TryBlockWriter.java revision 2942:08092deced3f 
1/*
2 * Copyright (c) 2009, 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.javap;
27
28import com.sun.tools.classfile.Code_attribute;
29import com.sun.tools.classfile.Code_attribute.Exception_data;
30import com.sun.tools.classfile.Instruction;
31import java.util.ArrayList;
32import java.util.HashMap;
33import java.util.List;
34import java.util.ListIterator;
35import java.util.Map;
36
37/**
38 * Annotate instructions with details about try blocks.
39 *
40 *  <p><b>This is NOT part of any supported API.
41 *  If you write code that depends on this, you do so at your own risk.
42 *  This code and its internal interfaces are subject to change or
43 *  deletion without notice.</b>
44 */
45public class TryBlockWriter extends InstructionDetailWriter {
46    public enum NoteKind {
47        START("try") {
48            public boolean match(Exception_data entry, int pc) {
49                return (pc == entry.start_pc);
50            }
51        },
52        END("end try") {
53            public boolean match(Exception_data entry, int pc) {
54                return (pc == entry.end_pc);
55            }
56        },
57        HANDLER("catch") {
58            public boolean match(Exception_data entry, int pc) {
59                return (pc == entry.handler_pc);
60            }
61        };
62        NoteKind(String text) {
63            this.text = text;
64        }
65        public abstract boolean match(Exception_data entry, int pc);
66        public final String text;
67    }
68
69    static TryBlockWriter instance(Context context) {
70        TryBlockWriter instance = context.get(TryBlockWriter.class);
71        if (instance == null)
72            instance = new TryBlockWriter(context);
73        return instance;
74    }
75
76    protected TryBlockWriter(Context context) {
77        super(context);
78        context.put(TryBlockWriter.class, this);
79        constantWriter = ConstantWriter.instance(context);
80    }
81
82    public void reset(Code_attribute attr) {
83        indexMap = new HashMap<>();
84        pcMap = new HashMap<>();
85        for (int i = 0; i < attr.exception_table.length; i++) {
86            Exception_data entry = attr.exception_table[i];
87            indexMap.put(entry, i);
88            put(entry.start_pc, entry);
89            put(entry.end_pc, entry);
90            put(entry.handler_pc, entry);
91        }
92    }
93
94    public void writeDetails(Instruction instr) {
95        writeTrys(instr, NoteKind.END);
96        writeTrys(instr, NoteKind.START);
97        writeTrys(instr, NoteKind.HANDLER);
98    }
99
100    public void writeTrys(Instruction instr, NoteKind kind) {
101        String indent = space(2); // get from Options?
102        int pc = instr.getPC();
103        List<Exception_data> entries = pcMap.get(pc);
104        if (entries != null) {
105            for (ListIterator<Exception_data> iter =
106                    entries.listIterator(kind == NoteKind.END ? entries.size() : 0);
107                    kind == NoteKind.END ? iter.hasPrevious() : iter.hasNext() ; ) {
108                Exception_data entry =
109                        kind == NoteKind.END ? iter.previous() : iter.next();
110                if (kind.match(entry, pc)) {
111                    print(indent);
112                    print(kind.text);
113                    print("[");
114                    print(indexMap.get(entry));
115                    print("] ");
116                    if (entry.catch_type == 0)
117                        print("finally");
118                    else {
119                        print("#" + entry.catch_type);
120                        print(" // ");
121                        constantWriter.write(entry.catch_type);
122                    }
123                    println();
124                }
125            }
126        }
127    }
128
129    private void put(int pc, Exception_data entry) {
130        List<Exception_data> list = pcMap.get(pc);
131        if (list == null) {
132            list = new ArrayList<>();
133            pcMap.put(pc, list);
134        }
135        if (!list.contains(entry))
136            list.add(entry);
137    }
138
139    private Map<Integer, List<Exception_data>> pcMap;
140    private Map<Exception_data, Integer> indexMap;
141    private ConstantWriter constantWriter;
142}
143