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