/*

 * 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 "classfile/javaClasses.inline.hpp"

#include "jfr/recorder/jfrRecorder.hpp"

#include "jfr/recorder/checkpoint/jfrCheckpointManager.hpp"

#include "jfr/recorder/checkpoint/jfrCheckpointWriter.hpp"

#include "jfr/recorder/checkpoint/types/jfrTypeManager.hpp"

#include "jfr/recorder/checkpoint/types/traceid/jfrTraceIdEpoch.hpp"

#include "jfr/recorder/service/jfrOptionSet.hpp"

#include "jfr/recorder/storage/jfrMemorySpace.inline.hpp"

#include "jfr/recorder/storage/jfrStorageUtils.inline.hpp"

#include "jfr/recorder/repository/jfrChunkWriter.hpp"

#include "jfr/utilities/jfrBigEndian.hpp"

#include "jfr/utilities/jfrTypes.hpp"

#include "logging/log.hpp"

#include "memory/resourceArea.hpp"

#include "runtime/mutexLocker.hpp"

#include "runtime/orderAccess.hpp"

#include "runtime/os.inline.hpp"

#include "runtime/safepoint.hpp"

typedef JfrCheckpointManager::Buffer* BufferPtr;

static JfrCheckpointManager* _instance = NULL;

JfrCheckpointManager& JfrCheckpointManager::instance() {

  return *_instance;

}

JfrCheckpointManager* JfrCheckpointManager::create(JfrChunkWriter& cw) {

  assert(_instance == NULL, "invariant");

  _instance = new JfrCheckpointManager(cw);

  return _instance;

}

void JfrCheckpointManager::destroy() {

  assert(_instance != NULL, "invariant");

  delete _instance;

  _instance = NULL;

}

JfrCheckpointManager::JfrCheckpointManager(JfrChunkWriter& cw) :

  _free_list_mspace(NULL),

  _epoch_transition_mspace(NULL),

  _lock(NULL),

  _service_thread(NULL),

  _chunkwriter(cw),

  _checkpoint_epoch_state(JfrTraceIdEpoch::epoch()) {}

JfrCheckpointManager::~JfrCheckpointManager() {

  if (_free_list_mspace != NULL) {

    delete _free_list_mspace;

  }

  if (_epoch_transition_mspace != NULL) {

    delete _epoch_transition_mspace;

  }

  if (_lock != NULL) {

    delete _lock;

  }

}

static const size_t unlimited_mspace_size = 0;

static const size_t checkpoint_buffer_cache_count = 2;

static const size_t checkpoint_buffer_size = 512 * K;

static JfrCheckpointMspace* create_mspace(size_t buffer_size, size_t limit, size_t cache_count, JfrCheckpointManager* system) {

  JfrCheckpointMspace* mspace = new JfrCheckpointMspace(buffer_size, limit, cache_count, system);

  if (mspace != NULL) {

    mspace->initialize();

  }

  return mspace;

}

bool JfrCheckpointManager::initialize() {

  assert(_free_list_mspace == NULL, "invariant");

  _free_list_mspace = create_mspace(checkpoint_buffer_size, unlimited_mspace_size, checkpoint_buffer_cache_count, this);

  if (_free_list_mspace == NULL) {

    return false;

  }

  assert(_epoch_transition_mspace == NULL, "invariant");

  _epoch_transition_mspace = create_mspace(checkpoint_buffer_size, unlimited_mspace_size, checkpoint_buffer_cache_count, this);

  if (_epoch_transition_mspace == NULL) {

    return false;

  }

    return false;

  }

}

bool JfrCheckpointManager::use_epoch_transition_mspace(const Thread* thread) const {

  return _service_thread != thread && OrderAccess::load_acquire(&_checkpoint_epoch_state) != JfrTraceIdEpoch::epoch();

}

void JfrCheckpointManager::synchronize_epoch() {

  assert(_checkpoint_epoch_state != JfrTraceIdEpoch::epoch(), "invariant");

  OrderAccess::storestore();

  _checkpoint_epoch_state = JfrTraceIdEpoch::epoch();

}

void JfrCheckpointManager::shift_epoch() {

  debug_only(const u1 current_epoch = JfrTraceIdEpoch::current();)

  JfrTraceIdEpoch::shift_epoch();

  assert(current_epoch != JfrTraceIdEpoch::current(), "invariant");

}

void JfrCheckpointManager::register_service_thread(const Thread* thread) {

  _service_thread = thread;

