/**
    * 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.
   */
  package org.apache.hadoop.hbase.regionserver.querymatcher;
  
  import java.io.IOException;
  
  import org.apache.hadoop.hbase.Cell;
  import org.apache.hadoop.hbase.HConstants;
  import org.apache.hadoop.hbase.KeepDeletedCells;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.filter.Filter;
  import org.apache.hadoop.hbase.regionserver.DeleteTracker;
  import org.apache.hadoop.hbase.regionserver.RegionCoprocessorHost;
  import org.apache.hadoop.hbase.regionserver.ScanInfo;
  import org.apache.hadoop.hbase.regionserver.ScanType;
  
  /**
   * Query matcher for compaction.
   */
  @InterfaceAudience.Private
  public abstract class CompactionScanQueryMatcher extends ScanQueryMatcher {
  
    /** readPoint over which the KVs are unconditionally included */
    protected final long maxReadPointToTrackVersions;
  
    /** Keeps track of deletes */
    protected final DeleteTracker deletes;
  
    /** whether to return deleted rows */
    protected final KeepDeletedCells keepDeletedCells;
  
    protected CompactionScanQueryMatcher(ScanInfo scanInfo, DeleteTracker deletes,
        long readPointToUse, long oldestUnexpiredTS, long now) {
      super(createStartKeyFromRow(HConstants.EMPTY_START_ROW, scanInfo), scanInfo,
          new ScanWildcardColumnTracker(scanInfo.getMinVersions(), scanInfo.getMaxVersions(),
              oldestUnexpiredTS),
          oldestUnexpiredTS, now);
      this.maxReadPointToTrackVersions = readPointToUse;
      this.deletes = deletes;
      this.keepDeletedCells = scanInfo.getKeepDeletedCells();
    }
  
    @Override
    public boolean hasNullColumnInQuery() {
      return true;
    }
  
    @Override
    public boolean isUserScan() {
      return false;
    }
  
    @Override
    public boolean moreRowsMayExistAfter(Cell cell) {
      return true;
    }
  
    @Override
    public Filter getFilter() {
      // no filter when compaction
      return null;
    }
  
    @Override
    public Cell getNextKeyHint(Cell cell) throws IOException {
      // no filter, so no key hint.
      return null;
    }
  
    @Override
    protected void reset() {
      deletes.reset();
    }
  
    protected final void trackDelete(Cell cell) {
      // If keepDeletedCells is true, then we only remove cells by versions or TTL during
      // compaction, so we do not need to track delete here.
      // If keepDeletedCells is TTL and the delete marker is expired, then we can make sure that the
      // minVerions is larger than 0(otherwise we will just return at preCheck). So here we still
      // need to track the delete marker to see if it masks some cells.
      if (keepDeletedCells == KeepDeletedCells.FALSE
          || (keepDeletedCells == KeepDeletedCells.TTL && cell.getTimestamp() < oldestUnexpiredTS)) {
        deletes.add(cell);
      }
   }
 
   public static CompactionScanQueryMatcher create(ScanInfo scanInfo, ScanType scanType,
       long readPointToUse, long earliestPutTs, long oldestUnexpiredTS, long now,
       byte[] dropDeletesFromRow, byte[] dropDeletesToRow,
       RegionCoprocessorHost regionCoprocessorHost) throws IOException {
     DeleteTracker deleteTracker = instantiateDeleteTracker(regionCoprocessorHost);
     if (dropDeletesFromRow == null) {
       if (scanType == ScanType.COMPACT_RETAIN_DELETES) {
         return new MinorCompactionScanQueryMatcher(scanInfo, deleteTracker, readPointToUse,
             oldestUnexpiredTS, now);
       } else {
         return new MajorCompactionScanQueryMatcher(scanInfo, deleteTracker, readPointToUse,
             earliestPutTs, oldestUnexpiredTS, now);
       }
     } else {
       return new StripeCompactionScanQueryMatcher(scanInfo, deleteTracker, readPointToUse,
           earliestPutTs, oldestUnexpiredTS, now, dropDeletesFromRow, dropDeletesToRow);
     }
   }
 }