    001// Copyright 2013 The Apache Software Foundation
    002//
    003// Licensed under the Apache License, Version 2.0 (the "License");
    004// you may not use this file except in compliance with the License.
    005// You may obtain a copy of the License at
    006//
    007// http://www.apache.org/licenses/LICENSE-2.0
    008//
    009// Unless required by applicable law or agreed to in writing, software
    010// distributed under the License is distributed on an "AS IS" BASIS,
    011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    012// See the License for the specific language governing permissions and
    013// limitations under the License.
    014
    015package org.apache.tapestry5.internal.webresources;
    016
    017import com.yahoo.platform.yui.compressor.CssCompressor;
    018import org.apache.commons.io.IOUtils;
    019import org.apache.tapestry5.ioc.OperationTracker;
    020import org.apache.tapestry5.ioc.internal.util.InternalUtils;
    021import org.apache.tapestry5.services.assets.AssetChecksumGenerator;
    022import org.apache.tapestry5.services.assets.StreamableResource;
    023import org.slf4j.Logger;
    024
    025import java.io.*;
    026
    027/**
    028 * A wrapper around YUI Compressor. This module does not have a dependency on YUICompressor;
    029 * isntead a local copy of the YUICompressor CSS minimizer is kept (because the reset of YUICompressor
    030 * is painful to mix due to how it attempts to patch Rhino).
    031 */
    032public class CSSMinimizer extends AbstractMinimizer
    033{
    034    public CSSMinimizer(Logger logger, OperationTracker tracker, AssetChecksumGenerator checksumGenerator)
    035    {
    036        super(logger, tracker, checksumGenerator, "text/css");
    037    }
    038
    039    @Override
    040    protected InputStream doMinimize(StreamableResource resource) throws IOException
    041    {
    042        StringWriter writer = new StringWriter(1000);
    043        Reader reader = new InputStreamReader(resource.openStream());
    044
    045        try
    046        {
    047            new CssCompressor(reader).compress(writer, -1);
    048
    049            writer.flush();
    050
    051            return IOUtils.toInputStream(writer.getBuffer());
    052        } finally
    053        {
    054            InternalUtils.close(reader);
    055            InternalUtils.close(writer);
    056        }
    057    }
    058}