/*
* Copyright 2011 The Apache Software Foundation
*
* 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 java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutput;
import java.io.DataOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.io.RawComparator;
import static org.apache.hadoop.hbase.io.hfile.HFile.MIN_FORMAT_VERSION;
import static org.apache.hadoop.hbase.io.hfile.HFile.MAX_FORMAT_VERSION;
import com.google.common.io.NullOutputStream;
/**
* The {@link HFile} has a fixed trailer which contains offsets to other
* variable parts of the file. Also includes basic metadata on this file. The
* trailer size is fixed within a given {@link HFile} format version only, but
* we always store the version number as the last four-byte integer of the file.
* The version number itself is split into two portions, a major
* version and a minor version.
* The last three bytes of a file is the major
* version and a single preceding byte is the minor number. The major version
* determines which readers/writers to use to read/write a hfile while a minor
* version determines smaller changes in hfile format that do not need a new
* reader/writer type.
*/
public class FixedFileTrailer {
private static final Log LOG = LogFactory.getLog(FixedFileTrailer.class);
/**
* We store the comparator class name as a fixed-length field in the trailer.
*/
private static final int MAX_COMPARATOR_NAME_LENGTH = 128;
/**
* Offset to the fileinfo data, a small block of vitals. Necessary in v1 but
* only potentially useful for pretty-printing in v2.
*/
private long fileInfoOffset;
/**
* In version 1, the offset to the data block index. Starting from version 2,
* the meaning of this field is the offset to the section of the file that
* should be loaded at the time the file is being opened, and as of the time
* of writing, this happens to be the offset of the file info section.
*/
private long loadOnOpenDataOffset;
/** The number of entries in the root data index. */
private int dataIndexCount;
/** Total uncompressed size of all blocks of the data index */
private long uncompressedDataIndexSize;
/** The number of entries in the meta index */
private int metaIndexCount;
/** The total uncompressed size of keys/values stored in the file. */
private long totalUncompressedBytes;
/**
* The number of key/value pairs in the file. This field was int in version 1,
* but is now long.
*/
private long entryCount;
/** The compression codec used for all blocks. */
private Compression.Algorithm compressionCodec = Compression.Algorithm.NONE;
/**
* The number of levels in the potentially multi-level data index. Used from
* version 2 onwards.
*/
private int numDataIndexLevels;
/** The offset of the first data block. */
private long firstDataBlockOffset;
/**
* It is guaranteed that no key/value data blocks start after this offset in
* the file.
*/
private long lastDataBlockOffset;
/** Raw key comparator class name in version 2 */
private String comparatorClassName = RawComparator.class.getName();
/** The {@link HFile} format major version. */
private final int majorVersion;
/** The {@link HFile} format minor version. */
private final int minorVersion;
FixedFileTrailer(int majorVersion, int minorVersion) {
this.majorVersion = majorVersion;
this.minorVersion = minorVersion;
HFile.checkFormatVersion(majorVersion);
}
private static int[] computeTrailerSizeByVersion() {
int versionToSize[] = new int[HFile.MAX_FORMAT_VERSION + 1];
for (int version = MIN_FORMAT_VERSION;
version <= MAX_FORMAT_VERSION;
++version) {
FixedFileTrailer fft = new FixedFileTrailer(version,
HFileBlock.MINOR_VERSION_NO_CHECKSUM);
DataOutputStream dos = new DataOutputStream(new NullOutputStream());
try {
fft.serialize(dos);
} catch (IOException ex) {
// The above has no reason to fail.
throw new RuntimeException(ex);
}
versionToSize[version] = dos.size();
}
return versionToSize;
}
private static int getMaxTrailerSize() {
int maxSize = 0;
for (int version = MIN_FORMAT_VERSION;
version <= MAX_FORMAT_VERSION;
++version)
maxSize = Math.max(getTrailerSize(version), maxSize);
return maxSize;
}
private static final int TRAILER_SIZE[] = computeTrailerSizeByVersion();
private static final int MAX_TRAILER_SIZE = getMaxTrailerSize();
static int getTrailerSize(int version) {
return TRAILER_SIZE[version];
}
public int getTrailerSize() {
return getTrailerSize(majorVersion);
}
/**
* Write the trailer to a data stream. We support writing version 1 for
* testing and for determining version 1 trailer size. It is also easy to see
* what fields changed in version 2.
