text: //------------------------------------------------------------------------------
  /*
      This file is part of jbcoind: https://github.com/jbcoin/jbcoind
      Copyright (c) 2012, 2013 JBCoin Labs Inc.
  
      Permission to use, copy, modify, and/or distribute this software for any
      purpose  with  or without fee is hereby granted, provided that the above
      copyright notice and this permission notice appear in all copies.
  
      THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
      WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
      MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
      ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
      WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
      ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
      OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
  //==============================================================================
  
  #ifndef JBCOIN_NODESTORE_SCHEDULER_H_INCLUDED
  #define JBCOIN_NODESTORE_SCHEDULER_H_INCLUDED
  
  #include <jbcoin/nodestore/Task.h>
  #include <chrono>
  
  namespace jbcoin {
  namespace NodeStore {
  
  /** Contains information about a fetch operation. */
  struct FetchReport
  {
      explicit FetchReport() = default;
  
      std::chrono::milliseconds elapsed;
      bool isAsync;
      bool wentToDisk;
      bool wasFound;
  };
  
  /** Contains information about a batch write operation. */
  struct BatchWriteReport
  {
      explicit BatchWriteReport() = default;
  
      std::chrono::milliseconds elapsed;
      int writeCount;
  };
  
  /** Scheduling for asynchronous backend activity
  
      For improved performance, a backend has the option of performing writes
      in batches. These writes can be scheduled using the provided scheduler
      object.
  
      @see BatchWriter
  */
  class Scheduler
  {
  public:
      virtual ~Scheduler() = default;
  
      /** Schedules a task.
          Depending on the implementation, the task may be invoked either on
          the current thread of execution, or an unspecified implementation-defined
          foreign thread.
      */
      virtual void scheduleTask (Task& task) = 0;
  
      /** Reports completion of a fetch
          Allows the scheduler to monitor the node store's performance
      */
      virtual void onFetch (FetchReport const& report) = 0;
  
      /** Reports the completion of a batch write
          Allows the scheduler to monitor the node store's performance
      */
      virtual void onBatchWrite (BatchWriteReport const& report) = 0;
  };
  
  }
  }
  
  #endif
  