heap_record_scanner.h

/* Copyright (c) 2021 OceanBase and/or its affiliates. All rights reserved.
miniob is licensed under Mulan PSL v2.
You can use this software according to the terms and conditions of the Mulan PSL v2.
You may obtain a copy of Mulan PSL v2 at:
         http://license.coscl.org.cn/MulanPSL2
THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
See the Mulan PSL v2 for more details. */
 
#pragma once
 
#include "storage/record/record_scanner.h"
#include "storage/buffer/disk_buffer_pool.h"
#include "storage/trx/trx.h"
 
class HeapRecordScanner : public RecordScanner
{
public:
  HeapRecordScanner(Table *table, DiskBufferPool &buffer_pool, Trx *trx, LogHandler &log_handler, ReadWriteMode mode,
      ConditionFilter *condition_filter)
      : table_(table),
        disk_buffer_pool_(&buffer_pool),
        trx_(trx),
        log_handler_(&log_handler),
        rw_mode_(mode),
        condition_filter_(condition_filter)
  {}
  ~HeapRecordScanner() override { close_scan(); }
 
  RC open_scan() override;
 
  RC close_scan() override;
 
  RC next(Record &record) override;
 
private:
  RC fetch_next_record();
 
  RC fetch_next_record_in_page();
 
private:
  // TODO 对于一个纯粹的record遍历器来说，不应该关心表和事务
  Table *table_ = nullptr;  
 
  DiskBufferPool *disk_buffer_pool_ = nullptr;  
  Trx            *trx_              = nullptr;  
  LogHandler     *log_handler_      = nullptr;
  ReadWriteMode   rw_mode_ = ReadWriteMode::READ_WRITE;  
 
  BufferPoolIterator bp_iterator_;                    
  ConditionFilter   *condition_filter_    = nullptr;  
  RecordPageHandler *record_page_handler_ = nullptr;  
  RecordPageIterator record_page_iterator_;           
  Record             next_record_;                    
};