1 /*
2 * Copyright (c) 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.util.ArrayList;
29 import java.util.HashSet;
30 import java.util.List;
31 import java.util.Objects;
32 import java.util.Set;
33 import com.sun.tools.classfile.Instruction.TypeKind;
34 import static com.sun.tools.classfile.ConstantPool.*;
35
36 /**
37 * A utility class to find where in a ClassFile references
38 * a {@link CONSTANT_Methodref_info method},
39 * a {@link CONSTANT_InterfaceMethodref_info interface method},
40 * or a {@link CONSTANT_Fieldref_info field}.
41 */
42 public final class ReferenceFinder {
43 /**
44 * Filter for ReferenceFinder of what constant pool entries for reference lookup.
45 */
46 public interface Filter {
47 /**
48 * Decides if the given CPRefInfo entry should be accepted or filtered.
49 *
50 * @param cpool ConstantPool of the ClassFile being parsed
51 * @param cpref constant pool entry representing a reference to
52 * a fields method, and interface method.
53 * @return {@code true} if accepted; otherwise {@code false}
54 */
55 boolean accept(ConstantPool cpool, CPRefInfo cpref);
56 }
57
58 /**
59 * Visitor of individual method of a ClassFile that references the
60 * accepted field, method, or interface method references.
61 */
62 public interface Visitor {
63 /**
64 * Invoked for a method containing one or more accepted CPRefInfo entries
65 *
66 * @param cf ClassFile
67 * @param method Method that does the references the accepted references
68 * @param refs Accepted constant pool method/field reference
69 */
70 void visit(ClassFile cf, Method method, List<CPRefInfo> refConstantPool);
71 }
72
73 private final Filter filter;
74 private final Visitor visitor;
75
76 /**
77 * Constructor.
78 */
79 public ReferenceFinder(Filter filter, Visitor visitor) {
80 this.filter = Objects.requireNonNull(filter);
81 this.visitor = Objects.requireNonNull(visitor);
82 }
83
84 /**
85 * Parses a given ClassFile and invoke the visitor if there is any reference
86 * to the constant pool entries referencing field, method, or
87 * interface method that are accepted. This method will return
88 * {@code true} if there is one or more accepted constant pool entries
89 * to lookup; otherwise, it will return {@code false}.
90 *
91 * @param cf ClassFile
92 * @return {@code true} if the given class file is processed to lookup
93 * references
94 * @throws ConstantPoolException if an error of the constant pool
95 */
96 public boolean parse(ClassFile cf) throws ConstantPoolException {
97 List<Integer> cprefs = new ArrayList<>();
98 int index = 1;
99 for (ConstantPool.CPInfo cpInfo : cf.constant_pool.entries()) {
100 if (cpInfo.accept(cpVisitor, cf.constant_pool)) {
101 cprefs.add(index);
102 }
103 index += cpInfo.size();
104 }
105
106 if (cprefs.isEmpty()) {
107 return false;
108 }
109
110 for (Method m : cf.methods) {
111 Set<Integer> ids = new HashSet<>();
112 Code_attribute c_attr = (Code_attribute) m.attributes.get(Attribute.Code);
113 if (c_attr != null) {
114 for (Instruction instr : c_attr.getInstructions()) {
115 int idx = instr.accept(codeVisitor, cprefs);
116 if (idx > 0) {
117 ids.add(idx);
118 }
119 }
120 }
121 if (ids.size() > 0) {
122 List<CPRefInfo> refInfos = new ArrayList<>(ids.size());
123 for (int id : ids) {
124 refInfos.add(CPRefInfo.class.cast(cf.constant_pool.get(id)));
125 }
126 visitor.visit(cf, m, refInfos);
127 }
128 }
129 return true;
130 }
131
132 private ConstantPool.Visitor<Boolean,ConstantPool> cpVisitor =
