/*
    *
    * 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.io.hfile;
  
  import static org.apache.hadoop.hbase.io.compress.Compression.Algorithm.GZ;
  import static org.apache.hadoop.hbase.io.compress.Compression.Algorithm.NONE;
  import static org.junit.Assert.*;
  
  import java.io.ByteArrayOutputStream;
  import java.io.DataOutputStream;
  import java.io.IOException;
  import java.io.OutputStream;
  import java.nio.ByteBuffer;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.Random;
  import java.util.concurrent.Callable;
  import java.util.concurrent.ExecutionException;
  import java.util.concurrent.Executor;
  import java.util.concurrent.ExecutorCompletionService;
  import java.util.concurrent.Executors;
  import java.util.concurrent.Future;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.fs.FSDataInputStream;
  import org.apache.hadoop.fs.FSDataOutputStream;
  import org.apache.hadoop.fs.FileSystem;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.hbase.HBaseTestingUtility;
  import org.apache.hadoop.hbase.HConstants;
  import org.apache.hadoop.hbase.KeyValue;
  import org.apache.hadoop.hbase.testclassification.MediumTests;
  import org.apache.hadoop.hbase.Tag;
  import org.apache.hadoop.hbase.fs.HFileSystem;
  import org.apache.hadoop.hbase.io.compress.Compression;
  import org.apache.hadoop.hbase.io.compress.Compression.Algorithm;
  import org.apache.hadoop.hbase.io.encoding.DataBlockEncoding;
  import org.apache.hadoop.hbase.util.Bytes;
  import org.apache.hadoop.hbase.util.ChecksumType;
  import org.apache.hadoop.hbase.util.ClassSize;
  import org.apache.hadoop.io.WritableUtils;
  import org.apache.hadoop.io.compress.Compressor;
  import org.junit.Before;
  import org.junit.Test;
  import org.junit.experimental.categories.Category;
  import org.junit.runner.RunWith;
  import org.junit.runners.Parameterized;
  import org.junit.runners.Parameterized.Parameters;
  import org.mockito.Mockito;
  
  @Category(MediumTests.class)
  @RunWith(Parameterized.class)
  public class TestHFileBlock {
    // change this value to activate more logs
    private static final boolean detailedLogging = false;
    private static final boolean[] BOOLEAN_VALUES = new boolean[] { false, true };
  
    private static final Log LOG = LogFactory.getLog(TestHFileBlock.class);
  
    static final Compression.Algorithm[] COMPRESSION_ALGORITHMS = { NONE, GZ };
  
    private static final int NUM_TEST_BLOCKS = 1000;
    private static final int NUM_READER_THREADS = 26;
  
    // Used to generate KeyValues
    private static int NUM_KEYVALUES = 50;
    private static int FIELD_LENGTH = 10;
    private static float CHANCE_TO_REPEAT = 0.6f;
  
    private static final HBaseTestingUtility TEST_UTIL = new HBaseTestingUtility();
    private FileSystem fs;
  
    private final boolean includesMemstoreTS;
    private final boolean includesTag;
    public TestHFileBlock(boolean includesMemstoreTS, boolean includesTag) {
      this.includesMemstoreTS = includesMemstoreTS;
      this.includesTag = includesTag;
    }
 
   @Parameters
   public static Collection<Object[]> parameters() {
     return HBaseTestingUtility.MEMSTORETS_TAGS_PARAMETRIZED;
   }
 
   @Before
   public void setUp() throws IOException {
     fs = HFileSystem.get(TEST_UTIL.getConfiguration());
   }
 
   static void writeTestBlockContents(DataOutputStream dos) throws IOException {
     // This compresses really well.
     for (int i = 0; i < 1000; ++i)
       dos.writeInt(i / 100);
   }
 
   static int writeTestKeyValues(HFileBlock.Writer hbw, int seed, boolean includesMemstoreTS,
       boolean useTag) throws IOException {
     List<KeyValue> keyValues = new ArrayList<KeyValue>();
     Random randomizer = new Random(42l + seed); // just any fixed number
 
     // generate keyValues
     for (int i = 0; i < NUM_KEYVALUES; ++i) {
       byte[] row;
       long timestamp;
       byte[] family;
       byte[] qualifier;
       byte[] value;
 
