/**
    * 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.snapshot;
  
  import static org.junit.Assert.assertEquals;
  import static org.junit.Assert.assertFalse;
  import static org.junit.Assert.assertTrue;
  
  import java.io.IOException;
  import java.util.Collections;
  import java.util.ArrayList;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  import java.util.TreeSet;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.fs.FSDataOutputStream;
  import org.apache.hadoop.fs.FileSystem;
  import org.apache.hadoop.fs.FileStatus;
  import org.apache.hadoop.fs.FSDataInputStream;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.fs.PathFilter;
  import org.apache.hadoop.hbase.HBaseTestingUtility;
  import org.apache.hadoop.hbase.HColumnDescriptor;
  import org.apache.hadoop.hbase.HConstants;
  import org.apache.hadoop.hbase.HRegionInfo;
  import org.apache.hadoop.hbase.HTableDescriptor;
  import org.apache.hadoop.hbase.TableName;
  import org.apache.hadoop.hbase.TableNotEnabledException;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.client.Admin;
  import org.apache.hadoop.hbase.client.BufferedMutator;
  import org.apache.hadoop.hbase.client.Durability;
  import org.apache.hadoop.hbase.client.HTable;
  import org.apache.hadoop.hbase.client.Put;
  import org.apache.hadoop.hbase.client.Table;
  import org.apache.hadoop.hbase.errorhandling.ForeignExceptionDispatcher;
  import org.apache.hadoop.hbase.client.RegionReplicaUtil;
  import org.apache.hadoop.hbase.io.HFileLink;
  import org.apache.hadoop.hbase.master.HMaster;
  import org.apache.hadoop.hbase.master.MasterFileSystem;
  import org.apache.hadoop.hbase.protobuf.ProtobufUtil;
  import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.SnapshotDescription;
  import org.apache.hadoop.hbase.protobuf.generated.SnapshotProtos.SnapshotRegionManifest;
  import org.apache.hadoop.hbase.protobuf.generated.MasterProtos.IsSnapshotDoneRequest;
  import org.apache.hadoop.hbase.protobuf.generated.MasterProtos.IsSnapshotDoneResponse;
  import org.apache.hadoop.hbase.regionserver.HRegionFileSystem;
  import org.apache.hadoop.hbase.regionserver.HRegionServer;
  import org.apache.hadoop.hbase.regionserver.Region;
  import org.apache.hadoop.hbase.util.Bytes;
  import org.apache.hadoop.hbase.util.FSTableDescriptors;
  import org.apache.hadoop.hbase.util.FSVisitor;
  import org.apache.hadoop.hbase.util.FSUtils;
  import org.apache.hadoop.hbase.util.MD5Hash;
  import org.junit.Assert;
  
  import com.google.protobuf.ServiceException;
  
  /**
   * Utilities class for snapshots
   */
  @InterfaceAudience.Private
  public final class SnapshotTestingUtils {
  
    private static final Log LOG = LogFactory.getLog(SnapshotTestingUtils.class);
    private static byte[] KEYS = Bytes.toBytes("0123456789");
  
    private SnapshotTestingUtils() {
      // private constructor for utility class
    }
  
    /**
     * Assert that we don't have any snapshots lists
     *
     * @throws IOException
     *           if the admin operation fails
     */
    public static void assertNoSnapshots(Admin admin) throws IOException {
      assertEquals("Have some previous snapshots", 0, admin.listSnapshots()
          .size());
   }
 
   /**
    * Make sure that there is only one snapshot returned from the master and its
    * name and table match the passed in parameters.
    */
   public static List<SnapshotDescription> assertExistsMatchingSnapshot(
       Admin admin, String snapshotName, TableName tableName)
       throws IOException {
     // list the snapshot
     List<SnapshotDescription> snapshots = admin.listSnapshots();
 
     List<SnapshotDescription> returnedSnapshots = new ArrayList<SnapshotDescription>();
     for (SnapshotDescription sd : snapshots) {
       if (snapshotName.equals(sd.getName()) &&
           tableName.equals(TableName.valueOf(sd.getTable()))) {
         returnedSnapshots.add(sd);
       }
     }
 
     Assert.assertTrue("No matching snapshots found.", returnedSnapshots.size()>0);
     return returnedSnapshots;
   }
 