}

void JfrCheckpointManager::register_full(BufferPtr t, Thread* thread) {

  // nothing here at the moment

  assert(t->retired(), "invariant");

}

void JfrCheckpointManager::lock() {

  assert(!_lock->owned_by_self(), "invariant");

  _lock->lock_without_safepoint_check();

}

void JfrCheckpointManager::unlock() {

  _lock->unlock();

}

#ifdef ASSERT

bool JfrCheckpointManager::is_locked() const {

  return _lock->owned_by_self();

}

static void assert_free_lease(const BufferPtr buffer) {

  assert(buffer != NULL, "invariant");

  assert(buffer->acquired_by_self(), "invariant");

  assert(buffer->lease(), "invariant");

}

static void assert_release(const BufferPtr buffer) {

  assert(buffer != NULL, "invariant");

  assert(buffer->lease(), "invariant");

  assert(buffer->acquired_by_self(), "invariant");

}

#endif // ASSERT

static BufferPtr lease_free(size_t size, JfrCheckpointMspace* mspace, size_t retry_count, Thread* thread) {

  static const size_t max_elem_size = mspace->min_elem_size(); // min is max

  BufferPtr buffer;

  if (size <= max_elem_size) {

    BufferPtr buffer = mspace_get_free_lease_with_retry(size, mspace, retry_count, thread);

    if (buffer != NULL) {

      DEBUG_ONLY(assert_free_lease(buffer);)

      return buffer;

    }

  }

  buffer = mspace_allocate_transient_lease_to_free(size, mspace, thread);

  DEBUG_ONLY(assert_free_lease(buffer);)

  return buffer;

}

static const size_t lease_retry = 10;

BufferPtr JfrCheckpointManager::lease_buffer(Thread* thread, size_t size /* 0 */) {

  JfrCheckpointManager& manager = instance();

  if (manager.use_epoch_transition_mspace(thread)) {

    return lease_free(size, manager._epoch_transition_mspace, lease_retry, thread);

  }

  return lease_free(size, manager._free_list_mspace, lease_retry, thread);

}

/*

* If the buffer was a "lease" from the free list, release back.

*

* The buffer is effectively invalidated for the thread post-return,

* and the caller should take means to ensure that it is not referenced.

*/

static void release(BufferPtr const buffer, Thread* thread) {

  DEBUG_ONLY(assert_release(buffer);)

  buffer->clear_lease();

  buffer->release();

}

BufferPtr JfrCheckpointManager::flush(BufferPtr old, size_t used, size_t requested, Thread* thread) {

  assert(old != NULL, "invariant");

  assert(old->lease(), "invariant");

  if (0 == requested) {

    // indicates a lease is being returned

    release(old, thread);

    return NULL;

  }

  // migration of in-flight information

  BufferPtr const new_buffer = lease_buffer(thread, used + requested);

  if (new_buffer != NULL) {

    migrate_outstanding_writes(old, new_buffer, used, requested);

  }

  release(old, thread);

  return new_buffer; // might be NULL

}

// offsets into the JfrCheckpointEntry

static const juint starttime_offset = sizeof(jlong);

static const juint duration_offset = starttime_offset + sizeof(jlong);

static const juint flushpoint_offset = duration_offset + sizeof(jlong);

static const juint types_offset = flushpoint_offset + sizeof(juint);

static const juint payload_offset = types_offset + sizeof(juint);

template <typename Return>

static Return read_data(const u1* data) {

  return JfrBigEndian::read<Return>(data);

}

static jlong total_size(const u1* data) {

  return read_data<jlong>(data);

}

static jlong starttime(const u1* data) {

  return read_data<jlong>(data + starttime_offset);

}

static jlong duration(const u1* data) {

  return read_data<jlong>(data + duration_offset);

}

static bool is_flushpoint(const u1* data) {

  return read_data<juint>(data + flushpoint_offset) == (juint)1;

}

static juint number_of_types(const u1* data) {

  return read_data<juint>(data + types_offset);

}

static void write_checkpoint_header(JfrChunkWriter& cw, intptr_t offset_prev_cp_event, const u1* data) {

  cw.reserve(sizeof(u4));

  cw.write((u8)EVENT_CHECKPOINT);

  cw.write(starttime(data));

  cw.write(duration(data));

  cw.write((jlong)offset_prev_cp_event);

  cw.write(is_flushpoint(data));

  cw.write(number_of_types(data));

