001    /**
002     * Licensed to the Apache Software Foundation (ASF) under one
003     * or more contributor license agreements.  See the NOTICE file
004     * distributed with this work for additional information
005     * regarding copyright ownership.  The ASF licenses this file
006     * to you under the Apache License, Version 2.0 (the
007     * "License"); you may not use this file except in compliance
008     * with the License.  You may obtain a copy of the License at
009     *
010     *     http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing, software
013     * distributed under the License is distributed on an "AS IS" BASIS,
014     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015     * See the License for the specific language governing permissions and
016     * limitations under the License.
017     */
018    package org.apache.hadoop.hdfs.server.namenode.snapshot;
019    
020    import java.io.DataOutput;
021    import java.io.IOException;
022    import java.util.List;
023    
024    import org.apache.hadoop.hdfs.server.namenode.FSImageSerialization;
025    import org.apache.hadoop.hdfs.server.namenode.INode;
026    import org.apache.hadoop.hdfs.server.namenode.INode.BlocksMapUpdateInfo;
027    import org.apache.hadoop.hdfs.server.namenode.INodeFile;
028    import org.apache.hadoop.hdfs.server.namenode.INodeFileAttributes;
029    import org.apache.hadoop.hdfs.server.namenode.Quota;
030    import org.apache.hadoop.hdfs.server.namenode.snapshot.SnapshotFSImageFormat.ReferenceMap;
031    
032    /**
033     * The difference of an {@link INodeFile} between two snapshots.
034     */
035    public class FileDiff extends
036        AbstractINodeDiff<INodeFile, INodeFileAttributes, FileDiff> {
037    
038      /** The file size at snapshot creation time. */
039      private final long fileSize;
040    
041      FileDiff(int snapshotId, INodeFile file) {
042        super(snapshotId, null, null);
043        fileSize = file.computeFileSize();
044      }
045    
046      /** Constructor used by FSImage loading */
047      FileDiff(int snapshotId, INodeFileAttributes snapshotINode,
048          FileDiff posteriorDiff, long fileSize) {
049        super(snapshotId, snapshotINode, posteriorDiff);
050        this.fileSize = fileSize;
051      }
052    
053      /** @return the file size in the snapshot. */
054      public long getFileSize() {
055        return fileSize;
056      }
057      
058      @Override
059      Quota.Counts combinePosteriorAndCollectBlocks(INodeFile currentINode,
060          FileDiff posterior, BlocksMapUpdateInfo collectedBlocks,
061          final List<INode> removedINodes) {
062        return currentINode.getFileWithSnapshotFeature()
063            .updateQuotaAndCollectBlocks(currentINode, posterior, collectedBlocks,
064                removedINodes);
065      }
066      
067      @Override
068      public String toString() {
069        return super.toString() + " fileSize=" + fileSize + ", rep="
070            + (snapshotINode == null? "?": snapshotINode.getFileReplication());
071      }
072    
073      @Override
074      void write(DataOutput out, ReferenceMap referenceMap) throws IOException {
075        writeSnapshot(out);
076        out.writeLong(fileSize);
077    
078        // write snapshotINode
079        if (snapshotINode != null) {
080          out.writeBoolean(true);
081          FSImageSerialization.writeINodeFileAttributes(snapshotINode, out);
082        } else {
083          out.writeBoolean(false);
084        }
085      }
086    
087      @Override
088      Quota.Counts destroyDiffAndCollectBlocks(INodeFile currentINode,
089          BlocksMapUpdateInfo collectedBlocks, final List<INode> removedINodes) {
090        return currentINode.getFileWithSnapshotFeature()
091            .updateQuotaAndCollectBlocks(currentINode, this, collectedBlocks,
092                removedINodes);
093      }
094    }