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.commons;
61
62 import java.util.Collections;
63 import java.util.Comparator;
64
65 import jdk.internal.org.objectweb.asm.MethodVisitor;
66 import jdk.internal.org.objectweb.asm.Opcodes;
67 import jdk.internal.org.objectweb.asm.tree.MethodNode;
68 import jdk.internal.org.objectweb.asm.tree.TryCatchBlockNode;
69
70 /**
71 * A {@link MethodVisitor} adapter to sort the exception handlers. The handlers
72 * are sorted in a method innermost-to-outermost. This allows the programmer to
73 * add handlers without worrying about ordering them correctly with respect to
74 * existing, in-code handlers.
75 *
76 * Behavior is only defined for properly-nested handlers. If any "try" blocks
77 * overlap (something that isn't possible in Java code) then this may not do
78 * what you want. In fact, this adapter just sorts by the length of the "try"
79 * block, taking advantage of the fact that a given try block must be larger
80 * than any block it contains).
81 *
82 * @author Adrian Sampson
83 */
84 public class TryCatchBlockSorter extends MethodNode {
85
86 public TryCatchBlockSorter(
87 final MethodVisitor mv,
88 final int access,
89 final String name,
90 final String desc,
91 final String signature,
92 final String[] exceptions)
93 {
94 this(Opcodes.ASM4, mv, access, name, desc, signature, exceptions);
95 }
96
97 protected TryCatchBlockSorter(
98 final int api,
99 final MethodVisitor mv,
100 final int access,
101 final String name,
102 final String desc,
103 final String signature,
104 final String[] exceptions)
105 {
106 super(api, access, name, desc, signature, exceptions);
107 this.mv = mv;
108 }
109
110 @Override
111 public void visitEnd() {
112 // Compares TryCatchBlockNodes by the length of their "try" block.
113 Comparator<TryCatchBlockNode> comp = new Comparator<TryCatchBlockNode>() {
114
115 public int compare(TryCatchBlockNode t1, TryCatchBlockNode t2) {
116 int len1 = blockLength(t1);
117 int len2 = blockLength(t2);
118 return len1 - len2;
119 }
120
121 private int blockLength(TryCatchBlockNode block) {
122 int startidx = instructions.indexOf(block.start);
123 int endidx = instructions.indexOf(block.end);
124 return endidx - startidx;
125 }
126 };
127 Collections.sort(tryCatchBlocks, comp);
128 if (mv != null) {
129 accept(mv);
130 }
131 }
132 }