    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;
    018
    019import java.util.List;
    020
    021import org.apache.commons.compress.harmony.pack200.Pack200Exception;
    022import org.apache.commons.compress.harmony.unpack200.bytecode.ClassFileEntry;
    023import org.apache.commons.compress.harmony.unpack200.bytecode.ConstantPoolEntry;
    024
    025/**
    026 * SegmentConstantPool manages the constant pool used for re-creating class files.
    027 */
    028public class SegmentConstantPool {
    029
    030    public static final int ALL = 0;
    031    public static final int UTF_8 = 1;
    032
    033    public static final int CP_INT = 2;
    034
    035    // define in archive order
    036
    037    public static final int CP_FLOAT = 3;
    038    public static final int CP_LONG = 4;
    039    public static final int CP_DOUBLE = 5;
    040    public static final int CP_STRING = 6;
    041    public static final int CP_CLASS = 7;
    042    public static final int SIGNATURE = 8; // TODO and more to come --
    043    public static final int CP_DESCR = 9;
    044    public static final int CP_FIELD = 10;
    045    public static final int CP_METHOD = 11;
    046    public static final int CP_IMETHOD = 12;
    047    protected static final String REGEX_MATCH_ALL = ".*";
    048    protected static final String INITSTRING = "<init>";
    049    protected static final String REGEX_MATCH_INIT = "^" + INITSTRING + ".*";
    050
    051    /**
    052     * We don't want a dependency on regex in Pack200. The only place one exists is in matchSpecificPoolEntryIndex(). To
    053     * eliminate this dependency, we've implemented the world's stupidest regexMatch. It knows about the two forms we
    054     * care about: .* (aka REGEX_MATCH_ALL) {@code ^<init>;.*} (aka REGEX_MATCH_INIT) and will answer correctly if those
    055     * are passed as the regexString.
    056     *
    057     * @param regexString String against which the compareString will be matched
    058     * @param compareString String to match against the regexString
    059     * @return boolean true if the compareString matches the regexString; otherwise false.
    060     */
    061    protected static boolean regexMatches(final String regexString, final String compareString) {
    062        if (REGEX_MATCH_ALL.equals(regexString)) {
    063            return true;
    064        }
    065        if (REGEX_MATCH_INIT.equals(regexString)) {
    066            if (compareString.length() < (INITSTRING.length())) {
    067                return false;
    068            }
    069            return (INITSTRING.equals(compareString.substring(0, INITSTRING.length())));
    070        }
    071        throw new Error("regex trying to match a pattern I don't know: " + regexString);
    072    }
    073    private final CpBands bands;
    074    private final SegmentConstantPoolArrayCache arrayCache = new SegmentConstantPoolArrayCache();
    075
    076    /**
    077     * @param bands TODO
    078     */
    079    public SegmentConstantPool(final CpBands bands) {
    080        this.bands = bands;
    081    }
    082
    083    /**
    084     * Given the name of a class, answer the CPClass associated with that class. Answer null if the class doesn't exist.
    085     *
    086     * @param name Class name to look for (form: java/lang/Object)
    087     * @return CPClass for that class name, or null if not found.
    088     */
    089    public ConstantPoolEntry getClassPoolEntry(final String name) {
    090        final String[] classes = bands.getCpClass();
    091        final int index = matchSpecificPoolEntryIndex(classes, name, 0);
    092        if (index == -1) {
    093            return null;
    094        }
    095        try {
    096            return getConstantPoolEntry(CP_CLASS, index);
    097        } catch (final Pack200Exception ex) {
    098            throw new Error("Error getting class pool entry");
    099        }
    100    }
    101
    102    /**
    103     * Subset the constant pool of the specified type to be just that which has the specified class name. Answer the
    104     * ConstantPoolEntry at the desiredIndex of the subsetted pool.
