com.yahoo.platform.yui.compressor.CssCompressor Maven / Gradle / Ivy
The newest version!
/*
* YUI Compressor
* http://developer.yahoo.com/yui/compressor/
* Author: Julien Lecomte - http://www.julienlecomte.net/
* Author: Isaac Schlueter - http://foohack.com/
* Author: Stoyan Stefanov - http://phpied.com/
* Copyright (c) 2011 Yahoo! Inc. All rights reserved.
* The copyrights embodied in the content of this file are licensed
* by Yahoo! Inc. under the BSD (revised) open source license.
*/
package com.yahoo.platform.yui.compressor;
import java.io.IOException;
import java.io.Reader;
import java.io.Writer;
import java.util.regex.Pattern;
import java.util.regex.Matcher;
import java.util.ArrayList;
public class CssCompressor {
private StringBuffer srcsb = new StringBuffer();
public CssCompressor(Reader in) throws IOException {
// Read the stream...
int c;
while ((c = in.read()) != -1) {
srcsb.append((char) c);
}
}
// Leave data urls alone to increase parse performance.
protected String extractDataUrls(String css, ArrayList preservedTokens) {
int maxIndex = css.length() - 1;
int appendIndex = 0;
StringBuffer sb = new StringBuffer();
Pattern p = Pattern.compile("url\\(\\s*([\"']?)data\\:");
Matcher m = p.matcher(css);
/*
* Since we need to account for non-base64 data urls, we need to handle
* ' and ) being part of the data string. Hence switching to indexOf,
* to determine whether or not we have matching string terminators and
* handling sb appends directly, instead of using matcher.append* methods.
*/
while (m.find()) {
int startIndex = m.start() + 4; // "url(".length()
String terminator = m.group(1); // ', " or empty (not quoted)
if (terminator.length() == 0) {
terminator = ")";
}
boolean foundTerminator = false;
int endIndex = m.end() - 1;
while(foundTerminator == false && endIndex+1 <= maxIndex) {
endIndex = css.indexOf(terminator, endIndex+1);
if ((endIndex > 0) && (css.charAt(endIndex-1) != '\\')) {
foundTerminator = true;
if (!")".equals(terminator)) {
endIndex = css.indexOf(")", endIndex);
}
}
}
// Enough searching, start moving stuff over to the buffer
sb.append(css.substring(appendIndex, m.start()));
if (foundTerminator) {
String token = css.substring(startIndex, endIndex);
token = token.replaceAll("\\s+", "");
preservedTokens.add(token);
String preserver = "url(___YUICSSMIN_PRESERVED_TOKEN_" + (preservedTokens.size() - 1) + "___)";
sb.append(preserver);
appendIndex = endIndex + 1;
} else {
// No end terminator found, re-add the whole match. Should we throw/warn here?
sb.append(css.substring(m.start(), m.end()));
appendIndex = m.end();
}
}
sb.append(css.substring(appendIndex));
return sb.toString();
}
public void compress(Writer out, int linebreakpos)
throws IOException {
Pattern p;
Matcher m;
String css = srcsb.toString();
int startIndex = 0;
int endIndex = 0;
int i = 0;
int max = 0;
ArrayList preservedTokens = new ArrayList(0);
ArrayList comments = new ArrayList(0);
String token;
int totallen = css.length();
String placeholder;
css = this.extractDataUrls(css, preservedTokens);
StringBuffer sb = new StringBuffer(css);
// collect all comment blocks...
while ((startIndex = sb.indexOf("/*", startIndex)) >= 0) {
endIndex = sb.indexOf("*/", startIndex + 2);
if (endIndex < 0) {
endIndex = totallen;
}
token = sb.substring(startIndex + 2, endIndex);
comments.add(token);
sb.replace(startIndex + 2, endIndex, "___YUICSSMIN_PRESERVE_CANDIDATE_COMMENT_" + (comments.size() - 1) + "___");
startIndex += 2;
}
css = sb.toString();
// preserve strings so their content doesn't get accidentally minified
sb = new StringBuffer();
p = Pattern.compile("(\"([^\\\\\"]|\\\\.|\\\\)*\")|(\'([^\\\\\']|\\\\.|\\\\)*\')");
m = p.matcher(css);
while (m.find()) {
token = m.group();
char quote = token.charAt(0);
token = token.substring(1, token.length() - 1);
// maybe the string contains a comment-like substring?
