src/main/java/org/apache/maven/plugins/assembly/filter/ComponentsXmlArchiverFileFilter.java

package org.apache.maven.plugins.assembly.filter;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 */

import org.apache.maven.shared.utils.ReaderFactory;
import org.apache.maven.shared.utils.WriterFactory;
import org.codehaus.plexus.archiver.Archiver;
import org.codehaus.plexus.archiver.ArchiverException;
import org.codehaus.plexus.archiver.ResourceIterator;
import org.codehaus.plexus.archiver.UnArchiver;
import org.codehaus.plexus.component.annotations.Component;
import org.codehaus.plexus.components.io.fileselectors.FileInfo;
import org.codehaus.plexus.util.IOUtil;
import org.codehaus.plexus.util.xml.Xpp3Dom;
import org.codehaus.plexus.util.xml.Xpp3DomBuilder;
import org.codehaus.plexus.util.xml.Xpp3DomWriter;
import org.codehaus.plexus.util.xml.pull.XmlPullParserException;

import javax.annotation.Nonnull;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.Reader;
import java.io.Writer;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

/**
 * Components XML file filter.
 *
 * @author <a href="mailto:brett@apache.org">Brett Porter</a>
 *
 */
@Component( role = ContainerDescriptorHandler.class, hint = "plexus", instantiationStrategy = "per-lookup" )
public class ComponentsXmlArchiverFileFilter
    implements ContainerDescriptorHandler
{
    public static final String COMPONENTS_XML_PATH = "META-INF/plexus/components.xml";

    // [jdcasey] Switched visibility to protected to allow testing. Also, because this class isn't final, it should
    // allow
    // some minimal access to the components accumulated for extending classes.
    Map<String, Xpp3Dom> components;

    private boolean excludeOverride = false;

    void addComponentsXml( final Reader componentsReader )
        throws XmlPullParserException, IOException
    {
        Xpp3Dom newDom = Xpp3DomBuilder.build( componentsReader );

        if ( newDom != null )
        {
            newDom = newDom.getChild( "components" );
        }

        if ( newDom != null )
        {
            final Xpp3Dom[] children = newDom.getChildren();

            for ( final Xpp3Dom component : children )
            {
                if ( components == null )
                {
                    components = new LinkedHashMap<>();
                }

                final String role = component.getChild( "role" ).getValue();
                final Xpp3Dom child = component.getChild( "role-hint" );
                final String roleHint = child != null ? child.getValue() : "";

                final String key = role + roleHint;
                if ( !components.containsKey( key ) )
                {
                    components.put( key, component );
                }
            }
        }
    }

    private void addToArchive( final Archiver archiver )
        throws IOException
    {
        if ( components != null )
        {
            final File f = File.createTempFile( "maven-assembly-plugin", "tmp" );
            f.deleteOnExit();

            Writer fileWriter = null;
            try
            {
                fileWriter = WriterFactory.newXmlWriter( new FileOutputStream( f ) );
                final Xpp3Dom dom = new Xpp3Dom( "component-set" );
                final Xpp3Dom componentDom = new Xpp3Dom( "components" );
                dom.addChild( componentDom );

                for ( final Xpp3Dom component : components.values() )
                {
                    componentDom.addChild( component );
                }

                Xpp3DomWriter.write( fileWriter, dom );

                fileWriter.close();
                fileWriter = null;
            }
            finally
            {
                IOUtil.close( fileWriter );
            }

            excludeOverride = true;

            archiver.addFile( f, COMPONENTS_XML_PATH );

            excludeOverride = false;
        }
    }

    @Override
    public void finalizeArchiveCreation( final Archiver archiver )
    {
        // this will prompt the isSelected() call, below, for all resources added to the archive.
        // FIXME: This needs to be corrected in the AbstractArchiver, where
        // runArchiveFinalizers() is called before regular resources are added...
        // which is done because the manifest needs to be added first, and the
        // manifest-creation component is a finalizer in the assembly plugin...
        for ( final ResourceIterator it = archiver.getResources(); it.hasNext(); )
        {
            it.next();
        }

        try
        {
            addToArchive( archiver );
        }
        catch ( final IOException e )
        {
            throw new ArchiverException( "Error finalizing component-set for archive. Reason: " + e.getMessage(), e );
        }
    }

    @Override
    public List<String> getVirtualFiles()
    {
        if ( ( components != null ) && !components.isEmpty() )
        {
            return Collections.singletonList( COMPONENTS_XML_PATH );
        }

        return null;
    }

    @Override
    public boolean isSelected( @Nonnull final FileInfo fileInfo )
        throws IOException
    {
        if ( fileInfo.isFile() )
        {
            if ( excludeOverride )
            {
                return true;
            }

            String entry = fileInfo.getName().replace( '\\', '/' );

            if ( entry.startsWith( "/" ) )
            {
                entry = entry.substring( 1 );
            }

            if ( ComponentsXmlArchiverFileFilter.COMPONENTS_XML_PATH.equals( entry ) )
            {
                Reader reader = null;
                try
                {
                    reader = new BufferedReader( ReaderFactory.newXmlReader( fileInfo.getContents() ) );
                    addComponentsXml( reader );
                    reader.close();
                    reader = null;
                }
                catch ( final XmlPullParserException e )
                {
                    final IOException error =
                        new IOException( "Error finalizing component-set for archive. Reason: " + e.getMessage(), e );

                    throw error;
                }
                finally
                {
                    IOUtil.close( reader );
                }

                return false;
            }
            else
            {
                return true;
            }
        }
        else
        {
            return true;
        }
    }

    @Override
    public void finalizeArchiveExtraction( final UnArchiver unarchiver )
    {
    }

}