Source/JavaScriptCore/Scripts/cssmin.py

#!/usr/bin/env python

# Copyright (C) 2013 Apple Inc. All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
# THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
# BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
# THE POSSIBILITY OF SUCH DAMAGE.

import re

def cssminify(css):
    rules = (
        (r"\/\*.*?\*\/", ""),          # delete comments
        (r"\n", ""),                   # delete new lines
        (r"\s+", " "),                 # change multiple spaces to one space
        (r"\s?([;{},~>!])\s?", r"\1"), # delete space where it is not needed
        (r":\s", ":"),                 # delete spaces after colons, but not before. E.g. do not break selectors "a :focus", "b :matches(...)", "c :not(...)" where the leading space is significant
        (r"\s?([-+])(?:\s(?![0-9(])(?!var))", r"\1"), # delete whitespace around + and - when not followed by a number, paren, or var(). E.g. strip for selector "a + b" but not "calc(a + b)" which requires spaces.
        (r";}", "}")                   # change ';}' to '}' because the semicolon is not needed
    )

    css = css.replace("\r\n", "\n")
    for rule in rules:
        css = re.compile(rule[0], re.MULTILINE | re.UNICODE | re.DOTALL).sub(rule[1], css)
    return css

if __name__ == "__main__":
    import sys
    if sys.version_info[0] == 3 and sys.stdin.encoding != 'UTF-8':
        import io
        sys.stdin = io.TextIOWrapper(sys.stdin.buffer, encoding='UTF-8')
    sys.stdout.write(cssminify(sys.stdin.read()))