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Optimize memory usage in CssCompressor + API extensions #157

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Optimize memory usage in CssCompressor + API extensions #157

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91 changes: 50 additions & 41 deletions src/com/yahoo/platform/yui/compressor/CssCompressor.java
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Original file line number Diff line number Diff line change
Expand Up @@ -14,29 +14,37 @@
import java.io.IOException;
import java.io.Reader;
import java.io.Writer;
import java.nio.CharBuffer;
import java.util.regex.Pattern;
import java.util.regex.Matcher;
import java.util.ArrayList;

public class CssCompressor {

private StringBuffer srcsb = new StringBuffer();
private final CharSequence srcsb;

public CssCompressor(CharSequence in) {
this.srcsb = in;
}

public CssCompressor(Reader in) throws IOException {
// Read the stream...
int c;
while ((c = in.read()) != -1) {
srcsb.append((char) c);
final StringBuilder sb = new StringBuilder();
final CharBuffer buf = CharBuffer.allocate(2048);
while (in.read(buf) != -1) {
buf.flip();
sb.append(buf);
buf.clear();
}
srcsb = sb;
}

// Leave data urls alone to increase parse performance.
protected String extractDataUrls(String css, ArrayList preservedTokens) {
protected String extractDataUrls(String css, ArrayList<String> preservedTokens) {

int maxIndex = css.length() - 1;
int appendIndex = 0;

StringBuffer sb = new StringBuffer();
final StringBuilder sb = new StringBuilder(css.length());

Pattern p = Pattern.compile("(?i)url\\(\\s*([\"']?)data\\:");
Matcher m = p.matcher(css);
Expand Down Expand Up @@ -79,8 +87,7 @@ protected String extractDataUrls(String css, ArrayList preservedTokens) {
token = token.replaceAll("\\s+", "");
preservedTokens.add(token);

String preserver = "url(___YUICSSMIN_PRESERVED_TOKEN_" + (preservedTokens.size() - 1) + "___)";
sb.append(preserver);
sb.append("url(___YUICSSMIN_PRESERVED_TOKEN_").append(preservedTokens.size() - 1).append("___)");

appendIndex = endIndex + 1;
} else {
Expand All @@ -95,7 +102,7 @@ protected String extractDataUrls(String css, ArrayList preservedTokens) {
return sb.toString();
}

private String preserveOldIESpecificMatrixDefinition(String css, ArrayList preservedTokens) {
private String preserveOldIESpecificMatrixDefinition(String css, ArrayList<String> preservedTokens) {
StringBuffer sb = new StringBuffer();
Pattern p = Pattern.compile("\\s*filter:\\s*progid:DXImageTransform.Microsoft.Matrix\\(([^\\)]+)\\);");
Matcher m = p.matcher(css);
Expand All @@ -111,7 +118,11 @@ private String preserveOldIESpecificMatrixDefinition(String css, ArrayList prese

public void compress(Writer out, int linebreakpos)
throws IOException {
// Write the output...
out.write(compress(linebreakpos));
}

public String compress(int linebreakpos) {
Pattern p;
Matcher m;
String css = srcsb.toString();
Expand All @@ -120,15 +131,15 @@ public void compress(Writer out, int linebreakpos)
int endIndex = 0;
int i = 0;
int max = 0;
ArrayList preservedTokens = new ArrayList(0);
ArrayList comments = new ArrayList(0);
ArrayList<String> preservedTokens = new ArrayList<String>();
ArrayList<String> comments = new ArrayList<String>();
String token;
int totallen = css.length();
String placeholder;

css = this.extractDataUrls(css, preservedTokens);

StringBuffer sb = new StringBuffer(css);
final StringBuffer sb = new StringBuffer(css);

// collect all comment blocks...
while ((startIndex = sb.indexOf("/*", startIndex)) >= 0) {
Expand All @@ -145,7 +156,7 @@ public void compress(Writer out, int linebreakpos)
css = sb.toString();

// preserve strings so their content doesn't get accidentally minified
sb = new StringBuffer();
sb.setLength(0);
p = Pattern.compile("(\"([^\\\\\"]|\\\\.|\\\\)*\")|(\'([^\\\\\']|\\\\.|\\\\)*\')");
m = p.matcher(css);
while (m.find()) {
Expand All @@ -157,7 +168,7 @@ public void compress(Writer out, int linebreakpos)
// 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());
token = token.replace("___YUICSSMIN_PRESERVE_CANDIDATE_COMMENT_" + i + "___", comments.get(i));
}
}

Expand All @@ -175,7 +186,7 @@ public void compress(Writer out, int linebreakpos)
// strings are safe, now wrestle the comments
for (i = 0, max = comments.size(); i < max; i += 1) {

token = comments.get(i).toString();
token = comments.get(i);
placeholder = "___YUICSSMIN_PRESERVE_CANDIDATE_COMMENT_" + i + "___";

// ! in the first position of the comment means preserve
Expand Down Expand Up @@ -222,7 +233,7 @@ public void compress(Writer out, int linebreakpos)
// 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();
sb.setLength(0);
p = Pattern.compile("(^|\\})(([^\\{:])+:)+([^\\{]*\\{)");
m = p.matcher(css);
while (m.find()) {
Expand All @@ -241,7 +252,7 @@ public void compress(Writer out, int linebreakpos)
css = css.replaceAll("___YUICSSMIN_PSEUDOCLASSCOLON___", ":");

// retain space for special IE6 cases
sb = new StringBuffer();
sb.setLength(0);
p = Pattern.compile("(?i):first\\-(line|letter)(\\{|,)");
m = p.matcher(css);
while (m.find()) {
Expand All @@ -254,7 +265,7 @@ public void compress(Writer out, int linebreakpos)
css = css.replaceAll("\\*/ ", "*/");

