// Copyright 2013 The Apache Software Foundation
//
// 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.
package org.apache.tapestry5.internal.webresources;
import com.google.javascript.jscomp.*;
import com.google.javascript.jscomp.Compiler;
import org.apache.commons.io.IOUtils;
import org.apache.tapestry5.ioc.OperationTracker;
import org.apache.tapestry5.ioc.internal.util.CollectionFactory;
import org.apache.tapestry5.ioc.internal.util.InternalUtils;
import org.apache.tapestry5.services.assets.AssetChecksumGenerator;
import org.apache.tapestry5.services.assets.StreamableResource;
import org.slf4j.Logger;
import java.io.IOException;
import java.io.InputStream;
import java.util.Collections;
import java.util.List;
import java.util.logging.Level;
/**
* A wrapper around the Google Closure {@link Compiler} used to minimize
* a JavaScript resource.
*/
public class GoogleClosureMinimizer extends AbstractMinimizer
{
private final List<SourceFile> EXTERNS = Collections.emptyList();
static
{
Compiler.setLoggingLevel(Level.SEVERE);
}
public GoogleClosureMinimizer(Logger logger, OperationTracker tracker, AssetChecksumGenerator checksumGenerator)
{
super(logger, tracker, checksumGenerator, "text/javascript");
}
@Override
protected InputStream doMinimize(StreamableResource resource) throws IOException
{
// Don't bother to pool the Compiler
CompilerOptions options = new CompilerOptions();
options.setCodingConvention(new ClosureCodingConvention());
options.setOutputCharset("utf-8");
options.setWarningLevel(DiagnosticGroups.CHECK_VARIABLES, CheckLevel.WARNING);
Compiler compiler = new Compiler();
compiler.disableThreads();
SourceFile input = SourceFile.fromInputStream(resource.toString(), resource.openStream());
List<SourceFile> inputs = Collections.singletonList(input);
Result result = compiler.compile(EXTERNS, inputs, options);
if (result.success)
{
return IOUtils.toInputStream(compiler.toSource());
}
throw new RuntimeException(String.format("Compilation failed: %s.",
InternalUtils.join(CollectionFactory.newList(result.errors), ";")));
}
}