001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *   https://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied.  See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019package org.apache.commons.compress.harmony.unpack200.bytecode.forms;
020
021import org.apache.commons.compress.harmony.pack200.Pack200Exception;
022import org.apache.commons.compress.harmony.unpack200.SegmentConstantPool;
023import org.apache.commons.compress.harmony.unpack200.bytecode.ByteCode;
024import org.apache.commons.compress.harmony.unpack200.bytecode.CPClass;
025import org.apache.commons.compress.harmony.unpack200.bytecode.ClassFileEntry;
026import org.apache.commons.compress.harmony.unpack200.bytecode.OperandManager;
027
028/**
029 * 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.
030 * To allow the sender to create instances of either a specified class (which then becomes the new class) or the last used new class.
031 */
032public class NewClassRefForm extends ClassRefForm {
033
034    /**
035     * Constructs a new instance with the specified opcode, name, operandType and rewrite.
036     *
037     * @param opcode  index corresponding to the opcode's value.
038     * @param name    String printable name of the opcode.
039     * @param rewrite Operand positions (which will later be rewritten in ByteCodes) are indicated by -1.
040     */
041    public NewClassRefForm(final int opcode, final String name, final int[] rewrite) {
042        super(opcode, name, rewrite);
043    }
044
045    /*
046     * (non-Javadoc)
047     *
048     * @see org.apache.commons.compress.harmony.unpack200.bytecode.forms.ReferenceForm#setByteCodeOperands(org.apache.commons
049     * .compress.harmony.unpack200.bytecode.ByteCode, org.apache.commons.compress.harmony.unpack200.bytecode.OperandManager)
050     */
051    @Override
052    public void setByteCodeOperands(final ByteCode byteCode, final OperandManager operandManager, final int codeLength) throws Pack200Exception {
053        final int offset = getOffset(operandManager);
054        if (offset == 0) {
055            // Use current class
056            final SegmentConstantPool globalPool = operandManager.globalConstantPool();
057            final ClassFileEntry[] nested = { globalPool.getClassPoolEntry(operandManager.getCurrentClass()) };
058            byteCode.setNested(nested);
059            byteCode.setNestedPositions(new int[][] { { 0, 2 } });
060        } else {
061            // Look up the class in the classpool
062            try {
063                // Parent takes care of subtracting one from offset
064                // to adjust for 1-based global pool
065                setNestedEntries(byteCode, operandManager, offset);
066            } catch (final Pack200Exception ex) {
067                throw new Error("Got a pack200 exception. What to do?");
068            }
069        }
070        operandManager.setNewClass(((CPClass) byteCode.getNestedClassFileEntries()[0]).getName());
071    }
072}