org.apache.logging.log4j.util.PrivateSecurityManagerStackTraceUtil Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache license, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the license for the specific language governing permissions and
* limitations under the license.
*/
package org.apache.logging.log4j.util;
import java.util.ArrayDeque;
import java.util.Collections;
import java.util.Deque;
/**
* Internal utility to share a fast implementation of {@code #getCurrentStackTrace()}
* with the java 9 implementation of {@link StackLocator}.
*/
final class PrivateSecurityManagerStackTraceUtil {
private static final PrivateSecurityManager SECURITY_MANAGER;
static {
PrivateSecurityManager psm;
try {
final SecurityManager sm = System.getSecurityManager();
if (sm != null) {
sm.checkPermission(new RuntimePermission("createSecurityManager"));
}
psm = new PrivateSecurityManager();
} catch (final SecurityException ignored) {
psm = null;
}
SECURITY_MANAGER = psm;
}
private PrivateSecurityManagerStackTraceUtil() {
// Utility Class
}
static boolean isEnabled() {
return SECURITY_MANAGER != null;
}
/**
* Returns the current execution stack as a Deque of classes.
*
* The size of the Deque is the number of methods on the execution stack. The first element is the class that started
* execution on this thread, the next element is the class that was called next, and so on, until the last element: the
* method that called {@link SecurityManager#getClassContext()} to capture the stack.
*
*
* @return the execution stack.
*/
// benchmarks show that using the SecurityManager is much faster than looping through getCallerClass(int)
static Deque> getCurrentStackTrace() {
final Class[] array = SECURITY_MANAGER.getClassContext();
final Deque> classes = new ArrayDeque<>(array.length);
Collections.addAll(classes, array);
return classes;
}
private static final class PrivateSecurityManager extends SecurityManager {
@Override
protected Class[] getClassContext() {
return super.getClassContext();
}
}
}