    001/*
    002 *  Licensed to the Apache Software Foundation (ASF) under one or more
    003 *  contributor license agreements.  See the NOTICE file distributed with
    004 *  this work for additional information regarding copyright ownership.
    005 *  The ASF licenses this file to You under the Apache License, Version 2.0
    006 *  (the "License"); you may not use this file except in compliance with
    007 *  the License.  You may obtain a copy of the License at
    008 *
    009 *     http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 *  Unless required by applicable law or agreed to in writing, software
    012 *  distributed under the License is distributed on an "AS IS" BASIS,
    013 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 *  See the License for the specific language governing permissions and
    015 *  limitations under the License.
    016 */
    017package org.apache.commons.compress.harmony.unpack200.bytecode;
    018
    019import java.io.DataOutputStream;
    020import java.io.IOException;
    021import java.util.ArrayList;
    022import java.util.List;
    023
    024import org.apache.commons.compress.harmony.unpack200.Segment;
    025
    026public class CodeAttribute extends BCIRenumberedAttribute {
    027
    028    private static CPUTF8 attributeName;
    029    public static void setAttributeName(final CPUTF8 attributeName) {
    030        CodeAttribute.attributeName = attributeName;
    031    }
    032    public List<Attribute> attributes = new ArrayList<>();
    033    // instances
    034    public List<Integer> byteCodeOffsets = new ArrayList<>();
    035    public List<ByteCode> byteCodes = new ArrayList<>();
    036    public int codeLength;
    037    public List<ExceptionTableEntry> exceptionTable;
    038    public int maxLocals;
    039
    040    public int maxStack;
    041
    042    public CodeAttribute(final int maxStack, final int maxLocals, final byte[] codePacked, final Segment segment,
    043        final OperandManager operandManager, final List<ExceptionTableEntry> exceptionTable) {
    044        super(attributeName);
    045        this.maxLocals = maxLocals;
    046        this.maxStack = maxStack;
    047        this.codeLength = 0;
    048        this.exceptionTable = exceptionTable;
    049        byteCodeOffsets.add(Integer.valueOf(0));
    050        int byteCodeIndex = 0;
    051        for (int i = 0; i < codePacked.length; i++) {
    052            final ByteCode byteCode = ByteCode.getByteCode(codePacked[i] & 0xff);
    053            // Setting the offset must happen before extracting operands
    054            // because label bytecodes need to know their offsets.
    055            byteCode.setByteCodeIndex(byteCodeIndex);
    056            byteCodeIndex++;
    057            byteCode.extractOperands(operandManager, segment, codeLength);
    058            byteCodes.add(byteCode);
    059            codeLength += byteCode.getLength();
    060            final int lastBytecodePosition = byteCodeOffsets.get(byteCodeOffsets.size() - 1).intValue();
    061            // This code assumes all multiple byte bytecodes are
    062            // replaced by a single-byte bytecode followed by
    063            // another bytecode.
    064            if (byteCode.hasMultipleByteCodes()) {
    065                byteCodeOffsets.add(Integer.valueOf(lastBytecodePosition + 1));
    066                byteCodeIndex++;
    067            }
    068            // I've already added the first element (at 0) before
    069            // entering this loop, so make sure I don't add one
    070            // after the last element.
    071            if (i < (codePacked.length - 1)) {
    072                byteCodeOffsets.add(Integer.valueOf(lastBytecodePosition + byteCode.getLength()));
    073            }
    074            if (byteCode.getOpcode() == 0xC4) {
    075                // Special processing for wide bytecode - it knows what its
    076                // instruction is from the opcode manager, so ignore the
    077                // next instruction
    078                i++;
    079            }
    080        }
    081        // Now that all the bytecodes know their positions and
    082        // sizes, fix up the byte code targets
    083        // At this point, byteCodes may be a different size than
    084        // codePacked because of wide bytecodes.
    085        for (final ByteCode byteCode : byteCodes) {
    086            byteCode.applyByteCodeTargetFixup(this);
    087        }
    088    }
    089
    090    public void addAttribute(final Attribute attribute) {
    091        attributes.add(attribute);
    092        if (attribute instanceof LocalVariableTableAttribute) {
    093            ((LocalVariableTableAttribute) attribute).setCodeLength(codeLength);
    094        }
    095        if (attribute instanceof LocalVariableTypeTableAttribute) {
    096            ((LocalVariableTypeTableAttribute) attribute).setCodeLength(codeLength);
    097        }
    098    }
    099
    100    @Override
    101    protected int getLength() {
    102        int attributesSize = 0;
    103        for (final Attribute attribute : attributes) {
    104            attributesSize += attribute.getLengthIncludingHeader();
    105        }
    106        return 2 + 2 + 4 + codeLength + 2 + exceptionTable.size() * (2 + 2 + 2 + 2) + 2 + attributesSize;
    107    }
    108
    109    @Override
    110    protected ClassFileEntry[] getNestedClassFileEntries() {
    111        final List<ClassFileEntry> nestedEntries = new ArrayList<>(attributes.size() + byteCodes.size() + 10);
    112        nestedEntries.add(getAttributeName());
    113        nestedEntries.addAll(byteCodes);
    114        nestedEntries.addAll(attributes);
    115        // Don't forget to add the ExceptionTable catch_types
    116        for (final ExceptionTableEntry entry : exceptionTable) {
    117            final CPClass catchType = entry.getCatchType();
    118            // If the catch type is null, this is a finally
    119            // block. If it's not null, we need to add the
    120            // CPClass to the list of nested class file entries.
    121            if (catchType != null) {
    122                nestedEntries.add(catchType);
    123            }
    124        }
    125        return nestedEntries.toArray(ClassFileEntry.NONE);
    126    }
    127
    128    @Override
    129    protected int[] getStartPCs() {
    130        // Do nothing here as we've overriden renumber
    131        return null;
    132    }
    133
    134    @Override
    135    public void renumber(final List<Integer> byteCodeOffsets) {
    136        exceptionTable.forEach(entry -> entry.renumber(byteCodeOffsets));
    137    }
    138
    139    @Override
    140    protected void resolve(final ClassConstantPool pool) {
    141        super.resolve(pool);
    142        attributes.forEach(attribute -> attribute.resolve(pool));
    143        byteCodes.forEach(byteCode -> byteCode.resolve(pool));
    144        exceptionTable.forEach(byteCode -> byteCode.resolve(pool));
    145    }
    146
    147    @Override
    148    public String toString() {
    149        return "Code: " + getLength() + " bytes";
    150    }
    151
    152    @Override
    153    protected void writeBody(final DataOutputStream dos) throws IOException {
    154        dos.writeShort(maxStack);
    155        dos.writeShort(maxLocals);
    156
    157        dos.writeInt(codeLength);
    158        for (final ByteCode byteCode : byteCodes) {
    159            byteCode.write(dos);
    160        }
    161
    162        dos.writeShort(exceptionTable.size());
    163        for (final ExceptionTableEntry entry : exceptionTable) {
    164            entry.write(dos);
    165        }
    166
    167        dos.writeShort(attributes.size());
    168        for (final Attribute attribute : attributes) {
    169            attribute.write(dos);
    170        }
    171    }
    172}