1/*
2 * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 *   - Redistributions of source code must retain the above copyright
9 *     notice, this list of conditions and the following disclaimer.
10 *
11 *   - Redistributions in binary form must reproduce the above copyright
12 *     notice, this list of conditions and the following disclaimer in the
13 *     documentation and/or other materials provided with the distribution.
14 *
15 *   - Neither the name of Oracle nor the names of its
16 *     contributors may be used to endorse or promote products derived
17 *     from this software without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
20 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
21 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
23 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
24 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
25 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
26 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
27 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
28 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
29 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 */
31
32// Usage: jjs disassemble.js -- <.class-file-path>
33
34// Simple .class disassembler that uses bundled ObjectWeb ASM
35// classes in jdk8. WARNING: Bundled ObjectWeb ASM classes are
36// not part of official jdk8 API. It can be changed/removed
37// without notice. So, this script is brittle by design!
38
39// This example demonstrates passing arguments to script
40// from jjs command line, nio and ASM usage.
41
42// classes used
43var FileSystems = Java.type("java.nio.file.FileSystems");
44var Files = Java.type("java.nio.file.Files");
45var System = Java.type("java.lang.System");
46var PrintWriter = Java.type("java.io.PrintWriter");
47
48// WARNING: uses non-API classes of jdk8!
49var ClassReader = Java.type("jdk.internal.org.objectweb.asm.ClassReader");
50var TraceClassVisitor = Java.type("jdk.internal.org.objectweb.asm.util.TraceClassVisitor");
51
52// convert file name to Path instance
53function path(file) {
54    return FileSystems.default.getPath(file);
55}
56
57// read all file content as a byte[]
58function readAllBytes(file) {
59    return Files.readAllBytes(path(file));
60}
61
62// disassemble .class byte[] and prints output to stdout
63function disassemble(bytecode) {
64    var pw = new PrintWriter(System.out);
65    new ClassReader(bytecode).accept(new TraceClassVisitor(pw), 0);
66}
67
68// check for command line arg (for .class file name)
69if (arguments.length == 0 || !arguments[0].endsWith('.class')) {
70    print("Usage: jjs disassemble -- <.class file>");
71    exit(1);
72}
73
74// disassemble the given .class file
75disassemble(readAllBytes(arguments[0]));
76