com.erigir.maven.plugin.processor.JavascriptCompilerFileProcessor Maven / Gradle / Ivy

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package com.erigir.maven.plugin.processor;

import com.erigir.maven.plugin.JavascriptCompilation;
import com.google.common.collect.Lists;
import com.google.javascript.jscomp.CompilationLevel;
import com.google.javascript.jscomp.CompilerOptions;
import com.google.javascript.jscomp.Compiler;
import com.google.javascript.jscomp.Result;
import com.google.javascript.jscomp.SourceFile;
import org.apache.commons.io.IOUtils;
import org.apache.maven.plugin.MojoExecutionException;
import org.apache.maven.plugin.logging.Log;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.Charset;
import java.util.Arrays;
import java.util.Enumeration;
import java.util.List;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;

/**
 Copyright 2014 Christopher Weiss

 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.

 NOTE : Borrowed heavily from http://blog.bolinfest.com/2009/11/calling-closure-compiler-from-java.html
 **/
public class JavascriptCompilerFileProcessor extends AbstractFileProcessor {
    private JavascriptCompilation.JSCompilationMode mode;
    private List cacheDefaultExterns;

    public boolean innerProcess(Log log, File src, File dst) throws MojoExecutionException, IOException {
        CompilationLevel level = fromMode();
        log.debug("ClosureCompile at level "+level+" on : "+src);
        String out = compile(level,getDefaultExterns(),Arrays.asList(SourceFile.fromFile(src)));
        IOUtils.write(out, new FileOutputStream(dst));
        return true;
    }

    public final String compile(CompilationLevel level, String code)
            throws IOException {
        return compile(level, Arrays.asList(SourceFile.fromCode("input.js",code)));
    }

    public final String compile(CompilationLevel level,  List input)
            throws IOException {
        return compile(level, getDefaultExterns(), input);
    }

    /**
         * @param input JavaScript source code to compile.
         * @return The compiled version of the code.
         */
    public final String compile(CompilationLevel level, List externs, List input)
    throws IOException{
        Compiler compiler = new Compiler();

        CompilerOptions options = new CompilerOptions();
        // level is used here, but additional options could be set, too.
        level.setOptionsForCompilationLevel(
                options);

        Result results = compiler.compile(externs, input, options);

        if (results.success)
        {
            // The compiler is responsible for generating the compiled code; it is not
            // accessible via the Result.
            return compiler.toSource();
        }
        else
        {
            // Failed - just return the uncompressed stuff
            StringBuilder sb = new StringBuilder();
            for (SourceFile s: input)
            {
                sb.append(s.getCode());
                sb.append("\n");
            }
            return sb.toString();
        }
    }

    private CompilationLevel fromMode()
    {
        CompilationLevel rval = null;
        switch(mode)
        {
            case CLOSURE_WHITESPACE : rval = CompilationLevel.WHITESPACE_ONLY; break;
            case CLOSURE_BASIC:  rval = CompilationLevel.SIMPLE_OPTIMIZATIONS; break;
            case CLOSURE_ADVANCED : rval = CompilationLevel.ADVANCED_OPTIMIZATIONS; break;
            default : rval = CompilationLevel.WHITESPACE_ONLY; break;
        }
        return rval;
    }

    private synchronized List getDefaultExterns() throws IOException
    {
        if (cacheDefaultExterns==null)
        {
            cacheDefaultExterns = buildDefaultExterns();
        }
        return cacheDefaultExterns;
    }

    /**
     * These come from Google as part of the package
     * @return a mutable list
     * @throws IOException
     */
    private List buildDefaultExterns() throws IOException {

        File tempFile = File.createTempFile("def-ext",".zip");
        IOUtils.copy(Compiler.class.getResourceAsStream(
                "/externs.zip"), new FileOutputStream(tempFile));

        List externs = Lists.newLinkedList();


        ZipFile zipFile = new ZipFile(tempFile);

        Enumeration entries = zipFile.entries();

        while(entries.hasMoreElements()){
            ZipEntry entry = entries.nextElement();
            InputStream stream = zipFile.getInputStream(entry);
            externs.add(SourceFile.fromInputStream(entry.getName(), stream, Charset.forName("UTF-8")));
        }

        return externs;
    }

    public void setMode(JavascriptCompilation.JSCompilationMode mode) {
        this.mode = mode;
    }
}