   /**
    * Make sure that there is only one snapshot returned from the master
    */
   public static void assertOneSnapshotThatMatches(Admin admin,
       SnapshotDescription snapshot) throws IOException {
     assertOneSnapshotThatMatches(admin, snapshot.getName(),
         TableName.valueOf(snapshot.getTable()));
   }
 
   /**
    * Make sure that there is only one snapshot returned from the master and its
    * name and table match the passed in parameters.
    */
   public static List<SnapshotDescription> assertOneSnapshotThatMatches(
       Admin admin, String snapshotName, TableName tableName)
       throws IOException {
     // list the snapshot
     List<SnapshotDescription> snapshots = admin.listSnapshots();
 
     assertEquals("Should only have 1 snapshot", 1, snapshots.size());
     assertEquals(snapshotName, snapshots.get(0).getName());
     assertEquals(tableName, TableName.valueOf(snapshots.get(0).getTable()));
 
     return snapshots;
   }
 
   /**
    * Make sure that there is only one snapshot returned from the master and its
    * name and table match the passed in parameters.
    */
   public static List<SnapshotDescription> assertOneSnapshotThatMatches(
       Admin admin, byte[] snapshot, TableName tableName) throws IOException {
     return assertOneSnapshotThatMatches(admin, Bytes.toString(snapshot),
         tableName);
   }
 
   public static void confirmSnapshotValid(HBaseTestingUtility testUtil,
       SnapshotDescription snapshotDescriptor, TableName tableName, byte[] family)
       throws IOException {
     MasterFileSystem mfs = testUtil.getHBaseCluster().getMaster().getMasterFileSystem();
     confirmSnapshotValid(snapshotDescriptor, tableName, family,
         mfs.getRootDir(), testUtil.getHBaseAdmin(), mfs.getFileSystem());
   }
 
   /**
    * Confirm that the snapshot contains references to all the files that should
    * be in the snapshot.
    */
   public static void confirmSnapshotValid(
       SnapshotDescription snapshotDescriptor, TableName tableName,
       byte[] testFamily, Path rootDir, Admin admin, FileSystem fs)
       throws IOException {
     ArrayList nonEmptyTestFamilies = new ArrayList(1);
     nonEmptyTestFamilies.add(testFamily);
     confirmSnapshotValid(snapshotDescriptor, tableName,
       nonEmptyTestFamilies, null, rootDir, admin, fs);
   }
 
   /**
    * Confirm that the snapshot has no references files but only metadata.
    */
   public static void confirmEmptySnapshotValid(
       SnapshotDescription snapshotDescriptor, TableName tableName,
       byte[] testFamily, Path rootDir, Admin admin, FileSystem fs)
       throws IOException {
     ArrayList emptyTestFamilies = new ArrayList(1);
     emptyTestFamilies.add(testFamily);
     confirmSnapshotValid(snapshotDescriptor, tableName,
       null, emptyTestFamilies, rootDir, admin, fs);
   }
 
   /**
    * Confirm that the snapshot contains references to all the files that should
    * be in the snapshot. This method also perform some redundant check like
    * the existence of the snapshotinfo or the regioninfo which are done always
    * by the MasterSnapshotVerifier, at the end of the snapshot operation.
    */
   public static void confirmSnapshotValid(
       SnapshotDescription snapshotDescriptor, TableName tableName,
       List<byte[]> nonEmptyTestFamilies, List<byte[]> emptyTestFamilies,
       Path rootDir, Admin admin, FileSystem fs) throws IOException {
     final Configuration conf = admin.getConfiguration();
 
     // check snapshot dir
     Path snapshotDir = SnapshotDescriptionUtils.getCompletedSnapshotDir(
         snapshotDescriptor, rootDir);
     assertTrue(fs.exists(snapshotDir));
 
     SnapshotDescription desc = SnapshotDescriptionUtils.readSnapshotInfo(fs, snapshotDir);
 
     // Extract regions and families with store files
     final Set<byte[]> snapshotFamilies = new TreeSet<byte[]>(Bytes.BYTES_COMPARATOR);
 