// one, maybe more? put'em back then
if (token.indexOf("___YUICSSMIN_PRESERVE_CANDIDATE_COMMENT_") >= 0) {
for (i = 0, max = comments.size(); i < max; i += 1) {
token = token.replace("___YUICSSMIN_PRESERVE_CANDIDATE_COMMENT_" + i + "___", comments.get(i).toString());
}
}
// minify alpha opacity in filter strings
token = token.replaceAll("(?i)progid:DXImageTransform.Microsoft.Alpha\\(Opacity=", "alpha(opacity=");
preservedTokens.add(token);
String preserver = quote + "___YUICSSMIN_PRESERVED_TOKEN_" + (preservedTokens.size() - 1) + "___" + quote;
m.appendReplacement(sb, preserver);
}
m.appendTail(sb);
css = sb.toString();
// strings are safe, now wrestle the comments
for (i = 0, max = comments.size(); i < max; i += 1) {
token = comments.get(i).toString();
placeholder = "___YUICSSMIN_PRESERVE_CANDIDATE_COMMENT_" + i + "___";
// ! in the first position of the comment means preserve
// so push to the preserved tokens while stripping the !
if (token.startsWith("!")) {
preservedTokens.add(token);
css = css.replace(placeholder, "___YUICSSMIN_PRESERVED_TOKEN_" + (preservedTokens.size() - 1) + "___");
continue;
}
// \ in the last position looks like hack for Mac/IE5
// shorten that to /*\*/ and the next one to /**/
if (token.endsWith("\\")) {
preservedTokens.add("\\");
css = css.replace(placeholder, "___YUICSSMIN_PRESERVED_TOKEN_" + (preservedTokens.size() - 1) + "___");
i = i + 1; // attn: advancing the loop
preservedTokens.add("");
css = css.replace("___YUICSSMIN_PRESERVE_CANDIDATE_COMMENT_" + i + "___", "___YUICSSMIN_PRESERVED_TOKEN_" + (preservedTokens.size() - 1) + "___");
continue;
}
// keep empty comments after child selectors (IE7 hack)
// e.g. html >/**/ body
if (token.length() == 0) {
startIndex = css.indexOf(placeholder);
if (startIndex > 2) {
if (css.charAt(startIndex - 3) == '>') {
preservedTokens.add("");
css = css.replace(placeholder, "___YUICSSMIN_PRESERVED_TOKEN_" + (preservedTokens.size() - 1) + "___");
}
}
}
// in all other cases kill the comment
css = css.replace("/*" + placeholder + "*/", "");
}
// Normalize all whitespace strings to single spaces. Easier to work with that way.
css = css.replaceAll("\\s+", " ");
// Remove the spaces before the things that should not have spaces before them.
// But, be careful not to turn "p :link {...}" into "p:link{...}"
// Swap out any pseudo-class colons with the token, and then swap back.
sb = new StringBuffer();
p = Pattern.compile("(^|\\})(([^\\{:])+:)+([^\\{]*\\{)");
m = p.matcher(css);
while (m.find()) {
String s = m.group();
s = s.replaceAll(":", "___YUICSSMIN_PSEUDOCLASSCOLON___");
s = s.replaceAll( "\\\\", "\\\\\\\\" ).replaceAll( "\\$", "\\\\\\$" );
m.appendReplacement(sb, s);
}
m.appendTail(sb);
css = sb.toString();
// Remove spaces before the things that should not have spaces before them.
css = css.replaceAll("\\s+([!{};:>+\\(\\)\\],])", "$1");
// bring back the colon
css = css.replaceAll("___YUICSSMIN_PSEUDOCLASSCOLON___", ":");
// retain space for special IE6 cases
css = css.replaceAll(":first\\-(line|letter)(\\{|,)", ":first-$1 $2");
// no space after the end of a preserved comment
css = css.replaceAll("\\*/ ", "*/");
// If there is a @charset, then only allow one, and push to the top of the file.
css = css.replaceAll("^(.*)(@charset \"[^\"]*\";)", "$2$1");
css = css.replaceAll("^(\\s*@charset [^;]+;\\s*)+", "$1");
// Put the space back in some cases, to support stuff like
// @media screen and (-webkit-min-device-pixel-ratio:0){
css = css.replaceAll("\\band\\(", "and (");
// Remove the spaces after the things that should not have spaces after them.
css = css.replaceAll("([!{}:;>+\\(\\[,])\\s+", "$1");
// remove unnecessary semicolons
css = css.replaceAll(";+}", "}");
// Replace 0(px,em,%) with 0.
css = css.replaceAll("([\\s:])(0)(px|em|%|in|cm|mm|pc|pt|ex)", "$1$2");
// Replace 0 0 0 0; with 0.
