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 java.util.Objects;
022
023import org.apache.commons.compress.harmony.pack200.Pack200Exception;
024import org.apache.commons.compress.harmony.unpack200.SegmentConstantPool;
025import org.apache.commons.compress.harmony.unpack200.bytecode.ByteCode;
026import org.apache.commons.compress.harmony.unpack200.bytecode.ClassFileEntry;
027import org.apache.commons.compress.harmony.unpack200.bytecode.OperandManager;
028
029/**
030 * Abstract class of all ByteCodeForms which add a nested entry from the globalConstantPool.
031 */
032public abstract class ReferenceForm extends ByteCodeForm {
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 ReferenceForm(final int opcode, final String name, final int[] rewrite) {
042        super(opcode, name, rewrite);
043    }
044
045    protected abstract int getOffset(OperandManager operandManager);
046
047    protected abstract int getPoolID();
048
049    /*
050     * (non-Javadoc)
051     *
052     * @see org.apache.commons.compress.harmony.unpack200.bytecode.forms.ByteCodeForm#setByteCodeOperands(org.apache.commons.
053     * compress.harmony.unpack200.bytecode.ByteCode, org.apache.commons.compress.harmony.unpack200.bytecode.OperandTable,
054     * org.apache.commons.compress.harmony.unpack200.Segment)
055     */
056    @Override
057    public void setByteCodeOperands(final ByteCode byteCode, final OperandManager operandManager, final int codeLength) throws Pack200Exception {
058        final int offset = getOffset(operandManager);
059        try {
060            setNestedEntries(byteCode, operandManager, offset);
061        } catch (final Pack200Exception ex) {
062            throw new Error("Got a pack200 exception. What to do?");
063        }
064    }
065
066    /**
067     * Sets the nested entries.
068     *
069     * @param byteCode byte codes.
070     * @param operandManager Operand manager.
071     * @param offset offset.
072     * @throws Pack200Exception if support for a type is not supported or the offset not in the range [0, {@link Integer#MAX_VALUE}].
073     */
074    protected void setNestedEntries(final ByteCode byteCode, final OperandManager operandManager, final int offset) throws Pack200Exception {
075        final SegmentConstantPool globalPool = operandManager.globalConstantPool();
076        final ClassFileEntry[] nested = { globalPool.getConstantPoolEntry(getPoolID(), offset) };
077        Objects.requireNonNull(nested[0], "Null nested entries are not allowed");
078        byteCode.setNested(nested);
079        byteCode.setNestedPositions(new int[][] { { 0, 2 } });
080    }
081}