/*
    * 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
    *
   *   https://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.classfile.CodeException;
  
  /**
   * This class represents an exception handler, that is, specifies the region where a handler is active and an instruction
   * where the actual handling is done. pool as parameters. Opposed to the JVM specification the end of the handled region
   * is set to be inclusive, for example all instructions between start and end are protected including the start and end
   * instructions (handles) themselves. The end of the region is automatically mapped to be exclusive when calling
   * getCodeException(), that is, there is no difference semantically.
   *
   * @see MethodGen
   * @see CodeException
   * @see InstructionHandle
   */
  public final class CodeExceptionGen implements InstructionTargeter, Cloneable {
  
      static final CodeExceptionGen[] EMPTY_ARRAY = {};
  
      private InstructionHandle startPc;
      private InstructionHandle endPc;
      private InstructionHandle handlerPc;
      private ObjectType catchType;
  
      /**
       * Add an exception handler, that is, specify region where a handler is active and an instruction where the actual handling
       * is done.
       *
       * @param startPc Start of handled region (inclusive).
       * @param endPc End of handled region (inclusive).
       * @param handlerPc Where handling is done.
       * @param catchType which exception is handled, null for ANY.
       */
      public CodeExceptionGen(final InstructionHandle startPc, final InstructionHandle endPc, final InstructionHandle handlerPc, final ObjectType catchType) {
          setStartPC(startPc);
          setEndPC(endPc);
          setHandlerPC(handlerPc);
          this.catchType = catchType;
      }
  
      @Override
      public Object clone() {
          try {
              return super.clone();
          } catch (final CloneNotSupportedException e) {
              throw new UnsupportedOperationException("Clone Not Supported", e); // never happens
          }
      }
  
      /**
       * @return true, if ih is target of this handler.
       */
      @Override
      public boolean containsTarget(final InstructionHandle ih) {
          return startPc == ih || endPc == ih || handlerPc == ih;
      }
  
      /**
       * Gets the type of the Exception to catch, 'null' for ANY.
       *
       * @return the type of the Exception to catch, 'null' for ANY.
       */
      public ObjectType getCatchType() {
          return catchType;
      }
  
      /**
       * Gets CodeException object.
       *
       * This relies on that the instruction list has already been dumped to byte code or that the 'setPositions' methods
       * has been called for the instruction list.
       *
       * @param cp constant pool.
       * @return the CodeException object.
       */
      public CodeException getCodeException(final ConstantPoolGen cp) {
          return new CodeException(startPc.getPosition(), endPc.getPosition() + endPc.getInstruction().getLength(), handlerPc.getPosition(),
              catchType == null ? 0 : cp.addClass(catchType));
      }
  
      /**
      * Gets the end of handled region (inclusive).
      *
      * @return end of handled region (inclusive).
      */
     public InstructionHandle getEndPC() {
         return endPc;
     }
 
     /**
      * Gets the start of handler.
      *
      * @return start of handler.
      */
     public InstructionHandle getHandlerPC() {
         return handlerPc;
     }
 
     /**
      * Gets the start of handled region (inclusive).
      *
      * @return start of handled region (inclusive).
      */
     public InstructionHandle getStartPC() {
         return startPc;
     }
 
     /**
      * Sets the type of the Exception to catch. Set 'null' for ANY.
      *
      * @param catchType the type of the Exception to catch.
      */
     public void setCatchType(final ObjectType catchType) {
         this.catchType = catchType;
     }
 
     /**
      * Sets end of handler.
      *
      * @param endPc End of handled region (inclusive).
      */
     public void setEndPC(final InstructionHandle endPc) { // TODO could be package-protected?
         BranchInstruction.notifyTarget(this.endPc, endPc, this);
         this.endPc = endPc;
     }
 
     /**
      * Sets handler code.
      *
      * @param handlerPc Start of handler.
      */
     public void setHandlerPC(final InstructionHandle handlerPc) { // TODO could be package-protected?
         BranchInstruction.notifyTarget(this.handlerPc, handlerPc, this);
         this.handlerPc = handlerPc;
     }
 
     /**
      * Sets start of handler.
      *
      * @param startPc Start of handled region (inclusive).
      */
     public void setStartPC(final InstructionHandle startPc) { // TODO could be package-protected?
         BranchInstruction.notifyTarget(this.startPc, startPc, this);
         this.startPc = startPc;
     }
 
     @Override
     public String toString() {
         return "CodeExceptionGen(" + startPc + ", " + endPc + ", " + handlerPc + ")";
     }
 
     /**
      * @param oldIh old target, either start or end.
      * @param newIh new target.
      */
     @Override
     public void updateTarget(final InstructionHandle oldIh, final InstructionHandle newIh) {
         boolean targeted = false;
         if (startPc == oldIh) {
             targeted = true;
             setStartPC(newIh);
         }
         if (endPc == oldIh) {
             targeted = true;
             setEndPC(newIh);
         }
         if (handlerPc == oldIh) {
             targeted = true;
             setHandlerPC(newIh);
         }
         if (!targeted) {
             throw new ClassGenException("Not targeting " + oldIh + ", but {" + startPc + ", " + endPc + ", " + handlerPc + "}");
         }
     }
 }