     SnapshotManifest manifest = SnapshotManifest.open(conf, fs, snapshotDir, desc);
     Map<String, SnapshotRegionManifest> regionManifests = manifest.getRegionManifestsMap();
     for (SnapshotRegionManifest regionManifest: regionManifests.values()) {
       SnapshotReferenceUtil.visitRegionStoreFiles(regionManifest,
           new SnapshotReferenceUtil.StoreFileVisitor() {
         @Override
         public void storeFile(final HRegionInfo regionInfo, final String family,
               final SnapshotRegionManifest.StoreFile storeFile) throws IOException {
           snapshotFamilies.add(Bytes.toBytes(family));
         }
       });
     }
 
     // Verify that there are store files in the specified families
     if (nonEmptyTestFamilies != null) {
       for (final byte[] familyName: nonEmptyTestFamilies) {
         assertTrue(snapshotFamilies.contains(familyName));
       }
     }
 
     // Verify that there are no store files in the specified families
     if (emptyTestFamilies != null) {
       for (final byte[] familyName: emptyTestFamilies) {
         assertFalse(snapshotFamilies.contains(familyName));
       }
     }
 
     // check the region snapshot for all the regions
     List<HRegionInfo> regions = admin.getTableRegions(tableName);
     // remove the non-default regions
     RegionReplicaUtil.removeNonDefaultRegions(regions);
     assertEquals(regions.size(), regionManifests.size());
 
     // Verify Regions (redundant check, see MasterSnapshotVerifier)
     for (HRegionInfo info : regions) {
       String regionName = info.getEncodedName();
       assertTrue(regionManifests.containsKey(regionName));
     }
   }
 
   /**
    * Helper method for testing async snapshot operations. Just waits for the
    * given snapshot to complete on the server by repeatedly checking the master.
    *
    * @param master: the master running the snapshot
    * @param snapshot: the snapshot to check
    * @param sleep: amount to sleep between checks to see if the snapshot is done
    * @throws ServiceException if the snapshot fails
    */
   public static void waitForSnapshotToComplete(HMaster master,
       SnapshotDescription snapshot, long sleep) throws ServiceException {
     final IsSnapshotDoneRequest request = IsSnapshotDoneRequest.newBuilder()
         .setSnapshot(snapshot).build();
     IsSnapshotDoneResponse done = IsSnapshotDoneResponse.newBuilder()
         .buildPartial();
     while (!done.getDone()) {
       done = master.getMasterRpcServices().isSnapshotDone(null, request);
       try {
         Thread.sleep(sleep);
       } catch (InterruptedException e) {
         throw new ServiceException(e);
       }
     }
   }
 
   /*
    * Take snapshot with maximum of numTries attempts, ignoring CorruptedSnapshotException
    * except for the last CorruptedSnapshotException
    */
   public static void snapshot(Admin admin,
       final String snapshotName, final String tableName,
       SnapshotDescription.Type type, int numTries) throws IOException {
     int tries = 0;
     CorruptedSnapshotException lastEx = null;
     while (tries++ < numTries) {
       try {
         admin.snapshot(snapshotName, TableName.valueOf(tableName), type);
         return;
       } catch (CorruptedSnapshotException cse) {
         LOG.warn("Got CorruptedSnapshotException", cse);
         lastEx = cse;
       }
     }
     throw lastEx;
   }
 
   public static void cleanupSnapshot(Admin admin, byte[] tableName)
       throws IOException {
     SnapshotTestingUtils.cleanupSnapshot(admin, Bytes.toString(tableName));
   }
 
   public static void cleanupSnapshot(Admin admin, String snapshotName)
       throws IOException {
     // delete the taken snapshot
     admin.deleteSnapshot(snapshotName);
     assertNoSnapshots(admin);
   }
 
   /**
    * Expect the snapshot to throw an error when checking if the snapshot is
    * complete
    *
    * @param master master to check
    * @param snapshot the {@link SnapshotDescription} request to pass to the master
    * @param clazz expected exception from the master
    */
   public static void expectSnapshotDoneException(HMaster master,
       IsSnapshotDoneRequest snapshot,
       Class<? extends HBaseSnapshotException> clazz) {
     try {
       master.getMasterRpcServices().isSnapshotDone(null, snapshot);
       Assert.fail("didn't fail to lookup a snapshot");
     } catch (ServiceException se) {
       try {
         throw ProtobufUtil.getRemoteException(se);
       } catch (HBaseSnapshotException e) {
         assertEquals("Threw wrong snapshot exception!", clazz, e.getClass());
       } catch (Throwable t) {
         Assert.fail("Threw an unexpected exception:" + t);
       }
     }
   }
 
