1 /*
   2  * Copyright (c) 2007, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package com.sun.tools.classfile;
  27 
  28 import java.io.IOException;
  29 
  30 /**
  31  * See JVMS, section 4.4.
  32  *
  33  *  <p><b>This is NOT part of any supported API.
  34  *  If you write code that depends on this, you do so at your own risk.
  35  *  This code and its internal interfaces are subject to change or
  36  *  deletion without notice.</b>
  37  */
  38 public class Descriptor {
  39     public static class InvalidDescriptor extends DescriptorException {
  40         private static final long serialVersionUID = 1L;
  41         InvalidDescriptor(String desc) {
  42             this.desc = desc;
  43             this.index = -1;
  44         }
  45 
  46         InvalidDescriptor(String desc, int index) {
  47             this.desc = desc;
  48             this.index = index;
  49         }
  50 
  51         @Override
  52         public String getMessage() {
  53             // i18n
  54             if (index == -1)
  55                 return "invalid descriptor \"" + desc + "\"";
  56             else
  57                 return "descriptor is invalid at offset " + index + " in \"" + desc + "\"";
  58         }
  59 
  60         public final String desc;
  61         public final int index;
  62 
  63     }
  64 
  65     public Descriptor(ClassReader cr) throws IOException {
  66         this(cr.readUnsignedShort());
  67     }
  68 
  69     public Descriptor(int index) {
  70         this.index = index;
  71 
  72     }
  73 
  74     public String getValue(ConstantPool constant_pool) throws ConstantPoolException {
  75         return constant_pool.getUTF8Value(index);
  76     }
  77 
  78     public int getParameterCount(ConstantPool constant_pool)
  79             throws ConstantPoolException, InvalidDescriptor {
  80         String desc = getValue(constant_pool);
  81         int end = desc.indexOf(")");
  82         if (end == -1)
  83             throw new InvalidDescriptor(desc);
  84         parse(desc, 0, end + 1);
  85         return count;
  86 
  87     }
  88 
  89     public String getParameterTypes(ConstantPool constant_pool)
  90             throws ConstantPoolException, InvalidDescriptor {
  91         String desc = getValue(constant_pool);
  92         int end = desc.indexOf(")");
  93         if (end == -1)
  94             throw new InvalidDescriptor(desc);
  95         return parse(desc, 0, end + 1);
  96     }
  97 
  98     public String getReturnType(ConstantPool constant_pool)
  99             throws ConstantPoolException, InvalidDescriptor {
 100         String desc = getValue(constant_pool);
 101         int end = desc.indexOf(")");
 102         if (end == -1)
 103             throw new InvalidDescriptor(desc);
 104         return parse(desc, end + 1, desc.length());
 105     }
 106 
 107     public String getFieldType(ConstantPool constant_pool)
 108             throws ConstantPoolException, InvalidDescriptor {
 109         String desc = getValue(constant_pool);
 110         return parse(desc, 0, desc.length());
 111     }
 112 
 113     private String parse(String desc, int start, int end)
 114             throws InvalidDescriptor {
 115         int p = start;
 116         StringBuilder sb = new StringBuilder();
 117         int dims = 0;
 118         count = 0;
 119 
 120         while (p < end) {
 121             String type;
 122             char ch;
 123             switch (ch = desc.charAt(p++)) {
 124                 case '(':
 125                     sb.append('(');
 126                     continue;
 127 
 128                 case ')':
 129                     sb.append(')');
 130                     continue;
 131 
 132                 case '[':
 133                     dims++;
 134                     continue;
 135 
 136                 case 'B':
 137                     type = "byte";
 138                     break;
 139 
 140                 case 'C':
 141                     type = "char";
 142                     break;
 143 
 144                 case 'D':
 145                     type = "double";
 146                     break;
 147 
 148                 case 'F':
 149                     type = "float";
 150                     break;
 151 
 152                 case 'I':
 153                     type = "int";
 154                     break;
 155 
 156                 case 'J':
 157                     type = "long";
 158                     break;
 159 
 160                 case 'Q':
 161                 case 'L':
 162                     int sep = desc.indexOf(';', p);
 163                     if (sep == -1)
 164                         throw new InvalidDescriptor(desc, p - 1);
 165                     type = desc.substring(p, sep).replace('/', '.');
 166                     p = sep + 1;
 167                     break;
 168 
 169                 case 'S':
 170                     type = "short";
 171                     break;
 172 
 173                 case 'Z':
 174                     type = "boolean";
 175                     break;
 176 
 177                 case 'V':
 178                     type = "void";
 179                     break;
 180 
 181                 default:
 182                     throw new InvalidDescriptor(desc, p - 1);
 183             }
 184 
 185             if (sb.length() > 1 && sb.charAt(0) == '(')
 186                 sb.append(", ");
 187             sb.append(type);
 188             for ( ; dims > 0; dims-- )
 189                 sb.append("[]");
 190 
 191             count++;
 192         }
 193 
 194         return sb.toString();
 195     }
 196 
 197     public final int index;
 198     private int count;
 199 }