/*

 * Copyright (c) 2016, 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 "classfile/javaClasses.inline.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/repository/jfrChunkWriter.hpp"

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

#include "jfr/recorder/stringpool/jfrStringPool.hpp"

#include "jfr/recorder/stringpool/jfrStringPoolWriter.hpp"

#include "jfr/utilities/jfrTypes.hpp"

#include "logging/log.hpp"

#include "runtime/mutexLocker.hpp"

#include "runtime/safepoint.hpp"

#include "runtime/thread.inline.hpp"

typedef JfrStringPool::Buffer* BufferPtr;

static JfrStringPool* _instance = NULL;

static uint64_t store_generation = 0;

static uint64_t serialized_generation = 0;

inline void set_generation(uint64_t value, uint64_t* const dest) {

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

  Atomic::release_store(dest, value);

}

static void increment_store_generation() {

  const uint64_t current_serialized = Atomic::load_acquire(&serialized_generation);

  const uint64_t current_stored = Atomic::load_acquire(&store_generation);

  if (current_serialized == current_stored) {

    set_generation(current_serialized + 1, &store_generation);

  }

}

static bool increment_serialized_generation() {

  const uint64_t current_stored = Atomic::load_acquire(&store_generation);

  const uint64_t current_serialized = Atomic::load_acquire(&serialized_generation);

  if (current_stored != current_serialized) {

    set_generation(current_stored, &serialized_generation);

    return true;

  }

  return false;

}

bool JfrStringPool::is_modified() {

  return increment_serialized_generation();

}

JfrStringPool& JfrStringPool::instance() {

  return *_instance;

}

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

  store_generation = 0;

  serialized_generation = 0;

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

  _instance = new JfrStringPool(cw);

  return _instance;

}

void JfrStringPool::destroy() {

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

  delete _instance;

  _instance = NULL;

}

JfrStringPool::JfrStringPool(JfrChunkWriter& cw) : _free_list_mspace(NULL), _lock(NULL), _chunkwriter(cw) {}

JfrStringPool::~JfrStringPool() {

  if (_free_list_mspace != NULL) {

    delete _free_list_mspace;

  }

  if (_lock != NULL) {

    delete _lock;

  }

}

static const size_t unlimited_mspace_size = 0;

static const size_t string_pool_cache_count = 2;

static const size_t string_pool_buffer_size = 512 * K;

bool JfrStringPool::initialize() {

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

  _free_list_mspace = new JfrStringPoolMspace(string_pool_buffer_size, unlimited_mspace_size, string_pool_cache_count, this);

  if (_free_list_mspace == NULL || !_free_list_mspace->initialize()) {

    return false;

  }

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

  _lock = new Mutex(Monitor::leaf - 1, "Checkpoint mutex", Mutex::_allow_vm_block_flag, Monitor::_safepoint_check_never);

  return _lock != NULL;

}

/*

* If the buffer was a "lease" from the global system, 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 any longer.

*/

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

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

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

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

  buffer->clear_lease();

  buffer->release();

}

BufferPtr JfrStringPool::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

}

static const size_t lease_retry = 10;

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

  BufferPtr buffer = mspace_get_free_lease_with_retry(size, instance()._free_list_mspace, lease_retry, thread);

  if (buffer == NULL) {

    buffer = mspace_allocate_transient_lease_to_free(size,  instance()._free_list_mspace, thread);

  }

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

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

  return buffer;

}

bool JfrStringPool::add(bool epoch, jlong id, jstring string, JavaThread* jt) {

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

  const bool current_epoch = JfrTraceIdEpoch::epoch();

  if (current_epoch != epoch) {

    return current_epoch;

  }

  {

    JfrStringPoolWriter writer(jt);

    writer.write(id);

    writer.write(string);

    writer.inc_nof_strings();

  }

  increment_store_generation();

  return current_epoch;

}

template <template <typename> class Operation>

class StringPoolOp {

 public:

  typedef JfrStringPoolBuffer Type;

 private:

  Operation<Type> _op;

  Thread* _thread;

  size_t _strings_processed;

 public:

  StringPoolOp() : _op(), _thread(Thread::current()), _strings_processed(0) {}

  StringPoolOp(JfrChunkWriter& writer, Thread* thread) : _op(writer), _thread(thread), _strings_processed(0) {}

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

    assert(buffer->acquired_by(_thread) || buffer->retired(), "invariant");

    const uint64_t nof_strings_used = buffer->string_count();

    assert(nof_strings_used > 0, "invariant");

    buffer->set_string_top(buffer->string_top() + nof_strings_used);

    // "size processed" for string pool buffers is the number of processed string elements

    _strings_processed += nof_strings_used;

    return _op.write(buffer, data, size);

  }

  size_t processed() { return _strings_processed; }

};

template <typename T>

class StringPoolDiscarderStub {

 public:

  typedef T Type;

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

    // stub only, discard happens at higher level

    return true;

  }

};

typedef StringPoolOp<UnBufferedWriteToChunk> WriteOperation;

typedef StringPoolOp<StringPoolDiscarderStub> DiscardOperation;

typedef ExclusiveOp<WriteOperation> ExclusiveWriteOperation;

typedef ExclusiveOp<DiscardOperation> ExclusiveDiscardOperation;

typedef ReleaseOp<JfrStringPoolMspace> StringPoolReleaseOperation;

typedef CompositeOperation<ExclusiveWriteOperation, StringPoolReleaseOperation> StringPoolWriteOperation;

typedef CompositeOperation<ExclusiveDiscardOperation, StringPoolReleaseOperation> StringPoolDiscardOperation;

size_t JfrStringPool::write() {

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

  WriteOperation wo(_chunkwriter, thread);

  ExclusiveWriteOperation ewo(wo);

  StringPoolReleaseOperation spro(_free_list_mspace, thread, false);

  StringPoolWriteOperation spwo(&ewo, &spro);

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

  process_free_list(spwo, _free_list_mspace);

  return wo.processed();

}

size_t JfrStringPool::write_at_safepoint() {

  assert(SafepointSynchronize::is_at_safepoint(), "invariant");

  return write();

}

size_t JfrStringPool::clear() {

  increment_serialized_generation();

  DiscardOperation discard_operation;

  ExclusiveDiscardOperation edo(discard_operation);

  StringPoolReleaseOperation spro(_free_list_mspace, Thread::current(), false);

  StringPoolDiscardOperation spdo(&edo, &spro);

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

  process_free_list(spdo, _free_list_mspace);

  return discard_operation.processed();

}

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

  // nothing here at the moment

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

  assert(t->acquired_by(thread), "invariant");

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

}

void JfrStringPool::lock() {

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

  _lock->lock_without_safepoint_check();

}

void JfrStringPool::unlock() {

  _lock->unlock();

}

#ifdef ASSERT

bool JfrStringPool::is_locked() const {

  return _lock->owned_by_self();

}

#endif