   /**
    * List all the HFiles in the given table
    *
    * @param fs: FileSystem where the table lives
    * @param tableDir directory of the table
    * @return array of the current HFiles in the table (could be a zero-length array)
    * @throws IOException on unexecpted error reading the FS
    */
   public static ArrayList<String> listHFileNames(final FileSystem fs, final Path tableDir)
       throws IOException {
     final ArrayList<String> hfiles = new ArrayList<String>();
     FSVisitor.visitTableStoreFiles(fs, tableDir, new FSVisitor.StoreFileVisitor() {
       @Override
       public void storeFile(final String region, final String family, final String hfileName)
           throws IOException {
         hfiles.add(hfileName);
       }
     });
     Collections.sort(hfiles);
     return hfiles;
   }
 
   /**
    * Take a snapshot of the specified table and verify that the given family is
    * not empty. Note that this will leave the table disabled
    * in the case of an offline snapshot.
    */
   public static void createSnapshotAndValidate(Admin admin,
       TableName tableName, String familyName, String snapshotNameString,
       Path rootDir, FileSystem fs, boolean onlineSnapshot)
       throws Exception {
     ArrayList<byte[]> nonEmptyFamilyNames = new ArrayList<byte[]>(1);
     nonEmptyFamilyNames.add(Bytes.toBytes(familyName));
     createSnapshotAndValidate(admin, tableName, nonEmptyFamilyNames, /* emptyFamilyNames= */ null,
                               snapshotNameString, rootDir, fs, onlineSnapshot);
   }
 
   /**
    * Take a snapshot of the specified table and verify the given families.
    * Note that this will leave the table disabled in the case of an offline snapshot.
    */
   public static void createSnapshotAndValidate(Admin admin,
       TableName tableName, List<byte[]> nonEmptyFamilyNames, List<byte[]> emptyFamilyNames,
       String snapshotNameString, Path rootDir, FileSystem fs, boolean onlineSnapshot)
         throws Exception {
     if (!onlineSnapshot) {
       try {
         admin.disableTable(tableName);
       } catch (TableNotEnabledException tne) {
         LOG.info("In attempting to disable " + tableName + " it turns out that the this table is " +
             "already disabled.");
       }
     }
     admin.snapshot(snapshotNameString, tableName);
 
     List<SnapshotDescription> snapshots = SnapshotTestingUtils.assertExistsMatchingSnapshot(admin,
       snapshotNameString, tableName);
     if (snapshots == null || snapshots.size() != 1) {
       Assert.fail("Incorrect number of snapshots for table " + tableName);
     }
 
     SnapshotTestingUtils.confirmSnapshotValid(snapshots.get(0), tableName, nonEmptyFamilyNames,
       emptyFamilyNames, rootDir, admin, fs);
   }
 
   /**
    * Corrupt the specified snapshot by deleting some files.
    *
    * @param util {@link HBaseTestingUtility}
    * @param snapshotName name of the snapshot to corrupt
    * @return array of the corrupted HFiles
    * @throws IOException on unexecpted error reading the FS
    */
   public static ArrayList corruptSnapshot(final HBaseTestingUtility util, final String snapshotName)
       throws IOException {
     final MasterFileSystem mfs = util.getHBaseCluster().getMaster().getMasterFileSystem();
     final FileSystem fs = mfs.getFileSystem();
 
     Path snapshotDir = SnapshotDescriptionUtils.getCompletedSnapshotDir(snapshotName,
                                                                         mfs.getRootDir());
     SnapshotDescription snapshotDesc = SnapshotDescriptionUtils.readSnapshotInfo(fs, snapshotDir);
     final TableName table = TableName.valueOf(snapshotDesc.getTable());
 
