deep-c-rsc/JCGO/goclsp/vm/gnu/classpath/VMStackWalker.java
2021-07-16 17:12:20 -05:00

104 lines
3.2 KiB
Java

/*
* @(#) $(JCGO)/goclsp/vm/gnu/classpath/VMStackWalker.java --
* VM specific methods for Java stack access.
**
* Project: JCGO (http://www.ivmaisoft.com/jcgo/)
* Copyright (C) 2001-2007 Ivan Maidanski <ivmai@ivmaisoft.com>
* All rights reserved.
**
* Class specification origin: GNU Classpath v0.93 vm/reference
*/
/*
* This is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
**
* This software 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 (GPL) for more details.
**
* Linking this library statically or dynamically with other modules is
* making a combined work based on this library. Thus, the terms and
* conditions of the GNU General Public License cover the whole
* combination.
**
* As a special exception, the copyright holders of this library give you
* permission to link this library with independent modules to produce an
* executable, regardless of the license terms of these independent
* modules, and to copy and distribute the resulting executable under
* terms of your choice, provided that you also meet, for each linked
* independent module, the terms and conditions of the license of that
* module. An independent module is a module which is not derived from
* or based on this library. If you modify this library, you may extend
* this exception to your version of the library, but you are not
* obligated to do so. If you do not wish to do so, delete this
* exception statement from your version.
*/
package gnu.classpath;
public final class VMStackWalker
{
private VMStackWalker() {}
public static Class[] getClassContext()
{
Class caller = getCallingClassAt0(1);
if (caller == null)
return new Class[] { Object.class }; /* hack */
Class[] context = new Class[10];
int count = 0;
do
{
if (context.length <= count)
{
Class[] newContext = new Class[(count >> 1) + count];
System.arraycopy(context, 0, newContext, 0, count);
context = newContext;
}
context[count++] = caller;
} while ((caller = getCallingClassAt0(count + 1)) != null);
if (context.length > count)
{
Class[] newContext = new Class[count];
System.arraycopy(context, 0, newContext, 0, count);
context = newContext;
}
return context;
}
public static Class getCallingClass()
{
return getCallingClassAt0(2);
}
public static ClassLoader getCallingClassLoader()
{
Class caller = getCallingClassAt0(2);
return caller != null ? getClassLoader(caller) : null;
}
public static ClassLoader getClassLoader(Class klass)
{
if (klass == null)
throw new NullPointerException();
return VMAccessorJavaLang.getClassLoaderVMClass(klass);
}
public static ClassLoader firstNonNullClassLoader()
{
ClassLoader loader = null;
Class caller;
for (int depth = 2; (caller = getCallingClassAt0(depth)) != null; depth++)
if ((loader = getClassLoader(caller)) != null)
break;
return loader;
}
private static native Class getCallingClassAt0(int depth); /* JVM-core */
}