.message)

# Removes elements which are also in c2 from c1:
subConfig(config_data1,config_data2)

# Ready to roll out
lines = io.BytesIO()
config_data1.write(lines)

lines.seek(0)
for line in io.TextIOWrapper(lines):
    if args.inline_comments: line = re.sub(r' = (.*?)  #', r' = \1 #', line)
    if args.trailing_space:
        print(line.rstrip())
    else:
        print(line, end='')