content: /*
   *  This file is part of AndroidIDE.
   *
   *  AndroidIDE is free software: you can redistribute it and/or modify
   *  it under the terms of the GNU General Public License as published by
   *  the Free Software Foundation, either version 3 of the License, or
   *  (at your option) any later version.
   *
   *  AndroidIDE is distributed in the hope that it will be useful,
   *  but WITHOUT ANY WARRANTY; without even the implied warranty of
   *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   *  GNU General Public License for more details.
   *
   *  You should have received a copy of the GNU General Public License
   *   along with AndroidIDE.  If not, see <https://www.gnu.org/licenses/>.
   */
  
  /*
   * reserved comment block
   * DO NOT REMOVE OR ALTER!
   */
  package jaxp.sun.org.apache.bcel.internal.util;
  
  /* ====================================================================
   * The Apache Software License, Version 1.1
   *
   * Copyright (c) 2001 The Apache Software Foundation.  All rights
   * reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   *
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   *
   * 3. The end-user documentation included with the redistribution,
   *    if any, must include the following acknowledgment:
   *       "This product includes software developed by the
   *        Apache Software Foundation (http://www.apache.org/)."
   *    Alternately, this acknowledgment may appear in the software itself,
   *    if and wherever such third-party acknowledgments normally appear.
   *
   * 4. The names "Apache" and "Apache Software Foundation" and
   *    "Apache BCEL" must not be used to endorse or promote products
   *    derived from this software without prior written permission. For
   *    written permission, please contact apache@apache.org.
   *
   * 5. Products derived from this software may not be called "Apache",
   *    "Apache BCEL", nor may "Apache" appear in their name, without
   *    prior written permission of the Apache Software Foundation.
   *
   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   */
  
  import java.util.Hashtable;
  import java.io.*;
  import jaxp.sun.org.apache.bcel.internal.*;
  import jaxp.sun.org.apache.bcel.internal.classfile.*;
  
  import jaxp.sun.org.apache.bcel.internal.Constants;
  import jaxp.sun.org.apache.bcel.internal.classfile.ClassParser;
  import jaxp.sun.org.apache.bcel.internal.classfile.ConstantClass;
  import jaxp.sun.org.apache.bcel.internal.classfile.ConstantPool;
  import jaxp.sun.org.apache.bcel.internal.classfile.ConstantUtf8;
  import jaxp.sun.org.apache.bcel.internal.classfile.JavaClass;
  import jaxp.sun.org.apache.bcel.internal.classfile.Utility;
  
  /**
   * <p>Drop in replacement for the standard class loader of the JVM. You can use it
   * in conjunction with the JavaWrapper to dynamically modify/create classes
   * as they're requested.</p>
   *
   * <p>This class loader recognizes special requests in a distinct
   * format, i.e., when the name of the requested class contains with
   * "$$BCEL$$" it calls the createClass() method with that name
   * (everything bevor the $$BCEL$$ is considered to be the package
   * name. You can subclass the class loader and override that
   * method. "Normal" classes class can be modified by overriding the
   * modifyClass() method which is called just before defineClass().</p>
   *
   * <p>There may be a number of packages where you have to use the default
   * class loader (which may also be faster). You can define the set of packages
   * where to use the system class loader in the constructor. The default value contains
   * "java.", "sun.", "javax."</p>
   *
   * @author  <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
   * @see JavaWrapper
   * @see ClassPath
   */
  public class ClassLoader extends java.lang.ClassLoader {
    private Hashtable classes = new Hashtable(); // Hashtable is synchronized thus thread-safe
    private String[] ignored_packages = {
      "java.", "javax.", "sun."
    };
    private Repository repository = SyntheticRepository.getInstance();
    private java.lang.ClassLoader deferTo = ClassLoader.getSystemClassLoader();
  
    public ClassLoader() {
    }
  
    public ClassLoader(java.lang.ClassLoader deferTo) {
      this.deferTo = deferTo;
      this.repository = new ClassLoaderRepository(deferTo);
    }
  
