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