#!/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: kompare,v 1.6 2006/12/14 19:59:05 mef Exp $
#

import sys, re, os

def process(file):
    ORDER = []
    CONFIGS = {}
    for line in file.readlines():
        iline = line.lower()
        iline = iline.strip()
        if len(iline)==0: continue
        firstchar = iline[0]

        if firstchar == '#':
            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]="is not set"
                ORDER.append(config)
            else:
                # skip over comments that do not contain the "is not set" string
                pass

        else:
            offset = iline.find('=')
            if offset  <> -1:
                config = line[line.find("CONFIG"):offset].strip()
                if CONFIGS.has_key(config): print "duplicate entry %s" % config
                CONFIGS[config] = line[offset+1:].strip()
                ORDER.append(config)
        
    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
    ADD     Added config (exists in to.config, but not in from.config)
    REM     Removed config (exists in from.config, but not in to.config)
    BLT     Builtin
    MOD     Module
    DIS     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]))

newstate = {None:'REMOVED',"is not set":'DISABLE','y':'BUILTIN','m':'MODULE '}
keys = neworder
seen = {}
for key in keys:
    o = old.get(key,None)
    n = new[key]
    if n==o and not showall: continue
    try:
       print "%6s -> %6s : %s" % (newstate.get(o,o),newstate.get(n,n),key)
    except IOError, e:
	#print e
        sys.exit(0)

    seen[key] = None

# not sure we care about what options have been removed
# from from.config file
oldstate = {None:'REMOVED',"is not set":'DISABLE','y':'BUILTIN','m':'MODULE '}
keys = oldorder
for key in keys:
    if seen.has_key(key): continue
    n = new.get(key,None)
    o = old[key]
    if n == o and not showall: continue
    try:
       print "%6s -> %6s : %s" % (oldstate.get(o,o),oldstate.get(n,n),key)
    except IOError, e:
	#print e
        sys.exit(0)