in tapestry-webresources/src/main/java/org/apache/tapestry5/internal/webresources/CssCompressor.java [176:616]
public static String compress(String uncompressedCss) throws IOException {
Pattern p;
Matcher m;
String css = uncompressedCss;
int startIndex = 0;
int endIndex = 0;
int i = 0;
int max = 0;
List<String> preservedTokens = new ArrayList<>();
List<String> preservedCssVars = new ArrayList<>();
List<String> comments = new ArrayList<>();
String token;
int totallen = css.length();
String placeholder;
StringBuilder sb = new StringBuilder(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();
// we need to preserve tokens in two steps, as the "var" is inside of "calc", but
// thanks to TAP5-2753, the calc tokens needs to be restored, some optimizations
// around operators, and then css vars would be broken.
css = preserveToken(css, "var", PRESERVE_CSS_VARS, false, "CSS_VAR", preservedCssVars);
css = preserveToken(css, "url", PRESERVE_TOKEN_URL, true, "TOKEN", preservedTokens);
css = preserveToken(css, "calc", PRESERVE_TOKEN_CALC, false, "TOKEN", preservedTokens);
css = preserveToken(css, "progid:DXImageTransform.Microsoft.Matrix",
PRESERVE_TOKEN_PROGID_DX_IMAGE_TRANSFORM_MICROSOFT_MATRIX, false, "TOKEN", preservedTokens);
// preserve strings so their content doesn't get accidentally minified
StringBuffer sbuffer = new StringBuffer();
p = PRESERVE_STRINGS;
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 = MINIFY_ALPHA_OPACITY_FILTER_STRINGS.matcher(token).replaceAll("alpha(opacity=");
preservedTokens.add(token);
String preserver = quote + "___YUICSSMIN_PRESERVED_TOKEN_" + (preservedTokens.size() - 1) + "___" + quote;
m.appendReplacement(sbuffer, preserver);
}
m.appendTail(sbuffer);
css = sbuffer.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 + "*/", "");
}
// preserve \9 IE hack
final String backslash9 = "\\9";
while (css.indexOf(backslash9) > -1) {
preservedTokens.add(backslash9);
css = css.replace(backslash9, "___YUICSSMIN_PRESERVED_TOKEN_" + (preservedTokens.size() - 1) + "___");
}
// Normalize all whitespace strings to single spaces. Easier to work with that
// way.
css = WHITESPACE.matcher(css).replaceAll(" ");
// 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.
sbuffer = new StringBuffer();
p = UNNECESSARY_SPACES1;
m = p.matcher(css);
while (m.find()) {
String s = m.group();
s = s.replace(":", PSEUDO_CLASS_COLON.pattern());
s = s.replace("\\", "\\\\");
s = s.replace("$", "\\$");
m.appendReplacement(sbuffer, s);
}
m.appendTail(sbuffer);
css = sbuffer.toString();
// Remove spaces before the things that should not have spaces before them.
css = UNNECESSARY_SPACES2.matcher(css).replaceAll("$1");
// Restore spaces for !important
css = IMPORTANT.matcher(css).replaceAll(" !important");
// bring back the colon
css = PSEUDO_CLASS_COLON.matcher(css).replaceAll(":");
// retain space for special IE6 cases
sbuffer = new StringBuffer();
p = IE6_SPACE;
m = p.matcher(css);
while (m.find()) {
m.appendReplacement(sbuffer, ":first-" + m.group(1).toLowerCase() + " " + m.group(2));
}
m.appendTail(sbuffer);
css = sbuffer.toString();
// no space after the end of a preserved comment
css = css.replace("*/ ", "*/");
// TODO: Charset handling is broken if more than two charsets
// If there are multiple @charset directives, push them to the top of the file.
sbuffer = new StringBuffer();
p = CHARSET_DIRECTIVE;
m = p.matcher(css);
while (m.find()) {
String s = m.group(1).replace("\\", "\\\\").replace("$", "\\$");
m.appendReplacement(sbuffer, m.group(2).toLowerCase() + m.group(3) + s);
}
m.appendTail(sbuffer);
css = sbuffer.toString();
// When all @charset are at the top, remove the second and after (as they are
// completely ignored).