// If there are multiple @charset directives, push them to the top of the file.
sb = new StringBuffer();
sb.setLength(0);
p = Pattern.compile("(?i)^(.*)(@charset)( \"[^\"]*\";)");
m = p.matcher(css);
while (m.find()) {
Expand All @@ -264,7 +275,7 @@ public void compress(Writer out, int linebreakpos)
css = sb.toString();

// When all @charset are at the top, remove the second and after (as they are completely ignored).
sb = new StringBuffer();
sb.setLength(0);
p = Pattern.compile("(?i)^((\\s*)(@charset)( [^;]+;\\s*))+");
m = p.matcher(css);
while (m.find()) {
Expand All @@ -274,38 +285,38 @@ public void compress(Writer out, int linebreakpos)
css = sb.toString();

// lowercase some popular @directives (@charset is done right above)
sb = new StringBuffer();
sb.setLength(0);
p = Pattern.compile("(?i)@(font-face|import|(?:-(?:atsc|khtml|moz|ms|o|wap|webkit)-)?keyframe|media|page|namespace)");
m = p.matcher(css);
while (m.find()) {
m.appendReplacement(sb, '@' + m.group(1).toLowerCase());
}
m.appendTail(sb);
css = sb.toString();

// lowercase some more common pseudo-elements
sb = new StringBuffer();
sb.setLength(0);
p = Pattern.compile("(?i):(active|after|before|checked|disabled|empty|enabled|first-(?:child|of-type)|focus|hover|last-(?:child|of-type)|link|only-(?:child|of-type)|root|:selection|target|visited)");
m = p.matcher(css);
while (m.find()) {
m.appendReplacement(sb, ':' + m.group(1).toLowerCase());
}
m.appendTail(sb);
css = sb.toString();

// lowercase some more common functions
sb = new StringBuffer();
sb.setLength(0);
p = Pattern.compile("(?i):(lang|not|nth-child|nth-last-child|nth-last-of-type|nth-of-type|(?:-(?:moz|webkit)-)?any)\\(");
m = p.matcher(css);
while (m.find()) {
m.appendReplacement(sb, ':' + m.group(1).toLowerCase() + '(');
}
m.appendTail(sb);
css = sb.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
sb = new StringBuffer();
sb.setLength(0);
p = Pattern.compile("(?i)([:,\\( ]\\s*)(attr|color-stop|from|rgba|to|url|(?:-(?:atsc|khtml|moz|ms|o|wap|webkit)-)?(?:calc|max|min|(?:repeating-)?(?:linear|radial)-gradient)|-webkit-gradient)");
m = p.matcher(css);
while (m.find()) {
Expand Down Expand Up @@ -337,7 +348,7 @@ public void compress(Writer out, int linebreakpos)

// Replace background-position:0; with background-position:0 0;
// same for transform-origin
sb = new StringBuffer();
sb.setLength(0);
p = Pattern.compile("(?i)(background-position|webkit-mask-position|transform-origin|webkit-transform-origin|moz-transform-origin|o-transform-origin|ms-transform-origin):0(;|})");
m = p.matcher(css);
while (m.find()) {
Expand All @@ -353,10 +364,10 @@ public void compress(Writer out, int linebreakpos)
// 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();
sb.setLength(0);
while (m.find()) {
String[] rgbcolors = m.group(1).split(",");
StringBuffer hexcolor = new StringBuffer("#");
StringBuilder hexcolor = new StringBuilder("#");
for (i = 0; i < rgbcolors.length; i++) {
int val = Integer.parseInt(rgbcolors[i]);
if (val < 16) {
Expand Down Expand Up @@ -386,7 +397,7 @@ public void compress(Writer out, int linebreakpos)
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();
sb.setLength(0);
int index = 0;

while (m.find(index)) {
Expand All @@ -397,19 +408,19 @@ public void compress(Writer out, int linebreakpos)

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));
sb.append(m.group(1)).append("#").append(m.group(2)).append(m.group(3)).append(m.group(4)).append(m.group(5)).append(m.group(6)).append(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());
sb.append("#").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());
sb.append("#").append((m.group(2) + m.group(3) + m.group(4) + m.group(5) + m.group(6) + m.group(7)).toLowerCase());
}
}

Expand All @@ -432,7 +443,7 @@ public void compress(Writer out, int linebreakpos)
css = css.replaceAll("(:|\\s)(#800000)(;|})", "$1maroon$3");

// border: none -> border:0
sb = new StringBuffer();
sb.setLength(0);
p = Pattern.compile("(?i)(border|border-top|border-right|border-bottom|border-left|outline|background):none(;|})");
m = p.matcher(css);
while (m.find()) {
Expand Down Expand Up @@ -462,7 +473,8 @@ public void compress(Writer out, int linebreakpos)
// that case to split long lines after a specific column.
i = 0;
int linestartpos = 0;
sb = new StringBuffer(css);
sb.setLength(0);
sb.append(css);
while (i < sb.length()) {
char c = sb.charAt(i++);
if (c == '}' && i - linestartpos > linebreakpos) {
Expand All @@ -480,13 +492,10 @@ public void compress(Writer out, int linebreakpos)

// restore preserved comments and strings
for(i = preservedTokens.size() - 1; i >= 0 ; i--) {
css = css.replace("___YUICSSMIN_PRESERVED_TOKEN_" + i + "___", preservedTokens.get(i).toString());
css = css.replace("___YUICSSMIN_PRESERVED_TOKEN_" + i + "___", preservedTokens.get(i));
}

// Trim the final string (for any leading or trailing white spaces)
css = css.trim();

// Write the output...
out.write(css);
return css.trim();
}
}