       // generate it or repeat, it should compress well
       if (0 < i && randomizer.nextFloat() < CHANCE_TO_REPEAT) {
         row = keyValues.get(randomizer.nextInt(keyValues.size())).getRow();
       } else {
         row = new byte[FIELD_LENGTH];
         randomizer.nextBytes(row);
       }
       if (0 == i) {
         family = new byte[FIELD_LENGTH];
         randomizer.nextBytes(family);
       } else {
         family = keyValues.get(0).getFamily();
       }
       if (0 < i && randomizer.nextFloat() < CHANCE_TO_REPEAT) {
         qualifier = keyValues.get(
             randomizer.nextInt(keyValues.size())).getQualifier();
       } else {
         qualifier = new byte[FIELD_LENGTH];
         randomizer.nextBytes(qualifier);
       }
       if (0 < i && randomizer.nextFloat() < CHANCE_TO_REPEAT) {
         value = keyValues.get(randomizer.nextInt(keyValues.size())).getValue();
       } else {
         value = new byte[FIELD_LENGTH];
         randomizer.nextBytes(value);
       }
       if (0 < i && randomizer.nextFloat() < CHANCE_TO_REPEAT) {
         timestamp = keyValues.get(
             randomizer.nextInt(keyValues.size())).getTimestamp();
       } else {
         timestamp = randomizer.nextLong();
       }
       if (!useTag) {
         keyValues.add(new KeyValue(row, family, qualifier, timestamp, value));
       } else {
         keyValues.add(new KeyValue(row, family, qualifier, timestamp, value, new Tag[] { new Tag(
             (byte) 1, Bytes.toBytes("myTagVal")) }));
       }
     }
 
     // sort it and write to stream
     int totalSize = 0;
     Collections.sort(keyValues, KeyValue.COMPARATOR);
 
     for (KeyValue kv : keyValues) {
       totalSize += kv.getLength();
       if (includesMemstoreTS) {
         long memstoreTS = randomizer.nextLong();
         kv.setSequenceId(memstoreTS);
         totalSize += WritableUtils.getVIntSize(memstoreTS);
       }
       hbw.write(kv);
     }
     return totalSize;
   }
 
   public byte[] createTestV1Block(Compression.Algorithm algo)
       throws IOException {
     Compressor compressor = algo.getCompressor();
     ByteArrayOutputStream baos = new ByteArrayOutputStream();
     OutputStream os = algo.createCompressionStream(baos, compressor, 0);
     DataOutputStream dos = new DataOutputStream(os);
     BlockType.META.write(dos); // Let's make this a meta block.
     writeTestBlockContents(dos);
     dos.flush();
     algo.returnCompressor(compressor);
     return baos.toByteArray();
   }
 
   static HFileBlock.Writer createTestV2Block(Compression.Algorithm algo,
       boolean includesMemstoreTS, boolean includesTag) throws IOException {
     final BlockType blockType = BlockType.DATA;
     HFileContext meta = new HFileContextBuilder()
                         .withCompression(algo)
                         .withIncludesMvcc(includesMemstoreTS)
                         .withIncludesTags(includesTag)
                         .withBytesPerCheckSum(HFile.DEFAULT_BYTES_PER_CHECKSUM)
                         .build();
     HFileBlock.Writer hbw = new HFileBlock.Writer(null, meta);
     DataOutputStream dos = hbw.startWriting(blockType);
     writeTestBlockContents(dos);
     dos.flush();
     hbw.ensureBlockReady();
     assertEquals(1000 * 4, hbw.getUncompressedSizeWithoutHeader());
     hbw.release();
     return hbw;
   }
 
   public String createTestBlockStr(Compression.Algorithm algo,
       int correctLength, boolean useTag) throws IOException {
     HFileBlock.Writer hbw = createTestV2Block(algo, includesMemstoreTS, useTag);
     byte[] testV2Block = hbw.getHeaderAndDataForTest();
     int osOffset = HConstants.HFILEBLOCK_HEADER_SIZE + 9;
     if (testV2Block.length == correctLength) {
       // Force-set the "OS" field of the gzip header to 3 (Unix) to avoid
       // variations across operating systems.
       // See http://www.gzip.org/zlib/rfc-gzip.html for gzip format.
       // We only make this change when the compressed block length matches.
       // Otherwise, there are obviously other inconsistencies.
       testV2Block[osOffset] = 3;
     }
     return Bytes.toStringBinary(testV2Block);
   }
 
   @Test
   public void testNoCompression() throws IOException {
     CacheConfig cacheConf = Mockito.mock(CacheConfig.class);
     Mockito.when(cacheConf.isBlockCacheEnabled()).thenReturn(false);
 
     HFileBlock block =
       createTestV2Block(NONE, includesMemstoreTS, false).getBlockForCaching(cacheConf);
     assertEquals(4000, block.getUncompressedSizeWithoutHeader());
     assertEquals(4004, block.getOnDiskSizeWithoutHeader());
     assertTrue(block.isUnpacked());
   }
 
