text: #ifndef __DIRTY_PAGE_FLUSHER_H__
  #define __DIRTY_PAGE_FLUSHER_H__
  
  /*
   * Copyright 2014 Open Connectome Project (http://openconnecto.me)
   * Written by Da Zheng (zhengda1936@gmail.com)
   *
   * This file is part of SAFSlib.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  #include "common.h"
  
  namespace safs
  {
  
  class thread_safe_page;
  class io_interface;
  
  class dirty_page_flusher
  {
  public:
  	virtual ~dirty_page_flusher() {
  	}
  
  	/**
  	 * This method flushes dirty pages with the specified io instance.
  	 * The method has to be thread-safe, as it will be invoked in different
  	 * thread contexts. It also shouldn't block threads.
  	 */
  	virtual void flush_dirty_pages(thread_safe_page *pages[], int num,
  			io_interface &io) = 0;
  
  	virtual int flush_dirty_pages(page_filter *filter, int max_num) = 0;
  };
  
  }
  
  #endif
  