From 6603026f1bfec02e3486c52270a09a355a1bf914 Mon Sep 17 00:00:00 2001
From: Sven Gothel <sgothel@jausoft.com>
Date: Mon, 19 Aug 2019 02:58:22 +0200
Subject: Bug 1363: Java 11: Resolve Buffers.Cleaner implementation

As of Java9, sun.misc.Cleaner has moved to jdk.internal.ref.Cleaner.
However, access has been made (under the table) via sun.misc.Unsafe,
which we are using for now as we cannot set the jdk.internal.ref.Cleaner method accessible.

In this regard, we had to change our Cleaner.clean(..) method using a ByteBuffer
instead of a Buffer object paramter.

All tests have passed, no more illegal access case running on Java11 has been exposed.
---
 src/java/com/jogamp/common/nio/Buffers.java | 54 ++++++++++++++++++++++++-----
 1 file changed, 46 insertions(+), 8 deletions(-)

(limited to 'src/java/com/jogamp/common/nio/Buffers.java')

diff --git a/src/java/com/jogamp/common/nio/Buffers.java b/src/java/com/jogamp/common/nio/Buffers.java
index fb23627..5125ee8 100644
--- a/src/java/com/jogamp/common/nio/Buffers.java
+++ b/src/java/com/jogamp/common/nio/Buffers.java
@@ -39,6 +39,7 @@
  */
 package com.jogamp.common.nio;
 
+import java.lang.reflect.Field;
 import java.lang.reflect.Method;
 import java.nio.Buffer;
 import java.nio.ByteBuffer;
@@ -56,6 +57,7 @@ import com.jogamp.common.util.ReflectionUtil;
 import com.jogamp.common.util.ValueConv;
 
 import jogamp.common.Debug;
+import jogamp.common.os.PlatformPropsImpl;
 
 /**
  * Utility methods allowing easy {@link java.nio.Buffer} manipulations.
@@ -1165,22 +1167,42 @@ public class Buffers {
      * Access to NIO {@link sun.misc.Cleaner}, allowing caller to deterministically clean a given {@link sun.nio.ch.DirectBuffer}.
      */
     public static class Cleaner {
+        private static final Object theUnsafe;
         private static final Method mbbCleaner;
         private static final Method cClean;
         private static final boolean hasCleaner;
         /** OK to be lazy on thread synchronization, just for early out **/
         private static volatile boolean cleanerError;
         static {
+            final Object[] _theUnsafe = { null };
             final Method[] _mbbCleaner = { null };
             final Method[] _cClean = { null };
             if( AccessController.doPrivileged(new PrivilegedAction<Boolean>() {
                 @Override
                 public Boolean run() {
                     try {
-                        _mbbCleaner[0] = ReflectionUtil.getMethod("sun.nio.ch.DirectBuffer", "cleaner", null, Buffers.class.getClassLoader());
-                        _mbbCleaner[0].setAccessible(true);
-                        _cClean[0] = Class.forName("sun.misc.Cleaner").getMethod("clean");
-                        _cClean[0].setAccessible(true);
+                        if(PlatformPropsImpl.JAVA_9) {
+                            // Using: sun.misc.Unsafe { public void invokeCleaner(java.nio.ByteBuffer directBuffer); }
+                            _mbbCleaner[0] = null;
+                            final Class<?> unsafeClass = Class.forName("sun.misc.Unsafe");
+                            {
+                                final Field f = unsafeClass.getDeclaredField("theUnsafe");
+                                f.setAccessible(true);
+                                _theUnsafe[0] = f.get(null);
+                            }
+                            _cClean[0] = unsafeClass.getMethod("invokeCleaner", java.nio.ByteBuffer.class);
+                            _cClean[0].setAccessible(true);
+                        } else {
+                            _mbbCleaner[0] = ReflectionUtil.getMethod("sun.nio.ch.DirectBuffer", "cleaner", null, Buffers.class.getClassLoader());
+                            _mbbCleaner[0].setAccessible(true);
+                            final Class<?> cleanerType = _mbbCleaner[0].getReturnType();
+                            // Java >= 9: jdk.internal.ref.Cleaner (NOT accessible!)
+                            //            "Unable to make public void jdk.internal.ref.Cleaner.clean() accessible:
+                            //             module java.base does not "exports jdk.internal.ref" to unnamed module"
+                            // Java <= 8: sun.misc.Cleaner OK
+                            _cClean[0] = cleanerType.getMethod("clean");
+                            _cClean[0].setAccessible(true);
+                        }
                         return Boolean.TRUE;
                     } catch(final Throwable t) {
                         if( DEBUG ) {
@@ -1189,27 +1211,43 @@ public class Buffers {
                         }
                         return Boolean.FALSE;
                     } } } ).booleanValue() ) {
+                theUnsafe = _theUnsafe[0];
                 mbbCleaner = _mbbCleaner[0];
                 cClean = _cClean[0];
-                hasCleaner = null != mbbCleaner && null != cClean;
+                hasCleaner = PlatformPropsImpl.JAVA_9 ? null != theUnsafe && null != cClean : null != mbbCleaner && null != cClean;
             } else {
+                theUnsafe = null;
                 mbbCleaner = null;
                 cClean = null;
                 hasCleaner = false;
             }
             cleanerError = !hasCleaner;
+            if( DEBUG ) {
+                System.err.print("Buffers.Cleaner.init: hasCleaner: "+hasCleaner+", cleanerError "+cleanerError);
+                if( null != mbbCleaner ) {
+                    System.err.print(", using Cleaner class: "+mbbCleaner.getReturnType().getName());
+                }
+                if( null != theUnsafe ) {
+                    System.err.print(", using sun.misc.Unsafe::invokeCleaner(..);");
+                }
+                System.err.println();
+            }
         }
         /**
          * If {@code b} is an direct NIO buffer, i.e {@link sun.nio.ch.DirectBuffer},
          * calls it's {@link sun.misc.Cleaner} instance {@code clean()} method.
          * @return {@code true} if successful, otherwise {@code false}.
          */
-        public static boolean clean(final Buffer b) {
-            if( !hasCleaner || cleanerError || !b.isDirect() ) {
+        public static boolean clean(final ByteBuffer bb) {
+            if( !hasCleaner || cleanerError || !bb.isDirect() ) {
                 return false;
             }
             try {
-                cClean.invoke(mbbCleaner.invoke(b));
+                if( PlatformPropsImpl.JAVA_9 ) {
+                    cClean.invoke(theUnsafe, bb);
+                } else {
+                    cClean.invoke(mbbCleaner.invoke(bb));
+                }
                 return true;
             } catch(final Throwable t) {
                 cleanerError = true;
-- 
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