--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jdk.jfr/share/classes/jdk/jfr/internal/ChunksChannel.java	Tue May 15 20:24:34 2018 +0200
@@ -0,0 +1,145 @@
+/*
+ * Copyright (c) 2012, 2018, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code 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
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package jdk.jfr.internal;
+
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.nio.channels.FileChannel;
+import java.nio.channels.ReadableByteChannel;
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+
+final class ChunksChannel implements ReadableByteChannel {
+    private final Iterator<RepositoryChunk> chunks;
+    private RepositoryChunk                 current;
+    private ReadableByteChannel             channel;
+
+    public ChunksChannel(List<RepositoryChunk> chunks) throws IOException {
+        if (chunks.isEmpty()) {
+            throw new FileNotFoundException("No chunks");
+        }
+        List<RepositoryChunk> l = new ArrayList<>(chunks.size());
+        for (RepositoryChunk c : chunks) {
+            c.use(); // keep alive while we're reading.
+            l.add(c);
+        }
+        this.chunks = l.iterator();
+        nextChannel();
+    }
+
+    private boolean nextChunk() {
+        if (!chunks.hasNext()) {
+            return false;
+        }
+        current = chunks.next();
+        return true;
+    }
+
+    private boolean nextChannel() throws IOException {
+        if (!nextChunk()) {
+            return false;
+        }
+
+        channel = current.newChannel();
+        return true;
+    }
+
+    @Override
+    public int read(ByteBuffer dst) throws IOException {
+        for (;;) {
+            if (channel != null) {
+                assert current != null;
+                int r = channel.read(dst);
+                if (r != -1) {
+                    return r;
+                }
+                channel.close();
+                current.release();
+                channel = null;
+                current = null;
+            }
+            if (!nextChannel()) {
+                return -1;
+            }
+        }
+    }
+
+    public long transferTo(FileChannel out) throws IOException {
+        long pos = 0;
+        for (;;) {
+            if (channel != null) {
+                assert current != null;
+
+                long rem = current.getSize();
+
+                while (rem > 0) {
+                    long n = Math.min(rem, 1024 * 1024);
+                    long w = out.transferFrom(channel, pos, n);
+                    pos += w;
+                    rem -= w;
+                }
+
+                channel.close();
+                current.release();
+
+                channel = null;
+                current = null;
+            }
+            if (!nextChannel()) {
+                return pos;
+            }
+        }
+    }
+
+    @Override
+    public void close() throws IOException {
+        if (channel != null) {
+            channel.close();
+            channel = null;
+        }
+        while (current != null) {
+            current.release();
+            current = null;
+            if (!nextChunk()) {
+                return;
+            }
+        }
+    }
+
+    @Override
+    public boolean isOpen() {
+        return channel != null;
+    }
+
+    @Override
+    @SuppressWarnings("deprecation")
+    protected void finalize() throws Throwable {
+        super.finalize();
+        close();
+    }
+}