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.google.javascript.jscomp.*; 018import com.google.javascript.jscomp.Compiler; 019import org.apache.commons.io.IOUtils; 020import org.apache.tapestry5.ioc.OperationTracker; 021import org.apache.tapestry5.ioc.internal.util.CollectionFactory; 022import org.apache.tapestry5.ioc.internal.util.InternalUtils; 023import org.apache.tapestry5.services.assets.AssetChecksumGenerator; 024import org.apache.tapestry5.services.assets.StreamableResource; 025import org.slf4j.Logger; 026 027import java.io.IOException; 028import java.io.InputStream; 029import java.util.Collections; 030import java.util.List; 031import java.util.logging.Level; 032 033/** 034 * A wrapper around the Google Closure {@link Compiler} used to minimize 035 * a JavaScript resource. 036 */ 037public class GoogleClosureMinimizer extends AbstractMinimizer 038{ 039 private final List<SourceFile> EXTERNS = Collections.emptyList(); 040 041 static 042 { 043 Compiler.setLoggingLevel(Level.SEVERE); 044 } 045 046 public GoogleClosureMinimizer(Logger logger, OperationTracker tracker, AssetChecksumGenerator checksumGenerator) 047 { 048 super(logger, tracker, checksumGenerator, "text/javascript"); 049 } 050 051 @Override 052 protected InputStream doMinimize(StreamableResource resource) throws IOException 053 { 054 // Don't bother to pool the Compiler 055 056 CompilerOptions options = new CompilerOptions(); 057 options.setCodingConvention(new ClosureCodingConvention()); 058 options.setOutputCharset("utf-8"); 059 options.setWarningLevel(DiagnosticGroups.CHECK_VARIABLES, CheckLevel.WARNING); 060 061 Compiler compiler = new Compiler(); 062 063 compiler.disableThreads(); 064 065 SourceFile input = SourceFile.fromInputStream(resource.toString(), resource.openStream()); 066 067 List<SourceFile> inputs = Collections.singletonList(input); 068 069 Result result = compiler.compile(EXTERNS, inputs, options); 070 071 if (result.success) 072 { 073 return IOUtils.toInputStream(compiler.toSource()); 074 } 075 076 throw new RuntimeException(String.format("Compilation failed: %s.", 077 InternalUtils.join(CollectionFactory.newList(result.errors), ";"))); 078 } 079}