css = css.replaceAll(":0 0 0 0(;|})", ":0$1");
css = css.replaceAll(":0 0 0(;|})", ":0$1");
css = css.replaceAll(":0 0(;|})", ":0$1");
// Replace background-position:0; with background-position:0 0;
// same for transform-origin
sb = new StringBuffer();
p = Pattern.compile("(?i)(background-position|transform-origin|webkit-transform-origin|moz-transform-origin|o-transform-origin|ms-transform-origin):0(;|})");
m = p.matcher(css);
while (m.find()) {
m.appendReplacement(sb, m.group(1).toLowerCase() + ":0 0" + m.group(2));
}
m.appendTail(sb);
css = sb.toString();
// Replace 0.6 to .6, but only when preceded by : or a white-space
css = css.replaceAll("(:|\\s)0+\\.(\\d+)", "$1.$2");
// Shorten colors from rgb(51,102,153) to #336699
// This makes it more likely that it'll get further compressed in the next step.
p = Pattern.compile("rgb\\s*\\(\\s*([0-9,\\s]+)\\s*\\)");
m = p.matcher(css);
sb = new StringBuffer();
while (m.find()) {
String[] rgbcolors = m.group(1).split(",");
StringBuffer hexcolor = new StringBuffer("#");
for (i = 0; i < rgbcolors.length; i++) {
int val = Integer.parseInt(rgbcolors[i]);
if (val < 16) {
hexcolor.append("0");
}
hexcolor.append(Integer.toHexString(val));
}
m.appendReplacement(sb, hexcolor.toString());
}
m.appendTail(sb);
css = sb.toString();
// Shorten colors from #AABBCC to #ABC. Note that we want to make sure
// the color is not preceded by either ", " or =. Indeed, the property
// filter: chroma(color="#FFFFFF");
// would become
// filter: chroma(color="#FFF");
// which makes the filter break in IE.
// We also want to make sure we're only compressing #AABBCC patterns inside { }, not id selectors ( #FAABAC {} )
// We also want to avoid compressing invalid values (e.g. #AABBCCD to #ABCD)
p = Pattern.compile("(\\=\\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])" + "(:?\\}|[^0-9a-fA-F{][^{]*?\\})");
m = p.matcher(css);
sb = new StringBuffer();
int index = 0;
while (m.find(index)) {
sb.append(css.substring(index, m.start()));
boolean isFilter = (m.group(1) != null && !"".equals(m.group(1)));
if (isFilter) {
// Restore, as is. Compression will break filters
sb.append(m.group(1) + "#" + m.group(2) + m.group(3) + m.group(4) + m.group(5) + m.group(6) + m.group(7));
} else {
if( m.group(2).equalsIgnoreCase(m.group(3)) &&
m.group(4).equalsIgnoreCase(m.group(5)) &&
m.group(6).equalsIgnoreCase(m.group(7))) {
// #AABBCC pattern
sb.append("#" + (m.group(3) + m.group(5) + m.group(7)).toLowerCase());
} else {
// Non-compressible color, restore, but lower case.
sb.append("#" + (m.group(2) + m.group(3) + m.group(4) + m.group(5) + m.group(6) + m.group(7)).toLowerCase());
}
}
index = m.end(7);
}
sb.append(css.substring(index));
css = sb.toString();
// border: none -> border:0
sb = new StringBuffer();
p = Pattern.compile("(?i)(border|border-top|border-right|border-bottom|border-right|outline|background):none(;|})");
m = p.matcher(css);
while (m.find()) {
m.appendReplacement(sb, m.group(1).toLowerCase() + ":0" + m.group(2));
}
m.appendTail(sb);
css = sb.toString();
// shorter opacity IE filter
css = css.replaceAll("(?i)progid:DXImageTransform.Microsoft.Alpha\\(Opacity=", "alpha(opacity=");
// Remove empty rules.
css = css.replaceAll("[^\\}\\{/;]+\\{\\}", "");
// TODO: Should this be after we re-insert tokens. These could alter the break points. However then
// we'd need to make sure we don't break in the middle of a string etc.
if (linebreakpos >= 0) {
// Some source control tools don't like it when files containing lines longer
// than, say 8000 characters, are checked in. The linebreak option is used in
// that case to split long lines after a specific column.
i = 0;
int linestartpos = 0;
sb = new StringBuffer(css);
while (i < sb.length()) {
char c = sb.charAt(i++);
if (c == '}' && i - linestartpos > linebreakpos) {
sb.insert(i, '\n');
linestartpos = i;
}
}
css = sb.toString();
}
// Replace multiple semi-colons in a row by a single one
// See SF bug #1980989
css = css.replaceAll(";;+", ";");
// restore preserved comments and strings
for(i = 0, max = preservedTokens.size(); i < max; i++) {
css = css.replace("___YUICSSMIN_PRESERVED_TOKEN_" + i + "___", preservedTokens.get(i).toString());
}
// Trim the final string (for any leading or trailing white spaces)
css = css.trim();
// Write the output...
out.write(css);
}
}