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1   /*
2    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
3    *
4    * This code is free software; you can redistribute it and/or modify it
5    * under the terms of the GNU General Public License version 2 only, as
6    * published by the Free Software Foundation.  Oracle designates this
7    * particular file as subject to the "Classpath" exception as provided
8    * by Oracle in the LICENSE file that accompanied this code.
9    *
10   * This code is distributed in the hope that it will be useful, but WITHOUT
11   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
13   * version 2 for more details (a copy is included in the LICENSE file that
14   * accompanied this code).
15   *
16   * You should have received a copy of the GNU General Public License version
17   * 2 along with this work; if not, write to the Free Software Foundation,
18   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19   *
20   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21   * or visit www.oracle.com if you need additional information or have any
22   * questions.
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24  
25  /*
26   * This file is available under and governed by the GNU General Public
27   * License version 2 only, as published by the Free Software Foundation.
28   * However, the following notice accompanied the original version of this
29   * file:
30   *
31   * ASM: a very small and fast Java bytecode manipulation framework
32   * Copyright (c) 2000-2013 INRIA, France Telecom
33   * All rights reserved.
34   *
35   * Redistribution and use in source and binary forms, with or without
36   * modification, are permitted provided that the following conditions
37   * are met:
38   * 1. Redistributions of source code must retain the above copyright
39   *    notice, this list of conditions and the following disclaimer.
40   * 2. Redistributions in binary form must reproduce the above copyright
41   *    notice, this list of conditions and the following disclaimer in the
42   *    documentation and/or other materials provided with the distribution.
43   * 3. Neither the name of the copyright holders nor the names of its
44   *    contributors may be used to endorse or promote products derived from
45   *    this software without specific prior written permission.
46   *
47   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
48   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
49   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
50   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
51   * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
52   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
53   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
54   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
55   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
56   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
57   * THE POSSIBILITY OF SUCH DAMAGE.
58   */
59  
60  package jdk.internal.org.objectweb.asm;
61  
62  /**
63   * The path to a type argument, wildcard bound, array element type, or static
64   * inner type within an enclosing type.
65   *
66   * @author Eric Bruneton
67   */
68  public class TypePath {
69  
70      /**
71       * A type path step that steps into the element type of an array type. See
72       * {@link #getStep getStep}.
73       */
74      public final static int ARRAY_ELEMENT = 0;
75  
76      /**
77       * A type path step that steps into the nested type of a class type. See
78       * {@link #getStep getStep}.
79       */
80      public final static int INNER_TYPE = 1;
81  
82      /**
83       * A type path step that steps into the bound of a wildcard type. See
84       * {@link #getStep getStep}.
85       */
86      public final static int WILDCARD_BOUND = 2;
87  
88      /**
89       * A type path step that steps into a type argument of a generic type. See
90       * {@link #getStep getStep}.
91       */
92      public final static int TYPE_ARGUMENT = 3;
93  
94      /**
95       * The byte array where the path is stored, in Java class file format.
96       */
97      byte[] b;
98  
99      /**
100      * The offset of the first byte of the type path in 'b'.
101      */
102     int offset;
103 
104     /**
105      * Creates a new type path.
106      *
107      * @param b
108      *            the byte array containing the type path in Java class file
109      *            format.
110      * @param offset
111      *            the offset of the first byte of the type path in 'b'.
112      */
113     TypePath(byte[] b, int offset) {
114         this.b = b;
115         this.offset = offset;
116     }
117 
118     /**
119      * Returns the length of this path.
120      *
121      * @return the length of this path.
122      */
123     public int getLength() {
124         return b[offset];
125     }
126 
127     /**
128      * Returns the value of the given step of this path.
129      *
130      * @param index
131      *            an index between 0 and {@link #getLength()}, exclusive.
132      * @return {@link #ARRAY_ELEMENT ARRAY_ELEMENT}, {@link #INNER_TYPE
133      *         INNER_TYPE}, {@link #WILDCARD_BOUND WILDCARD_BOUND}, or
134      *         {@link #TYPE_ARGUMENT TYPE_ARGUMENT}.
135      */
136     public int getStep(int index) {
137         return b[offset + 2 * index + 1];
138     }
139 
140     /**
141      * Returns the index of the type argument that the given step is stepping
142      * into. This method should only be used for steps whose value is
143      * {@link #TYPE_ARGUMENT TYPE_ARGUMENT}.
144      *
145      * @param index
146      *            an index between 0 and {@link #getLength()}, exclusive.
147      * @return the index of the type argument that the given step is stepping
148      *         into.
149      */
150     public int getStepArgument(int index) {
151         return b[offset + 2 * index + 2];
152     }
153 
154     /**
155      * Converts a type path in string form, in the format used by
156      * {@link #toString()}, into a TypePath object.
157      *
158      * @param typePath
159      *            a type path in string form, in the format used by
160      *            {@link #toString()}. May be null or empty.
161      * @return the corresponding TypePath object, or null if the path is empty.
162      */
163     public static TypePath fromString(final String typePath) {
164         if (typePath == null || typePath.length() == 0) {
165             return null;
166         }
167         int n = typePath.length();
168         ByteVector out = new ByteVector(n);
169         out.putByte(0);
170         for (int i = 0; i < n;) {
171             char c = typePath.charAt(i++);
172             if (c == '[') {
173                 out.put11(ARRAY_ELEMENT, 0);
174             } else if (c == '.') {
175                 out.put11(INNER_TYPE, 0);
176             } else if (c == '*') {
177                 out.put11(WILDCARD_BOUND, 0);
178             } else if (c >= '0' && c <= '9') {
179                 int typeArg = c - '0';
180                 while (i < n && (c = typePath.charAt(i)) >= '0' && c <= '9') {
181                     typeArg = typeArg * 10 + c - '0';
182                     i += 1;
183                 }
184                 out.put11(TYPE_ARGUMENT, typeArg);
185             }
186         }
187         out.data[0] = (byte) (out.length / 2);
188         return new TypePath(out.data, 0);
189     }
190 
191     /**
192      * Returns a string representation of this type path. {@link #ARRAY_ELEMENT
193      * ARRAY_ELEMENT} steps are represented with '[', {@link #INNER_TYPE
194      * INNER_TYPE} steps with '.', {@link #WILDCARD_BOUND WILDCARD_BOUND} steps
195      * with '*' and {@link #TYPE_ARGUMENT TYPE_ARGUMENT} steps with their type
196      * argument index in decimal form.
197      */
198     @Override
199     public String toString() {
200         int length = getLength();
201         StringBuilder result = new StringBuilder(length * 2);
202         for (int i = 0; i < length; ++i) {
203             switch (getStep(i)) {
204             case ARRAY_ELEMENT:
205                 result.append('[');
206                 break;
207             case INNER_TYPE:
208                 result.append('.');
209                 break;
210             case WILDCARD_BOUND:
211                 result.append('*');
212                 break;
213             case TYPE_ARGUMENT:
214                 result.append(getStepArgument(i));
215                 break;
216             default:
217                 result.append('_');
218             }
219         }
220         return result.toString();
221     }
222 }