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.
23 */
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) 2000-2011 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.signature;
61
62 /**
63 * A parser for signature literals, as defined in the Java Virtual Machine Specification (JVMS), to
64 * visit them with a SignatureVisitor.
65 *
66 * @see <a href="https://docs.oracle.com/javase/specs/jvms/se9/html/jvms-4.html#jvms-4.7.9.1">JVMS
67 * 4.7.9.1</a>
68 * @author Thomas Hallgren
69 * @author Eric Bruneton
70 */
71 public class SignatureReader {
72
73 /** The JVMS signature to be read. */
74 private final String signatureValue;
75
76 /**
77 * Constructs a {@link SignatureReader} for the given signature.
78 *
79 * @param signature A <i>JavaTypeSignature</i>, <i>ClassSignature</i> or <i>MethodSignature</i>.
80 */
81 public SignatureReader(final String signature) {
82 this.signatureValue = signature;
83 }
84
85 /**
86 * Makes the given visitor visit the signature of this {@link SignatureReader}. This signature is
87 * the one specified in the constructor (see {@link #SignatureReader}). This method is intended to
88 * be called on a {@link SignatureReader} that was created using a <i>ClassSignature</i> (such as
89 * the <code>signature</code> parameter of the {@link jdk.internal.org.objectweb.asm.ClassVisitor#visit}
90 * method) or a <i>MethodSignature</i> (such as the <code>signature</code> parameter of the {@link
91 * jdk.internal.org.objectweb.asm.ClassVisitor#visitMethod} method).
92 *
93 * @param signatureVistor the visitor that must visit this signature.
94 */
95 public void accept(final SignatureVisitor signatureVistor) {
96 String signature = this.signatureValue;
97 int length = signature.length();
98 int offset; // Current offset in the parsed signature (parsed from left to right).
99 char currentChar; // The signature character at 'offset', or just before.
100
101 // If the signature starts with '<', it starts with TypeParameters, i.e. a formal type parameter
102 // identifier, followed by one or more pair ':',ReferenceTypeSignature (for its class bound and
103 // interface bounds).
104 if (signature.charAt(0) == '<') {
105 // Invariant: offset points to the second character of a formal type parameter name at the
106 // beginning of each iteration of the loop below.
107 offset = 2;
108 do {
109 // The formal type parameter name is everything between offset - 1 and the first ':'.
110 int classBoundStartOffset = signature.indexOf(':', offset);
111 signatureVistor.visitFormalTypeParameter(
112 signature.substring(offset - 1, classBoundStartOffset));
113
114 // If the character after the ':' class bound marker is not the start of a
115 // ReferenceTypeSignature, it means the class bound is empty (which is a valid case).
116 offset = classBoundStartOffset + 1;
117 currentChar = signature.charAt(offset);
118 if (currentChar == 'L' || currentChar == '[' || currentChar == 'T') {
119 offset = parseType(signature, offset, signatureVistor.visitClassBound());
120 }
121
122 // While the character after the class bound or after the last parsed interface bound
123 // is ':', we need to parse another interface bound.
124 while ((currentChar = signature.charAt(offset++)) == ':') {
125 offset = parseType(signature, offset, signatureVistor.visitInterfaceBound());
126 }
127
128 // At this point a TypeParameter has been fully parsed, and we need to parse the next one
129 // (note that currentChar is now the first character of the next TypeParameter, and that
130 // offset points to the second character), unless the character just after this
131 // TypeParameter signals the end of the TypeParameters.
132 } while (currentChar != '>');
133 } else {
134 offset = 0;
135 }
136
137 // If the (optional) TypeParameters is followed by '(' this means we are parsing a
138 // MethodSignature, which has JavaTypeSignature type inside parentheses, followed by a Result
139 // type and optional ThrowsSignature types.
140 if (signature.charAt(offset) == '(') {
141 offset++;
142 while (signature.charAt(offset) != ')') {
143 offset = parseType(signature, offset, signatureVistor.visitParameterType());
144 }
145 // Use offset + 1 to skip ')'.
146 offset = parseType(signature, offset + 1, signatureVistor.visitReturnType());
147 while (offset < length) {
148 // Use offset + 1 to skip the first character of a ThrowsSignature, i.e. '^'.
149 offset = parseType(signature, offset + 1, signatureVistor.visitExceptionType());
150 }
151 } else {
152 // Otherwise we are parsing a ClassSignature (by hypothesis on the method input), which has
153 // one or more ClassTypeSignature for the super class and the implemented interfaces.
