hazard_pointer.h

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/*
The MIT License (MIT)

Copyright (c) 2015 University of Central Florida's Computer Software Engineering
Scalable & Secure Systems (CSE - S3) Lab

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/
#ifndef TERVEL_MEMORY_HP_HAZARD_POINTER_H_
#define TERVEL_MEMORY_HP_HAZARD_POINTER_H_

#include <atomic>
#include <utility>

#include <assert.h>
#include <stddef.h>
#include <memory>
#include <cstdint>

#include <tervel/util/info.h>
#include <tervel/util/util.h>
#include <tervel/util/memory/hp/list_manager.h>

namespace tervel {
namespace util {
namespace memory {
namespace hp {

class Element;

class HazardPointer {
 public:
  enum class SlotID : size_t {SHORTUSE = 0, SHORTUSE2, PROG_ASSUR, END};

  explicit HazardPointer(int num_threads);
  ~HazardPointer();

  // -------
  // Static Functions
  // -------

  static bool watch(SlotID slot_id, Element *elem, std::atomic<void *> *address,
        void *expected, HazardPointer * const hazard_pointer =
        tervel::tl_thread_info->get_hazard_pointer());

  static bool watch(SlotID slot_id, void *value, std::atomic<void *> *address
      , void *expected, HazardPointer * const hazard_pointer =
      tervel::tl_thread_info->get_hazard_pointer());

  static void unwatch(SlotID slot_id, HazardPointer * const hazard_pointer =
        tervel::tl_thread_info->get_hazard_pointer());

  static void unwatch(SlotID slot_id, Element *descr,
          HazardPointer * const hazard_pointer =
          tervel::tl_thread_info->get_hazard_pointer());

  static bool is_watched(Element *descr, HazardPointer * const hazard_pointer =
        tervel::tl_thread_info->get_hazard_pointer());

  static bool is_watched(void *value, HazardPointer * const hazard_pointer =
        tervel::tl_thread_info->get_hazard_pointer());


  // -------
  // Member Functions
  // -------
  void watch(SlotID slot, void *value) {
    watches_[get_slot(slot)].store(value);
  }

  void clear_watch(SlotID slot) {
    watches_[get_slot(slot)].store(nullptr);
  }


  bool contains(void *value) {
    for (size_t i = 0; i < num_slots_; i++) {
      if (watches_[i].load() == value) {
        return true;
      }
    }
    return false;
  }

 private:
  size_t get_slot(SlotID id) {
    size_t s = static_cast<size_t>(id) + (static_cast<size_t>(SlotID::END) *
          tervel::tl_thread_info->get_thread_id());
    assert(s < num_slots_);
    return s;
  }

  std::unique_ptr<std::atomic<void *>[]> watches_;
  const size_t num_slots_;

 public:
  // Shared HP Element list manager
  util::memory::hp::ListManager hp_list_manager_;


  DISALLOW_COPY_AND_ASSIGN(HazardPointer);
};  // HazardPointer


}  // namespace hp
}  // namespace memory
}  // namepsace UTIL
}  // namespace tervel

#endif  // TERVEL_MEMORY_HP_HAZARD_POINTER_H_