ReferenceFinder.java revision 2942:08092deced3f 
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
26package com.sun.tools.classfile;
27
28import java.util.ArrayList;
29import java.util.HashSet;
30import java.util.List;
31import java.util.Objects;
32import java.util.Set;
33import com.sun.tools.classfile.Instruction.TypeKind;
34import 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 */
42public 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 visitInterfaceMethodref(CONSTANT_InterfaceMethodref_info info, ConstantPool cpool) {
140            return filter.accept(cpool, info);
141        }
142
143        public Boolean visitMethodref(CONSTANT_Methodref_info info, ConstantPool cpool) {
144            return filter.accept(cpool, info);
145        }
146
147        public Boolean visitFieldref(CONSTANT_Fieldref_info info, ConstantPool cpool) {
148            return filter.accept(cpool, info);
149        }
150
151        public Boolean visitDouble(CONSTANT_Double_info info, ConstantPool cpool) {
152            return false;
153        }
154
155        public Boolean visitFloat(CONSTANT_Float_info info, ConstantPool cpool) {
156            return false;
157        }
158
159        public Boolean visitInteger(CONSTANT_Integer_info info, ConstantPool cpool) {
160            return false;
161        }
162
163        public Boolean visitInvokeDynamic(CONSTANT_InvokeDynamic_info info, ConstantPool cpool) {
164            return false;
165        }
166
167        public Boolean visitLong(CONSTANT_Long_info info, ConstantPool cpool) {
168            return false;
169        }
170
171        public Boolean visitNameAndType(CONSTANT_NameAndType_info info, ConstantPool cpool) {
172            return false;
173        }
174
175        public Boolean visitMethodHandle(CONSTANT_MethodHandle_info info, ConstantPool cpool) {
176            return false;
177        }
178
179        public Boolean visitMethodType(CONSTANT_MethodType_info info, ConstantPool cpool) {
180            return false;
181        }
182
183        public Boolean visitString(CONSTANT_String_info info, ConstantPool cpool) {
184            return false;
185        }
186
187        public Boolean visitUtf8(CONSTANT_Utf8_info info, ConstantPool cpool) {
188            return false;
189        }
190    };
191
192    private Instruction.KindVisitor<Integer, List<Integer>> codeVisitor =
193            new Instruction.KindVisitor<Integer, List<Integer>>()
194    {
195        public Integer visitNoOperands(Instruction instr, List<Integer> p) {
196            return 0;
197        }
198
199        public Integer visitArrayType(Instruction instr, TypeKind kind, List<Integer> p) {
200            return 0;
201        }
202
203        public Integer visitBranch(Instruction instr, int offset, List<Integer> p) {
204            return 0;
205        }
206
207        public Integer visitConstantPoolRef(Instruction instr, int index, List<Integer> p) {
208            return p.contains(index) ? index : 0;
209        }
210
211        public Integer visitConstantPoolRefAndValue(Instruction instr, int index, int value, List<Integer> p) {
212            return p.contains(index) ? index : 0;
213        }
214
215        public Integer visitLocal(Instruction instr, int index, List<Integer> p) {
216            return 0;
217        }
218
219        public Integer visitLocalAndValue(Instruction instr, int index, int value, List<Integer> p) {
220            return 0;
221        }
222
223        public Integer visitLookupSwitch(Instruction instr, int default_, int npairs, int[] matches, int[] offsets, List<Integer> p) {
224            return 0;
225        }
226
227        public Integer visitTableSwitch(Instruction instr, int default_, int low, int high, int[] offsets, List<Integer> p) {
228            return 0;
229        }
230
231        public Integer visitValue(Instruction instr, int value, List<Integer> p) {
232            return 0;
233        }
234
235        public Integer visitUnknown(Instruction instr, List<Integer> p) {
236            return 0;
237        }
238    };
239}
240
241