sbuffer = new StringBuffer();
p = CHARSET_MULTIPLE;
m = p.matcher(css);
while (m.find()) {
String group2 = m.group(2);
String group3 = m.group(3);
String group4 = m.group(4);
m.appendReplacement(sbuffer, group2 + group3.toLowerCase() + group4);
}
m.appendTail(sbuffer);
css = sbuffer.toString();
// lowercase some popular @directives (@charset is done right above)
sbuffer = new StringBuffer();
p = LOWERCASE_DIRECTIVES;
m = p.matcher(css);
while (m.find()) {
m.appendReplacement(sbuffer, '@' + m.group(1).toLowerCase());
}
m.appendTail(sbuffer);
css = sbuffer.toString();
// lowercase some more common pseudo-elements
sbuffer = new StringBuffer();
p = LOWERCAUSE_PSEUDO_CLASSES;
m = p.matcher(css);
while (m.find()) {
m.appendReplacement(sbuffer, ':' + m.group(1).toLowerCase());
}
m.appendTail(sbuffer);
css = sbuffer.toString();
// lowercase some more common functions
sbuffer = new StringBuffer();
p = LOWERCASE_FUNCTIONS1;
m = p.matcher(css);
while (m.find()) {
m.appendReplacement(sbuffer, ':' + m.group(1).toLowerCase() + '(');
}
m.appendTail(sbuffer);
css = sbuffer.toString();
// lower case some common function that can be values
// NOTE: rgb() isn't useful as we replace with #hex later, as well as and() is
// already done for us right after this
sbuffer = new StringBuffer();
p = LOWERCASE_FUNCTIONS2;
m = p.matcher(css);
while (m.find()) {
m.appendReplacement(sbuffer, m.group(1) + m.group(2).toLowerCase());
}
m.appendTail(sbuffer);
css = sbuffer.toString();
// Put the space back in some cases, to support stuff like
// @media screen and (-webkit-min-device-pixel-ratio:0){
css = RESTORE_AND_SPACE.matcher(css).replaceAll("and (");
// Remove the spaces after the things that should not have spaces after them.
css = TRAILING_SPACES.matcher(css).replaceAll("$1");
// remove unnecessary semicolons
css = UNNECESSARY_SEMICOLON.matcher(css).replaceAll("}");
// Replace 0(px,em) with 0. (don't replace seconds are they are needed for
// transitions to be valid)
String oldCss;
p = ZERO_UNITS;
do {
oldCss = css;
m = p.matcher(css);
css = m.replaceAll("$1$20");
} while (!(css.equals(oldCss)));
// We do the same with % but don't replace the 0% in keyframes
p = ZERO_PERCENTAGE;
do {
oldCss = css;
m = p.matcher(css);
css = m.replaceAll("$1$20");
} while (!(css.equals(oldCss)));
// Replace the keyframe 100% step with 'to' which is shorter
p = KEYFRAME_TO;
do {
oldCss = css;
m = p.matcher(css);
css = m.replaceAll("$1to{");
} while (!(css.equals(oldCss)));
// Replace 0(px,em,%) with 0 inside groups (e.g. -MOZ-RADIAL-GRADIENT(CENTER
// 45DEG, CIRCLE CLOSEST-SIDE, ORANGE 0%, RED 100%))
p = ZERO_UNITS_GROUPS;
do {
oldCss = css;
m = p.matcher(css);
css = m.replaceAll("($10");
} while (!(css.equals(oldCss)));
// Replace x.0(px,em,%) with x(px,em,%).
css = UNNECESSARY_DOT_ZERO1.matcher(css).replaceAll("$1$2");
// Replace .0(px,em,%) with 0(px,em,%).
css = UNNECESSARY_DOT_ZERO2.matcher(css).replaceAll("$1\\0$2");
// Replace 0 0 0 0; with 0.
css = ZERO_VALUE_1.matcher(css).replaceAll(":0$1");
css = ZERO_VALUE_2.matcher(css).replaceAll(":0$1");
css = ZERO_VALUE_3.matcher(css).replaceAll(":0$1");
// Replace background-position:0; with background-position:0 0;
// same for transform-origin
sbuffer = new StringBuffer();
p = BACKGROUND_POSITION_TRANSFORM_ORIGIN;
m = p.matcher(css);
while (m.find()) {
m.appendReplacement(sbuffer, m.group(1).toLowerCase() + ":0 0" + m.group(2));
}
m.appendTail(sbuffer);
css = sbuffer.toString();
// Replace 0.6 to .6, but only when preceded by : or a white-space
css = RESTORE_DOT_ZERO.matcher(css).replaceAll("$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 = RGB;
m = p.matcher(css);
sbuffer = 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");
}
// If someone passes an RGB value that's too big to express in two characters,
// round down.
