/*

 * 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();

}