package com.googlecode.htmlcompressor.compressor;
/*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import java.io.IOException;
import java.io.InputStream;
import java.io.StringWriter;
import java.util.ArrayList;
import java.util.List;
import java.util.logging.Level;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;
import com.google.common.collect.Lists;
import com.google.common.io.LimitInputStream;
import com.google.javascript.jscomp.CompilationLevel;
import com.google.javascript.jscomp.Compiler;
import com.google.javascript.jscomp.CompilerOptions;
import com.google.javascript.jscomp.JSSourceFile;
import com.google.javascript.jscomp.Result;
import com.google.javascript.jscomp.WarningLevel;
/**
* Basic JavaScript compressor implementation using <a href="http://code.google.com/closure/compiler/">Google Closure Compiler</a>
* that could be used by {@link HtmlCompressor} for inline JavaScript compression.
*
* @author <a href="mailto:[email protected]">Sergiy Kovalchuk</a>
*
* @see HtmlCompressor#setJavaScriptCompressor(Compressor)
* @see <a href="http://code.google.com/closure/compiler/">Google Closure Compiler</a>
*/
public class ClosureJavaScriptCompressor implements Compressor {
public static final String COMPILATION_LEVEL_SIMPLE = "simple";
public static final String COMPILATION_LEVEL_ADVANCED = "advanced";
public static final String COMPILATION_LEVEL_WHITESPACE = "whitespace";
//Closure compiler default settings
private CompilerOptions compilerOptions = new CompilerOptions();
private CompilationLevel compilationLevel = CompilationLevel.SIMPLE_OPTIMIZATIONS;
private Level loggingLevel = Level.SEVERE;
private WarningLevel warningLevel = WarningLevel.DEFAULT;
private boolean customExternsOnly = false;
private List<JSSourceFile> externs = null;
public ClosureJavaScriptCompressor() {
}
public ClosureJavaScriptCompressor(CompilationLevel compilationLevel) {
this.compilationLevel = compilationLevel;
}
@Override
public String compress(String source) {
StringWriter writer = new StringWriter();
//prepare source
List<JSSourceFile> input = new ArrayList<JSSourceFile>();
input.add(JSSourceFile.fromCode("source.js", source));
//prepare externs
List<JSSourceFile> externsList = new ArrayList<JSSourceFile>();
if(compilationLevel.equals(CompilationLevel.ADVANCED_OPTIMIZATIONS)) {
//default externs
if(!customExternsOnly) {
try {
externsList = getDefaultExterns();
} catch (IOException e) {
e.printStackTrace();
}
}
//add user defined externs
if(externs != null) {
for(JSSourceFile extern : externs) {
externsList.add(extern);
}
}
//add empty externs
if(externsList.size() == 0) {
externsList.add(JSSourceFile.fromCode("externs.js", ""));
}
} else {
//empty externs
externsList.add(JSSourceFile.fromCode("externs.js", ""));
}
Compiler.setLoggingLevel(loggingLevel);
Compiler compiler = new Compiler();
compiler.disableThreads();
compilationLevel.setOptionsForCompilationLevel(compilerOptions);
warningLevel.setOptionsForWarningLevel(compilerOptions);
Result result = compiler.compile(externsList, input, compilerOptions);
if (result.success) {
writer.write(compiler.toSource());
} else {
writer.write(source);
}
return writer.toString();
}
//read default externs from closure.jar
private List<JSSourceFile> getDefaultExterns() throws IOException {
InputStream input = ClosureJavaScriptCompressor.class.getResourceAsStream("/externs.zip");
ZipInputStream zip = new ZipInputStream(input);
List<JSSourceFile> externs = Lists.newLinkedList();
for (ZipEntry entry = null; (entry = zip.getNextEntry()) != null;) {
LimitInputStream entryStream = new LimitInputStream(zip, entry.getSize());
externs.add(JSSourceFile.fromInputStream(entry.getName(), entryStream));
}
return externs;
}
/**
* Returns level of optimization that is applied when compiling JavaScript code.
*
* @return <code>CompilationLevel</code> that is applied when compiling JavaScript code.
*
* @see <a href="http://closure-compiler.googlecode.com/svn/trunk/javadoc/com/google/javascript/jscomp/CompilationLevel.html">CompilationLevel</a>
*/
public CompilationLevel getCompilationLevel() {
return compilationLevel;
}
/**
* Sets level of optimization that should be applied when compiling JavaScript code.
* If none is provided, <code>CompilationLevel.SIMPLE_OPTIMIZATIONS</code> will be used by default.
*
* <p><b>Warning:</b> Using <code>CompilationLevel.ADVANCED_OPTIMIZATIONS</code> could
* break inline JavaScript if externs are not set properly.