     final ArrayList corruptedFiles = new ArrayList();
     final Configuration conf = util.getConfiguration();
     SnapshotReferenceUtil.visitTableStoreFiles(conf, fs, snapshotDir, snapshotDesc,
         new SnapshotReferenceUtil.StoreFileVisitor() {
       @Override
       public void storeFile(final HRegionInfo regionInfo, final String family,
             final SnapshotRegionManifest.StoreFile storeFile) throws IOException {
         String region = regionInfo.getEncodedName();
         String hfile = storeFile.getName();
         HFileLink link = HFileLink.build(conf, table, region, family, hfile);
         if (corruptedFiles.size() % 2 == 0) {
           fs.delete(link.getAvailablePath(fs), true);
           corruptedFiles.add(hfile);
         }
       }
     });
 
     assertTrue(corruptedFiles.size() > 0);
     return corruptedFiles;
   }
 
   // ==========================================================================
   //  Snapshot Mock
   // ==========================================================================
   public static class SnapshotMock {
     private final static String TEST_FAMILY = "cf";
     public final static int TEST_NUM_REGIONS = 4;
 
     private final Configuration conf;
     private final FileSystem fs;
     private final Path rootDir;
 
     static class RegionData {
       public HRegionInfo hri;
       public Path tableDir;
       public Path[] files;
 
       public RegionData(final Path tableDir, final HRegionInfo hri, final int nfiles) {
         this.tableDir = tableDir;
         this.hri = hri;
         this.files = new Path[nfiles];
       }
     }
 
     public static class SnapshotBuilder {
       private final RegionData[] tableRegions;
       private final SnapshotDescription desc;
       private final HTableDescriptor htd;
       private final Configuration conf;
       private final FileSystem fs;
       private final Path rootDir;
       private Path snapshotDir;
       private int snapshotted = 0;
 
       public SnapshotBuilder(final Configuration conf, final FileSystem fs,
           final Path rootDir, final HTableDescriptor htd,
           final SnapshotDescription desc, final RegionData[] tableRegions)
           throws IOException {
         this.fs = fs;
         this.conf = conf;
         this.rootDir = rootDir;
         this.htd = htd;
         this.desc = desc;
         this.tableRegions = tableRegions;
         this.snapshotDir = SnapshotDescriptionUtils.getWorkingSnapshotDir(desc, rootDir);
         new FSTableDescriptors(conf)
           .createTableDescriptorForTableDirectory(snapshotDir, htd, false);
       }
 
       public HTableDescriptor getTableDescriptor() {
         return this.htd;
       }
 
       public SnapshotDescription getSnapshotDescription() {
         return this.desc;
       }
 
       public Path getSnapshotsDir() {
         return this.snapshotDir;
       }
 
       public Path[] addRegion() throws IOException {
         return addRegion(desc);
       }
 
       public Path[] addRegionV1() throws IOException {
         return addRegion(desc.toBuilder()
                           .setVersion(SnapshotManifestV1.DESCRIPTOR_VERSION)
                           .build());
       }
 
       public Path[] addRegionV2() throws IOException {
         return addRegion(desc.toBuilder()
                           .setVersion(SnapshotManifestV2.DESCRIPTOR_VERSION)
                           .build());
       }
 
       private Path[] addRegion(final SnapshotDescription desc) throws IOException {
         if (this.snapshotted == tableRegions.length) {
           throw new UnsupportedOperationException("No more regions in the table");
         }
 
         RegionData regionData = tableRegions[this.snapshotted++];
         ForeignExceptionDispatcher monitor = new ForeignExceptionDispatcher(desc.getName());
         SnapshotManifest manifest = SnapshotManifest.create(conf, fs, snapshotDir, desc, monitor);
         manifest.addRegion(regionData.tableDir, regionData.hri);
         return regionData.files;
       }
 
       private void corruptFile(Path p) throws IOException {
         String manifestName = p.getName();
 
         // Rename the original region-manifest file
         Path newP = new Path(p.getParent(), manifestName + "1");
         fs.rename(p, newP);
 
         // Create a new region-manifest file
         FSDataOutputStream out = fs.create(p);
 
         //Copy the first 25 bytes of the original region-manifest into the new one,
         //make it a corrupted region-manifest file.
         FSDataInputStream input = fs.open(newP);
         byte[] buffer = new byte[25];
         int len = input.read(0, buffer, 0, 25);
         if (len > 1) {
           out.write(buffer, 0, len - 1);
         }
         out.close();
 
