/*
 * Copyright  2000-2004 The Apache Software Foundation
 *
 *  Licensed 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. 
 *
 */ 
package org.apache.bcel.generic;


import org.apache.bcel.Constants;
import org.apache.bcel.classfile.LocalVariable;

/** 
 * This class represents a local variable within a method. It contains its
 * scope, name and type. The generated LocalVariable object can be obtained
 * with getLocalVariable which needs the instruction list and the constant
 * pool as parameters.
 *
 * @version $Id$
 * @author  <A HREF="mailto:m.dahm@gmx.de">M. Dahm</A>
 * @see     LocalVariable
 * @see     MethodGen
 */
public class LocalVariableGen
  implements InstructionTargeter, NamedAndTyped, Cloneable,
	     java.io.Serializable
{
  private int         index;
  private String      name;
  private Type        type;
  private InstructionHandle start, end;

  /**
   * Generate a local variable that with index `index'. Note that double and long
   * variables need two indexs. Index indices have to be provided by the user.
   *
   * @param index index of local variable
   * @param name its name
   * @param type its type
   * @param start from where the instruction is valid (null means from the start)
   * @param end until where the instruction is valid (null means to the end)
   */
  public LocalVariableGen(int index, String name, Type type,
			  InstructionHandle start, InstructionHandle end) {
    if((index < 0) || (index > Constants.MAX_SHORT))
      throw new ClassGenException("Invalid index index: " + index);
    
    this.name  = name;
    this.type  = type;
    this.index  = index;
    setStart(start);
    setEnd(end);
  }

  /**
   * Get LocalVariable object.
   *
   * This relies on that the instruction list has already been dumped to byte code or
   * or that the `setPositions' methods has been called for the instruction list.
   *
   * Note that for local variables whose scope end at the last
   * instruction of the method's code, the JVM specification is ambiguous:
   * both a start_pc+length ending at the last instruction and
   * start_pc+length ending at first index beyond the end of the code are
   * valid.
   *
   * @param cp constant pool
   */
  public LocalVariable getLocalVariable(ConstantPoolGen cp) {
    int start_pc        = start.getPosition();
    int length          = end.getPosition() - start_pc;

    if(length > 0)
      length += end.getInstruction().getLength();
    
    int name_index      = cp.addUtf8(name);
    int signature_index = cp.addUtf8(type.getSignature());

    return new LocalVariable(start_pc, length, name_index,
			     signature_index, index, cp.getConstantPool());
  }

  public void        setIndex(int index)           { this.index = index; }
  public int         getIndex()                   { return index; }
  public void        setName(String name)        { this.name = name; }
  public String      getName()                   { return name; }
  public void        setType(Type type)          { this.type = type; }
  public Type        getType()                   { return type; }

  public InstructionHandle getStart()                  { return start; }
  public InstructionHandle getEnd()                    { return end; }

  public void setStart(InstructionHandle start) {
    BranchInstruction.notifyTarget(this.start, start, this);
    this.start = start;
  }

  public void setEnd(InstructionHandle end) {
    BranchInstruction.notifyTarget(this.end, end, this);
    this.end = end;
  }

  /**
   * @param old_ih old target, either start or end
   * @param new_ih new target
   */
  public void updateTarget(InstructionHandle old_ih, InstructionHandle new_ih) {
    boolean targeted = false;

    if(start == old_ih) {
      targeted = true;
      setStart(new_ih);
    }

    if(end == old_ih) {
      targeted = true;
      setEnd(new_ih);
    }

    if(!targeted)
      throw new ClassGenException("Not targeting " + old_ih + ", but {" + start + ", " +
				  end + "}");
  }

  /**
   * @return true, if ih is target of this variable
   */
  public boolean containsTarget(InstructionHandle ih) {
    return (start == ih) || (end == ih);
  }

  /** @return a hash code value for the object.
   */
  public int hashCode() { 
    int hc = index;
    if (start != null)
      hc ^= start.hashCode();
    if (end != null) 
      hc ^= end.hashCode();
    return hc;
  }

  /**
   * We consider to local variables to be equal, if the use the same index and
   * are valid in the same range.
   */
  public boolean equals(Object o) {
    if(!(o instanceof LocalVariableGen))
      return false;

    LocalVariableGen l = (LocalVariableGen)o;
    return (l.index == index) && (l.start == start) && (l.end == end);
  } 

  public String toString() {
    return "LocalVariableGen(" + name +  ", " + type +  ", " + start + ", " + end + ")";
  }

  public Object clone() {
    try {
      return super.clone();
    } catch(CloneNotSupportedException e) {
      System.err.println(e);
      return null;
    }
  }
}

@@ -4737,118 +4737,138 @@
  %7B %0A
-    int hc = index;%0A    if (start != null)%0A 
+%09//If the user changes the name or type, problems with the targeter hashmap will occur%0A
     
+int
  hc 
-%5E= start.hashCode();%0A    if (end != null) %0A      hc %5E= end
+= index %5E name.hashCode() %5E type
 .has

remove start and end hashing from LocalVariableGen's hashCode, as these values are changed after this LocalVariableGen is added to a HashMap. Change hashCode to be based on index, name and type. These means the problem still occurs if a change is made to the name or type. But this 'might' happen, as opposed to start/end absolutely happening. -- A real fix should be developed in the future.