| -rw-r--r-- | scripts/builder/cssmin.py | 223 |
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diff --git a/scripts/builder/cssmin.py b/scripts/builder/cssmin.py new file mode 100644 index 0000000..32ddf77 --- a/dev/null +++ b/scripts/builder/cssmin.py @@ -0,0 +1,223 @@ +#!/usr/bin/env python +# -*- coding: utf-8 -*- + +"""`cssmin` - A Python port of the YUI CSS compressor.""" + + +from StringIO import StringIO # The pure-Python StringIO supports unicode. +import re + + +__version__ = '0.1.4' + + +def remove_comments(css): + """Remove all CSS comment blocks.""" + + iemac = False + preserve = False + comment_start = css.find("/*") + while comment_start >= 0: + # Preserve comments that look like `/*!...*/`. + # Slicing is used to make sure we don"t get an IndexError. + preserve = css[comment_start + 2:comment_start + 3] == "!" + + comment_end = css.find("*/", comment_start + 2) + if comment_end < 0: + if not preserve: + css = css[:comment_start] + break + elif comment_end >= (comment_start + 2): + if css[comment_end - 1] == "\\": + # This is an IE Mac-specific comment; leave this one and the + # following one alone. + comment_start = comment_end + 2 + iemac = True + elif iemac: + comment_start = comment_end + 2 + iemac = False + elif not preserve: + css = css[:comment_start] + css[comment_end + 2:] + else: + comment_start = comment_end + 2 + comment_start = css.find("/*", comment_start) + + return css + + +def remove_unnecessary_whitespace(css): + """Remove unnecessary whitespace characters.""" + + def pseudoclasscolon(css): + + """ + Prevents 'p :link' from becoming 'p:link'. + + Translates 'p :link' into 'p ___PSEUDOCLASSCOLON___link'; this is + translated back again later. + """ + + regex = re.compile(r"(^|\})(([^\{\:])+\:)+([^\{]*\{)") + match = regex.search(css) + while match: + css = ''.join([ + css[:match.start()], + match.group().replace(":", "___PSEUDOCLASSCOLON___"), + css[match.end():]]) + match = regex.search(css) + return css + + css = pseudoclasscolon(css) + # Remove spaces from before things. + css = re.sub(r"\s+([!{};:>+\(\)\],])", r"\1", css) + + # If there is a `@charset`, then only allow one, and move to the beginning. + css = re.sub(r"^(.*)(@charset \"[^\"]*\";)", r"\2\1", css) + css = re.sub(r"^(\s*@charset [^;]+;\s*)+", r"\1", css) + + # Put the space back in for a few cases, such as `@media screen` and + # `(-webkit-min-device-pixel-ratio:0)`. + css = re.sub(r"\band\(", "and (", css) + + # Put the colons back. + css = css.replace('___PSEUDOCLASSCOLON___', ':') + + # Remove spaces from after things. + css = re.sub(r"([!{}:;>+\(\[,])\s+", r"\1", css) + + return css + + +def remove_unnecessary_semicolons(css): + """Remove unnecessary semicolons.""" + + return re.sub(r";+\}", "}", css) + + +def remove_empty_rules(css): + """Remove empty rules.""" + + return re.sub(r"[^\}\{]+\{\}", "", css) + + +def normalize_rgb_colors_to_hex(css): + """Convert `rgb(51,102,153)` to `#336699`.""" + + regex = re.compile(r"rgb\s*\(\s*([0-9,\s]+)\s*\)") + match = regex.search(css) + while match: + colors = map(lambda s: s.strip(), match.group(1).split(",")) + hexcolor = '#%.2x%.2x%.2x' % tuple(map(int, colors)) + css = css.replace(match.group(), hexcolor) + match = regex.search(css) + return css + + +def condense_zero_units(css): + """Replace `0(px, em, %, etc)` with `0`.""" + + return re.sub(r"([\s:])(0)(px|em|%|in|cm|mm|pc|pt|ex)", r"\1\2", css) + + +def condense_multidimensional_zeros(css): + """Replace `:0 0 0 0;`, `:0 0 0;` etc. with `:0;`.""" + + css = css.replace(":0 0 0 0;", ":0;") + css = css.replace(":0 0 0;", ":0;") + css = css.replace(":0 0;", ":0;") + + # Revert `background-position:0;` to the valid `background-position:0 0;`. + css = css.replace("background-position:0;", "background-position:0 0;") + + return css + + +def condense_floating_points(css): + """Replace `0.6` with `.6` where possible.""" + + return re.sub(r"(:|\s)0+\.(\d+)", r"\1.\2", css) + + +def condense_hex_colors(css): + """Shorten colors from #AABBCC to #ABC where possible.""" + + regex = re.compile(r"([^\"'=\s])(\s*)#([0-9a-fA-F])([0-9a-fA-F])([0-9a-fA-F])([0-9a-fA-F])([0-9a-fA-F])([0-9a-fA-F])") + match = regex.search(css) + while match: + first = match.group(3) + match.group(5) + match.group(7) + second = match.group(4) + match.group(6) + match.group(8) + if first.lower() == second.lower(): + css = css.replace(match.group(), match.group(1) + match.group(2) + '#' + first) + match = regex.search(css, match.end() - 3) + else: + match = regex.search(css, match.end()) + return css + + +def condense_whitespace(css): + """Condense multiple adjacent whitespace characters into one.""" + + return re.sub(r"\s+", " ", css) + + +def condense_semicolons(css): + """Condense multiple adjacent semicolon characters into one.""" + + return re.sub(r";;+", ";", css) + + +def wrap_css_lines(css, line_length): + """Wrap the lines of the given CSS to an approximate length.""" + + lines = [] + line_start = 0 + for i, char in enumerate(css): + # It's safe to break after `}` characters. + if char == '}' and (i - line_start >= line_length): + lines.append(css[line_start:i + 1]) + line_start = i + 1 + + if line_start < len(css): + lines.append(css[line_start:]) + return '\n'.join(lines) + + +def cssmin(css, wrap=None): + css = remove_comments(css) + css = condense_whitespace(css) + # A pseudo class for the Box Model Hack + # (see http://tantek.com/CSS/Examples/boxmodelhack.html) + css = css.replace('"\\"}\\""', "___PSEUDOCLASSBMH___") + css = remove_unnecessary_whitespace(css) + css = remove_unnecessary_semicolons(css) + css = condense_zero_units(css) + css = condense_multidimensional_zeros(css) + css = condense_floating_points(css) + css = normalize_rgb_colors_to_hex(css) + css = condense_hex_colors(css) + if wrap is not None: + css = wrap_css_lines(css, wrap) + css = css.replace("___PSEUDOCLASSBMH___", '"\\"}\\""') + css = condense_semicolons(css) + return css.strip() + + +def main(): + import optparse + import sys + + p = optparse.OptionParser( + prog="cssmin", version=__version__, + usage="%prog [--wrap N]", + description="""Reads raw CSS from stdin, and writes compressed CSS to stdout.""") + + p.add_option( + '-w', '--wrap', type='int', default=None, metavar='N', + help="Wrap output to approximately N chars per line.") + + options, args = p.parse_args() + sys.stdout.write(cssmin(sys.stdin.read(), wrap=options.wrap)) + + +if __name__ == '__main__': + main() |