001package org.apache.maven.project;
002
003/*
004 * Licensed to the Apache Software Foundation (ASF) under one
005 * or more contributor license agreements.  See the NOTICE file
006 * distributed with this work for additional information
007 * regarding copyright ownership.  The ASF licenses this file
008 * to you under the Apache License, Version 2.0 (the
009 * "License"); you may not use this file except in compliance
010 * with the License.  You may obtain a copy of the License at
011 *
012 *   http://www.apache.org/licenses/LICENSE-2.0
013 *
014 * Unless required by applicable law or agreed to in writing,
015 * software distributed under the License is distributed on an
016 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
017 * KIND, either express or implied.  See the License for the
018 * specific language governing permissions and limitations
019 * under the License.
020 */
021
022import org.codehaus.plexus.util.ReaderFactory;
023import org.codehaus.plexus.util.xml.Xpp3Dom;
024import org.codehaus.plexus.util.xml.Xpp3DomBuilder;
025import org.codehaus.plexus.util.xml.pull.XmlPullParserException;
026
027import java.io.BufferedInputStream;
028import java.io.File;
029import java.io.FileInputStream;
030import java.io.IOException;
031import java.io.InputStream;
032import java.util.ArrayList;
033import java.util.List;
034import java.util.jar.JarFile;
035import java.util.zip.ZipEntry;
036
037/**
038 * Creates an extension descriptor from some XML stream.
039 *
040 * @author Benjamin Bentmann
041 */
042public class ExtensionDescriptorBuilder
043{
044
045    /**
046     * @since 3.3.0
047     */
048    public String getExtensionDescriptorLocation()
049    {
050        return "META-INF/maven/extension.xml";
051    }
052
053    /**
054     * Extracts the extension descriptor (if any) from the specified JAR file.
055     *
056     * @param extensionJar The JAR file or directory to extract the descriptor from, must not be {@code null}.
057     * @return The extracted descriptor or {@code null} if no descriptor was found.
058     * @throws IOException If the descriptor is present but could not be parsed.
059     */
060    public ExtensionDescriptor build( File extensionJar )
061        throws IOException
062    {
063        ExtensionDescriptor extensionDescriptor = null;
064
065        if ( extensionJar.isFile() )
066        {
067            try ( JarFile pluginJar = new JarFile( extensionJar, false ) )
068            {
069                ZipEntry pluginDescriptorEntry = pluginJar.getEntry( getExtensionDescriptorLocation() );
070
071                if ( pluginDescriptorEntry != null )
072                {
073                    try ( InputStream is = pluginJar.getInputStream( pluginDescriptorEntry ) )
074                    {
075                        extensionDescriptor = build( is );
076                    }
077                }
078            }
079        }
080        else
081        {
082            File pluginXml = new File( extensionJar, getExtensionDescriptorLocation() );
083
084            if ( pluginXml.canRead() )
085            {
086                try ( InputStream is = new BufferedInputStream( new FileInputStream( pluginXml ) ) )
087                {
088                    extensionDescriptor = build( is );
089                }
090            }
091        }
092
093        return extensionDescriptor;
094    }
095
096    /**
097     * @since 3.3.0
098     */
099    public ExtensionDescriptor build( InputStream is )
100        throws IOException
101    {
102        ExtensionDescriptor extensionDescriptor = new ExtensionDescriptor();
103
104        Xpp3Dom dom;
105        try
106        {
107            dom = Xpp3DomBuilder.build( ReaderFactory.newXmlReader( is ) );
108        }
109        catch ( XmlPullParserException e )
110        {
111            throw (IOException) new IOException( e.getMessage() ).initCause( e );
112        }
113
114        if ( !"extension".equals( dom.getName() ) )
115        {
116            throw new IOException( "Unexpected root element \"" + dom.getName() + "\", expected \"extension\"" );
117        }
118
119        extensionDescriptor.setExportedPackages( parseStrings( dom.getChild( "exportedPackages" ) ) );
120
121        extensionDescriptor.setExportedArtifacts( parseStrings( dom.getChild( "exportedArtifacts" ) ) );
122
123        return extensionDescriptor;
124    }
125
126    private List<String> parseStrings( Xpp3Dom dom )
127    {
128        List<String> strings = null;
129
130        if ( dom != null )
131        {
132            strings = new ArrayList<>();
133
134            for ( Xpp3Dom child : dom.getChildren() )
135            {
136                String string = child.getValue();
137                if ( string != null )
138                {
139                    string = string.trim();
140                    if ( string.length() > 0 )
141                    {
142                        strings.add( string );
143                    }
144                }
145            }
146        }
147
148        return strings;
149    }
150
151}