}

static void write_checkpoint_content(JfrChunkWriter& cw, const u1* data, size_t size) {

  assert(data != NULL, "invariant");

  cw.write_unbuffered(data + payload_offset, size);

}

static size_t write_checkpoint_event(JfrChunkWriter& cw, const u1* data) {

  assert(data != NULL, "invariant");

  const intptr_t previous_checkpoint_event = cw.previous_checkpoint_offset();

  const intptr_t event_begin = cw.current_offset();

  const intptr_t offset_to_previous_checkpoint_event = 0 == previous_checkpoint_event ? 0 : previous_checkpoint_event - event_begin;

  const jlong total_checkpoint_size = total_size(data);

  write_checkpoint_header(cw, offset_to_previous_checkpoint_event, data);

  write_checkpoint_content(cw, data, total_checkpoint_size - sizeof(JfrCheckpointEntry));

  const jlong checkpoint_event_size = cw.current_offset() - event_begin;

  cw.write_padded_at_offset<u4>(checkpoint_event_size, event_begin);

  cw.set_previous_checkpoint_offset(event_begin);

  return (size_t)total_checkpoint_size;

}

static size_t write_checkpoints(JfrChunkWriter& cw, const u1* data, size_t size) {

  assert(cw.is_valid(), "invariant");

  assert(data != NULL, "invariant");

  assert(size > 0, "invariant");

  const u1* const limit = data + size;

  const u1* next_entry = data;

  size_t processed = 0;

  while (next_entry < limit) {

    const size_t checkpoint_size = write_checkpoint_event(cw, next_entry);

    processed += checkpoint_size;

    next_entry += checkpoint_size;

  }

  assert(next_entry == limit, "invariant");

  return processed;

}

template <typename T>

class CheckpointWriteOp {

 private:

  JfrChunkWriter& _writer;

  size_t _processed;

 public:

  typedef T Type;

  CheckpointWriteOp(JfrChunkWriter& writer) : _writer(writer), _processed(0) {}

  bool write(Type* t, const u1* data, size_t size) {

    _processed += write_checkpoints(_writer, data, size);

    return true;

  }

  size_t processed() const { return _processed; }

};

typedef CheckpointWriteOp<JfrCheckpointMspace::Type> WriteOperation;

typedef MutexedWriteOp<WriteOperation> MutexedWriteOperation;

typedef ReleaseOp<JfrCheckpointMspace> CheckpointReleaseOperation;

typedef CompositeOperation<MutexedWriteOperation, CheckpointReleaseOperation> CheckpointWriteOperation;

static size_t write_mspace_exclusive(JfrCheckpointMspace* mspace, JfrChunkWriter& chunkwriter) {

  Thread* const thread = Thread::current();

  WriteOperation wo(chunkwriter);

  MutexedWriteOperation mwo(wo);

  CheckpointReleaseOperation cro(mspace, thread, false);

  CheckpointWriteOperation cpwo(&mwo, &cro);

  assert(mspace->is_full_empty(), "invariant");

  process_free_list(cpwo, mspace);

  return wo.processed();

}

size_t JfrCheckpointManager::write() {

  const size_t processed = write_mspace_exclusive(_free_list_mspace, _chunkwriter);

  synchronize_epoch();

  return processed;

}

size_t JfrCheckpointManager::write_epoch_transition_mspace() {

  return write_mspace_exclusive(_epoch_transition_mspace, _chunkwriter);

}

typedef DiscardOp<DefaultDiscarder<JfrBuffer> > DiscardOperation;

size_t JfrCheckpointManager::clear() {

  DiscardOperation discarder(mutexed); // mutexed discard mode

  process_free_list(discarder, _free_list_mspace);

  process_free_list(discarder, _epoch_transition_mspace);

  synchronize_epoch();

  return discarder.processed();

}

size_t JfrCheckpointManager::write_types() {

  JfrCheckpointWriter writer(false, true, Thread::current());

  return writer.used_size();

}

size_t JfrCheckpointManager::write_safepoint_types() {

  // this is also a "flushpoint"

  JfrCheckpointWriter writer(true, true, Thread::current());

  return writer.used_size();

}

void JfrCheckpointManager::write_type_set() {

}

void JfrCheckpointManager::write_type_set_for_unloaded_classes() {

  assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint!");

}

void JfrCheckpointManager::create_thread_checkpoint(JavaThread* jt) {

}

void JfrCheckpointManager::write_thread_checkpoint(JavaThread* jt) {

}