descriptor_pool.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_RC_DESCRIPTOR_POOL_H_
#define TERVEL_MEMORY_RC_DESCRIPTOR_POOL_H_

#include <tervel/util/info.h>
#include <tervel/util/util.h>
#include <tervel/util/system.h>
#include <tervel/util/descriptor.h>
#include <tervel/util/memory/rc/pool_element.h>
#include <tervel/util/memory/rc/pool_manager.h>

namespace tervel {
namespace util {
namespace memory {
namespace rc {

class PoolManager;
class DescriptorPool {
 public:
  DescriptorPool(PoolManager *manager, uint64_t pool_id, int prefill = TERVEL_MEM_RC_MIN_NODES)
      : manager_(manager)
      , pool_id_(pool_id)
      , safe_pool_{nullptr}
      , unsafe_pool_{nullptr}
      , safe_pool_count_(0)
      , unsafe_pool_count_(0) {
    this->reserve(prefill);
  }
  ~DescriptorPool() {
    this->send_unsafe_to_manager();
    this->send_safe_to_manager();
  }

  void reserve(size_t num_descriptors = TERVEL_MEM_RC_MIN_NODES);

  template<typename DescrType, typename... Args>
  DescrType * get_descriptor(Args&&... args);

  void free_descriptor(tervel::util::Descriptor *descr, bool dont_check=false);


 private:
  // -------------------------
  // FOR DEALING WITH ELEMENTS
  // -------------------------

  PoolElement * get_from_pool(bool allocate_new = true);



  // -------------------------
  // FOR DEALING WITH MANAGERS
  // -------------------------

  void send_safe_to_manager();

  void send_unsafe_to_manager();

  void offload();

  // --------------------------------
  // DEALS WITH SAFE AND UNSAFE LISTS
  // --------------------------------

  void add_to_safe(tervel::util::Descriptor* descr);

  void add_to_unsafe(tervel::util::Descriptor* descr);

  void try_clear_unsafe_pool(bool dont_check = false);

  bool verify_pool_count(PoolElement *pool, uint64_t count);
  // -------
  // MEMBERS
  // -------

  PoolManager *manager_;

  uint64_t pool_id_;

  PoolElement *safe_pool_ {nullptr};

  PoolElement *unsafe_pool_ {nullptr};

  uint64_t safe_pool_count_ {0};
  uint64_t unsafe_pool_count_ {0};

  DISALLOW_COPY_AND_ASSIGN(DescriptorPool);
};

// IMPLEMENTATIONS
// ===============

template<typename DescrType, typename... Args>
DescrType * DescriptorPool::get_descriptor(Args&&... args) {
  PoolElement *elem = this->get_from_pool();
  if (elem == nullptr) {
    return nullptr;
  } else {
    elem->init_descriptor<DescrType>(std::forward<Args>(args)...);
    DescrType * descr = reinterpret_cast<DescrType *>(elem->descriptor());
    return descr;
  }
}

}  // namespace rc
}  // namespace memory
}  // namespace util
}  // namespace tervel

#endif  // TERVEL_MEMORY_RC_DESCRIPTOR_POOL_H_