   @Test
   public void testGzipCompression() throws IOException {
     final String correctTestBlockStr =
         "DATABLK*\\x00\\x00\\x00>\\x00\\x00\\x0F\\xA0\\xFF\\xFF\\xFF\\xFF"
             + "\\xFF\\xFF\\xFF\\xFF"
             + "\\x0" + ChecksumType.getDefaultChecksumType().getCode()
             + "\\x00\\x00@\\x00\\x00\\x00\\x00["
             // gzip-compressed block: http://www.gzip.org/zlib/rfc-gzip.html
             + "\\x1F\\x8B"  // gzip magic signature
             + "\\x08"  // Compression method: 8 = "deflate"
             + "\\x00"  // Flags
             + "\\x00\\x00\\x00\\x00"  // mtime
             + "\\x00"  // XFL (extra flags)
             // OS (0 = FAT filesystems, 3 = Unix). However, this field
             // sometimes gets set to 0 on Linux and Mac, so we reset it to 3.
             // This appears to be a difference caused by the availability
             // (and use) of the native GZ codec.
             + "\\x03"
             + "\\xED\\xC3\\xC1\\x11\\x00 \\x08\\xC00DD\\xDD\\x7Fa"
             + "\\xD6\\xE8\\xA3\\xB9K\\x84`\\x96Q\\xD3\\xA8\\xDB\\xA8e\\xD4c"
             + "\\xD46\\xEA5\\xEA3\\xEA7\\xE7\\x00LI\\x5Cs\\xA0\\x0F\\x00\\x00"
             + "\\x00\\x00\\x00\\x00"; //  4 byte checksum (ignored)
     final int correctGzipBlockLength = 95;
     final String testBlockStr = createTestBlockStr(GZ, correctGzipBlockLength, false);
     // We ignore the block checksum because createTestBlockStr can change the
     // gzip header after the block is produced
     assertEquals(correctTestBlockStr.substring(0, correctGzipBlockLength - 4),
       testBlockStr.substring(0, correctGzipBlockLength - 4));
   }
 
   @Test
   public void testReaderV2() throws IOException {
     testReaderV2Internals();
   }
 
   protected void testReaderV2Internals() throws IOException {
     if(includesTag) {
       TEST_UTIL.getConfiguration().setInt("hfile.format.version", 3);
     }
     for (Compression.Algorithm algo : COMPRESSION_ALGORITHMS) {
       for (boolean pread : new boolean[] { false, true }) {
           LOG.info("testReaderV2: Compression algorithm: " + algo +
                    ", pread=" + pread);
         Path path = new Path(TEST_UTIL.getDataTestDir(), "blocks_v2_"
             + algo);
         FSDataOutputStream os = fs.create(path);
         HFileContext meta = new HFileContextBuilder()
                            .withCompression(algo)
                            .withIncludesMvcc(includesMemstoreTS)
                            .withIncludesTags(includesTag)
                            .withBytesPerCheckSum(HFile.DEFAULT_BYTES_PER_CHECKSUM)
                            .build();
         HFileBlock.Writer hbw = new HFileBlock.Writer(null,
            meta);
         long totalSize = 0;
         for (int blockId = 0; blockId < 2; ++blockId) {
           DataOutputStream dos = hbw.startWriting(BlockType.DATA);
           for (int i = 0; i < 1234; ++i)
             dos.writeInt(i);
           hbw.writeHeaderAndData(os);
           totalSize += hbw.getOnDiskSizeWithHeader();
         }
         os.close();
 
         FSDataInputStream is = fs.open(path);
         meta = new HFileContextBuilder()
         .withHBaseCheckSum(true)
         .withIncludesMvcc(includesMemstoreTS)
         .withIncludesTags(includesTag)
         .withCompression(algo).build();
         HFileBlock.FSReader hbr = new HFileBlock.FSReaderImpl(is, totalSize, meta);
         HFileBlock b = hbr.readBlockData(0, -1, pread);
         is.close();
         assertEquals(0, HFile.getChecksumFailuresCount());
 
         b.sanityCheck();
         assertEquals(4936, b.getUncompressedSizeWithoutHeader());
         assertEquals(algo == GZ ? 2173 : 4936,
                      b.getOnDiskSizeWithoutHeader() - b.totalChecksumBytes());
         HFileBlock expected = b;
 
         if (algo == GZ) {
           is = fs.open(path);
           hbr = new HFileBlock.FSReaderImpl(is, totalSize, meta);
           b = hbr.readBlockData(0, 2173 + HConstants.HFILEBLOCK_HEADER_SIZE +
                                 b.totalChecksumBytes(), pread);
           assertEquals(expected, b);
           int wrongCompressedSize = 2172;
           try {
             b = hbr.readBlockData(0, wrongCompressedSize
                 + HConstants.HFILEBLOCK_HEADER_SIZE, pread);
             fail("Exception expected");
           } catch (IOException ex) {
             String expectedPrefix = "Passed in onDiskSizeWithHeader=";
             assertTrue("Invalid exception message: '" + ex.getMessage()
                 + "'.\nMessage is expected to start with: '" + expectedPrefix
                 + "'", ex.getMessage().startsWith(expectedPrefix));
           }
           is.close();
         }
       }
     }
   }
 
