/*
 * 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.commons.compress.harmony.unpack200.bytecode.forms;

import org.apache.commons.compress.harmony.pack200.Pack200Exception;
import org.apache.commons.compress.harmony.unpack200.SegmentConstantPool;
import org.apache.commons.compress.harmony.unpack200.bytecode.ByteCode;
import org.apache.commons.compress.harmony.unpack200.bytecode.CPClass;
import org.apache.commons.compress.harmony.unpack200.bytecode.ClassFileEntry;
import org.apache.commons.compress.harmony.unpack200.bytecode.OperandManager;

/**
 * This class is an extension of the ClassRefForm. It has two purposes: 1. To keep track of the last type used in a new() instruction in the current class. 2.
 * To allow the sender to create instances of either a specified class (which then becomes the new class) or the last used new class.
 */
public class NewClassRefForm extends ClassRefForm {

    /**
     * Constructs a new instance with the specified opcode, name, operandType and rewrite.
     *
     * @param opcode  index corresponding to the opcode's value.
     * @param name    String printable name of the opcode.
     * @param rewrite Operand positions (which will later be rewritten in ByteCodes) are indicated by -1.
     */
    public NewClassRefForm(final int opcode, final String name, final int[] rewrite) {
        super(opcode, name, rewrite);
    }

    /*
     * (non-Javadoc)
     *
     * @see org.apache.commons.compress.harmony.unpack200.bytecode.forms.ReferenceForm#setByteCodeOperands(org.apache.commons
     * .compress.harmony.unpack200.bytecode.ByteCode, org.apache.commons.compress.harmony.unpack200.bytecode.OperandManager)
     */
    @Override
    public void setByteCodeOperands(final ByteCode byteCode, final OperandManager operandManager, final int codeLength) throws Pack200Exception {
        final int offset = getOffset(operandManager);
        if (offset == 0) {
            // Use current class
            final SegmentConstantPool globalPool = operandManager.globalConstantPool();
            final ClassFileEntry[] nested = { globalPool.getClassPoolEntry(operandManager.getCurrentClass()) };
            byteCode.setNested(nested);
            byteCode.setNestedPositions(new int[][] { { 0, 2 } });
        } else {
            // Look up the class in the classpool
            try {
                // Parent takes care of subtracting one from offset
                // to adjust for 1-based global pool
                setNestedEntries(byteCode, operandManager, offset);
            } catch (final Pack200Exception ex) {
                throw new Error("Got a pack200 exception. What to do?");
            }
        }
        operandManager.setNewClass(((CPClass) byteCode.getNestedClassFileEntries()[0]).getName());
    }
}
