    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 */
    017
    018package org.apache.bcel.classfile;
    019
    020import java.io.DataInput;
    021import java.io.DataOutputStream;
    022import java.io.IOException;
    023import java.util.Arrays;
    024
    025import org.apache.bcel.Const;
    026
    027/**
    028 * This class is derived from <em>Attribute</em> and represents the list of modules required, exported, opened or
    029 * provided by a module. There may be at most one Module attribute in a ClassFile structure.
    030 *
    031 * @see Attribute
    032 * @since 6.4.0
    033 */
    034public final class Module extends Attribute {
    035
    036    /**
    037     * The module file name extension.
    038     *
    039     * @since 6.7.0
    040     */
    041    public static final String EXTENSION = ".jmod";
    042
    043    private static String getClassNameAtIndex(final ConstantPool cp, final int index, final boolean compactClassName) {
    044        final String className = cp.getConstantString(index, Const.CONSTANT_Class);
    045        if (compactClassName) {
    046            return Utility.compactClassName(className, false);
    047        }
    048        return className;
    049    }
    050    private final int moduleNameIndex;
    051    private final int moduleFlags;
    052
    053    private final int moduleVersionIndex;
    054    private ModuleRequires[] requiresTable;
    055    private ModuleExports[] exportsTable;
    056    private ModuleOpens[] opensTable;
    057    private final int usesCount;
    058    private final int[] usesIndex;
    059
    060    private ModuleProvides[] providesTable;
    061
    062    /**
    063     * Constructs object from input stream.
    064     *
    065     * @param nameIndex Index in constant pool
    066     * @param length Content length in bytes
    067     * @param input Input stream
    068     * @param constantPool Array of constants
    069     * @throws IOException if an I/O error occurs.
    070     */
    071    Module(final int nameIndex, final int length, final DataInput input, final ConstantPool constantPool) throws IOException {
    072        super(Const.ATTR_MODULE, nameIndex, length, constantPool);
    073
    074        moduleNameIndex = input.readUnsignedShort();
    075        moduleFlags = input.readUnsignedShort();
    076        moduleVersionIndex = input.readUnsignedShort();
    077
    078        final int requiresCount = input.readUnsignedShort();
    079        requiresTable = new ModuleRequires[requiresCount];
    080        for (int i = 0; i < requiresCount; i++) {
    081            requiresTable[i] = new ModuleRequires(input);
    082        }
    083
    084        final int exportsCount = input.readUnsignedShort();
    085        exportsTable = new ModuleExports[exportsCount];
    086        for (int i = 0; i < exportsCount; i++) {
    087            exportsTable[i] = new ModuleExports(input);
    088        }
    089
    090        final int opensCount = input.readUnsignedShort();
    091        opensTable = new ModuleOpens[opensCount];
    092        for (int i = 0; i < opensCount; i++) {
    093            opensTable[i] = new ModuleOpens(input);
    094        }
    095
    096        usesCount = input.readUnsignedShort();
    097        usesIndex = new int[usesCount];
    098        for (int i = 0; i < usesCount; i++) {
    099            usesIndex[i] = input.readUnsignedShort();
    100        }
    101
    102        final int providesCount = input.readUnsignedShort();
    103        providesTable = new ModuleProvides[providesCount];
    104        for (int i = 0; i < providesCount; i++) {
    105            providesTable[i] = new ModuleProvides(input);
    106        }
    107    }
    108
    109    /**
    110     * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class.
    111     * I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
    112     *
    113     * @param v Visitor object
    114     */
    115    @Override
    116    public void accept(final Visitor v) {
    117        v.visitModule(this);
    118    }
    119
    120    /**
    121     * @return deep copy of this attribute
    122     */
    123    @Override
    124    public Attribute copy(final ConstantPool constantPool) {
    125        final Module c = (Module) clone();
    126
    127        c.requiresTable = new ModuleRequires[requiresTable.length];
    128        Arrays.setAll(c.requiresTable, i -> requiresTable[i].copy());
    129
    130        c.exportsTable = new ModuleExports[exportsTable.length];
    131        Arrays.setAll(c.exportsTable, i -> exportsTable[i].copy());
    132
    133        c.opensTable = new ModuleOpens[opensTable.length];
    134        Arrays.setAll(c.opensTable, i -> opensTable[i].copy());
    135
    136        c.providesTable = new ModuleProvides[providesTable.length];
    137        Arrays.setAll(c.providesTable, i -> providesTable[i].copy());
    138
    139        c.setConstantPool(constantPool);
    140        return c;
    141    }
    142
    143    /**
    144     * Dump Module attribute to file stream in binary format.
    145     *
    146     * @param file Output file stream
    147     * @throws IOException if an I/O error occurs.
