hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/snapshot/Snapshot.java - hadoop - Git at Google

 /**
  * 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.hdfs.server.namenode.snapshot;

 import java.io.DataInput;
 import java.io.DataOutput;
 import java.io.IOException;
 import java.text.SimpleDateFormat;
 import java.util.Arrays;
 import java.util.Comparator;
 import java.util.Date;

 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.hdfs.DFSUtil;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants;
 import org.apache.hadoop.hdfs.server.namenode.AclFeature;
 import org.apache.hadoop.hdfs.server.namenode.ContentSummaryComputationContext;
 import org.apache.hadoop.hdfs.server.namenode.FSImageFormat;
 import org.apache.hadoop.hdfs.server.namenode.FSImageSerialization;
 import org.apache.hadoop.hdfs.server.namenode.INode;
 import org.apache.hadoop.hdfs.server.namenode.INodeDirectory;
 import org.apache.hadoop.hdfs.server.namenode.XAttrFeature;
 import org.apache.hadoop.hdfs.util.ReadOnlyList;

 import com.google.common.base.Predicate;
 import com.google.common.collect.Iterables;
 import com.google.common.collect.Lists;
 import org.apache.hadoop.security.AccessControlException;

 /** Snapshot of a sub-tree in the namesystem. */
 @InterfaceAudience.Private
 public class Snapshot implements Comparable<byte[]> {
   /**
    * This id is used to indicate the current state (vs. snapshots)
    */
   public static final int CURRENT_STATE_ID = Integer.MAX_VALUE - 1;
   public static final int NO_SNAPSHOT_ID = -1;

   /**
    * The pattern for generating the default snapshot name.
    * E.g. s20130412-151029.033
    */
   private static final String DEFAULT_SNAPSHOT_NAME_PATTERN = "'s'yyyyMMdd-HHmmss.SSS";

   public static String generateDefaultSnapshotName() {
     return new SimpleDateFormat(DEFAULT_SNAPSHOT_NAME_PATTERN).format(new Date());
   }

   public static String getSnapshotPath(String snapshottableDir,
       String snapshotRelativePath) {
     final StringBuilder b = new StringBuilder(snapshottableDir);
     if (b.charAt(b.length() - 1) != Path.SEPARATOR_CHAR) {
       b.append(Path.SEPARATOR);
     }
     return b.append(HdfsConstants.DOT_SNAPSHOT_DIR)
         .append(Path.SEPARATOR)
         .append(snapshotRelativePath)
         .toString();
   }

   /**
    * Get the name of the given snapshot.
    * @param s The given snapshot.
    * @return The name of the snapshot, or an empty string if {@code s} is null
    */
   static String getSnapshotName(Snapshot s) {
     return s != null ? s.getRoot().getLocalName() : "";
   }

   public static int getSnapshotId(Snapshot s) {
     return s == null ? CURRENT_STATE_ID : s.getId();
   }

   /**
    * Compare snapshot with IDs, where null indicates the current status thus
    * is greater than any non-null snapshot.
    */
   public static final Comparator<Snapshot> ID_COMPARATOR
       = new Comparator<Snapshot>() {
     @Override
     public int compare(Snapshot left, Snapshot right) {
       return ID_INTEGER_COMPARATOR.compare(Snapshot.getSnapshotId(left),
           Snapshot.getSnapshotId(right));
     }
   };

   /**
    * Compare snapshot with IDs, where null indicates the current status thus
    * is greater than any non-null ID.
    */
   public static final Comparator<Integer> ID_INTEGER_COMPARATOR
       = new Comparator<Integer>() {
     @Override
     public int compare(Integer left, Integer right) {
       // Snapshot.CURRENT_STATE_ID means the current state, thus should be the
       // largest
       return left - right;
     }
   };

   /**
    * Find the latest snapshot that 1) covers the given inode (which means the
    * snapshot was either taken on the inode or taken on an ancestor of the
    * inode), and 2) was taken before the given snapshot (if the given snapshot
    * is not null).
    *
    * @param inode the given inode that the returned snapshot needs to cover
    * @param anchor the returned snapshot should be taken before this given id.
    * @return id of the latest snapshot that covers the given inode and was taken
    *         before the the given snapshot (if it is not null).
    */
   public static int findLatestSnapshot(INode inode, final int anchor) {
     int latest = NO_SNAPSHOT_ID;
     for(; inode != null; inode = inode.getParent()) {
       if (inode.isDirectory()) {
         final INodeDirectory dir = inode.asDirectory();
         if (dir.isWithSnapshot()) {
           latest = dir.getDiffs().updatePrior(anchor, latest);
         }
       }
     }
     return latest;
   }

   static Snapshot read(DataInput in, FSImageFormat.Loader loader)
       throws IOException {
     final int snapshotId = in.readInt();
     final INode root = loader.loadINodeWithLocalName(false, in, false);
     return new Snapshot(snapshotId, root.asDirectory(), null);
   }

   /** The root directory of the snapshot. */
   static public class Root extends INodeDirectory {
     Root(INodeDirectory other) {
       // Always preserve ACL, XAttr.
       super(other, false, Lists.newArrayList(
         Iterables.filter(Arrays.asList(other.getFeatures()), new Predicate<Feature>() {