154 offset = parseType(signature, offset, signatureVistor.visitSuperclass());
155 while (offset < length) {
156 offset = parseType(signature, offset, signatureVistor.visitInterface());
157 }
158 }
159 }
160
161 /**
162 * Makes the given visitor visit the signature of this {@link SignatureReader}. This signature is
163 * the one specified in the constructor (see {@link #SignatureReader}). This method is intended to
164 * be called on a {@link SignatureReader} that was created using a <i>JavaTypeSignature</i>, such
165 * as the <code>signature</code> parameter of the {@link
166 * jdk.internal.org.objectweb.asm.ClassVisitor#visitField} or {@link
167 * jdk.internal.org.objectweb.asm.MethodVisitor#visitLocalVariable} methods.
168 *
169 * @param signatureVisitor the visitor that must visit this signature.
170 */
171 public void acceptType(final SignatureVisitor signatureVisitor) {
172 parseType(signatureValue, 0, signatureVisitor);
173 }
174
175 /**
176 * Parses a JavaTypeSignature and makes the given visitor visit it.
177 *
178 * @param signature a string containing the signature that must be parsed.
179 * @param startOffset index of the first character of the signature to parsed.
180 * @param signatureVisitor the visitor that must visit this signature.
181 * @return the index of the first character after the parsed signature.
182 */
183 private static int parseType(
184 final String signature, final int startOffset, final SignatureVisitor signatureVisitor) {
185 int offset = startOffset; // Current offset in the parsed signature.
186 char currentChar = signature.charAt(offset++); // The signature character at 'offset'.
187
188 // Switch based on the first character of the JavaTypeSignature, which indicates its kind.
189 switch (currentChar) {
190 case 'Z':
191 case 'C':
192 case 'B':
193 case 'S':
194 case 'I':
195 case 'F':
196 case 'J':
197 case 'D':
198 case 'V':
199 // Case of a BaseType or a VoidDescriptor.
200 signatureVisitor.visitBaseType(currentChar);
201 return offset;
202
203 case '[':
204 // Case of an ArrayTypeSignature, a '[' followed by a JavaTypeSignature.
205 return parseType(signature, offset, signatureVisitor.visitArrayType());
206
207 case 'T':
208 // Case of TypeVariableSignature, an identifier between 'T' and ';'.
209 int endOffset = signature.indexOf(';', offset);
210 signatureVisitor.visitTypeVariable(signature.substring(offset, endOffset));
211 return endOffset + 1;
212
213 case 'L':
214 // Case of a ClassTypeSignature, which ends with ';'.
215 // These signatures have a main class type followed by zero or more inner class types
216 // (separated by '.'). Each can have type arguments, inside '<' and '>'.
217 int start = offset; // The start offset of the currently parsed main or inner class name.
218 boolean visited = false; // Whether the currently parsed class name has been visited.
219 boolean inner = false; // Whether we are currently parsing an inner class type.
220 // Parses the signature, one character at a time.
221 while (true) {
222 currentChar = signature.charAt(offset++);
223 if (currentChar == '.' || currentChar == ';') {
224 // If a '.' or ';' is encountered, this means we have fully parsed the main class name
225 // or an inner class name. This name may already have been visited it is was followed by
226 // type arguments between '<' and '>'. If not, we need to visit it here.
227 if (!visited) {
228 String name = signature.substring(start, offset - 1);
229 if (inner) {
230 signatureVisitor.visitInnerClassType(name);
231 } else {
232 signatureVisitor.visitClassType(name);
233 }
234 }
235 // If we reached the end of the ClassTypeSignature return, otherwise start the parsing
236 // of a new class name, which is necessarily an inner class name.
237 if (currentChar == ';') {
238 signatureVisitor.visitEnd();
239 break;
240 }
241 start = offset;
242 visited = false;
243 inner = true;
244 } else if (currentChar == '<') {
245 // If a '<' is encountered, this means we have fully parsed the main class name or an
246 // inner class name, and that we now need to parse TypeArguments. First, we need to
247 // visit the parsed class name.
248 String name = signature.substring(start, offset - 1);
249 if (inner) {
250 signatureVisitor.visitInnerClassType(name);
251 } else {
252 signatureVisitor.visitClassType(name);
253 }
254 visited = true;
255 // Now, parse the TypeArgument(s), one at a time.
256 while ((currentChar = signature.charAt(offset)) != '>') {
257 switch (currentChar) {
258 case '*':
259 // Unbounded TypeArgument.
260 ++offset;
261 signatureVisitor.visitTypeArgument();
262 break;
263 case '+':
264 case '-':
265 // Extends or Super TypeArgument. Use offset + 1 to skip the '+' or '-'.
266 offset =
267 parseType(
268 signature, offset + 1, signatureVisitor.visitTypeArgument(currentChar));
269 break;
270 default:
271 // Instanceof TypeArgument. The '=' is implicit.
272 offset = parseType(signature, offset, signatureVisitor.visitTypeArgument('='));
273 break;
274 }
275 }
276 }
277 }
278 return offset;
279
280 default:
281 throw new IllegalArgumentException();
282 }
283 }
284 }
285