         // Delete the original region-manifest
         fs.delete(newP);
       }
 
       /**
        * Corrupt one region-manifest file
        *
        * @throws IOException on unexecpted error from the FS
        */
       public void corruptOneRegionManifest() throws IOException {
         FileStatus[] manifestFiles = FSUtils.listStatus(fs, snapshotDir, new PathFilter() {
           @Override public boolean accept(Path path) {
             return path.getName().startsWith(SnapshotManifestV2.SNAPSHOT_MANIFEST_PREFIX);
           }
         });
 
         if (manifestFiles.length == 0) return;
 
         // Just choose the first one
         Path p = manifestFiles[0].getPath();
         corruptFile(p);
       }
 
       public void missOneRegionSnapshotFile() throws IOException {
         FileStatus[] manifestFiles = FSUtils.listStatus(fs, snapshotDir);
         for (FileStatus fileStatus : manifestFiles) {
           String fileName = fileStatus.getPath().getName();
           if (fileName.endsWith(SnapshotDescriptionUtils.SNAPSHOTINFO_FILE)
             || fileName.endsWith(".tabledesc")
             || fileName.endsWith(SnapshotDescriptionUtils.SNAPSHOT_TMP_DIR_NAME)) {
               fs.delete(fileStatus.getPath(), true);
           }
         }
       }
 
       /**
        * Corrupt data-manifest file
        *
        * @throws IOException on unexecpted error from the FS
        */
       public void corruptDataManifest() throws IOException {
         FileStatus[] manifestFiles = FSUtils.listStatus(fs, snapshotDir, new PathFilter() {
           @Override
           public boolean accept(Path path) {
             return path.getName().startsWith(SnapshotManifest.DATA_MANIFEST_NAME);
           }
         });
 
         if (manifestFiles.length == 0) return;
 
         // Just choose the first one
         Path p = manifestFiles[0].getPath();
         corruptFile(p);
       }
 
       public Path commit() throws IOException {
         ForeignExceptionDispatcher monitor = new ForeignExceptionDispatcher(desc.getName());
         SnapshotManifest manifest = SnapshotManifest.create(conf, fs, snapshotDir, desc, monitor);
         manifest.addTableDescriptor(htd);
         manifest.consolidate();
         SnapshotDescriptionUtils.completeSnapshot(desc, rootDir, snapshotDir, fs);
         snapshotDir = SnapshotDescriptionUtils.getCompletedSnapshotDir(desc, rootDir);
         return snapshotDir;
       }
 
       public void consolidate() throws IOException {
         ForeignExceptionDispatcher monitor = new ForeignExceptionDispatcher(desc.getName());
         SnapshotManifest manifest = SnapshotManifest.create(conf, fs, snapshotDir, desc, monitor);
         manifest.addTableDescriptor(htd);
         manifest.consolidate();
       }
     }
 
     public SnapshotMock(final Configuration conf, final FileSystem fs, final Path rootDir) {
       this.fs = fs;
       this.conf = conf;
       this.rootDir = rootDir;
     }
 
     public SnapshotBuilder createSnapshotV1(final String snapshotName, final String tableName)
         throws IOException {
       return createSnapshot(snapshotName, tableName, SnapshotManifestV1.DESCRIPTOR_VERSION);
     }
 
     public SnapshotBuilder createSnapshotV1(final String snapshotName, final String tableName,
         final int numRegions) throws IOException {
       return createSnapshot(snapshotName, tableName, numRegions, SnapshotManifestV1.DESCRIPTOR_VERSION);
     }
 
     public SnapshotBuilder createSnapshotV2(final String snapshotName, final String tableName)
         throws IOException {
       return createSnapshot(snapshotName, tableName, SnapshotManifestV2.DESCRIPTOR_VERSION);
     }
 
     public SnapshotBuilder createSnapshotV2(final String snapshotName, final String tableName,
         final int numRegions) throws IOException {
       return createSnapshot(snapshotName, tableName, numRegions, SnapshotManifestV2.DESCRIPTOR_VERSION);
     }
 
     private SnapshotBuilder createSnapshot(final String snapshotName, final String tableName,
         final int version) throws IOException {
       return createSnapshot(snapshotName, tableName, TEST_NUM_REGIONS, version);
     }
 
     private SnapshotBuilder createSnapshot(final String snapshotName, final String tableName,
         final int numRegions, final int version) throws IOException {
       HTableDescriptor htd = createHtd(tableName);
       RegionData[] regions = createTable(htd, numRegions);
 
