Merge branch 'issue-21' into develop, Closed #21

lib/minify/cssmin.py

@@ -0,0 +1,202 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+# `cssmin.py` - A Python port of the YUI CSS compressor.
+
+
+from StringIO import StringIO # The pure-Python StringIO supports unicode.
+import re
+
+
+__version__ = '0.1.1'
+
+
+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 = 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()