*
* @param compilationLevel Optimization level to use, could be set to <code>CompilationLevel.ADVANCED_OPTIMIZATIONS</code>, <code>CompilationLevel.SIMPLE_OPTIMIZATIONS</code>, <code>CompilationLevel.WHITESPACE_ONLY</code>
*
* @see <a href="http://code.google.com/closure/compiler/docs/api-tutorial3.html">Advanced Compilation and Externs</a>
* @see <a href="http://code.google.com/closure/compiler/docs/compilation_levels.html">Closure Compiler Compilation Levels</a>
* @see <a href="http://closure-compiler.googlecode.com/svn/trunk/javadoc/com/google/javascript/jscomp/CompilationLevel.html">CompilationLevel</a>
*/
public void setCompilationLevel(CompilationLevel compilationLevel) {
this.compilationLevel = compilationLevel;
}
/**
* Returns options that are used by the Closure compiler.
*
* @return <code>CompilerOptions</code> that are used by the compiler
*
* @see <a href="http://closure-compiler.googlecode.com/svn/trunk/javadoc/com/google/javascript/jscomp/CompilerOptions.html">CompilerOptions</a>
*/
public CompilerOptions getCompilerOptions() {
return compilerOptions;
}
/**
* Sets options that will be used by the Closure compiler.
* If none is provided, default options constructor will be used: <code>new CompilerOptions()</code>.
*
* @param compilerOptions <code>CompilerOptions</code> that will be used by the compiler
*
* @see <a href="http://closure-compiler.googlecode.com/svn/trunk/javadoc/com/google/javascript/jscomp/CompilerOptions.html">CompilerOptions</a>
*/
public void setCompilerOptions(CompilerOptions compilerOptions) {
this.compilerOptions = compilerOptions;
}
/**
* Returns logging level used by the Closure compiler.
*
* @return <code>Level</code> of logging used by the Closure compiler
*/
public Level getLoggingLevel() {
return loggingLevel;
}
/**
* Sets logging level for the Closure compiler.
*
* @param loggingLevel logging level for the Closure compiler.
*
* @see java.util.logging.Level
*/
public void setLoggingLevel(Level loggingLevel) {
this.loggingLevel = loggingLevel;
}
/**
* Returns <code>JSSourceFile</code> used as a reference during the compression
* at <code>CompilationLevel.ADVANCED_OPTIMIZATIONS</code> level.
*
* @return <code>JSSourceFile</code> used as a reference during compression
*/
public List<JSSourceFile> getExterns() {
return externs;
}
/**
* Sets external JavaScript files that are used as a reference for function declarations if
* <code>CompilationLevel.ADVANCED_OPTIMIZATIONS</code> compression level is used.
*
* <p>A number of default externs defined inside Closure's jar will be used besides user defined ones,
* to use only user defined externs set {@link #setCustomExternsOnly(boolean) setCustomExternsOnly(true)}
*
* <p><b>Warning:</b> Using <code>CompilationLevel.ADVANCED_OPTIMIZATIONS</code> could
* break inline JavaScript if externs are not set properly.
*
* @param externs <code>JSSourceFile</code> to use as a reference during compression
*
* @see #setCompilationLevel(CompilationLevel)
* @see #setCustomExternsOnly(boolean)
* @see <a href="http://code.google.com/closure/compiler/docs/api-tutorial3.html">Advanced Compilation and Externs</a>
* @see <a href="http://closure-compiler.googlecode.com/svn/trunk/javadoc/com/google/javascript/jscomp/JSSourceFile.html">JSSourceFile</a>
*/
public void setExterns(List<JSSourceFile> externs) {
this.externs = externs;
}
/**
* Returns <code>WarningLevel</code> used by the Closure compiler
*
* @return <code>WarningLevel</code> used by the Closure compiler
*/
public WarningLevel getWarningLevel() {
return warningLevel;
}
/**
* Indicates the amount of information you want from the compiler about possible problems in your code.
*
* @param warningLevel <code>WarningLevel</code> to use
*
* @see <a href="http://code.google.com/closure/compiler/docs/api-ref.html">
*/
public void setWarningLevel(WarningLevel warningLevel) {
this.warningLevel = warningLevel;
}
/**
* Returns <code>true</code> if default externs defined inside Closure's jar are ignored
* and only user defined ones are used.
*
* @return <code>true</code> if default externs defined inside Closure's jar are ignored
* and only user defined ones are used
*/
public boolean isCustomExternsOnly() {
return customExternsOnly;
}
/**
* If set to <code>true</code>, default externs defined inside Closure's jar will be ignored
* and only user defined ones will be used.
*
* @param customExternsOnly <code>true</code> to skip default externs and use only user defined ones
*
* @see #setExterns(List)
* @see #setCompilationLevel(CompilationLevel)
*/
public void setCustomExternsOnly(boolean customExternsOnly) {
this.customExternsOnly = customExternsOnly;
}
}
