#!/usr/bin/env python

# package.py
#
# Python program to mimic the packages unmasked by '##' in package.mask across an 'emerge rsync'
#
# 	José Fonseca <j_r_fonseca@yahoo.co.uk>

def make_key(operator,category,package,version,release):
	key = package
	if operator:
		key = operator + key
		if operator == '=':
			key = key + '-' + version
	return key
	


if __name__ == "__main__":
	import sys, os, time, glob, re, string

	old = sys.argv[1]
	new = sys.argv[2]
	
	# Regular expressions to match the packages masks
	OPERATOR_RE = r"([*<>=~]+)"
	CATEGORY_RE = r"([0-9a-zA-Z]+-[0-9a-zA-Z]+)"
	PACKAGE_RE = r"([a-zA-Z+][-+_0-9a-zA-Z]*?)"
	NUMBER_RE = r"(?:[a-zA-Z]*[0-9]+|[0-9]+[a-zA-Z]*)"
	VERSION_RE = r"(" + NUMBER_RE + r"(?:[._]" + NUMBER_RE + r")*)"
	RELEASE_RE = r"(r[0-9]+)"
	EXTENSION_RE = r"[0-9a-zA-Z]+"
	MASK_RE = OPERATOR_RE + r"?(?:" + CATEGORY_RE + r"/)?" + PACKAGE_RE + r"(?:-" + VERSION_RE + r"\*?(?:-" + RELEASE_RE + r")?)?(?:\." + EXTENSION_RE + r")?"
	UNMASK_RE = r"##" + MASK_RE

	BEGIN_RE = r"^"
	END_RE = r"(?:[ 	].*)?\n$"
			
	mask_re = re.compile(BEGIN_RE + MASK_RE + END_RE)
	unmask_re = re.compile(BEGIN_RE + UNMASK_RE + END_RE)
	
	# Dictinary to old the unmasked packages keys. The key consists of the operator and package name to cope with multiple ocurrences of the same package
	unmasked = {};
	
	# Search for unmasked packages in the old package.mask
	f = open(old)
	l = f.readline()
	while l != "":	
		if unmask_re.match(l):
			begin,operator,category,package,version,release,end = unmask_re.split(l)
			key = make_key(operator,category,package,version,release)

			unmasked[key] = 1;
		
		l = f.readline()
	f.close()

	# Unmask them again on the new package.mask
	f = open(new)
	l = f.readline()
	while l != "":	
		if mask_re.match(l):
			begin,operator,category,package,version,release,end = mask_re.split(l)
			key = make_key(operator,category,package,version,release)
			
			if unmasked.has_key(key):
				print "##" + l,
			else:
				print l,
		else:
			print l,
		
		l = f.readline()
	f.close()