   /**
    * Test encoding/decoding data blocks.
    * @throws IOException a bug or a problem with temporary files.
    */
   @Test
   public void testDataBlockEncoding() throws IOException {
     testInternals();
   }
 
   private void testInternals() throws IOException {
     final int numBlocks = 5;
     if(includesTag) {
       TEST_UTIL.getConfiguration().setInt("hfile.format.version", 3);
     }
     for (Compression.Algorithm algo : COMPRESSION_ALGORITHMS) {
       for (boolean pread : new boolean[] { false, true }) {
         for (DataBlockEncoding encoding : DataBlockEncoding.values()) {
           Path path = new Path(TEST_UTIL.getDataTestDir(), "blocks_v2_"
               + algo + "_" + encoding.toString());
           FSDataOutputStream os = fs.create(path);
           HFileDataBlockEncoder dataBlockEncoder = (encoding != DataBlockEncoding.NONE) ?
               new HFileDataBlockEncoderImpl(encoding) : NoOpDataBlockEncoder.INSTANCE;
           HFileContext meta = new HFileContextBuilder()
                               .withCompression(algo)
                               .withIncludesMvcc(includesMemstoreTS)
                               .withIncludesTags(includesTag)
                               .withBytesPerCheckSum(HFile.DEFAULT_BYTES_PER_CHECKSUM)
                               .build();
           HFileBlock.Writer hbw = new HFileBlock.Writer(dataBlockEncoder, meta);
           long totalSize = 0;
           final List<Integer> encodedSizes = new ArrayList<Integer>();
           final List<ByteBuffer> encodedBlocks = new ArrayList<ByteBuffer>();
           for (int blockId = 0; blockId < numBlocks; ++blockId) {
             hbw.startWriting(BlockType.DATA);
             writeTestKeyValues(hbw, blockId, includesMemstoreTS, includesTag);
             hbw.writeHeaderAndData(os);
             int headerLen = HConstants.HFILEBLOCK_HEADER_SIZE;
             byte[] encodedResultWithHeader = hbw.getUncompressedBufferWithHeader().array();
             final int encodedSize = encodedResultWithHeader.length - headerLen;
             if (encoding != DataBlockEncoding.NONE) {
               // We need to account for the two-byte encoding algorithm ID that
               // comes after the 24-byte block header but before encoded KVs.
               headerLen += DataBlockEncoding.ID_SIZE;
             }
             byte[] encodedDataSection =
                 new byte[encodedResultWithHeader.length - headerLen];
             System.arraycopy(encodedResultWithHeader, headerLen,
                 encodedDataSection, 0, encodedDataSection.length);
             final ByteBuffer encodedBuf =
                 ByteBuffer.wrap(encodedDataSection);
             encodedSizes.add(encodedSize);
             encodedBlocks.add(encodedBuf);
             totalSize += hbw.getOnDiskSizeWithHeader();
           }
           os.close();
 
           FSDataInputStream is = fs.open(path);
           meta = new HFileContextBuilder()
                 .withHBaseCheckSum(true)
                 .withCompression(algo)
                 .withIncludesMvcc(includesMemstoreTS)
                 .withIncludesTags(includesTag)
                 .build();
           HFileBlock.FSReaderImpl hbr = new HFileBlock.FSReaderImpl(is, totalSize, meta);
           hbr.setDataBlockEncoder(dataBlockEncoder);
           hbr.setIncludesMemstoreTS(includesMemstoreTS);
           HFileBlock blockFromHFile, blockUnpacked;
           int pos = 0;
           for (int blockId = 0; blockId < numBlocks; ++blockId) {
             blockFromHFile = hbr.readBlockData(pos, -1, pread);
             assertEquals(0, HFile.getChecksumFailuresCount());
             blockFromHFile.sanityCheck();
             pos += blockFromHFile.getOnDiskSizeWithHeader();
             assertEquals((int) encodedSizes.get(blockId),
               blockFromHFile.getUncompressedSizeWithoutHeader());
             assertEquals(meta.isCompressedOrEncrypted(), !blockFromHFile.isUnpacked());
             long packedHeapsize = blockFromHFile.heapSize();
             blockUnpacked = blockFromHFile.unpack(meta, hbr);
             assertTrue(blockUnpacked.isUnpacked());
             if (meta.isCompressedOrEncrypted()) {
               LOG.info("packedHeapsize=" + packedHeapsize + ", unpackedHeadsize=" + blockUnpacked
                 .heapSize());
               assertFalse(packedHeapsize == blockUnpacked.heapSize());
               assertTrue("Packed heapSize should be < unpacked heapSize",
                 packedHeapsize < blockUnpacked.heapSize());
             }
             ByteBuffer actualBuffer = blockUnpacked.getBufferWithoutHeader();
             if (encoding != DataBlockEncoding.NONE) {
               // We expect a two-byte big-endian encoding id.
               assertEquals(
                 "Unexpected first byte with " + buildMessageDetails(algo, encoding, pread),
                 Long.toHexString(0), Long.toHexString(actualBuffer.get(0)));
               assertEquals(
                 "Unexpected second byte with " + buildMessageDetails(algo, encoding, pread),
                 Long.toHexString(encoding.getId()), Long.toHexString(actualBuffer.get(1)));
               actualBuffer.position(2);
               actualBuffer = actualBuffer.slice();
             }
 
