diff -r 5d043a159d5c -r 53dccc90a5be src/hotspot/share/jfr/recorder/repository/jfrChunk.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/jfr/recorder/repository/jfrChunk.cpp	Fri May 17 18:03:14 2019 +0200
@@ -0,0 +1,192 @@
+/*
+ * Copyright (c) 2012, 2019, 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/dcmd/jfrDcmds.hpp"
+#include "jfr/recorder/jfrRecorder.hpp"
+#include "jfr/recorder/repository/jfrChunk.hpp"
+#include "jfr/recorder/repository/jfrChunkWriter.hpp"
+#include "jfr/utilities/jfrTimeConverter.hpp"
+#include "logging/log.hpp"
+#include "runtime/os.inline.hpp"
+#include "runtime/thread.inline.hpp"
+
+static const u1 GUARD = 0xff;
+
+static jlong nanos_now() {
+  return os::javaTimeMillis() * JfrTimeConverter::NANOS_PER_MILLISEC;
+}
+
+static jlong ticks_now() {
+  return JfrTicks::now();
+}
+
+JfrChunk::JfrChunk() :
+  _path(NULL),
+  _start_ticks(0),
+  _previous_start_ticks(invalid_time),
+  _start_nanos(0),
+  _previous_start_nanos(invalid_time),
+  _last_update_nanos(0),
+  _last_checkpoint_offset(0),
+  _last_metadata_offset(0),
+  _generation(1) {}
+
+JfrChunk::~JfrChunk() {
+  reset();
+}
+
+void JfrChunk::reset() {
+  if (_path != NULL) {
+    JfrCHeapObj::free(_path, strlen(_path) + 1);
+    _path = NULL;
+  }
+  _last_checkpoint_offset = _last_metadata_offset = 0;
+  _generation = 1;
+}
+
+void JfrChunk::set_last_checkpoint_offset(int64_t offset) {
+  _last_checkpoint_offset = offset;
+}
+
+int64_t JfrChunk::last_checkpoint_offset() const {
+  return _last_checkpoint_offset;
+}
+
+int64_t JfrChunk::start_ticks() const {
+  assert(_start_ticks != 0, "invariant");
+  return _start_ticks;
+}
+
+int64_t JfrChunk::start_nanos() const {
+  assert(_start_nanos != 0, "invariant");
+  return _start_nanos;
+}
+
+int64_t JfrChunk::previous_start_ticks() const {
+  assert(_previous_start_ticks != invalid_time, "invariant");
+  return _previous_start_ticks;
+}
+
+int64_t JfrChunk::previous_start_nanos() const {
+  assert(_previous_start_nanos != invalid_time, "invariant");
+  return _previous_start_nanos;
+}
+
+void JfrChunk::update_start_ticks() {
+  _start_ticks = ticks_now();
+}
+
+void JfrChunk::update_start_nanos() {
+  _start_nanos = _last_update_nanos = nanos_now();
+}
+
+void JfrChunk::update() {
+  _last_update_nanos = nanos_now();
+}
+
+void JfrChunk::save_current_and_update_start_ticks() {
+  _previous_start_ticks = _start_ticks;
+  update_start_ticks();
+}
+
+void JfrChunk::save_current_and_update_start_nanos() {
+  _previous_start_nanos = _start_nanos;
+  update_start_nanos();
+}
+
+void JfrChunk::update_time_to_now() {
+  save_current_and_update_start_nanos();
+  save_current_and_update_start_ticks();
+}
+
+int64_t JfrChunk::last_chunk_duration() const {
+  assert(_previous_start_nanos != invalid_time, "invariant");
+  return _start_nanos - _previous_start_nanos;
+}
+
+static char* copy_path(const char* path) {
+  assert(path != NULL, "invariant");
+  const size_t path_len = strlen(path);
+  char* new_path = JfrCHeapObj::new_array<char>(path_len + 1);
+  strncpy(new_path, path, path_len + 1);
+  return new_path;
+}
+
+void JfrChunk::set_path(const char* path) {
+  if (_path != NULL) {
+    JfrCHeapObj::free(_path, strlen(_path) + 1);
+    _path = NULL;
+  }
+  if (path != NULL) {
+    _path = copy_path(path);
+  }
+}
+
+const char* JfrChunk::path() const {
+  return _path;
+}
+
+bool JfrChunk::is_started() const {
+  return _start_nanos != 0;
+}
+
+bool JfrChunk::is_finished() const {
+  return 0 == _generation;
+}
+
+bool JfrChunk::is_initial_flush() const {
+  return 0 == _last_metadata_offset;
+}
+
+int64_t JfrChunk::duration() const {
+  assert(_last_update_nanos >= _start_nanos, "invariant");
+  return _last_update_nanos - _start_nanos;
+}
+
+int64_t JfrChunk::last_metadata_offset() const {
+  return _last_metadata_offset;
+}
+
+void JfrChunk::set_last_metadata_offset(int64_t offset) {
+  if (0 == offset) {
+    return;
+  }
+  assert(offset > _last_metadata_offset, "invariant");
+  _last_metadata_offset = offset;
+}
+
+bool JfrChunk::has_metadata() const {
+  return 0 != _last_metadata_offset;
+}
+
+u1 JfrChunk::generation() const {
+  assert(_generation > 0, "invariant");
+  const u1 this_generation = _generation++;
+  if (GUARD == _generation) {
+    _generation = 1;
+  }
+  return this_generation;
+}
+