*
* @param outputStream
* @throws IOException
*/
void serialize(DataOutputStream outputStream) throws IOException {
HFile.checkFormatVersion(majorVersion);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
DataOutput baosDos = new DataOutputStream(baos);
BlockType.TRAILER.write(baosDos);
baosDos.writeLong(fileInfoOffset);
baosDos.writeLong(loadOnOpenDataOffset);
baosDos.writeInt(dataIndexCount);
if (majorVersion == 1) {
// This used to be metaIndexOffset, but it was not used in version 1.
baosDos.writeLong(0);
} else {
baosDos.writeLong(uncompressedDataIndexSize);
}
baosDos.writeInt(metaIndexCount);
baosDos.writeLong(totalUncompressedBytes);
if (majorVersion == 1) {
baosDos.writeInt((int) Math.min(Integer.MAX_VALUE, entryCount));
} else {
// This field is long from version 2 onwards.
baosDos.writeLong(entryCount);
}
baosDos.writeInt(compressionCodec.ordinal());
if (majorVersion > 1) {
baosDos.writeInt(numDataIndexLevels);
baosDos.writeLong(firstDataBlockOffset);
baosDos.writeLong(lastDataBlockOffset);
Bytes.writeStringFixedSize(baosDos, comparatorClassName,
MAX_COMPARATOR_NAME_LENGTH);
}
// serialize the major and minor versions
baosDos.writeInt(materializeVersion(majorVersion, minorVersion));
outputStream.write(baos.toByteArray());
}
/**
* Deserialize the fixed file trailer from the given stream. The version needs
* to already be specified. Make sure this is consistent with
* {@link #serialize(DataOutputStream)}.
*
* @param inputStream
* @param version
* @throws IOException
*/
void deserialize(DataInputStream inputStream) throws IOException {
HFile.checkFormatVersion(majorVersion);
BlockType.TRAILER.readAndCheck(inputStream);
fileInfoOffset = inputStream.readLong();
loadOnOpenDataOffset = inputStream.readLong();
dataIndexCount = inputStream.readInt();
if (majorVersion == 1) {
inputStream.readLong(); // Read and skip metaIndexOffset.
} else {
uncompressedDataIndexSize = inputStream.readLong();
}
metaIndexCount = inputStream.readInt();
totalUncompressedBytes = inputStream.readLong();
entryCount = majorVersion == 1 ? inputStream.readInt() : inputStream.readLong();
compressionCodec = Compression.Algorithm.values()[inputStream.readInt()];
if (majorVersion > 1) {
numDataIndexLevels = inputStream.readInt();
firstDataBlockOffset = inputStream.readLong();
lastDataBlockOffset = inputStream.readLong();
comparatorClassName =
Bytes.readStringFixedSize(inputStream, MAX_COMPARATOR_NAME_LENGTH);
}
int version = inputStream.readInt();
expectMajorVersion(extractMajorVersion(version));
expectMinorVersion(extractMinorVersion(version));
}
private void append(StringBuilder sb, String s) {
if (sb.length() > 0)
sb.append(", ");
sb.append(s);
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
append(sb, "fileinfoOffset=" + fileInfoOffset);
append(sb, "loadOnOpenDataOffset=" + loadOnOpenDataOffset);
append(sb, "dataIndexCount=" + dataIndexCount);
append(sb, "metaIndexCount=" + metaIndexCount);
append(sb, "totalUncomressedBytes=" + totalUncompressedBytes);
append(sb, "entryCount=" + entryCount);
append(sb, "compressionCodec=" + compressionCodec);
if (majorVersion == 2) {
append(sb, "uncompressedDataIndexSize=" + uncompressedDataIndexSize);
append(sb, "numDataIndexLevels=" + numDataIndexLevels);
append(sb, "firstDataBlockOffset=" + firstDataBlockOffset);
append(sb, "lastDataBlockOffset=" + lastDataBlockOffset);
append(sb, "comparatorClassName=" + comparatorClassName);
}
append(sb, "majorVersion=" + majorVersion);
append(sb, "minorVersion=" + minorVersion);
return sb.toString();
}
/**
* Reads a file trailer from the given file.
