com.eclipsesource.connect.mvc.internal.Compressors.java Source code

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Here is the source code for com.eclipsesource.connect.mvc.internal.Compressors.java

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/*******************************************************************************
 * Copyright (c) 2015 EclipseSource and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    Holger Staudacher - initial API and implementation, ongoing development
 ******************************************************************************/
package com.eclipsesource.connect.mvc.internal;

import static com.google.common.base.Charsets.UTF_8;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.StringWriter;

import org.mozilla.javascript.ErrorReporter;
import org.mozilla.javascript.EvaluatorException;

import com.google.common.io.CharSource;
import com.yahoo.platform.yui.compressor.CssCompressor;
import com.yahoo.platform.yui.compressor.JavaScriptCompressor;

public class Compressors {

    public static boolean isCompressable(String path) {
        return !path.contains(".min.") && (path.endsWith(".js") || path.endsWith(".css"));
    }

    public static String compress(String path, InputStream stream) {
        if (path.endsWith(".js") && !path.contains(".min.")) {
            return compressJs(stream);
        } else if (path.endsWith(".css") && !path.contains(".min.")) {
            return compressCss(stream);
        }
        return uncompressed(stream);
    }

    private static String compressJs(InputStream stream) {
        try (InputStreamReader reader = new InputStreamReader(stream, UTF_8)) {
            JavaScriptCompressor compressor = new JavaScriptCompressor(reader, new CompressionErrorHandler());
            try (StringWriter writer = new StringWriter()) {
                compressor.compress(writer, -1, true, false, false, false);
                return writer.toString();
            }
        } catch (EvaluatorException | IOException shouldNotHappen) {
            throw new IllegalStateException(shouldNotHappen);
        }
    }

    private static String compressCss(InputStream stream) {
        try (InputStreamReader reader = new InputStreamReader(stream, UTF_8)) {
            CssCompressor cssCompressor = new CssCompressor(reader);
            StringWriter writer = new StringWriter();
            cssCompressor.compress(writer, -1);
            writer.close();
            return writer.toString();
        } catch (IOException shouldNotHappen) {
            throw new IllegalStateException(shouldNotHappen);
        }
    }

    private static String uncompressed(InputStream stream) {
        try {
            return new CharSource() {

                @Override
                public Reader openStream() throws IOException {
                    return new InputStreamReader(stream, UTF_8);
                }
            }.read();
        } catch (IOException shouldNotHappen) {
            throw new IllegalStateException(shouldNotHappen);
        }
    }

    private static class CompressionErrorHandler implements ErrorReporter {

        @Override
        public void error(String arg0, String arg1, int arg2, String arg3, int arg4) {
            throw new IllegalStateException("Error during JavaScript compression");
        }

        @Override
        public EvaluatorException runtimeError(String arg0, String arg1, int arg2, String arg3, int arg4) {
            throw new IllegalStateException("Error during JavaScript compression");
        }

        @Override
        public void warning(String arg0, String arg1, int arg2, String arg3, int arg4) {
            throw new IllegalStateException("Error during JavaScript compression");
        }

    }

    private Compressors() {
        // prevent instantiations
    }
}