             ByteBuffer expectedBuffer = encodedBlocks.get(blockId);
             expectedBuffer.rewind();
 
             // test if content matches, produce nice message
             assertBuffersEqual(expectedBuffer, actualBuffer, algo, encoding, pread);
 
             // test serialized blocks
             for (boolean reuseBuffer : new boolean[] { false, true }) {
               ByteBuffer serialized = ByteBuffer.allocate(blockFromHFile.getSerializedLength());
               blockFromHFile.serialize(serialized);
               HFileBlock deserialized =
                 (HFileBlock) blockFromHFile.getDeserializer().deserialize(serialized, reuseBuffer);
               assertEquals(
                 "Serialization did not preserve block state. reuseBuffer=" + reuseBuffer,
                 blockFromHFile, deserialized);
               // intentional reference comparison
               if (blockFromHFile != blockUnpacked) {
                 assertEquals("Deserializaed block cannot be unpacked correctly.",
                   blockUnpacked, deserialized.unpack(meta, hbr));
               }
             }
           }
           is.close();
         }
       }
     }
   }
 
   static String buildMessageDetails(Algorithm compression, DataBlockEncoding encoding,
       boolean pread) {
     return String.format("compression %s, encoding %s, pread %s", compression, encoding, pread);
   }
 
   static void assertBuffersEqual(ByteBuffer expectedBuffer,
       ByteBuffer actualBuffer, Compression.Algorithm compression,
       DataBlockEncoding encoding, boolean pread) {
     if (!actualBuffer.equals(expectedBuffer)) {
       int prefix = 0;
       int minLimit = Math.min(expectedBuffer.limit(), actualBuffer.limit());
       while (prefix < minLimit &&
           expectedBuffer.get(prefix) == actualBuffer.get(prefix)) {
         prefix++;
       }
 
       fail(String.format(
           "Content mismatch for %s, commonPrefix %d, expected %s, got %s",
           buildMessageDetails(compression, encoding, pread), prefix,
           nextBytesToStr(expectedBuffer, prefix),
           nextBytesToStr(actualBuffer, prefix)));
     }
   }
 
   /**
    * Convert a few next bytes in the given buffer at the given position to
    * string. Used for error messages.
    */
   private static String nextBytesToStr(ByteBuffer buf, int pos) {
     int maxBytes = buf.limit() - pos;
     int numBytes = Math.min(16, maxBytes);
     return Bytes.toStringBinary(buf.array(), buf.arrayOffset() + pos,
         numBytes) + (numBytes < maxBytes ? "..." : "");
   }
 
   @Test
   public void testPreviousOffset() throws IOException {
     testPreviousOffsetInternals();
   }
 
   protected void testPreviousOffsetInternals() throws IOException {
     // TODO: parameterize these nested loops.
     for (Compression.Algorithm algo : COMPRESSION_ALGORITHMS) {
       for (boolean pread : BOOLEAN_VALUES) {
         for (boolean cacheOnWrite : BOOLEAN_VALUES) {
           Random rand = defaultRandom();
           LOG.info("testPreviousOffset:Compression algorithm: " + algo +
                    ", pread=" + pread +
                    ", cacheOnWrite=" + cacheOnWrite);
           Path path = new Path(TEST_UTIL.getDataTestDir(), "prev_offset");
           List<Long> expectedOffsets = new ArrayList<Long>();
           List<Long> expectedPrevOffsets = new ArrayList<Long>();
           List<BlockType> expectedTypes = new ArrayList<BlockType>();
           List<ByteBuffer> expectedContents = cacheOnWrite
               ? new ArrayList<ByteBuffer>() : null;
           long totalSize = writeBlocks(rand, algo, path, expectedOffsets,
               expectedPrevOffsets, expectedTypes, expectedContents);
 
