+/* gnu.gcj.runtime.StackTrace -- VM support methods for walking the
+ stack.
+ Copyright (C) 1998, 1999, 2002 Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath 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.
+
+GNU Classpath 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 for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING. If not, write to the
+Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+02111-1307 USA.
+
+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.gcj.runtime;
+
+import gnu.gcj.RawData;
+import java.util.TreeMap;
+import java.util.IdentityHashMap;
+import java.util.SortedMap;
+import gnu.gcj.runtime.NameFinder;
+import java.util.NoSuchElementException;
+
+/**
+ * VM dependent state and support methods for walking the stack.
+ * <p>
+ * This is the version used by libgcj (http://gcc.gnu.org/java/).
+ *
+ * @author Mark Wielaard (mark@klomp.org)
+ * @author Andrew Haley (aph@redhat.com)
+ */
+public final class StackTrace
+{
+ /**
+ * Fill in the stack trace with the top n frames on current
+ * execution stack. Can return null if the VM does not support
+ * capturing the VM execution state.
+ *
+ * @see Throwable#fillInStackTrace()
+ */
+ public StackTrace(int n)
+ {
+ fillInStackTrace(n, 1);
+ }
+
+ /**
+ * Fill in the stack trace with state of the entire execution stack,
+ * starting from frame <code>offset</code>. Can return null if the
+ * VM does not support capturing the VM execution state.
+ *
+ * This can be very expensive. If you only want part of the stack,
+ * see <code>Throwable.fillInStackTrace(int)</code>
+ *
+ * @see Throwable#fillInStackTrace()
+ */
+ public StackTrace()
+ {
+ int n = 64;
+
+ do
+ {
+ n *= 4;
+ fillInStackTrace(n, 1);
+ }
+ while (len >= n);
+ }
+
+ /**
+ * Return the class containing the execution point represented by
+ * the Nth frame down the stack. The zeroth frame represents the
+ * top of the stack, which is the method that called classAt().
+ *
+ * If the Nth frame down the stack was not create by a method
+ * invocation, return null.
+ *
+ * It is not necessary to call <code>fillInStackTrace()</code> with
+ * a size greater than N before calling this method; if the current
+ * stack trace is insufficiently large, it will be expanded as
+ * required. This requires some caution if
+ * <code>fillInStackTrace()</code> is called from a different
+ * invocation to the one that calls <code>classAt()</code>.
+ * classAt() will not call <code>fillInStackTrace()</code> unless N
+ * is greater than the current length.
+ *
+ */
+ public native Class classAt(int n);
+
+ /**
+ * Return the name of the method containing the execution point
+ * represented by the Nth frame down the stack. The zeroth frame
+ * represents the top of the stack, which is the method that called
+ * classAt().
+ *
+ * If the Nth frame down the stack was not create by a method
+ * invocation, return null.
+ *
+ * It is not necessary to call <code>fillInStackTrace()</code> with
+ * a size greater than N before calling this method; if the current
+ * stack trace is insufficiently large, it will be expanded as
+ * required. This requires some caution if
+ * <code>fillInStackTrace()</code> is called from a different
+ * invocation to the one that calls <code>classAt()</code>.
+ * classAt() will not call <code>fillInStackTrace()</code> unless N
+ * is greater than the current length.
+ *
+ */
+ public native String methodAt(int n);
+
+ /**
+ * Return the length of this stack trace.
+ *
+ */
+ public int length ()
+ {
+ return len;
+ }
+
+ private static native void update();
+ private static MethodRef methodAtAddress(RawData addr)
+ {
+ update();
+ synchronized (map)
+ {
+ return (MethodRef) map.get (addr);
+ }
+ }
+
+ gnu.gcj.RawData stackTraceAddrs()
+ {
+ return addrs;
+ }
+
+ private native void fillInStackTrace(int n, int offset);
+
+ private static native MethodRef getCompiledMethodRef(RawData addr);
+ private static IdentityHashMap map = new IdentityHashMap();
+
+ private gnu.gcj.RawData addrs;
+ private int len;
+}