    105     *
    106     * @param cp type of constant pool array to search
    107     * @param desiredIndex index of the constant pool
    108     * @param desiredClassName class to use to generate a subset of the pool
    109     * @return ConstantPoolEntry
    110     * @throws Pack200Exception TODO
    111     */
    112    public ConstantPoolEntry getClassSpecificPoolEntry(final int cp, final long desiredIndex,
    113        final String desiredClassName) throws Pack200Exception {
    114        final int index = (int) desiredIndex;
    115        int realIndex = -1;
    116        String[] array;
    117        switch (cp) {
    118        case CP_FIELD:
    119            array = bands.getCpFieldClass();
    120            break;
    121        case CP_METHOD:
    122            array = bands.getCpMethodClass();
    123            break;
    124        case CP_IMETHOD:
    125            array = bands.getCpIMethodClass();
    126            break;
    127        default:
    128            throw new Error("Don't know how to handle " + cp);
    129        }
    130        realIndex = matchSpecificPoolEntryIndex(array, desiredClassName, index);
    131        return getConstantPoolEntry(cp, realIndex);
    132    }
    133
    134    public ConstantPoolEntry getConstantPoolEntry(final int cp, final long value) throws Pack200Exception {
    135        final int index = (int) value;
    136        if (index == -1) {
    137            return null;
    138        }
    139        if (index < 0) {
    140            throw new Pack200Exception("Cannot have a negative range");
    141        }
    142        switch (cp) {
    143        case UTF_8:
    144            return bands.cpUTF8Value(index);
    145        case CP_INT:
    146            return bands.cpIntegerValue(index);
    147        case CP_FLOAT:
    148            return bands.cpFloatValue(index);
    149        case CP_LONG:
    150            return bands.cpLongValue(index);
    151        case CP_DOUBLE:
    152            return bands.cpDoubleValue(index);
    153        case CP_STRING:
    154            return bands.cpStringValue(index);
    155        case CP_CLASS:
    156            return bands.cpClassValue(index);
    157        case SIGNATURE:
    158            throw new Error("I don't know what to do with signatures yet");
    159            // return null /* new CPSignature(bands.getCpSignature()[index]) */;
    160        case CP_DESCR:
    161            throw new Error("I don't know what to do with descriptors yet");
    162            // return null /* new CPDescriptor(bands.getCpDescriptor()[index])
    163            // */;
    164        case CP_FIELD:
    165            return bands.cpFieldValue(index);
    166        case CP_METHOD:
    167            return bands.cpMethodValue(index);
    168        case CP_IMETHOD:
    169            return bands.cpIMethodValue(index);
    170        default:
    171            break;
    172        }
    173        // etc
    174        throw new Error("Get value incomplete");
    175    }
    176
    177    /**
    178     * Answer the init method for the specified class.
    179     *
    180     * @param cp constant pool to search (must be CP_METHOD)
    181     * @param value index of init method
    182     * @param desiredClassName String class name of the init method
    183     * @return CPMethod init method
    184     * @throws Pack200Exception TODO
    185     */
    186    public ConstantPoolEntry getInitMethodPoolEntry(final int cp, final long value, final String desiredClassName)
    187        throws Pack200Exception {
    188        int realIndex = -1;
    189        if (cp != CP_METHOD) {
    190            // TODO really an error?
