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/*
* Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package jdk.nashorn.internal.runtime;
import static jdk.nashorn.internal.parser.TokenType.EOF;
import jdk.nashorn.internal.parser.Lexer;
import jdk.nashorn.internal.parser.Token;
import jdk.nashorn.internal.parser.TokenStream;
import jdk.nashorn.internal.parser.TokenType;
/**
* Utilities for debugging Nashorn.
*
*/
public final class Debug {
private Debug() {
}
/**
* Return the topmost JavaScript frame in a stack trace
* @param t throwable that contains the stack trace
* @return line describing the topmost JavaScript frame
*/
public static String firstJSFrame(final Throwable t) {
for (final StackTraceElement ste : t.getStackTrace()) {
if (ECMAErrors.isScriptFrame(ste)) {
return ste.toString();
}
}
return "<native code>";
}
/**
* Return the topmost JavaScript frame from the current
* continuation
* @return line describing the topmost JavaScript frame
*/
public static String firstJSFrame() {
return firstJSFrame(new Throwable());
}
/**
* Return the system identity hashcode for an object as a human readable
* string
*
* @param x object
* @return system identity hashcode as string
*/
public static String id(final Object x) {
return String.format("0x%08x", System.identityHashCode(x));
}
/**
* Same as {@link Debug#id} but returns the identity hashcode as
* an integer
*
* @param x object
* @return system identity hashcode
*/
public static int intId(final Object x) {
return System.identityHashCode(x);
}
/**
* Return a stack trace element description at a depth from where we are not
*
* @param depth depth
* @return stack trace element as string
*/
public static String stackTraceElementAt(final int depth) {
return new Throwable().getStackTrace()[depth + 1].toString(); // add 1 to compensate for this method
}
/**
* Determine caller for tracing purposes.
* @param depth depth to trace
* @param count max depth
* @param ignores elements to ignore in stack trace
* @return caller
*/
public static String caller(final int depth, final int count, final String... ignores) {
String result = "";
final StackTraceElement[] callers = Thread.currentThread().getStackTrace();
int c = count;
loop:
for (int i = depth + 1; i < callers.length && c != 0; i++) {
final StackTraceElement element = callers[i];
final String method = element.getMethodName();
for (final String ignore : ignores) {
if (method.compareTo(ignore) == 0) {
continue loop;
}
}
result += (method + ":" + element.getLineNumber() +
" ").substring(0, 30);
c--;
}
return result.isEmpty() ? "<no caller>" : result;
}
/**
* Dump a token stream to stdout
*
* TODO: most other bugging goes to stderr, change?
*
* @param source the source
* @param lexer the lexer
* @param stream the stream to dump
*/
public static void dumpTokens(final Source source, final Lexer lexer, final TokenStream stream) {
TokenType type;
int k = 0;
do {
while (k > stream.last()) {
// Get more tokens.
lexer.lexify();
}
final long token = stream.get(k);
type = Token.descType(token);
System.out.println("" + k + ": " + Token.toString(source, token, true));
k++;
} while(type != EOF);
}
}
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