           FSDataInputStream is = fs.open(path);
           HFileContext meta = new HFileContextBuilder()
                               .withHBaseCheckSum(true)
                               .withIncludesMvcc(includesMemstoreTS)
                               .withIncludesTags(includesTag)
                               .withCompression(algo).build();
           HFileBlock.FSReader hbr = new HFileBlock.FSReaderImpl(is, totalSize, meta);
           long curOffset = 0;
           for (int i = 0; i < NUM_TEST_BLOCKS; ++i) {
             if (!pread) {
               assertEquals(is.getPos(), curOffset + (i == 0 ? 0 :
                 HConstants.HFILEBLOCK_HEADER_SIZE));
             }
 
             assertEquals(expectedOffsets.get(i).longValue(), curOffset);
             if (detailedLogging) {
               LOG.info("Reading block #" + i + " at offset " + curOffset);
             }
             HFileBlock b = hbr.readBlockData(curOffset, -1, pread);
             if (detailedLogging) {
               LOG.info("Block #" + i + ": " + b);
             }
             assertEquals("Invalid block #" + i + "'s type:",
                 expectedTypes.get(i), b.getBlockType());
             assertEquals("Invalid previous block offset for block " + i
                 + " of " + "type " + b.getBlockType() + ":",
                 (long) expectedPrevOffsets.get(i), b.getPrevBlockOffset());
             b.sanityCheck();
             assertEquals(curOffset, b.getOffset());
 
             // Now re-load this block knowing the on-disk size. This tests a
             // different branch in the loader.
             HFileBlock b2 = hbr.readBlockData(curOffset, b.getOnDiskSizeWithHeader(), pread);
             b2.sanityCheck();
 
             assertEquals(b.getBlockType(), b2.getBlockType());
             assertEquals(b.getOnDiskSizeWithoutHeader(),
                 b2.getOnDiskSizeWithoutHeader());
             assertEquals(b.getOnDiskSizeWithHeader(),
                 b2.getOnDiskSizeWithHeader());
             assertEquals(b.getUncompressedSizeWithoutHeader(),
                 b2.getUncompressedSizeWithoutHeader());
             assertEquals(b.getPrevBlockOffset(), b2.getPrevBlockOffset());
             assertEquals(curOffset, b2.getOffset());
             assertEquals(b.getBytesPerChecksum(), b2.getBytesPerChecksum());
             assertEquals(b.getOnDiskDataSizeWithHeader(),
                          b2.getOnDiskDataSizeWithHeader());
             assertEquals(0, HFile.getChecksumFailuresCount());
 
             curOffset += b.getOnDiskSizeWithHeader();
 
             if (cacheOnWrite) {
               // NOTE: cache-on-write testing doesn't actually involve a BlockCache. It simply
               // verifies that the unpacked value read back off disk matches the unpacked value
               // generated before writing to disk.
               b = b.unpack(meta, hbr);
               // b's buffer has header + data + checksum while
               // expectedContents have header + data only
               ByteBuffer bufRead = b.getBufferReadOnly();
               ByteBuffer bufExpected = expectedContents.get(i);
               boolean bytesAreCorrect = Bytes.compareTo(bufRead.array(),
                   bufRead.arrayOffset(),
                   bufRead.limit() - b.totalChecksumBytes(),
                   bufExpected.array(), bufExpected.arrayOffset(),
                   bufExpected.limit()) == 0;
               String wrongBytesMsg = "";
 
               if (!bytesAreCorrect) {
                 // Optimization: only construct an error message in case we
                 // will need it.
                 wrongBytesMsg = "Expected bytes in block #" + i + " (algo="
                     + algo + ", pread=" + pread
                     + ", cacheOnWrite=" + cacheOnWrite + "):\n";
                 wrongBytesMsg += Bytes.toStringBinary(bufExpected.array(),
                   bufExpected.arrayOffset(), Math.min(32 + 10, bufExpected.limit()))
                     + ", actual:\n"
                     + Bytes.toStringBinary(bufRead.array(),
                   bufRead.arrayOffset(), Math.min(32 + 10, bufRead.limit()));
                 if (detailedLogging) {
                   LOG.warn("expected header" +
                            HFileBlock.toStringHeader(bufExpected) +
                            "\nfound    header" +
                            HFileBlock.toStringHeader(bufRead));
                   LOG.warn("bufread offset " + bufRead.arrayOffset() +
                            " limit " + bufRead.limit() +
                            " expected offset " + bufExpected.arrayOffset() +
                            " limit " + bufExpected.limit());
                   LOG.warn(wrongBytesMsg);
                 }
               }
               assertTrue(wrongBytesMsg, bytesAreCorrect);
             }
           }
 