    191            throw new Error("Nothing but CP_METHOD can be an <init>");
    192        }
    193        realIndex = matchSpecificPoolEntryIndex(bands.getCpMethodClass(), bands.getCpMethodDescriptor(),
    194            desiredClassName, REGEX_MATCH_INIT, (int) value);
    195        return getConstantPoolEntry(cp, realIndex);
    196    }
    197
    198    public ClassFileEntry getValue(final int cp, final long value) throws Pack200Exception {
    199        final int index = (int) value;
    200        if (index == -1) {
    201            return null;
    202        }
    203        if (index < 0) {
    204            throw new Pack200Exception("Cannot have a negative range");
    205        }
    206        switch (cp) {
    207        case UTF_8:
    208            return bands.cpUTF8Value(index);
    209        case CP_INT:
    210            return bands.cpIntegerValue(index);
    211        case CP_FLOAT:
    212            return bands.cpFloatValue(index);
    213        case CP_LONG:
    214            return bands.cpLongValue(index);
    215        case CP_DOUBLE:
    216            return bands.cpDoubleValue(index);
    217        case CP_STRING:
    218            return bands.cpStringValue(index);
    219        case CP_CLASS:
    220            return bands.cpClassValue(index);
    221        case SIGNATURE:
    222            return bands.cpSignatureValue(index);
    223        case CP_DESCR:
    224            return bands.cpNameAndTypeValue(index);
    225        default:
    226            break;
    227        }
    228        throw new Error("Tried to get a value I don't know about: " + cp);
    229    }
    230
    231    /**
    232     * A number of things make use of subsets of structures. In one particular example, _super bytecodes will use a
    233     * subset of method or field classes which have just those methods / fields defined in the superclass. Similarly,
    234     * _this bytecodes use just those methods/fields defined in this class, and _init bytecodes use just those methods
    235     * that start with {@code <init>}.
    236     *
    237     * This method takes an array of names, a String to match for, an index and a boolean as parameters, and answers the
    238     * array position in the array of the indexth element which matches (or equals) the String (depending on the state
    239     * of the boolean)
    240     *
    241     * In other words, if the class array consists of: Object [position 0, 0th instance of Object] String [position 1,
    242     * 0th instance of String] String [position 2, 1st instance of String] Object [position 3, 1st instance of Object]
    243     * Object [position 4, 2nd instance of Object] then matchSpecificPoolEntryIndex(..., "Object", 2, false) will answer
    244     * 4. matchSpecificPoolEntryIndex(..., "String", 0, false) will answer 1.
    245     *
    246     * @param nameArray Array of Strings against which the compareString is tested
    247     * @param compareString String for which to search
    248     * @param desiredIndex nth element with that match (counting from 0)
    249     * @return int index into nameArray, or -1 if not found.
    250     */
    251    protected int matchSpecificPoolEntryIndex(final String[] nameArray, final String compareString,
    252        final int desiredIndex) {
    253        return matchSpecificPoolEntryIndex(nameArray, nameArray, compareString, REGEX_MATCH_ALL, desiredIndex);
    254    }
    255
    256    /**
    257     * This method's function is to look through pairs of arrays. It keeps track of the number of hits it finds using
    258     * the following basis of comparison for a hit: - the primaryArray[index] must be .equals() to the
    259     * primaryCompareString - the secondaryArray[index] .matches() the secondaryCompareString. When the desiredIndex
    260     * number of hits has been reached, the index into the original two arrays of the element hit is returned.
    261     *
    262     * @param primaryArray The first array to search
    263     * @param secondaryArray The second array (must be same .length as primaryArray)
    264     * @param primaryCompareString The String to compare against primaryArray using .equals()
    265     * @param secondaryCompareRegex The String to compare against secondaryArray using .matches()
    266     * @param desiredIndex The nth hit whose position we're seeking
    267     * @return int index that represents the position of the nth hit in primaryArray and secondaryArray
    268     */
    269    protected int matchSpecificPoolEntryIndex(final String[] primaryArray, final String[] secondaryArray,
    270        final String primaryCompareString, final String secondaryCompareRegex, final int desiredIndex) {
    271        int instanceCount = -1;
    272        final List<Integer> indexList = arrayCache.indexesForArrayKey(primaryArray, primaryCompareString);
    273        if (indexList.isEmpty()) {
    274            // Primary key not found, no chance of finding secondary
    275            return -1;
    276        }
    277
    278        for (final Integer element : indexList) {
    279            final int arrayIndex = element.intValue();
    280            if (regexMatches(secondaryCompareRegex, secondaryArray[arrayIndex])) {
    281                instanceCount++;
    282                if (instanceCount == desiredIndex) {
    283                    return arrayIndex;
    284                }
    285            }
    286        }
    287        // We didn't return in the for loop, so the desiredMatch
    288        // with desiredIndex must not exist in the arrays.
    289        return -1;
    290    }
    291}