    /** @param ignored_packages classes contained in these packages will be loaded
     * with the system class loader
     */
    public ClassLoader(String[] ignored_packages) {
      addIgnoredPkgs(ignored_packages);
    }
  
    public ClassLoader(java.lang.ClassLoader deferTo, String [] ignored_packages) {
      this.deferTo = deferTo;
      this.repository = new ClassLoaderRepository(deferTo);
  
      addIgnoredPkgs(ignored_packages);
    }
  
    private void addIgnoredPkgs(String[] ignored_packages) {
      String[] new_p = new String[ignored_packages.length + this.ignored_packages.length];
  
      System.arraycopy(this.ignored_packages, 0, new_p, 0, this.ignored_packages.length);
      System.arraycopy(ignored_packages, 0, new_p, this.ignored_packages.length,
                       ignored_packages.length);
  
      this.ignored_packages = new_p;
    }
  
    protected Class loadClass(String class_name, boolean resolve)
      throws ClassNotFoundException
    {
      Class cl = null;
  
      /* First try: lookup hash table.
       */
      if((cl=(Class)classes.get(class_name)) == null) {
        /* Second try: Load system class using system class loader. You better
         * don't mess around with them.
         */
        for(int i=0; i < ignored_packages.length; i++) {
          if(class_name.startsWith(ignored_packages[i])) {
            cl = deferTo.loadClass(class_name);
            break;
          }
        }
  
        if(cl == null) {
          JavaClass clazz = null;
  
          /* Third try: Special request?
           */
          if(class_name.indexOf("$$BCEL$$") >= 0)
            clazz = createClass(class_name);
          else { // Fourth try: Load classes via repository
            if ((clazz = repository.loadClass(class_name)) != null) {
              clazz = modifyClass(clazz);
            }
            else
              throw new ClassNotFoundException(class_name);
          }
  
          if(clazz != null) {
            byte[] bytes  = clazz.getBytes();
            cl = defineClass(class_name, bytes, 0, bytes.length);
          } else // Fourth try: Use default class loader
            cl = Class.forName(class_name);
        }
  
        if(resolve)
          resolveClass(cl);
      }
  
      classes.put(class_name, cl);
  
      return cl;
    }
  
    /** Override this method if you want to alter a class before it gets actually
     * loaded. Does nothing by default.
     */
    protected JavaClass modifyClass(JavaClass clazz) {
      return clazz;
    }
  
    /**
     * Override this method to create you own classes on the fly. The
     * name contains the special token $$BCEL$$. Everything before that
     * token is consddered to be a package name. You can encode you own
     * arguments into the subsequent string. You must regard however not
     * to use any "illegal" characters, i.e., characters that may not
     * appear in a Java class name too<br>
     *
     * The default implementation interprets the string as a encoded compressed
     * Java class, unpacks and decodes it with the Utility.decode() method, and
     * parses the resulting byte array and returns the resulting JavaClass object.
     *
     * @param class_name compressed byte code with "$$BCEL$$" in it
     */
    protected JavaClass createClass(String class_name) {
      int    index     = class_name.indexOf("$$BCEL$$");
      String real_name = class_name.substring(index + 8);
  
      JavaClass clazz = null;
      try {
        byte[]      bytes  = Utility.decode(real_name, true);
        ClassParser parser = new ClassParser(new ByteArrayInputStream(bytes), "foo");
  
        clazz = parser.parse();
      } catch(Throwable e) {
        e.printStackTrace();
        return null;
      }
  
      // Adapt the class name to the passed value
      ConstantPool cp = clazz.getConstantPool();
  
      ConstantClass cl = (ConstantClass)cp.getConstant(clazz.getClassNameIndex(),
                                                       Constants.CONSTANT_Class);
      ConstantUtf8 name = (ConstantUtf8)cp.getConstant(cl.getNameIndex(),
                                                       Constants.CONSTANT_Utf8);
      name.setBytes(class_name.replace('.', '/'));
  
      return clazz;
    }
  }
  