           assertEquals(curOffset, fs.getFileStatus(path).getLen());
           is.close();
         }
       }
     }
   }
 
   private Random defaultRandom() {
     return new Random(189237);
   }
 
   private class BlockReaderThread implements Callable<Boolean> {
     private final String clientId;
     private final HFileBlock.FSReader hbr;
     private final List<Long> offsets;
     private final List<BlockType> types;
     private final long fileSize;
 
     public BlockReaderThread(String clientId,
         HFileBlock.FSReader hbr, List<Long> offsets, List<BlockType> types,
         long fileSize) {
       this.clientId = clientId;
       this.offsets = offsets;
       this.hbr = hbr;
       this.types = types;
       this.fileSize = fileSize;
     }
 
     @Override
     public Boolean call() throws Exception {
       Random rand = new Random(clientId.hashCode());
       long endTime = System.currentTimeMillis() + 10000;
       int numBlocksRead = 0;
       int numPositionalRead = 0;
       int numWithOnDiskSize = 0;
       while (System.currentTimeMillis() < endTime) {
         int blockId = rand.nextInt(NUM_TEST_BLOCKS);
         long offset = offsets.get(blockId);
         boolean pread = rand.nextBoolean();
         boolean withOnDiskSize = rand.nextBoolean();
         long expectedSize =
           (blockId == NUM_TEST_BLOCKS - 1 ? fileSize
               : offsets.get(blockId + 1)) - offset;
 
         HFileBlock b;
         try {
           long onDiskSizeArg = withOnDiskSize ? expectedSize : -1;
           b = hbr.readBlockData(offset, onDiskSizeArg, pread);
         } catch (IOException ex) {
           LOG.error("Error in client " + clientId + " trying to read block at "
               + offset + ", pread=" + pread + ", withOnDiskSize=" +
               withOnDiskSize, ex);
           return false;
         }
 
         assertEquals(types.get(blockId), b.getBlockType());
         assertEquals(expectedSize, b.getOnDiskSizeWithHeader());
         assertEquals(offset, b.getOffset());
 
         ++numBlocksRead;
         if (pread)
           ++numPositionalRead;
         if (withOnDiskSize)
           ++numWithOnDiskSize;
       }
       LOG.info("Client " + clientId + " successfully read " + numBlocksRead +
         " blocks (with pread: " + numPositionalRead + ", with onDiskSize " +
         "specified: " + numWithOnDiskSize + ")");
 
       return true;
     }
 
   }
 
   @Test
   public void testConcurrentReading() throws Exception {
     testConcurrentReadingInternals();
   }
 
   protected void testConcurrentReadingInternals() throws IOException,
       InterruptedException, ExecutionException {
     for (Compression.Algorithm compressAlgo : COMPRESSION_ALGORITHMS) {
       Path path = new Path(TEST_UTIL.getDataTestDir(), "concurrent_reading");
       Random rand = defaultRandom();
       List<Long> offsets = new ArrayList<Long>();
       List<BlockType> types = new ArrayList<BlockType>();
       writeBlocks(rand, compressAlgo, path, offsets, null, types, null);
       FSDataInputStream is = fs.open(path);
       long fileSize = fs.getFileStatus(path).getLen();
       HFileContext meta = new HFileContextBuilder()
                           .withHBaseCheckSum(true)
                           .withIncludesMvcc(includesMemstoreTS)
                           .withIncludesTags(includesTag)
                           .withCompression(compressAlgo)
                           .build();
       HFileBlock.FSReader hbr = new HFileBlock.FSReaderImpl(is, fileSize, meta);
 
       Executor exec = Executors.newFixedThreadPool(NUM_READER_THREADS);
       ExecutorCompletionService<Boolean> ecs =
           new ExecutorCompletionService<Boolean>(exec);
 
       for (int i = 0; i < NUM_READER_THREADS; ++i) {
         ecs.submit(new BlockReaderThread("reader_" + (char) ('A' + i), hbr,
             offsets, types, fileSize));
       }
 
       for (int i = 0; i < NUM_READER_THREADS; ++i) {
         Future<Boolean> result = ecs.take();
         assertTrue(result.get());
         if (detailedLogging) {
           LOG.info(String.valueOf(i + 1)
             + " reader threads finished successfully (algo=" + compressAlgo
             + ")");
         }
       }
 
