    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.ByteArrayInputStream;
    021import java.io.DataInput;
    022import java.io.DataOutputStream;
    023import java.io.IOException;
    024
    025import org.apache.bcel.Const;
    026
    027/**
    028 * This class is derived from <em>Attribute</em> and represents a reference
    029 * to a GJ attribute.
    030 *
    031 * @version $Id$
    032 * @see     Attribute
    033 */
    034public final class Signature extends Attribute {
    035
    036    private int signature_index;
    037
    038
    039    /**
    040     * Initialize from another object. Note that both objects use the same
    041     * references (shallow copy). Use clone() for a physical copy.
    042     */
    043    public Signature(final Signature c) {
    044        this(c.getNameIndex(), c.getLength(), c.getSignatureIndex(), c.getConstantPool());
    045    }
    046
    047
    048    /**
    049     * Construct object from file stream.
    050     * @param name_index Index in constant pool to CONSTANT_Utf8
    051     * @param length Content length in bytes
    052     * @param input Input stream
    053     * @param constant_pool Array of constants
    054     * @throws IOException
    055     */
    056    Signature(final int name_index, final int length, final DataInput input, final ConstantPool constant_pool)
    057            throws IOException {
    058        this(name_index, length, input.readUnsignedShort(), constant_pool);
    059    }
    060
    061
    062    /**
    063     * @param name_index Index in constant pool to CONSTANT_Utf8
    064     * @param length Content length in bytes
    065     * @param signature_index Index in constant pool to CONSTANT_Utf8
    066     * @param constant_pool Array of constants
    067     */
    068    public Signature(final int name_index, final int length, final int signature_index, final ConstantPool constant_pool) {
    069        super(Const.ATTR_SIGNATURE, name_index, length, constant_pool);
    070        this.signature_index = signature_index;
    071    }
    072
    073
    074    /**
    075     * Called by objects that are traversing the nodes of the tree implicitely
    076     * defined by the contents of a Java class. I.e., the hierarchy of methods,
    077     * fields, attributes, etc. spawns a tree of objects.
    078     *
    079     * @param v Visitor object
    080     */
    081    @Override
    082    public void accept( final Visitor v ) {
    083        //System.err.println("Visiting non-standard Signature object");
    084        v.visitSignature(this);
    085    }
    086
    087
    088    /**
    089     * Dump source file attribute to file stream in binary format.
    090     *
    091     * @param file Output file stream
    092     * @throws IOException
    093     */
    094    @Override
    095    public final void dump( final DataOutputStream file ) throws IOException {
    096        super.dump(file);
    097        file.writeShort(signature_index);
    098    }
    099
    100
    101    /**
    102     * @return Index in constant pool of source file name.
    103     */
    104    public final int getSignatureIndex() {
    105        return signature_index;
    106    }
    107
    108
    109    /**
    110     * @param signature_index the index info the constant pool of this signature
    111     */
    112    public final void setSignatureIndex( final int signature_index ) {
    113        this.signature_index = signature_index;
    114    }
    115
    116
    117    /**
    118     * @return GJ signature.
    119     */
    120    public final String getSignature() {
    121        final ConstantUtf8 c = (ConstantUtf8) super.getConstantPool().getConstant(signature_index,
    122                Const.CONSTANT_Utf8);
    123        return c.getBytes();
    124    }
    125
    126    /**
    127     * Extends ByteArrayInputStream to make 'unreading' chars possible.
