--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/jfr/recorder/checkpoint/jfrMetadataEvent.cpp	Tue May 15 20:24:34 2018 +0200
@@ -0,0 +1,89 @@
+/*
+ * Copyright (c) 2016, 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.
+ *
+ * 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.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "jfr/jni/jfrJavaSupport.hpp"
+#include "jfr/recorder/checkpoint/jfrMetadataEvent.hpp"
+#include "jfr/recorder/repository/jfrChunkWriter.hpp"
+#include "oops/klass.inline.hpp"
+#include "oops/oop.inline.hpp"
+#include "oops/typeArrayOop.inline.hpp"
+#include "runtime/semaphore.hpp"
+#include "runtime/thread.inline.hpp"
+
+static jbyteArray _metadata_blob = NULL;
+static Semaphore metadata_mutex_semaphore(1);
+
+void JfrMetadataEvent::lock() {
+  metadata_mutex_semaphore.wait();
+}
+
+void JfrMetadataEvent::unlock() {
+  metadata_mutex_semaphore.signal();
+}
+
+static void write_metadata_blob(JfrChunkWriter& chunkwriter, jbyteArray metadata_blob) {
+  if (metadata_blob != NULL) {
+    const typeArrayOop arr = (typeArrayOop)JfrJavaSupport::resolve_non_null(metadata_blob);
+    assert(arr != NULL, "invariant");
+    const int length = arr->length();
+    const Klass* const k = arr->klass();
+    assert(k != NULL && k->is_array_klass(), "invariant");
+    const TypeArrayKlass* const byte_arr_klass = TypeArrayKlass::cast(k);
+    const jbyte* const data_address = arr->byte_at_addr(0);
+    chunkwriter.write_unbuffered(data_address, length);
+  }
+}
+
+// the semaphore is assumed to be locked  (was locked previous safepoint)
+size_t JfrMetadataEvent::write(JfrChunkWriter& chunkwriter, jlong metadata_offset) {
+  assert(chunkwriter.is_valid(), "invariant");
+  assert(chunkwriter.current_offset() == metadata_offset, "invariant");
+  // header
+  chunkwriter.reserve(sizeof(u4));
+  chunkwriter.write<u8>(EVENT_METADATA); // ID 0
+  // time data
+  chunkwriter.write(JfrTicks::now());
+  chunkwriter.write((u8)0); // duration
+  chunkwriter.write((u8)0); // metadata id
+  write_metadata_blob(chunkwriter, _metadata_blob); // payload
+  unlock(); // open up for java to provide updated metadata
+  // fill in size of metadata descriptor event
+  const jlong size_written = chunkwriter.current_offset() - metadata_offset;
+  chunkwriter.write_padded_at_offset((u4)size_written, metadata_offset);
+  return size_written;
+}
+
+void JfrMetadataEvent::update(jbyteArray metadata) {
+  JavaThread* thread = (JavaThread*)Thread::current();
+  assert(thread->is_Java_thread(), "invariant");
+  DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_vm(thread));
+  lock();
+  if (_metadata_blob != NULL) {
+    JfrJavaSupport::destroy_global_jni_handle(_metadata_blob);
+  }
+  const oop new_desc_oop = JfrJavaSupport::resolve_non_null(metadata);
+  _metadata_blob = new_desc_oop != NULL ? (jbyteArray)JfrJavaSupport::global_jni_handle(new_desc_oop, thread) : NULL;
+  unlock();
+}