#!/bin/env python
#
# compare: a tool to compare kernel config files
#
# Marc E. Fiuczynski <mef@cs.princeton.edu>
# Copyright (C) 2006 The Trustees of Princeton University
#
# $Id: compare,v 1.1 2006/11/30 16:39:29 mef Exp $
#

import sys, re, os

def process(file):
    ORDER = []
    CONFIGS = {}
    for line in file.readlines():
        iline = line.lower()

        offset=iline.find(" is not set")
        if offset <> -1:
            config = line[line.find("CONFIG"):offset].strip()
            if CONFIGS.has_key(config): print "duplicate entry %s" % config
            CONFIGS[config]=0
            ORDER.append(config)
            continue

        offset = iline.find("=y")
        if offset  <> -1:
            config = line[line.find("CONFIG"):offset].strip()
            if CONFIGS.has_key(config): print "duplicate entry %s" % config
            CONFIGS[config]=1
            ORDER.append(config)
            continue

        offset = iline.find("=m")
        if iline.find("=m") <> -1:
            config = line[line.find("CONFIG"):offset].strip()
            if CONFIGS.has_key(config): print "duplicate entry %s" % config
            CONFIGS[config]=2
            ORDER.append(config)
            continue

    return (CONFIGS,ORDER)


showall=False
args = sys.argv[1:]

if len(args) <=1:
    name = os.path.basename(sys.argv[0])
    print "USAGE: %s [options] from.config to.config" % name
    print """
Options
    -a    Show all differences

State Legend
    A     Added config (exists in to.config, but not in from.config)
    R     Removed config (exists in from.config, but not in to.config)
    B     Builtin
    M     Module
    D     Disabled
    """
    sys.exit(0)

if args[0] == "-a":
    showall = True
    args = args[1:]

(old,oldorder)= process(open(args[0]))
(new,neworder)= process(open(args[1]))

oldstate = {-1:'A',0:'D',1:'B',2:'M'}
newstate = {-1:'R',0:'D',1:'B',2:'M'}

keys = neworder
for key in keys:
    o = old.get(key,-1)
    n = new[key]
    if n==o and not showall: continue
    print "%c -> %c : %s" % (newstate[o],newstate[n],key)

# not sure we care about what options have been removed
# from from.config file
sys.exit(0)
keys = oldorder
for key in keys:
    n = new.get(key,-1)
    o = old[key]
    if n == -1 and not showall:
        print "%c -> %c : %s" % (oldstate[o],oldstate[n],key)