133 new ConstantPool.Visitor<Boolean,ConstantPool>()
134 {
135 public Boolean visitClass(CONSTANT_Class_info info, ConstantPool cpool) {
136 return false;
137 }
138
139 public Boolean visitFieldref(CONSTANT_Fieldref_info info, ConstantPool cpool) {
140 return filter.accept(cpool, info);
141 }
142
143 public Boolean visitDouble(CONSTANT_Double_info info, ConstantPool cpool) {
144 return false;
145 }
146
147 public Boolean visitFloat(CONSTANT_Float_info info, ConstantPool cpool) {
148 return false;
149 }
150
151 public Boolean visitInteger(CONSTANT_Integer_info info, ConstantPool cpool) {
152 return false;
153 }
154
155 public Boolean visitInterfaceMethodref(CONSTANT_InterfaceMethodref_info info, ConstantPool cpool) {
156 return filter.accept(cpool, info);
157 }
158
159 public Boolean visitInvokeDynamic(CONSTANT_InvokeDynamic_info info, ConstantPool cpool) {
160 return false;
161 }
162
163 public Boolean visitLong(CONSTANT_Long_info info, ConstantPool cpool) {
164 return false;
165 }
166
167 public Boolean visitMethodHandle(CONSTANT_MethodHandle_info info, ConstantPool cpool) {
168 return false;
169 }
170
171 public Boolean visitMethodref(CONSTANT_Methodref_info info, ConstantPool cpool) {
172 return filter.accept(cpool, info);
173 }
174
175 public Boolean visitMethodType(CONSTANT_MethodType_info info, ConstantPool cpool) {
176 return false;
177 }
178
179 public Boolean visitModule(CONSTANT_Module_info info, ConstantPool cpool) {
180 return false;
181 }
182
183 public Boolean visitNameAndType(CONSTANT_NameAndType_info info, ConstantPool cpool) {
184 return false;
185 }
186
187 public Boolean visitPackage(CONSTANT_Package_info info, ConstantPool cpool) {
188 return false;
189 }
190
191 public Boolean visitString(CONSTANT_String_info info, ConstantPool cpool) {
192 return false;
193 }
194
195 public Boolean visitUtf8(CONSTANT_Utf8_info info, ConstantPool cpool) {
196 return false;
197 }
198 };
199
200 private Instruction.KindVisitor<Integer, List<Integer>> codeVisitor =
201 new Instruction.KindVisitor<Integer, List<Integer>>()
202 {
203 public Integer visitNoOperands(Instruction instr, List<Integer> p) {
204 return 0;
205 }
206
207 public Integer visitArrayType(Instruction instr, TypeKind kind, List<Integer> p) {
208 return 0;
209 }
210
211 public Integer visitBranch(Instruction instr, int offset, List<Integer> p) {
212 return 0;
213 }
214
215 public Integer visitConstantPoolRef(Instruction instr, int index, List<Integer> p) {
216 return p.contains(index) ? index : 0;
217 }
218
219 public Integer visitConstantPoolRefAndValue(Instruction instr, int index, int value, List<Integer> p) {
220 return p.contains(index) ? index : 0;
221 }
222
223 public Integer visitLocal(Instruction instr, int index, List<Integer> p) {
224 return 0;
225 }
226
227 public Integer visitLocalAndValue(Instruction instr, int index, int value, List<Integer> p) {
228 return 0;
229 }
230
231 public Integer visitLookupSwitch(Instruction instr, int default_, int npairs, int[] matches, int[] offsets, List<Integer> p) {
232 return 0;
233 }
234
235 public Integer visitTableSwitch(Instruction instr, int default_, int low, int high, int[] offsets, List<Integer> p) {
236 return 0;
237 }
238
239 public Integer visitValue(Instruction instr, int value, List<Integer> p) {
240 return 0;
241 }
242
243 public Integer visitUnknown(Instruction instr, List<Integer> p) {
244 return 0;
245 }
246 };
247 }
248