       SnapshotDescription desc = SnapshotDescription.newBuilder()
         .setTable(htd.getNameAsString())
         .setName(snapshotName)
         .setVersion(version)
         .build();
 
       Path workingDir = SnapshotDescriptionUtils.getWorkingSnapshotDir(desc, rootDir);
       SnapshotDescriptionUtils.writeSnapshotInfo(desc, workingDir, fs);
       return new SnapshotBuilder(conf, fs, rootDir, htd, desc, regions);
     }
 
     public HTableDescriptor createHtd(final String tableName) {
       HTableDescriptor htd = new HTableDescriptor(tableName);
       htd.addFamily(new HColumnDescriptor(TEST_FAMILY));
       return htd;
     }
 
     private RegionData[] createTable(final HTableDescriptor htd, final int nregions)
         throws IOException {
       Path tableDir = FSUtils.getTableDir(rootDir, htd.getTableName());
       new FSTableDescriptors(conf).createTableDescriptorForTableDirectory(tableDir, htd, false);
 
       assertTrue(nregions % 2 == 0);
       RegionData[] regions = new RegionData[nregions];
       for (int i = 0; i < regions.length; i += 2) {
         byte[] startKey = Bytes.toBytes(0 + i * 2);
         byte[] endKey = Bytes.toBytes(1 + i * 2);
 
         // First region, simple with one plain hfile.
         HRegionInfo hri = new HRegionInfo(htd.getTableName(), startKey, endKey);
         HRegionFileSystem rfs = HRegionFileSystem.createRegionOnFileSystem(conf, fs, tableDir, hri);
         regions[i] = new RegionData(tableDir, hri, 3);
         for (int j = 0; j < regions[i].files.length; ++j) {
           Path storeFile = createStoreFile(rfs.createTempName());
           regions[i].files[j] = rfs.commitStoreFile(TEST_FAMILY, storeFile);
         }
 
         // Second region, used to test the split case.
         // This region contains a reference to the hfile in the first region.
         startKey = Bytes.toBytes(2 + i * 2);
         endKey = Bytes.toBytes(3 + i * 2);
         hri = new HRegionInfo(htd.getTableName());
         rfs = HRegionFileSystem.createRegionOnFileSystem(conf, fs, tableDir, hri);
         regions[i+1] = new RegionData(tableDir, hri, regions[i].files.length);
         for (int j = 0; j < regions[i].files.length; ++j) {
           String refName = regions[i].files[j].getName() + '.' + regions[i].hri.getEncodedName();
           Path refFile = createStoreFile(new Path(rootDir, refName));
           regions[i+1].files[j] = rfs.commitStoreFile(TEST_FAMILY, refFile);
         }
       }
       return regions;
     }
 
     private Path createStoreFile(final Path storeFile)
         throws IOException {
       FSDataOutputStream out = fs.create(storeFile);
       try {
         out.write(Bytes.toBytes(storeFile.toString()));
       } finally {
         out.close();
       }
       return storeFile;
     }
   }
 
   // ==========================================================================
   //  Table Helpers
   // ==========================================================================
   public static void waitForTableToBeOnline(final HBaseTestingUtility util,
                                             final TableName tableName)
       throws IOException, InterruptedException {
     HRegionServer rs = util.getRSForFirstRegionInTable(tableName);
     List<Region> onlineRegions = rs.getOnlineRegions(tableName);
     for (Region region : onlineRegions) {
       region.waitForFlushesAndCompactions();
     }
     // Wait up to 60 seconds for a table to be available.
     util.waitFor(60000, util.predicateTableAvailable(tableName));
   }
 
   public static void createTable(final HBaseTestingUtility util, final TableName tableName,
       int regionReplication, final byte[]... families) throws IOException, InterruptedException {
     HTableDescriptor htd = new HTableDescriptor(tableName);
     htd.setRegionReplication(regionReplication);
     for (byte[] family : families) {
       HColumnDescriptor hcd = new HColumnDescriptor(family);
       htd.addFamily(hcd);
     }
     byte[][] splitKeys = getSplitKeys();
     util.createTable(htd, splitKeys);
     assertEquals((splitKeys.length + 1) * regionReplication,
         util.getHBaseAdmin().getTableRegions(tableName).size());
   }
 
