/*
 * @project        The CERN Tape Archive (CTA)
 * @copyright      Copyright(C) 2003-2021 CERN
 * @license        This program is free software: you can redistribute it and/or modify
 *                 it under the terms of the GNU General Public License as published by
 *                 the Free Software Foundation, either version 3 of the License, or
 *                 (at your option) any later version.
 *
 *                 This program 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 for more details.
 *
 *                 You should have received a copy of the GNU General Public License
 *                 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#pragma once

#include "common/threading/BlockingQueue.hpp"
#include "common/threading/Thread.hpp"
#include "common/log/LogContext.hpp"

namespace castor {
namespace exception {
// Forward declaration  
class Exception;    
}
namespace tape {
namespace tapeserver {
namespace daemon {
// Forward declaration  
class MemBlock;
/**
 * The memory manager is responsible for allocating memory blocks and distributing
 * the free ones around to any class in need.
 */
class RecallMemoryManager {
public:
  
  /**
   * Constructor
   * @param numberOfBlocks: number of blocks to allocate
   * @param blockSize: size of each block
   */
  RecallMemoryManager(const size_t numberOfBlocks, const size_t blockSize,
          cta::log::LogContext&  lc);
  
  /**
   * Are all sheep back to the farm?
   * @return 
   */
  bool areBlocksAllBack() throw();
  
  /**
   * Takes back a block which has been released by one of the clients
   * @param mb: the pointer to the block
   */
  void releaseBlock(MemBlock *mb);
  
  /**
   * Pop a free block from the free block queue of the memory manager
   * @return pointer to a free block
   */
  MemBlock* getFreeBlock();
  
  /**
   * Destructor
   */
  ~RecallMemoryManager();
  
private:
  /**
   * Total number of allocated memory blocks
   */
  size_t m_totalNumberOfBlocks;
  
  /**
   * Container for the free blocks
   */
  cta::threading::BlockingQueue<MemBlock*> m_freeBlocks;
  
  /**
   * Logging. The class is not threaded, so it can be shared with its parent
   */
  cta::log::LogContext&  m_lc;
};

}}}}