core/sql/sort/ScratchFileMap.h

/**********************************************************************
// @@@ START COPYRIGHT @@@
//
// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you 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.
//
// @@@ END COPYRIGHT @@@
**********************************************************************/
#ifndef SCRATCHFILEMAP_H
#define SCRATCHFILEMAP_H

/* -*-C++-*-
******************************************************************************
*
* File:         ScratchFileMap.h
* RCS:          $Id: ScratchFileMap.h,v 1.1 2006/11/01 01:44:37  Exp $
*                               
* Description:  This class is a container class for all the scratch files that
*               are created and used by ArkSort.              
*                              
* Created:	    05/20/96
* Modified:     $ $Date: 2006/11/01 01:44:37 $ (GMT)
* Language:     C++
* Status:       $State: Exp $
*
******************************************************************************
*/

#include "Platform.h"

#include <string.h>
#include "CommonStructs.h"
#include "ScratchFile.h"
#include "NABasicObject.h"
#include "SortError.h"

class SQScratchFile;
//----------------------------------------------------------------------
// The data structure used to store information about multiple scratch
// file objects.
//----------------------------------------------------------------------

struct FileMap : public NABasicObject {

 short index_;
 Lng32  firstScrBlockWritten_;   //First scr block written to this scr file 

	SQScratchFile *scrFile_;
};

class ScratchFileMap : public NABasicObject {
  
  friend class ScratchSpace;
  friend class SortScratchSpace;

  public:

     ScratchFileMap(CollHeap* heap,
                SortError* sorterror,
		 NABoolean breakEnabled,
                short maxscrfiles);
     ~ScratchFileMap();
     void setBreakEnabled (NABoolean flag) { breakEnabled_ = flag; };
     void closeFiles(ScratchFile* keepFile = NULL);
     ScratchFile* createNewScrFile(
                          ScratchSpace *scratchSpace,
                          Int32 scratchMgmtOption,
                          Int32 scratchMaxOpens,
                          NABoolean preAllocateExtents,
                          NABoolean asynchReadQueue);

     ScratchFile* mapBlockNumToScrFile(SBN blockNum, Lng32 &blockOffset);
     void setFirstScrBlockNum(SBN blockNum);
     SBN getFirstScrBlockNum(ScratchFile *scr);
     Lng32 totalNumOfReads();
     Lng32 totalNumOfWrites(); 
     Lng32 totalNumOfAwaitio();
     void closeScrFilesUpto(SBN uptoBlockNum);

  private :
     short maxScratchFiles_;
     short numScratchFiles_;     //num of scratch files created thus far
     short currentScratchFiles_; //most recently referenced scratch file 
     FileMap *fileMap_; 
     SortError *sortError_;
     CollHeap *heap_;    
     NABoolean breakEnabled_;   
};

#endif