package org.apache.maven.shared.dependency.analyzer;

 /*

  * 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.codehaus.plexus.util.DirectoryScanner;

 import java.io.File;

 import java.io.FileInputStream;

 import java.io.IOException;

 import java.io.InputStream;

 import java.net.URI;

 import java.net.URISyntaxException;

 import java.net.URL;

 import java.util.jar.JarEntry;

 import java.util.jar.JarInputStream;

 /**

  * Utility to visit classes in a library given either as a jar file or an exploded directory.

  * 

  * @author <a href="mailto:markhobson@gmail.com">Mark Hobson</a>

  * @version $Id: ClassFileVisitorUtils.java 1400598 2012-10-21 08:50:43Z hboutemy $

  */

 public final class ClassFileVisitorUtils

 {

     // constants --------------------------------------------------------------

     private static final String[] CLASS_INCLUDES = { "**/*.class" };

     // constructors -----------------------------------------------------------

     private ClassFileVisitorUtils()

     {

         // private constructor for utility class

     }

     // public methods ---------------------------------------------------------

     public static void accept( URL url, ClassFileVisitor visitor )

         throws IOException

     {

         if ( url.getPath().endsWith( ".jar" ) )

         {

             acceptJar( url, visitor );

         }

         else if ( url.getProtocol().equalsIgnoreCase( "file" ) )

         {

             try

             {

                 File file = new File( new URI( url.toString() ) );

                 if ( file.isDirectory() )

                 {

                     acceptDirectory( file, visitor );

                 }

                 else if ( file.exists() )

                 {

                     throw new IllegalArgumentException( "Cannot accept visitor on URL: " + url );

                 }

             }

             catch ( URISyntaxException exception )

             {

                 IllegalArgumentException e = new IllegalArgumentException( "Cannot accept visitor on URL: " + url );

                 e.initCause( exception );

                 throw e;

             }

         }

         else

         {

             throw new IllegalArgumentException( "Cannot accept visitor on URL: " + url );

         }

     }

     // private methods --------------------------------------------------------

     private static void acceptJar( URL url, ClassFileVisitor visitor )

         throws IOException

     {

         JarInputStream in = new JarInputStream( url.openStream() );

         JarEntry entry = null;

         while ( ( entry = in.getNextJarEntry() ) != null )

         {

             String name = entry.getName();

             if ( name.endsWith( ".class" ) )

             {

                 visitClass( name, in, visitor );

             }

         }

         in.close();

     }

     private static void acceptDirectory( File directory, ClassFileVisitor visitor )

         throws IOException

     {

         if ( !directory.isDirectory() )

         {

             throw new IllegalArgumentException( "File is not a directory" );

         }

         DirectoryScanner scanner = new DirectoryScanner();

         scanner.setBasedir( directory );

         scanner.setIncludes( CLASS_INCLUDES );

         scanner.scan();

         String[] paths = scanner.getIncludedFiles();

         for ( String path : paths )

         {

             path = path.replace( File.separatorChar, '/' );

             File file = new File( directory, path );

             FileInputStream in = new FileInputStream( file );

             visitClass( path, in, visitor );

             in.close();

         }

     }

     private static void visitClass( String path, InputStream in, ClassFileVisitor visitor )

     {

         if ( !path.endsWith( ".class" ) )

         {

             throw new IllegalArgumentException( "Path is not a class" );

         }

         String className = path.substring( 0, path.length() - 6 );

         className = className.replace( '/', '.' );

         visitor.visitClass( className, in );

     }

 }