# Copyright (C) 2011 by the Massachusetts Institute of Technology.

# All rights reserved.

#

# Export of this software from the United States of America may

#   require a specific license from the United States Government.

#   It is the responsibility of any person or organization contemplating

#   export to obtain such a license before exporting.

#

# WITHIN THAT CONSTRAINT, permission to use, copy, modify, and

# distribute this software and its documentation for any purpose and

# without fee is hereby granted, provided that the above copyright

# notice appear in all copies and that both that copyright notice and

# this permission notice appear in supporting documentation, and that

# the name of M.I.T. not be used in advertising or publicity pertaining

# to distribution of the software without specific, written prior

# permission.  Furthermore if you modify this software you must label

# your software as modified software and not distribute it in such a

# fashion that it might be confused with the original M.I.T. software.

# M.I.T. makes no representations about the suitability of

# this software for any purpose.  It is provided "as is" without express

# or implied warranty.

# This program is intended to be used by "make check-copyright".  It

# checks for violations of the coding standards related to copyright

# and license statements in source code comments.

import os

import sys

import re

def warn(fname, ln, msg):

    print('%s: %d: %s' % (fname, ln + 1, msg))

def indicates_license(line):

    return 'Copyright' in line or 'COPYRIGHT' in line or 'License' in line

# Check a comment for boilerplate violations.  Return true if the comment

# is a license statement.

def check_comment(comment, fname, ln, code_seen, nonlicense_seen):

    text_seen = False

    is_license = False

    for line in comment:

        if not is_license and indicates_license(line):

            is_license = True

            if text_seen:

                warn(fname, ln, 'License begins after first line of comment')

            elif code_seen:

                warn(fname, ln, 'License after code')

            elif nonlicense_seen:

                warn(fname, ln, 'License after non-license comments')

            break

        # DB2 licenses start with '/*-' and we don't want to change them.

        if line != '' and line != '-':

            text_seen = True

    return is_license

def check_file(lines, fname):

    # Skip emacs mode line if present.

    ln = 0

    if '-*- mode: c;' in lines[ln]:

        ln += 1

    # Check filename comment if present.

    m = re.match(r'/\* ([^ ]*)( - .*)? \*/', lines[ln])

    if m:

        if m.group(1) != fname:

            warn(fname, ln, 'Wrong filename in comment')

        ln += 1

    # Scan for license statements.

    in_comment = False

    code_seen = False

    nonlicense_seen = False

    for line in lines[ln:]:

        # Strip out whitespace and comments contained within a line.

        if not in_comment:

            line = re.sub(r'/\*.*?\*/', '', line)

        line = line.strip()

        if not in_comment and '/*' in line:

            (line, sep, comment_part) = line.partition('/*')

            comment = [comment_part.strip()]

            comment_starts_at = ln

            in_comment = True

        elif in_comment and '*/' not in line:

            comment.append(line.lstrip('*').lstrip())

        elif in_comment:

            (comment_part, sep, line) = line.partition('*/')

            comment.append(comment_part.strip())

            is_license = check_comment(comment, fname, comment_starts_at,

                                       code_seen, nonlicense_seen)

            nonlicense_seen = nonlicense_seen or not is_license

            in_comment = False

        elif line.strip() != '':

            code_seen = True

        ln += 1

for fname in sys.argv[1:]:

    if fname.startswith('./'):

        fname = fname[2:]

    f = open(fname)

    lines = f.readlines()

    f.close()

    check_file(lines, fname)