    148     */
    149    @Override
    150    public void dump(final DataOutputStream file) throws IOException {
    151        super.dump(file);
    152
    153        file.writeShort(moduleNameIndex);
    154        file.writeShort(moduleFlags);
    155        file.writeShort(moduleVersionIndex);
    156
    157        file.writeShort(requiresTable.length);
    158        for (final ModuleRequires entry : requiresTable) {
    159            entry.dump(file);
    160        }
    161
    162        file.writeShort(exportsTable.length);
    163        for (final ModuleExports entry : exportsTable) {
    164            entry.dump(file);
    165        }
    166
    167        file.writeShort(opensTable.length);
    168        for (final ModuleOpens entry : opensTable) {
    169            entry.dump(file);
    170        }
    171
    172        file.writeShort(usesIndex.length);
    173        for (final int entry : usesIndex) {
    174            file.writeShort(entry);
    175        }
    176
    177        file.writeShort(providesTable.length);
    178        for (final ModuleProvides entry : providesTable) {
    179            entry.dump(file);
    180        }
    181    }
    182
    183    /**
    184     * @return table of exported interfaces
    185     * @see ModuleExports
    186     */
    187    public ModuleExports[] getExportsTable() {
    188        return exportsTable;
    189    }
    190
    191    /**
    192     * Gets flags for this module.
    193     * @return module flags
    194     * @since 6.10.0
    195     */
    196    public int getModuleFlags() {
    197        return moduleFlags;
    198    }
    199
    200    /**
    201     * Gets module name.
    202     * @param cp Array of constants
    203     * @return module name
    204     * @since 6.10.0
    205     */
    206    public String getModuleName(final ConstantPool cp) {
    207        return cp.getConstantString(moduleNameIndex, Const.CONSTANT_Module);
    208    }
    209
    210    /**
    211     * @return table of provided interfaces
    212     * @see ModuleOpens
    213     */
    214    public ModuleOpens[] getOpensTable() {
    215        return opensTable;
    216    }
    217
    218    /**
    219     * @return table of provided interfaces
    220     * @see ModuleProvides
    221     */
    222    public ModuleProvides[] getProvidesTable() {
    223        return providesTable;
    224    }
    225
    226    /**
    227     * @return table of required modules
    228     * @see ModuleRequires
    229     */
    230    public ModuleRequires[] getRequiresTable() {
    231        return requiresTable;
    232    }
    233
    234    /**
    235     * Gets the array of class names for this module's uses.
    236     * @param constantPool Array of constants usually obtained from the ClassFile object
    237     * @param compactClassName false for original constant pool value, true to replace '/' with '.'
    238     * @return array of used class names
    239     * @since 6.10.0
    240     */
    241    public String[] getUsedClassNames(final ConstantPool constantPool, final boolean compactClassName) {
    242        final String[] usedClassNames = new String[usesCount];
    243        for (int i = 0; i < usesCount; i++) {
    244            usedClassNames[i] = getClassNameAtIndex(constantPool, usesIndex[i], compactClassName);
    245        }
    246        return usedClassNames;
    247    }
    248
    249    /**
    250     * Gets version for this module.
    251     * @param cp Array of constants
    252     * @return version from constant pool, "0" if version index is 0
    253     * @since 6.10.0
    254     */
    255    public String getVersion(final ConstantPool cp) {
    256        return moduleVersionIndex == 0 ? "0" : cp.getConstantString(moduleVersionIndex, Const.CONSTANT_Utf8);
    257    }
    258
    259    /**
    260     * @return String representation, i.e., a list of packages.
    261     */
    262    @Override
    263    public String toString() {
    264        final ConstantPool cp = super.getConstantPool();
    265        final StringBuilder buf = new StringBuilder();
    266        buf.append("Module:\n");
    267        buf.append("  name:    ").append(Utility.pathToPackage(getModuleName(cp))).append("\n");
    268        buf.append("  flags:   ").append(String.format("%04x", moduleFlags)).append("\n");
    269        final String version = getVersion(cp);
    270        buf.append("  version: ").append(version).append("\n");
    271
    272        buf.append("  requires(").append(requiresTable.length).append("):\n");
    273        for (final ModuleRequires module : requiresTable) {
    274            buf.append("    ").append(module.toString(cp)).append("\n");
    275        }
    276
    277        buf.append("  exports(").append(exportsTable.length).append("):\n");
    278        for (final ModuleExports module : exportsTable) {
    279            buf.append("    ").append(module.toString(cp)).append("\n");
    280        }
    281
    282        buf.append("  opens(").append(opensTable.length).append("):\n");
    283        for (final ModuleOpens module : opensTable) {
    284            buf.append("    ").append(module.toString(cp)).append("\n");
    285        }
    286
    287        buf.append("  uses(").append(usesIndex.length).append("):\n");
    288        for (final int index : usesIndex) {
    289            final String className = getClassNameAtIndex(cp, index, true);
    290            buf.append("    ").append(className).append("\n");
    291        }
    292
    293        buf.append("  provides(").append(providesTable.length).append("):\n");
    294        for (final ModuleProvides module : providesTable) {
    295            buf.append("    ").append(module.toString(cp)).append("\n");
    296        }
    297
    298        return buf.substring(0, buf.length() - 1); // remove the last newline
    299    }
    300}