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 */
018package org.apache.hadoop.hdfs.server.namenode;
019
020import java.util.Iterator;
021import java.util.List;
022
023import org.apache.hadoop.fs.permission.FsPermission;
024import org.apache.hadoop.fs.permission.PermissionStatus;
025import org.apache.hadoop.hdfs.protocol.BlockStoragePolicy;
026import org.apache.hadoop.hdfs.protocol.QuotaExceededException;
027import org.apache.hadoop.hdfs.server.blockmanagement.BlockStoragePolicySuite;
028import org.apache.hadoop.hdfs.server.namenode.Quota.Counts;
029import org.apache.hadoop.util.GSet;
030import org.apache.hadoop.util.LightWeightGSet;
031
032import com.google.common.base.Preconditions;
033
034/**
035 * Storing all the {@link INode}s and maintaining the mapping between INode ID
036 * and INode.  
037 */
038public class INodeMap {
039  
040  static INodeMap newInstance(INodeDirectory rootDir) {
041    // Compute the map capacity by allocating 1% of total memory
042    int capacity = LightWeightGSet.computeCapacity(1, "INodeMap");
043    GSet<INode, INodeWithAdditionalFields> map
044        = new LightWeightGSet<INode, INodeWithAdditionalFields>(capacity);
045    map.put(rootDir);
046    return new INodeMap(map);
047  }
048  
049  /** Synchronized by external lock. */
050  private final GSet<INode, INodeWithAdditionalFields> map;
051  
052  public Iterator<INodeWithAdditionalFields> getMapIterator() {
053    return map.iterator();
054  }
055
056  private INodeMap(GSet<INode, INodeWithAdditionalFields> map) {
057    Preconditions.checkArgument(map != null);
058    this.map = map;
059  }
060  
061  /**
062   * Add an {@link INode} into the {@link INode} map. Replace the old value if 
063   * necessary. 
064   * @param inode The {@link INode} to be added to the map.
065   */
066  public final void put(INode inode) {
067    if (inode instanceof INodeWithAdditionalFields) {
068      map.put((INodeWithAdditionalFields)inode);
069    }
070  }
071  
072  /**
073   * Remove a {@link INode} from the map.
074   * @param inode The {@link INode} to be removed.
075   */
076  public final void remove(INode inode) {
077    map.remove(inode);
078  }
079  
080  /**
081   * @return The size of the map.
082   */
083  public int size() {
084    return map.size();
085  }
086  
087  /**
088   * Get the {@link INode} with the given id from the map.
089   * @param id ID of the {@link INode}.
090   * @return The {@link INode} in the map with the given id. Return null if no 
091   *         such {@link INode} in the map.
092   */
093  public INode get(long id) {
094    INode inode = new INodeWithAdditionalFields(id, null, new PermissionStatus(
095        "", "", new FsPermission((short) 0)), 0, 0) {
096      
097      @Override
098      void recordModification(int latestSnapshotId)
099          throws QuotaExceededException {
100      }
101      
102      @Override
103      public void destroyAndCollectBlocks(BlocksMapUpdateInfo collectedBlocks,
104          List<INode> removedINodes) {
105        // Nothing to do
106      }
107      
108      @Override
109      public Counts computeQuotaUsage(Counts counts, boolean useCache,
110          int lastSnapshotId) {
111        return null;
112      }
113      
114      @Override
115      public ContentSummaryComputationContext computeContentSummary(
116          ContentSummaryComputationContext summary) {
117        return null;
118      }
119      
120      @Override
121      public Counts cleanSubtree(int snapshotId, int priorSnapshotId,
122          BlocksMapUpdateInfo collectedBlocks, List<INode> removedINodes,
123          boolean countDiffChange) throws QuotaExceededException {
124        return null;
125      }
126
127      @Override
128      public byte getStoragePolicyID(){
129        return BlockStoragePolicySuite.ID_UNSPECIFIED;
130      }
131
132      @Override
133      public byte getLocalStoragePolicyID() {
134        return BlockStoragePolicySuite.ID_UNSPECIFIED;
135      }
136    };
137      
138    return map.get(inode);
139  }
140  
141  /**
142   * Clear the {@link #map}
143   */
144  public void clear() {
145    map.clear();
146  }
147}