# HG changeset patch
# User redestad
# Date 1503314077 -7200
#      Mon Aug 21 13:14:37 2017 +0200
# Node ID b8dc6078e91a7c229e80f8999a948e70086599ef
# Parent  4469f450455806ceb5c40cdcc923690a878ff85a
8185362: Replace use of AtomicReferenceFieldUpdater from BufferedInputStream with Unsafe
Reviewed-by: shade

diff --git a/src/java.base/share/classes/java/io/BufferedInputStream.java b/src/java.base/share/classes/java/io/BufferedInputStream.java
--- a/src/java.base/share/classes/java/io/BufferedInputStream.java
+++ b/src/java.base/share/classes/java/io/BufferedInputStream.java
@@ -24,7 +24,8 @@
  */
 
 package java.io;
-import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
+
+import jdk.internal.misc.Unsafe;
 
 /**
  * A <code>BufferedInputStream</code> adds
@@ -60,23 +61,17 @@
      */
     private static int MAX_BUFFER_SIZE = Integer.MAX_VALUE - 8;
 
+    private static final Unsafe U = Unsafe.getUnsafe();
+
+    private static final long BUF_OFFSET
+            = U.objectFieldOffset(BufferedInputStream.class, "buf");
+
     /**
      * The internal buffer array where the data is stored. When necessary,
      * it may be replaced by another array of
      * a different size.
      */
-    protected volatile byte buf[];
-
-    /**
-     * Atomic updater to provide compareAndSet for buf. This is
-     * necessary because closes can be asynchronous. We use nullness
-     * of buf[] as primary indicator that this stream is closed. (The
-     * "in" field is also nulled out on close.)
-     */
-    private static final
-        AtomicReferenceFieldUpdater<BufferedInputStream, byte[]> bufUpdater =
-        AtomicReferenceFieldUpdater.newUpdater
-        (BufferedInputStream.class,  byte[].class, "buf");
+    protected volatile byte[] buf;
 
     /**
      * The index one greater than the index of the last valid byte in
@@ -232,7 +227,7 @@
                     nsz = marklimit;
                 byte nbuf[] = new byte[nsz];
                 System.arraycopy(buffer, 0, nbuf, 0, pos);
-                if (!bufUpdater.compareAndSet(this, buffer, nbuf)) {
+                if (!U.compareAndSetObject(this, BUF_OFFSET, buffer, nbuf)) {
                     // Can't replace buf if there was an async close.
                     // Note: This would need to be changed if fill()
                     // is ever made accessible to multiple threads.
@@ -476,7 +471,7 @@
     public void close() throws IOException {
         byte[] buffer;
         while ( (buffer = buf) != null) {
-            if (bufUpdater.compareAndSet(this, buffer, null)) {
+            if (U.compareAndSetObject(this, BUF_OFFSET, buffer, null)) {
                 InputStream input = in;
                 in = null;
                 if (input != null)