// Probably should throw out a warning here, but generating valid CSS is a
// bigger concern.
if (val > 255) {
val = 255;
}
hexcolor.append(Integer.toHexString(val));
}
m.appendReplacement(sbuffer, hexcolor.toString());
}
m.appendTail(sbuffer);
css = sbuffer.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 = HEX_COLORS;
m = p.matcher(css);
sb = new StringBuilder();
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).concat("#").concat(m.group(2)).concat(m.group(3)).concat(m.group(4))
.concat(m.group(5)).concat(m.group(6)).concat(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("#".concat(m.group(3)).concat(m.group(5)).concat(m.group(7)).toLowerCase());
} else {
// Non-compressible color, restore, but lower case.
sb.append("#".concat(m.group(2)).concat(m.group(3)).concat(m.group(4))
.concat(m.group(5) + m.group(6) + m.group(7)).toLowerCase());
}
}
index = m.end(7);
}
sb.append(css.substring(index));
css = sb.toString();
// Replace #f00 -> red
css = COLOR_RED.matcher(css).replaceAll("$1red$3");
// Replace other short color keywords
css = COLOR_NAVY.matcher(css).replaceAll("$1navy$3");
css = COLOR_GRAY.matcher(css).replaceAll("$1gray$3");
css = COLOR_OLIVE.matcher(css).replaceAll("$1olive$3");
css = COLOR_PURPLE.matcher(css).replaceAll("$1purple$3");
css = COLOR_SILVER.matcher(css).replaceAll("$1silver$3");
css = COLOR_TEAL.matcher(css).replaceAll("$1teal$3");
css = COLOR_ORANGE.matcher(css).replaceAll("$1orange$3");
css = COLOR_MAROON.matcher(css).replaceAll("$1maroon$3");
// border: none -> border:0
sbuffer = new StringBuffer();
p = NONE;
m = p.matcher(css);
while (m.find()) {
m.appendReplacement(sbuffer, m.group(1).toLowerCase().concat(":0").concat(m.group(2)));
}
m.appendTail(sbuffer);
css = sbuffer.toString();
// TODO: Why are we doing this again?
// shorter opacity IE filter
css = css.replaceAll("(?i)progid:DXImageTransform.Microsoft.Alpha\\(Opacity=", "alpha(opacity=");
// Find a fraction that is used for Opera's -o-device-pixel-ratio query
// Add token to add the "\" back in later
css = OPERA_DEVICE_PIXEL_RATIO.matcher(css).replaceAll("($1:$2___YUI_QUERY_FRACTION___$3)");
// Remove empty rules.
css = EMPTY_RULE.matcher(css).replaceAll("");
// Add "\" back to fix Opera -o-device-pixel-ratio query
css = css.replaceAll("___YUI_QUERY_FRACTION___", "/");
// Replace multiple semi-colons in a row by a single one
// See SF bug #1980989
css = MULTI_SEMICOLON.matcher(css).replaceAll(";");
// restore preserved tokens
css = restorePreservedTokens(css, "TOKEN", preservedTokens);
// Add spaces back in between operators for css calc function
// https://developer.mozilla.org/en-US/docs/Web/CSS/calc
// Added by Eric Arnol-Martin (earnolmartin@gmail.com)
sbuffer = new StringBuffer();
p = CALC;
m = p.matcher(css);
while (m.find()) {
String s = m.group();
s = CALC_PLUS.matcher(s).replaceAll(" + ");
s = CALC_MINUS.matcher(s).replaceAll(" - ");
s = CALC_MULTI.matcher(s).replaceAll(" * ");
s = CALC_DIV.matcher(s).replaceAll(" / ");
m.appendReplacement(sbuffer, s);
}
m.appendTail(sbuffer);
css = sbuffer.toString();
// restore css variables AFTER calc func optimization
css = restorePreservedTokens(css, "CSS_VAR", preservedCssVars);
// Trim the final string (for any leading or trailing white spaces)
return css.trim();
}