           @Override
           public boolean apply(Feature input) {
             if (AclFeature.class.isInstance(input)
                 || XAttrFeature.class.isInstance(input)) {
               return true;
             }
             return false;
           }

         }))
         .toArray(new Feature[0]));
     }

     @Override
     public ReadOnlyList<INode> getChildrenList(int snapshotId) {
       return getParent().getChildrenList(snapshotId);
     }

     @Override
     public INode getChild(byte[] name, int snapshotId) {
       return getParent().getChild(name, snapshotId);
     }

     @Override
     public ContentSummaryComputationContext computeContentSummary(
         int snapshotId, ContentSummaryComputationContext summary)
         throws AccessControlException {
       return computeDirectoryContentSummary(summary, snapshotId);
     }

     @Override
     public String getFullPathName() {
       return getSnapshotPath(getParent().getFullPathName(), getLocalName());
     }

     /**
      * Get the full path name of the root directory of this snapshot.
      * @return full path to the root directory of the snapshot
      */
     public String getRootFullPathName() {
       return getParent().getFullPathName();
     }
   }

   /** Snapshot ID. */
   private final int id;
   /** The root directory of the snapshot. */
   private final Root root;

   Snapshot(int id, String name, INodeDirectory dir) {
     this(id, dir, dir);
     this.root.setLocalName(DFSUtil.string2Bytes(name));
   }

   Snapshot(int id, INodeDirectory dir, INodeDirectory parent) {
     this.id = id;
     this.root = new Root(dir);
     this.root.setParent(parent);
   }

   public int getId() {
     return id;
   }

   /** @return the root directory of the snapshot. */
   public Root getRoot() {
     return root;
   }

   @Override
   public int compareTo(byte[] bytes) {
     return root.compareTo(bytes);
   }

   @Override
   public boolean equals(Object that) {
     if (this == that) {
       return true;
     } else if (that == null || !(that instanceof Snapshot)) {
       return false;
     }
     return this.id == ((Snapshot)that).id;
   }

   @Override
   public int hashCode() {
     return id;
   }

   @Override
   public String toString() {
     return getClass().getSimpleName() + "." + root.getLocalName() + "(id=" + id + ")";
   }

   /** Serialize the fields to out */
   void write(DataOutput out) throws IOException {
     out.writeInt(id);
     // write root
     FSImageSerialization.writeINodeDirectory(root, out);
   }
 }
	/**
	* 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.hdfs.server.namenode.snapshot;

	import java.io.DataInput;
	import java.io.DataOutput;
	import java.io.IOException;
	import java.text.SimpleDateFormat;
	import java.util.Arrays;
	import java.util.Comparator;
	import java.util.Date;

	import org.apache.hadoop.classification.InterfaceAudience;
	import org.apache.hadoop.fs.Path;
	import org.apache.hadoop.hdfs.DFSUtil;
	import org.apache.hadoop.hdfs.protocol.HdfsConstants;
	import org.apache.hadoop.hdfs.server.namenode.AclFeature;
	import org.apache.hadoop.hdfs.server.namenode.ContentSummaryComputationContext;
	import org.apache.hadoop.hdfs.server.namenode.FSImageFormat;
	import org.apache.hadoop.hdfs.server.namenode.FSImageSerialization;
	import org.apache.hadoop.hdfs.server.namenode.INode;
	import org.apache.hadoop.hdfs.server.namenode.INodeDirectory;
	import org.apache.hadoop.hdfs.server.namenode.XAttrFeature;
	import org.apache.hadoop.hdfs.util.ReadOnlyList;

	import com.google.common.base.Predicate;
	import com.google.common.collect.Iterables;
	import com.google.common.collect.Lists;
	import org.apache.hadoop.security.AccessControlException;

	/** Snapshot of a sub-tree in the namesystem. */
	@InterfaceAudience.Private
	public class Snapshot implements Comparable<byte[]> {
	/**
	* This id is used to indicate the current state (vs. snapshots)
	*/
	public static final int CURRENT_STATE_ID = Integer.MAX_VALUE - 1;
	public static final int NO_SNAPSHOT_ID = -1;

	/**
	* The pattern for generating the default snapshot name.
	* E.g. s20130412-151029.033
	*/
	private static final String DEFAULT_SNAPSHOT_NAME_PATTERN = "'s'yyyyMMdd-HHmmss.SSS";

	public static String generateDefaultSnapshotName() {
	return new SimpleDateFormat(DEFAULT_SNAPSHOT_NAME_PATTERN).format(new Date());
	}

	public static String getSnapshotPath(String snapshottableDir,
	String snapshotRelativePath) {
	final StringBuilder b = new StringBuilder(snapshottableDir);
	if (b.charAt(b.length() - 1) != Path.SEPARATOR_CHAR) {
	b.append(Path.SEPARATOR);
	}
	return b.append(HdfsConstants.DOT_SNAPSHOT_DIR)
	.append(Path.SEPARATOR)
	.append(snapshotRelativePath)
	.toString();
	}

