    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;
    020
    021import java.io.DataOutputStream;
    022import java.io.IOException;
    023import java.util.ArrayList;
    024import java.util.List;
    025
    026import org.apache.commons.compress.harmony.pack200.Pack200Exception;
    027import org.apache.commons.compress.harmony.unpack200.Segment;
    028
    029public class CodeAttribute extends BCIRenumberedAttribute {
    030
    031    private static CPUTF8 attributeName;
    032
    033    public static void setAttributeName(final CPUTF8 attributeName) {
    034        CodeAttribute.attributeName = attributeName;
    035    }
    036
    037    public List<Attribute> attributes = new ArrayList<>();
    038    // instances
    039    public List<Integer> byteCodeOffsets = new ArrayList<>();
    040    public List<ByteCode> byteCodes = new ArrayList<>();
    041    public int codeLength;
    042    public List<ExceptionTableEntry> exceptionTable;
    043    public int maxLocals;
    044
    045    public int maxStack;
    046
    047    public CodeAttribute(final int maxStack, final int maxLocals, final byte[] codePacked, final Segment segment, final OperandManager operandManager,
    048            final List<ExceptionTableEntry> exceptionTable) throws Pack200Exception {
    049        super(attributeName);
    050        this.maxLocals = maxLocals;
    051        this.maxStack = maxStack;
    052        this.codeLength = 0;
    053        this.exceptionTable = exceptionTable;
    054        byteCodeOffsets.add(Integer.valueOf(0));
    055        int byteCodeIndex = 0;
    056        for (int i = 0; i < codePacked.length; i++) {
    057            final ByteCode byteCode = ByteCode.getByteCode(codePacked[i] & 0xff);
    058            // Setting the offset must happen before extracting operands
    059            // because label bytecodes need to know their offsets.
    060            byteCode.setByteCodeIndex(byteCodeIndex);
    061            byteCodeIndex++;
    062            byteCode.extractOperands(operandManager, segment, codeLength);
    063            byteCodes.add(byteCode);
    064            codeLength += byteCode.getLength();
    065            final int lastBytecodePosition = byteCodeOffsets.get(byteCodeOffsets.size() - 1).intValue();
    066            // This code assumes all multiple byte bytecodes are
    067            // replaced by a single-byte bytecode followed by
    068            // another bytecode.
    069            if (byteCode.hasMultipleByteCodes()) {
    070                byteCodeOffsets.add(Integer.valueOf(lastBytecodePosition + 1));
    071                byteCodeIndex++;
    072            }
    073            // I've already added the first element (at 0) before
    074            // entering this loop, so make sure I don't add one
    075            // after the last element.
    076            if (i < codePacked.length - 1) {
    077                byteCodeOffsets.add(Integer.valueOf(lastBytecodePosition + byteCode.getLength()));
    078            }
    079            if (byteCode.getOpcode() == 0xC4) {
    080                // Special processing for wide bytecode - it knows what its
    081                // instruction is from the opcode manager, so ignore the
    082                // next instruction
    083                i++;
    084            }
    085        }
    086        // Now that all the bytecodes know their positions and
    087        // sizes, fix up the byte code targets
    088        // At this point, byteCodes may be a different size than
    089        // codePacked because of wide bytecodes.
    090        for (final ByteCode byteCode : byteCodes) {
    091            byteCode.applyByteCodeTargetFixup(this);
    092        }
    093    }
    094
    095    public void addAttribute(final Attribute attribute) {
    096        attributes.add(attribute);
    097        if (attribute instanceof LocalVariableTableAttribute) {
    098            ((LocalVariableTableAttribute) attribute).setCodeLength(codeLength);
    099        }
    100        if (attribute instanceof LocalVariableTypeTableAttribute) {
    101            ((LocalVariableTypeTableAttribute) attribute).setCodeLength(codeLength);
    102        }
    103    }
    104
    105    @Override
    106    protected int getLength() {
    107        int attributesSize = 0;
    108        for (final Attribute attribute : attributes) {
    109            attributesSize += attribute.getLengthIncludingHeader();
    110        }
    111        return 2 + 2 + 4 + codeLength + 2 + exceptionTable.size() * (2 + 2 + 2 + 2) + 2 + attributesSize;
    112    }
    113
    114    @Override
    115    protected ClassFileEntry[] getNestedClassFileEntries() {
    116        final List<ClassFileEntry> nestedEntries = new ArrayList<>(attributes.size() + byteCodes.size() + 10);
    117        nestedEntries.add(getAttributeName());
    118        nestedEntries.addAll(byteCodes);
    119        nestedEntries.addAll(attributes);
    120        // Don't forget to add the ExceptionTable catch_types
    121        for (final ExceptionTableEntry entry : exceptionTable) {
    122            final CPClass catchType = entry.getCatchType();
    123            // If the catch type is null, this is a finally
    124            // block. If it's not null, we need to add the
    125            // CPClass to the list of nested class file entries.
    126            if (catchType != null) {
    127                nestedEntries.add(catchType);
    128            }
    129        }
    130        return nestedEntries.toArray(NONE);
    131    }
    132
    133    @Override
    134    protected int[] getStartPCs() {
    135        // Do nothing here as we've overriden renumber
    136        return null;
    137    }
    138
    139    @Override
    140    public void renumber(final List<Integer> byteCodeOffsets) {
    141        exceptionTable.forEach(entry -> entry.renumber(byteCodeOffsets));
    142    }
    143
    144    @Override
    145    protected void resolve(final ClassConstantPool pool) {
    146        super.resolve(pool);
    147        attributes.forEach(attribute -> attribute.resolve(pool));
    148        byteCodes.forEach(byteCode -> byteCode.resolve(pool));
    149        exceptionTable.forEach(byteCode -> byteCode.resolve(pool));
    150    }
    151
    152    @Override
    153    public String toString() {
    154        return "Code: " + getLength() + " bytes";
    155    }
    156
    157    @Override
    158    protected void writeBody(final DataOutputStream dos) throws IOException {
    159        dos.writeShort(maxStack);
    160        dos.writeShort(maxLocals);
    161
    162        dos.writeInt(codeLength);
    163        for (final ByteCode byteCode : byteCodes) {
    164            byteCode.write(dos);
    165        }
    166
    167        dos.writeShort(exceptionTable.size());
    168        for (final ExceptionTableEntry entry : exceptionTable) {
    169            entry.write(dos);
    170        }
    171
    172        dos.writeShort(attributes.size());
    173        for (final Attribute attribute : attributes) {
    174            attribute.write(dos);
    175        }
    176    }
    177}