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>
   */
  public final class ClassFileVisitorUtils
  {
  
      private ClassFileVisitorUtils()
      {
          // private constructor for utility class
      }
  
      /**
       * <p>accept.</p>
       *
       * @param url a {@link java.net.URL} object.
       * @param visitor a {@link org.apache.maven.shared.dependency.analyzer.ClassFileVisitor} object.
       * @throws java.io.IOException if any.
       */
      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 )
              {
                  throw new IllegalArgumentException( "Cannot accept visitor on URL: " + url,
                          exception );
              }
          }
          else
          {
              throw new IllegalArgumentException( "Cannot accept visitor on URL: " + url );
          }
      }
  
      // private methods --------------------------------------------------------
  
      private static void acceptJar( URL url, ClassFileVisitor visitor )
          throws IOException
      {
          try ( JarInputStream in = new JarInputStream( url.openStream() ) )
          {
              JarEntry entry;
              while ( ( entry = in.getNextJarEntry() ) != null )
              {
                  String name = entry.getName();
                  // ignore files like package-info.class and module-info.class
                 if ( name.endsWith( ".class" ) && name.indexOf( '-' ) == -1 )
                 {
                     visitClass( name, in, visitor );
                 }
             }
         }
     }
 
     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( new String[] { "**/*.class" } );
 
         scanner.scan();
 
         String[] paths = scanner.getIncludedFiles();
 
         for ( String path : paths )
         {
             path = path.replace( File.separatorChar, '/' );
 
             File file = new File( directory, path );
 
             try ( InputStream in = new FileInputStream( file ) )
             {
                 visitClass( path, in, visitor );
             }
         }
     }
 
     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 );
     }
 }