    128     */
    129    private static final class MyByteArrayInputStream extends ByteArrayInputStream {
    130
    131        MyByteArrayInputStream(final String data) {
    132            super(data.getBytes());
    133        }
    134
    135
    136        final String getData() {
    137            return new String(buf);
    138        }
    139
    140
    141        final void unread() {
    142            if (pos > 0) {
    143                pos--;
    144            }
    145        }
    146    }
    147
    148
    149    private static boolean identStart( final int ch ) {
    150        return ch == 'T' || ch == 'L';
    151    }
    152
    153
    154    private static void matchIdent( final MyByteArrayInputStream in, final StringBuilder buf ) {
    155        int ch;
    156        if ((ch = in.read()) == -1) {
    157            throw new RuntimeException("Illegal signature: " + in.getData()
    158                    + " no ident, reaching EOF");
    159        }
    160        //System.out.println("return from ident:" + (char)ch);
    161        if (!identStart(ch)) {
    162            final StringBuilder buf2 = new StringBuilder();
    163            int count = 1;
    164            while (Character.isJavaIdentifierPart((char) ch)) {
    165                buf2.append((char) ch);
    166                count++;
    167                ch = in.read();
    168            }
    169            if (ch == ':') { // Ok, formal parameter
    170                in.skip("Ljava/lang/Object".length());
    171                buf.append(buf2);
    172                ch = in.read();
    173                in.unread();
    174                //System.out.println("so far:" + buf2 + ":next:" +(char)ch);
    175            } else {
    176                for (int i = 0; i < count; i++) {
    177                    in.unread();
    178                }
    179            }
    180            return;
    181        }
    182        final StringBuilder buf2 = new StringBuilder();
    183        ch = in.read();
    184        do {
    185            buf2.append((char) ch);
    186            ch = in.read();
    187            //System.out.println("within ident:"+ (char)ch);
    188        } while ((ch != -1) && (Character.isJavaIdentifierPart((char) ch) || (ch == '/')));
    189        buf.append(buf2.toString().replace('/', '.'));
    190        //System.out.println("regular return ident:"+ (char)ch + ":" + buf2);
    191        if (ch != -1) {
    192            in.unread();
    193        }
    194    }
    195
    196
    197    private static void matchGJIdent( final MyByteArrayInputStream in, final StringBuilder buf ) {
    198        int ch;
    199        matchIdent(in, buf);
    200        ch = in.read();
    201        if ((ch == '<') || ch == '(') { // Parameterized or method
    202            //System.out.println("Enter <");
    203            buf.append((char) ch);
    204            matchGJIdent(in, buf);
    205            while (((ch = in.read()) != '>') && (ch != ')')) { // List of parameters
    206                if (ch == -1) {
    207                    throw new RuntimeException("Illegal signature: " + in.getData()
    208                            + " reaching EOF");
    209                }
    210                //System.out.println("Still no >");
    211                buf.append(", ");
    212                in.unread();
    213                matchGJIdent(in, buf); // Recursive call
    214            }
    215            //System.out.println("Exit >");
    216            buf.append((char) ch);
    217        } else {
    218            in.unread();
    219        }
    220        ch = in.read();
    221        if (identStart(ch)) {
    222            in.unread();
    223            matchGJIdent(in, buf);
    224        } else if (ch == ')') {
    225            in.unread();
    226            return;
    227        } else if (ch != ';') {
    228            throw new RuntimeException("Illegal signature: " + in.getData() + " read " + (char) ch);
    229        }
    230    }
    231
    232
    233    public static String translate( final String s ) {
    234        //System.out.println("Sig:" + s);
    235        final StringBuilder buf = new StringBuilder();
    236        matchGJIdent(new MyByteArrayInputStream(s), buf);
    237        return buf.toString();
    238    }
    239
    240
    241    // @since 6.0 is no longer final
    242    public static boolean isFormalParameterList( final String s ) {
    243        return s.startsWith("<") && (s.indexOf(':') > 0);
    244    }
    245
    246
    247    // @since 6.0 is no longer final
    248    public static boolean isActualParameterList( final String s ) {
    249        return s.startsWith("L") && s.endsWith(">;");
    250    }
    251
    252
    253    /**
    254     * @return String representation
    255     */
    256    @Override
    257    public final String toString() {
    258        final String s = getSignature();
    259        return "Signature: " + s;
    260    }
    261
    262
    263    /**
    264     * @return deep copy of this attribute
    265     */
    266    @Override
    267    public Attribute copy( final ConstantPool _constant_pool ) {
    268        return (Attribute) clone();
    269    }
    270}