*
* @param istream the input stream with the ability to seek. Does not have to
* be buffered, as only one read operation is made.
* @param fileSize the file size. Can be obtained using
* {@link org.apache.hadoop.fs.FileSystem#getFileStatus(
* org.apache.hadoop.fs.Path)}.
* @return the fixed file trailer read
* @throws IOException if failed to read from the underlying stream, or the
* trailer is corrupted, or the version of the trailer is
* unsupported
*/
public static FixedFileTrailer readFromStream(FSDataInputStream istream,
long fileSize) throws IOException {
int bufferSize = MAX_TRAILER_SIZE;
long seekPoint = fileSize - bufferSize;
if (seekPoint < 0) {
// It is hard to imagine such a small HFile.
seekPoint = 0;
bufferSize = (int) fileSize;
}
istream.seek(seekPoint);
ByteBuffer buf = ByteBuffer.allocate(bufferSize);
istream.readFully(buf.array(), buf.arrayOffset(),
buf.arrayOffset() + buf.limit());
// Read the version from the last int of the file.
buf.position(buf.limit() - Bytes.SIZEOF_INT);
int version = buf.getInt();
// Extract the major and minor versions.
int majorVersion = extractMajorVersion(version);
int minorVersion = extractMinorVersion(version);
try {
HFile.checkFormatVersion(majorVersion);
} catch (IllegalArgumentException iae) {
// In this context, an invalid version might indicate a corrupt HFile.
throw new IOException(iae);
}
int trailerSize = getTrailerSize(majorVersion);
FixedFileTrailer fft = new FixedFileTrailer(majorVersion, minorVersion);
fft.deserialize(new DataInputStream(new ByteArrayInputStream(buf.array(),
buf.arrayOffset() + bufferSize - trailerSize, trailerSize)));
return fft;
}
public void expectMajorVersion(int expected) {
if (majorVersion != expected) {
throw new IllegalArgumentException("Invalid HFile major version: "
+ majorVersion
+ " (expected: " + expected + ")");
}
}
public void expectMinorVersion(int expected) {
if (minorVersion != expected) {
throw new IllegalArgumentException("Invalid HFile minor version: "
+ minorVersion + " (expected: " + expected + ")");
}
}
public void expectAtLeastMajorVersion(int lowerBound) {
if (majorVersion < lowerBound) {
throw new IllegalArgumentException("Invalid HFile major version: "
+ majorVersion
+ " (expected: " + lowerBound + " or higher).");
}
}
public long getFileInfoOffset() {
return fileInfoOffset;
}
public void setFileInfoOffset(long fileInfoOffset) {
this.fileInfoOffset = fileInfoOffset;
}
public long getLoadOnOpenDataOffset() {
return loadOnOpenDataOffset;
}
public void setLoadOnOpenOffset(long loadOnOpenDataOffset) {
this.loadOnOpenDataOffset = loadOnOpenDataOffset;
}
public int getDataIndexCount() {
return dataIndexCount;
}
public void setDataIndexCount(int dataIndexCount) {
this.dataIndexCount = dataIndexCount;
}
public int getMetaIndexCount() {
return metaIndexCount;
}
public void setMetaIndexCount(int metaIndexCount) {
this.metaIndexCount = metaIndexCount;
}
public long getTotalUncompressedBytes() {
return totalUncompressedBytes;
}
public void setTotalUncompressedBytes(long totalUncompressedBytes) {
this.totalUncompressedBytes = totalUncompressedBytes;
}
public long getEntryCount() {
return entryCount;
}
public void setEntryCount(long newEntryCount) {
if (majorVersion == 1) {
int intEntryCount = (int) Math.min(Integer.MAX_VALUE, newEntryCount);