   public static byte[][] getSplitKeys() {
     byte[][] splitKeys = new byte[KEYS.length-2][];
     for (int i = 0; i < splitKeys.length; ++i) {
       splitKeys[i] = new byte[] { KEYS[i+1] };
     }
     return splitKeys;
   }
 
   public static void createTable(final HBaseTestingUtility util, final TableName tableName,
       final byte[]... families) throws IOException, InterruptedException {
     createTable(util, tableName, 1, families);
   }
 
   public static void loadData(final HBaseTestingUtility util, final TableName tableName, int rows,
       byte[]... families) throws IOException, InterruptedException {
     try (BufferedMutator mutator = util.getConnection().getBufferedMutator(tableName)) {
       loadData(util, mutator, rows, families);
     }
   }
 
   public static void loadData(final HBaseTestingUtility util, final BufferedMutator mutator, int rows,
       byte[]... families) throws IOException, InterruptedException {
     // Ensure one row per region
     assertTrue(rows >= KEYS.length);
     for (byte k0: KEYS) {
       byte[] k = new byte[] { k0 };
       byte[] value = Bytes.add(Bytes.toBytes(System.currentTimeMillis()), k);
       byte[] key = Bytes.add(k, Bytes.toBytes(MD5Hash.getMD5AsHex(value)));
       final byte[][] families1 = families;
       final byte[] key1 = key;
       final byte[] value1 = value;
       mutator.mutate(createPut(families1, key1, value1));
       rows--;
     }
 
     // Add other extra rows. more rows, more files
     while (rows-- > 0) {
       byte[] value = Bytes.add(Bytes.toBytes(System.currentTimeMillis()), Bytes.toBytes(rows));
       byte[] key = Bytes.toBytes(MD5Hash.getMD5AsHex(value));
       final byte[][] families1 = families;
       final byte[] key1 = key;
       final byte[] value1 = value;
       mutator.mutate(createPut(families1, key1, value1));
     }
     mutator.flush();
 
     waitForTableToBeOnline(util, mutator.getName());
   }
 
   private static Put createPut(final byte[][] families, final byte[] key, final byte[] value) {
     byte[] q = Bytes.toBytes("q");
     Put put = new Put(key);
     put.setDurability(Durability.SKIP_WAL);
     for (byte[] family: families) {
       put.add(family, q, value);
     }
     return put;
   }
 
   public static void deleteAllSnapshots(final Admin admin)
       throws IOException {
     // Delete all the snapshots
     for (SnapshotDescription snapshot: admin.listSnapshots()) {
       admin.deleteSnapshot(snapshot.getName());
     }
     SnapshotTestingUtils.assertNoSnapshots(admin);
   }
 
   public static void deleteArchiveDirectory(final HBaseTestingUtility util)
       throws IOException {
     // Ensure the archiver to be empty
     MasterFileSystem mfs = util.getMiniHBaseCluster().getMaster().getMasterFileSystem();
     Path archiveDir = new Path(mfs.getRootDir(), HConstants.HFILE_ARCHIVE_DIRECTORY);
     mfs.getFileSystem().delete(archiveDir, true);
   }
 
   public static void verifyRowCount(final HBaseTestingUtility util, final TableName tableName,
       long expectedRows) throws IOException {
     Table table = new HTable(util.getConfiguration(), tableName);
     try {
       assertEquals(expectedRows, util.countRows(table));
     } finally {
       table.close();
     }
   }
 
   public static void verifyReplicasCameOnline(TableName tableName, Admin admin,
       int regionReplication) throws IOException {
     List<HRegionInfo> regions = admin.getTableRegions(tableName);
     HashSet<HRegionInfo> set = new HashSet<HRegionInfo>();
     for (HRegionInfo hri : regions) {
       set.add(RegionReplicaUtil.getRegionInfoForDefaultReplica(hri));
       for (int i = 0; i < regionReplication; i++) {
         HRegionInfo replica = RegionReplicaUtil.getRegionInfoForReplica(hri, i);
         if (!regions.contains(replica)) {
           Assert.fail(replica + " is not contained in the list of online regions");
         }
       }
     }
     assert(set.size() == getSplitKeys().length + 1);
   }
 }