/*

 * Copyright (c) 2014, 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.

 *

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#ifndef SHARE_JFR_LEAKPROFILER_SAMPLING_OBJECTSAMPLER_HPP

#define SHARE_JFR_LEAKPROFILER_SAMPLING_OBJECTSAMPLER_HPP

#include "memory/allocation.hpp"

#include "jfr/utilities/jfrTime.hpp"

typedef u8 traceid;

class BoolObjectClosure;

class JavaThread;

class OopClosure;

class ObjectSample;

class SampleList;

class SamplePriorityQueue;

// Class reponsible for holding samples and

// making sure the samples are evenly distributed as

// new entries are added and removed.

class ObjectSampler : public CHeapObj<mtTracing> {

  friend class LeakProfiler;

  friend class StartOperation;

  friend class StopOperation;

 private:

  SamplePriorityQueue* _priority_queue;

  SampleList* _list;

  JfrTicks _last_sweep;

  size_t _total_allocated;

  size_t _threshold;

  size_t _size;

  bool _dead_samples;

  // Lifecycle

  explicit ObjectSampler(size_t size);

  ~ObjectSampler();

  static bool create(size_t size);

  static bool is_created();

  static void destroy();

  // Sampling

  static void sample(HeapWord* object, size_t size, JavaThread* thread);

  void add(HeapWord* object, size_t size, traceid thread_id, JavaThread* thread);

  void scavenge();

  void remove_dead(ObjectSample* sample);

  // Called by GC

  static void oops_do(BoolObjectClosure* is_alive, OopClosure* f);

  const ObjectSample* item_at(int index) const;

  ObjectSample* item_at(int index);

  int item_count() const;

 public:

  static ObjectSampler* sampler();

  // For operations that require exclusive access (non-safepoint)

  static ObjectSampler* acquire();

  static void release();

  const ObjectSample* first() const;

  ObjectSample* last() const;

  const ObjectSample* last_resolved() const;

  void set_last_resolved(const ObjectSample* sample);

  const JfrTicks& last_sweep() const;

};

#endif // SHARE_JFR_LEAKPROFILER_SAMPLING_OBJECTSAMPLER_HPP