if (intEntryCount != newEntryCount) {
LOG.info("Warning: entry count is " + newEntryCount + " but writing "
+ intEntryCount + " into the version " + majorVersion + " trailer");
}
entryCount = intEntryCount;
return;
}
entryCount = newEntryCount;
}
public Compression.Algorithm getCompressionCodec() {
return compressionCodec;
}
public void setCompressionCodec(Compression.Algorithm compressionCodec) {
this.compressionCodec = compressionCodec;
}
public int getNumDataIndexLevels() {
expectAtLeastMajorVersion(2);
return numDataIndexLevels;
}
public void setNumDataIndexLevels(int numDataIndexLevels) {
expectAtLeastMajorVersion(2);
this.numDataIndexLevels = numDataIndexLevels;
}
public long getLastDataBlockOffset() {
expectAtLeastMajorVersion(2);
return lastDataBlockOffset;
}
public void setLastDataBlockOffset(long lastDataBlockOffset) {
expectAtLeastMajorVersion(2);
this.lastDataBlockOffset = lastDataBlockOffset;
}
public long getFirstDataBlockOffset() {
expectAtLeastMajorVersion(2);
return firstDataBlockOffset;
}
public void setFirstDataBlockOffset(long firstDataBlockOffset) {
expectAtLeastMajorVersion(2);
this.firstDataBlockOffset = firstDataBlockOffset;
}
/**
* Returns the major version of this HFile format
*/
public int getMajorVersion() {
return majorVersion;
}
/**
* Returns the minor version of this HFile format
*/
int getMinorVersion() {
return minorVersion;
}
@SuppressWarnings("rawtypes")
public void setComparatorClass(Class<? extends RawComparator> klass) {
expectAtLeastMajorVersion(2);
comparatorClassName = klass.getName();
}
@SuppressWarnings("unchecked")
private static Class<? extends RawComparator<byte[]>> getComparatorClass(
String comparatorClassName) throws IOException {
try {
return (Class<? extends RawComparator<byte[]>>)
Class.forName(comparatorClassName);
} catch (ClassNotFoundException ex) {
throw new IOException(ex);
}
}
public static RawComparator<byte[]> createComparator(
String comparatorClassName) throws IOException {
try {
return getComparatorClass(comparatorClassName).newInstance();
} catch (InstantiationException e) {
throw new IOException(e);
} catch (IllegalAccessException e) {
throw new IOException(e);
}
}
RawComparator<byte[]> createComparator() throws IOException {
expectAtLeastMajorVersion(2);
return createComparator(comparatorClassName);
}
public long getUncompressedDataIndexSize() {
if (majorVersion == 1)
return 0;
return uncompressedDataIndexSize;
}
public void setUncompressedDataIndexSize(
long uncompressedDataIndexSize) {
expectAtLeastMajorVersion(2);
this.uncompressedDataIndexSize = uncompressedDataIndexSize;
}
/**
* Extracts the major version for a 4-byte serialized version data.
* The major version is the 3 least significant bytes
*/
private static int extractMajorVersion(int serializedVersion) {
return (serializedVersion & 0x00ffffff);
}
/**
* Extracts the minor version for a 4-byte serialized version data.
* The major version are the 3 the most significant bytes
*/
private static int extractMinorVersion(int serializedVersion) {
return (serializedVersion >>> 24);
}
/**
* Create a 4 byte serialized version number by combining the
* minor and major version numbers.
*/
private static int materializeVersion(int majorVersion, int minorVersion) {
return ((majorVersion & 0x00ffffff) | (minorVersion << 24));
}
}