Git interface to Python difflib module

gitdiff.py

#!/usr/bin/env python3
"""
Git interface to difflib.py
"""

import sys
import os
import time
import difflib
import re

_, path, oldfile, oldhex, oldmode, newfile, newhex, newmode = sys.argv

oldname = 'a/' + path
newname = 'b/' + path

if oldmode == '.':
    oldname = '/dev/null'
if newmode == '.':
    newname = '/dev/null'

with open(oldfile) as ff:
    oldlines = ff.readlines()
with open(newfile) as tf:
    newlines = tf.readlines()

diff_lines = difflib.unified_diff(oldlines, newlines, oldname, newname)

rerange = re.compile('^@@ -.* \+.* @@')
redel = re.compile(r'^-')
readd = re.compile(r'^\+')
reold = re.compile(r'^--- ')
renew = re.compile(r'^\+\+\+ ')

red ='\033[91m'
green = '\033[92m'
yellow = '\033[93m'
blue = '\033[94m'
end = '\033[0m'

def color_lines():
    for line in diff_lines:
        line = line.rstrip('\r\n')
        if redel.match(line) and not reold.match(line):
            yield red + line + end + '\n'
        elif readd.match(line) and not renew.match(line):
            yield green + line + end + '\n'
        elif rerange.match(line):
            yield blue + line + end + '\n'
        else:
            yield line + '\n'

# Always color output
sys.stdout.writelines(color_lines())