	/**
	* Get the name of the given snapshot.
	* @param s The given snapshot.
	* @return The name of the snapshot, or an empty string if {@code s} is null
	*/
	static String getSnapshotName(Snapshot s) {
	return s != null ? s.getRoot().getLocalName() : "";
	}

	public static int getSnapshotId(Snapshot s) {
	return s == null ? CURRENT_STATE_ID : s.getId();
	}

	/**
	* Compare snapshot with IDs, where null indicates the current status thus
	* is greater than any non-null snapshot.
	*/
	public static final Comparator<Snapshot> ID_COMPARATOR
	= new Comparator<Snapshot>() {
	@Override
	public int compare(Snapshot left, Snapshot right) {
	return ID_INTEGER_COMPARATOR.compare(Snapshot.getSnapshotId(left),
	Snapshot.getSnapshotId(right));
	}
	};

	/**
	* Compare snapshot with IDs, where null indicates the current status thus
	* is greater than any non-null ID.
	*/
	public static final Comparator<Integer> ID_INTEGER_COMPARATOR
	= new Comparator<Integer>() {
	@Override
	public int compare(Integer left, Integer right) {
	// Snapshot.CURRENT_STATE_ID means the current state, thus should be the
	// largest
	return left - right;
	}
	};

	/**
	* Find the latest snapshot that 1) covers the given inode (which means the
	* snapshot was either taken on the inode or taken on an ancestor of the
	* inode), and 2) was taken before the given snapshot (if the given snapshot
	* is not null).
	*
	* @param inode the given inode that the returned snapshot needs to cover
	* @param anchor the returned snapshot should be taken before this given id.
	* @return id of the latest snapshot that covers the given inode and was taken
	* before the the given snapshot (if it is not null).
	*/
	public static int findLatestSnapshot(INode inode, final int anchor) {
	int latest = NO_SNAPSHOT_ID;
	for(; inode != null; inode = inode.getParent()) {
	if (inode.isDirectory()) {
	final INodeDirectory dir = inode.asDirectory();
	if (dir.isWithSnapshot()) {
	latest = dir.getDiffs().updatePrior(anchor, latest);
	}
	}
	}
	return latest;
	}

	static Snapshot read(DataInput in, FSImageFormat.Loader loader)
	throws IOException {
	final int snapshotId = in.readInt();
	final INode root = loader.loadINodeWithLocalName(false, in, false);
	return new Snapshot(snapshotId, root.asDirectory(), null);
	}

	/** The root directory of the snapshot. */
	static public class Root extends INodeDirectory {
	Root(INodeDirectory other) {
	// Always preserve ACL, XAttr.
	super(other, false, Lists.newArrayList(
	Iterables.filter(Arrays.asList(other.getFeatures()), new Predicate<Feature>() {

	@Override
	public boolean apply(Feature input) {
	if (AclFeature.class.isInstance(input)
	\|\| XAttrFeature.class.isInstance(input)) {
	return true;
	}
	return false;
	}

	}))
	.toArray(new Feature[0]));
	}

	@Override
	public ReadOnlyList<INode> getChildrenList(int snapshotId) {
	return getParent().getChildrenList(snapshotId);
	}

	@Override
	public INode getChild(byte[] name, int snapshotId) {
	return getParent().getChild(name, snapshotId);
	}

	@Override
	public ContentSummaryComputationContext computeContentSummary(
	int snapshotId, ContentSummaryComputationContext summary)
	throws AccessControlException {
	return computeDirectoryContentSummary(summary, snapshotId);
	}

	@Override
	public String getFullPathName() {
	return getSnapshotPath(getParent().getFullPathName(), getLocalName());
	}

	/**
	* Get the full path name of the root directory of this snapshot.
	* @return full path to the root directory of the snapshot
	*/
	public String getRootFullPathName() {
	return getParent().getFullPathName();
	}
	}

	/** Snapshot ID. */
	private final int id;
	/** The root directory of the snapshot. */
	private final Root root;

	Snapshot(int id, String name, INodeDirectory dir) {
	this(id, dir, dir);
	this.root.setLocalName(DFSUtil.string2Bytes(name));
	}

	Snapshot(int id, INodeDirectory dir, INodeDirectory parent) {
	this.id = id;
	this.root = new Root(dir);
	this.root.setParent(parent);
	}

	public int getId() {
	return id;
	}

	/** @return the root directory of the snapshot. */
	public Root getRoot() {
	return root;
	}

	@Override
	public int compareTo(byte[] bytes) {
	return root.compareTo(bytes);
	}

	@Override
	public boolean equals(Object that) {
	if (this == that) {
	return true;
	} else if (that == null \|\| !(that instanceof Snapshot)) {
	return false;
	}
	return this.id == ((Snapshot)that).id;
	}

	@Override
	public int hashCode() {
	return id;
	}

	@Override
	public String toString() {
	return getClass().getSimpleName() + "." + root.getLocalName() + "(id=" + id + ")";
	}

	/** Serialize the fields to out */
	void write(DataOutput out) throws IOException {
	out.writeInt(id);
	// write root
	FSImageSerialization.writeINodeDirectory(root, out);
	}
	}