/*
    * 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.classfile;
  
  import java.io.DataInput;
  import java.io.DataOutputStream;
  import java.io.IOException;
  
  import org.apache.bcel.Const;
  import org.apache.bcel.util.Args;
  
  /**
   * This attribute exists for local or anonymous classes and ... there can be only one.
   *
   * @since 6.0
   */
  public class EnclosingMethod extends Attribute {
  
      // Pointer to the CONSTANT_Class_info structure representing the
      // innermost class that encloses the declaration of the current class.
      private int classIndex;
  
      // If the current class is not immediately enclosed by a method or
      // constructor, then the value of the method_index item must be zero.
      // Otherwise, the value of the method_index item must point to a
      // CONSTANT_NameAndType_info structure representing the name and the
      // type of a method in the class referenced by the class we point
      // to in the class_index. *It is the compiler responsibility* to
      // ensure that the method identified by this index is the closest
      // lexically enclosing method that includes the local/anonymous class.
      private int methodIndex;
  
      // Ctors - and code to read an attribute in.
      EnclosingMethod(final int nameIndex, final int len, final DataInput input, final ConstantPool cpool) throws IOException {
          this(nameIndex, len, input.readUnsignedShort(), input.readUnsignedShort(), cpool);
      }
  
      private EnclosingMethod(final int nameIndex, final int len, final int classIndex, final int methodIndex, final ConstantPool cpool) {
          super(Const.ATTR_ENCLOSING_METHOD, nameIndex, Args.require(len, 4, "EnclosingMethod attribute length"), cpool);
          this.classIndex = Args.requireU2(classIndex, 0, cpool.getLength(), "EnclosingMethod class index");
          this.methodIndex = Args.requireU2(methodIndex, "EnclosingMethod method index");
      }
  
      @Override
      public void accept(final Visitor v) {
          v.visitEnclosingMethod(this);
      }
  
      @Override
      public Attribute copy(final ConstantPool constantPool) {
          return (Attribute) clone();
      }
  
      @Override
      public final void dump(final DataOutputStream file) throws IOException {
          super.dump(file);
          file.writeShort(classIndex);
          file.writeShort(methodIndex);
      }
  
      public final ConstantClass getEnclosingClass() {
          return super.getConstantPool().getConstant(classIndex, Const.CONSTANT_Class, ConstantClass.class);
      }
  
      // Accessors
      public final int getEnclosingClassIndex() {
          return classIndex;
      }
  
      public final ConstantNameAndType getEnclosingMethod() {
          if (methodIndex == 0) {
              return null;
          }
          return super.getConstantPool().getConstant(methodIndex, Const.CONSTANT_NameAndType, ConstantNameAndType.class);
      }
  
      public final int getEnclosingMethodIndex() {
          return methodIndex;
      }
  
      public final void setEnclosingClassIndex(final int idx) {
          classIndex = idx;
      }
 
     public final void setEnclosingMethodIndex(final int idx) {
         methodIndex = idx;
     }
 }