1 /*
2 * Copyright (c) 2010, 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 jdk.nashorn.internal.runtime;
27
28 import static jdk.nashorn.internal.parser.TokenType.EOF;
29
30 import jdk.nashorn.api.scripting.NashornException;
31 import jdk.nashorn.internal.parser.Lexer;
32 import jdk.nashorn.internal.parser.Token;
33 import jdk.nashorn.internal.parser.TokenStream;
34 import jdk.nashorn.internal.parser.TokenType;
35
36 /**
37 * Utilities for debugging Nashorn.
38 *
39 */
40 public final class Debug {
41 private Debug() {
42 }
43
44 /**
45 * Return the topmost JavaScript frame in a stack trace
46 * @param t throwable that contains the stack trace
47 * @return line describing the topmost JavaScript frame
48 */
49 public static String firstJSFrame(final Throwable t) {
50 for (final StackTraceElement ste : t.getStackTrace()) {
51 if (ECMAErrors.isScriptFrame(ste)) {
52 return ste.toString();
53 }
54 }
55 return "<native code>";
56 }
57
58 /**
59 * Return the topmost JavaScript frame from the current
60 * continuation
61 * @return line describing the topmost JavaScript frame
62 */
63 public static String firstJSFrame() {
64 return firstJSFrame(new Throwable());
65 }
66
67 /**
68 * Return a formatted script stack trace string with frames information separated by '\n'.
69 * This is a shortcut for {@code NashornException.getScriptStackString(new Throwable())}.
70 * @return formatted stack trace string
71 */
72 public static String scriptStack() {
73 return NashornException.getScriptStackString(new Throwable());
74 }
75
76 /**
77 * Return the system identity hashcode for an object as a human readable
78 * string
79 *
80 * @param x object
81 * @return system identity hashcode as string
82 */
83 public static String id(final Object x) {
84 return String.format("0x%08x", System.identityHashCode(x));
85 }
86
87 /**
88 * Same as {@link Debug#id} but returns the identity hashcode as
89 * an integer
90 *
91 * @param x object
92 * @return system identity hashcode
93 */
94 public static int intId(final Object x) {
95 return System.identityHashCode(x);
96 }
97
98 /**
99 * Return a stack trace element description at a depth from where we are not
100 *
101 * @param depth depth
102 * @return stack trace element as string
103 */
104 public static String stackTraceElementAt(final int depth) {
105 return new Throwable().getStackTrace()[depth + 1].toString(); // add 1 to compensate for this method
106 }
107
108 /**
109 * Determine caller for tracing purposes.
110 * @param depth depth to trace
111 * @param count max depth
112 * @param ignores elements to ignore in stack trace
113 * @return caller
114 */
115 public static String caller(final int depth, final int count, final String... ignores) {
116 String result = "";
117 final StackTraceElement[] callers = Thread.currentThread().getStackTrace();
118
119 int c = count;
120 loop:
121 for (int i = depth + 1; i < callers.length && c != 0; i++) {
122 final StackTraceElement element = callers[i];
123 final String method = element.getMethodName();
124
125 for (final String ignore : ignores) {
126 if (method.compareTo(ignore) == 0) {
127 continue loop;
128 }
129 }
130
131 result += (method + ":" + element.getLineNumber() +
132 " ").substring(0, 30);
133 c--;
134 }
135
136 return result.isEmpty() ? "<no caller>" : result;
137 }
138
139 /**
140 * Dump a token stream to stdout
141 *
142 * TODO: most other bugging goes to stderr, change?
143 *
144 * @param source the source
145 * @param lexer the lexer
146 * @param stream the stream to dump
147 */
148 public static void dumpTokens(final Source source, final Lexer lexer, final TokenStream stream) {
149 TokenType type;
150 int k = 0;
151 do {
152 while (k > stream.last()) {
153 // Get more tokens.
154 lexer.lexify();
155 }
156
157 final long token = stream.get(k);
158 type = Token.descType(token);
159 System.out.println("" + k + ": " + Token.toString(source, token, true));
160 k++;
161 } while(type != EOF);
162 }
163
164 }