Check git history for additional copyright lines

copyright.py

import subprocess
import os

def argsort(seq):
    # http://stackoverflow.com/questions/3071415/efficient-method-to-calculate-the-rank-vector-of-a-list-in-python
    return sorted(range(len(seq)), key = seq.__getitem__)

def check_file(f, start_commit, omit_commits):
    if not f.endswith('.vala'):
        return
    
    fn = os.path.join(dir, f)
    commits = subprocess.check_output(['git', 'log', '%s..HEAD' % start_commit, '--no-merges',
        '--format=format:%an//%ai//%s//%h',
        '--', fn]).split('\n')
    
    authors = {}
    for l in commits:
        try:
            author, date, subject, hash_ = l.split('//')
        except ValueError:
            continue
        
        if hash_ in omit_commits or "code style" in subject.lower() or "code formatting" in subject.lower():
            continue
        if author not in authors:
            authors[author] = set()
        year = date.split('-')[0]
        authors[author].add(year)
    if authors == {}:
        return
    
    auths = authors.keys()
    auth_sort = argsort([min(authors[a]) for a in auths])
    
    head = []
    with open(fn, 'r') as source:
        line = source.readline()
        while len(line) > 1:
            head.append(line)
            line = source.readline()
    
    res = ""
    for i in xrange(len(auth_sort)):
        a = auths[auth_sort[i]]
        copyright_line = ([l for l in head if a in l] or [""])[0]
        new_years = [y for y in sorted(authors[a]) if y not in copyright_line]
        if new_years:
            res += " * Copyright %s %s\n" % (", ".join(new_years), a)
    
    if res:
        print fn
        print res

if __name__ == '__main__':
    import sys
    if len(sys.argv) < 3:
        print "Usage: %s <directory> <starting commit>" % sys.argv[0]
        exit(1)
    
    for dir, dirs, files in os.walk(sys.argv[1]):
        for f in files:
            check_file(f, sys.argv[2], sys.argv[3:])