       is.close();
     }
   }
 
   private long writeBlocks(Random rand, Compression.Algorithm compressAlgo,
       Path path, List<Long> expectedOffsets, List<Long> expectedPrevOffsets,
       List<BlockType> expectedTypes, List<ByteBuffer> expectedContents
   ) throws IOException {
     boolean cacheOnWrite = expectedContents != null;
     FSDataOutputStream os = fs.create(path);
     HFileContext meta = new HFileContextBuilder()
                         .withHBaseCheckSum(true)
                         .withIncludesMvcc(includesMemstoreTS)
                         .withIncludesTags(includesTag)
                         .withCompression(compressAlgo)
                         .withBytesPerCheckSum(HFile.DEFAULT_BYTES_PER_CHECKSUM)
                         .build();
     HFileBlock.Writer hbw = new HFileBlock.Writer(null, meta);
     Map<BlockType, Long> prevOffsetByType = new HashMap<BlockType, Long>();
     long totalSize = 0;
     for (int i = 0; i < NUM_TEST_BLOCKS; ++i) {
       long pos = os.getPos();
       int blockTypeOrdinal = rand.nextInt(BlockType.values().length);
       if (blockTypeOrdinal == BlockType.ENCODED_DATA.ordinal()) {
         blockTypeOrdinal = BlockType.DATA.ordinal();
       }
       BlockType bt = BlockType.values()[blockTypeOrdinal];
       DataOutputStream dos = hbw.startWriting(bt);
       int size = rand.nextInt(500);
       for (int j = 0; j < size; ++j) {
         // This might compress well.
         dos.writeShort(i + 1);
         dos.writeInt(j + 1);
       }
 
       if (expectedOffsets != null)
         expectedOffsets.add(os.getPos());
 
       if (expectedPrevOffsets != null) {
         Long prevOffset = prevOffsetByType.get(bt);
         expectedPrevOffsets.add(prevOffset != null ? prevOffset : -1);
         prevOffsetByType.put(bt, os.getPos());
       }
 
       expectedTypes.add(bt);
 
       hbw.writeHeaderAndData(os);
       totalSize += hbw.getOnDiskSizeWithHeader();
 
       if (cacheOnWrite)
         expectedContents.add(hbw.getUncompressedBufferWithHeader());
 
       if (detailedLogging) {
         LOG.info("Written block #" + i + " of type " + bt
             + ", uncompressed size " + hbw.getUncompressedSizeWithoutHeader()
             + ", packed size " + hbw.getOnDiskSizeWithoutHeader()
             + " at offset " + pos);
       }
     }
     os.close();
     LOG.info("Created a temporary file at " + path + ", "
         + fs.getFileStatus(path).getLen() + " byte, compression=" +
         compressAlgo);
     return totalSize;
   }
 
   @Test
   public void testBlockHeapSize() {
     testBlockHeapSizeInternals();
   }
 
   protected void testBlockHeapSizeInternals() {
     if (ClassSize.is32BitJVM()) {
       assertTrue(HFileBlock.BYTE_BUFFER_HEAP_SIZE == 64);
     } else {
       assertTrue(HFileBlock.BYTE_BUFFER_HEAP_SIZE == 80);
     }
 
     for (int size : new int[] { 100, 256, 12345 }) {
       byte[] byteArr = new byte[HConstants.HFILEBLOCK_HEADER_SIZE + size];
       ByteBuffer buf = ByteBuffer.wrap(byteArr, 0, size);
       HFileContext meta = new HFileContextBuilder()
                           .withIncludesMvcc(includesMemstoreTS)
                           .withIncludesTags(includesTag)
                           .withHBaseCheckSum(false)
                           .withCompression(Algorithm.NONE)
                           .withBytesPerCheckSum(HFile.DEFAULT_BYTES_PER_CHECKSUM)
                           .withChecksumType(ChecksumType.NULL).build();
       HFileBlock block = new HFileBlock(BlockType.DATA, size, size, -1, buf,
           HFileBlock.FILL_HEADER, -1, 0, -1, meta);
       long byteBufferExpectedSize =
           ClassSize.align(ClassSize.estimateBase(buf.getClass(), true)
               + HConstants.HFILEBLOCK_HEADER_SIZE + size);
       long hfileMetaSize =  ClassSize.align(ClassSize.estimateBase(HFileContext.class, true));
       long hfileBlockExpectedSize =
           ClassSize.align(ClassSize.estimateBase(HFileBlock.class, true));
       long expected = hfileBlockExpectedSize + byteBufferExpectedSize + hfileMetaSize;
       assertEquals("Block data size: " + size + ", byte buffer expected " +
           "size: " + byteBufferExpectedSize + ", HFileBlock class expected " +
           "size: " + hfileBlockExpectedSize + ";", expected,
           block.heapSize());
     }
   }
 }