/*
* 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.encoding;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import org.apache.hadoop.hbase.Cell;
import org.apache.hadoop.hbase.CellComparator;
import org.apache.hadoop.hbase.CellUtil;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.KeyValue;
import org.apache.hadoop.hbase.KeyValue.KVComparator;
import org.apache.hadoop.hbase.KeyValue.SamePrefixComparator;
import org.apache.hadoop.hbase.KeyValue.Type;
import org.apache.hadoop.hbase.KeyValueUtil;
import org.apache.hadoop.hbase.SettableSequenceId;
import org.apache.hadoop.hbase.classification.InterfaceAudience;
import org.apache.hadoop.hbase.io.HeapSize;
import org.apache.hadoop.hbase.io.TagCompressionContext;
import org.apache.hadoop.hbase.io.hfile.BlockType;
import org.apache.hadoop.hbase.io.hfile.HFileContext;
import org.apache.hadoop.hbase.io.util.LRUDictionary;
import org.apache.hadoop.hbase.util.ByteBufferUtils;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.hbase.util.ClassSize;
import org.apache.hadoop.io.WritableUtils;
/**
* Base class for all data block encoders that use a buffer.
*/
@InterfaceAudience.Private
abstract class BufferedDataBlockEncoder implements DataBlockEncoder {
private static int INITIAL_KEY_BUFFER_SIZE = 512;
@Override
public ByteBuffer decodeKeyValues(DataInputStream source,
HFileBlockDecodingContext blkDecodingCtx) throws IOException {
if (blkDecodingCtx.getClass() != HFileBlockDefaultDecodingContext.class) {
throw new IOException(this.getClass().getName() + " only accepts "
+ HFileBlockDefaultDecodingContext.class.getName() + " as the decoding context.");
}
HFileBlockDefaultDecodingContext decodingCtx =
(HFileBlockDefaultDecodingContext) blkDecodingCtx;
if (decodingCtx.getHFileContext().isIncludesTags()
&& decodingCtx.getHFileContext().isCompressTags()) {
if (decodingCtx.getTagCompressionContext() != null) {
// It will be overhead to create the TagCompressionContext again and again for every block
// decoding.
decodingCtx.getTagCompressionContext().clear();
} else {
try {
TagCompressionContext tagCompressionContext = new TagCompressionContext(
LRUDictionary.class, Byte.MAX_VALUE);
decodingCtx.setTagCompressionContext(tagCompressionContext);
} catch (Exception e) {
throw new IOException("Failed to initialize TagCompressionContext", e);
}
}
}
return internalDecodeKeyValues(source, 0, 0, decodingCtx);
}
protected static class SeekerState implements Cell {
protected ByteBuffer currentBuffer;
protected TagCompressionContext tagCompressionContext;
protected int valueOffset = -1;
protected int keyLength;
protected int valueLength;
protected int lastCommonPrefix;
protected int tagsLength = 0;
protected int tagsOffset = -1;
protected int tagsCompressedLength = 0;
protected boolean uncompressTags = true;
/** We need to store a copy of the key. */
protected byte[] keyBuffer = new byte[INITIAL_KEY_BUFFER_SIZE];
protected byte[] tagsBuffer = new byte[INITIAL_KEY_BUFFER_SIZE];
protected long memstoreTS;
protected int nextKvOffset;
protected KeyValue.KeyOnlyKeyValue currentKey = new KeyValue.KeyOnlyKeyValue();
protected boolean isValid() {
return valueOffset != -1;
}
protected void invalidate() {
valueOffset = -1;
tagsCompressedLength = 0;
currentKey = new KeyValue.KeyOnlyKeyValue();
uncompressTags = true;
currentBuffer = null;
}
protected void ensureSpaceForKey() {
if (keyLength > keyBuffer.length) {
// rare case, but we need to handle arbitrary length of key
int newKeyBufferLength = Math.max(keyBuffer.length, 1) * 2;
while (keyLength > newKeyBufferLength) {
newKeyBufferLength *= 2;
}
byte[] newKeyBuffer = new byte[newKeyBufferLength];
System.arraycopy(keyBuffer, 0, newKeyBuffer, 0, keyBuffer.length);
keyBuffer = newKeyBuffer;
}
}
protected void ensureSpaceForTags() {
if (tagsLength > tagsBuffer.length) {
// rare case, but we need to handle arbitrary length of tags
int newTagsBufferLength = Math.max(tagsBuffer.length, 1) * 2;
while (tagsLength > newTagsBufferLength) {
newTagsBufferLength *= 2;
}
byte[] newTagsBuffer = new byte[newTagsBufferLength];
System.arraycopy(tagsBuffer, 0, newTagsBuffer, 0, tagsBuffer.length);
tagsBuffer = newTagsBuffer;
}
}
protected void setKey(byte[] keyBuffer, long memTS) {
currentKey.setKey(keyBuffer, 0, keyLength);
memstoreTS = memTS;
}
/**
* Copy the state from the next one into this instance (the previous state
* placeholder). Used to save the previous state when we are advancing the
* seeker to the next key/value.
*/
protected void copyFromNext(SeekerState nextState) {
if (keyBuffer.length != nextState.keyBuffer.length) {
keyBuffer = nextState.keyBuffer.clone();
} else if (!isValid()) {
// Note: we can only call isValid before we override our state, so this
// comes before all the assignments at the end of this method.
System.arraycopy(nextState.keyBuffer, 0, keyBuffer, 0,
nextState.keyLength);
} else {
// don't copy the common prefix between this key and the previous one
System.arraycopy(nextState.keyBuffer, nextState.lastCommonPrefix,
keyBuffer, nextState.lastCommonPrefix, nextState.keyLength
- nextState.lastCommonPrefix);
}
currentKey = nextState.currentKey;
valueOffset = nextState.valueOffset;
keyLength = nextState.keyLength;
valueLength = nextState.valueLength;
lastCommonPrefix = nextState.lastCommonPrefix;
nextKvOffset = nextState.nextKvOffset;
memstoreTS = nextState.memstoreTS;
currentBuffer = nextState.currentBuffer;
if (nextState.tagCompressionContext != null) {
tagCompressionContext = nextState.tagCompressionContext;
}
}
@Override
public byte[] getRowArray() {
return currentKey.getRowArray();
}
@Override
public int getRowOffset() {
return Bytes.SIZEOF_SHORT;
}
@Override
public short getRowLength() {
return currentKey.getRowLength();
}
@Override
public byte[] getFamilyArray() {
return currentKey.getFamilyArray();
}
@Override
public int getFamilyOffset() {
return currentKey.getFamilyOffset();
}
@Override
public byte getFamilyLength() {
return currentKey.getFamilyLength();
}
@Override
public byte[] getQualifierArray() {
return currentKey.getQualifierArray();
}
@Override
public int getQualifierOffset() {
return currentKey.getQualifierOffset();
}
@Override
public int getQualifierLength() {
return currentKey.getQualifierLength();
}
@Override
public long getTimestamp() {
return currentKey.getTimestamp();
}
@Override
public byte getTypeByte() {
return currentKey.getTypeByte();
}
@Override
public long getMvccVersion() {
return memstoreTS;
}
@Override
public long getSequenceId() {
return memstoreTS;
}
@Override
public byte[] getValueArray() {
return currentBuffer.array();
}
@Override
public int getValueOffset() {
return currentBuffer.arrayOffset() + valueOffset;
}
@Override
public int getValueLength() {
return valueLength;
}
@Override
public byte[] getTagsArray() {
if (tagCompressionContext != null) {
return tagsBuffer;
}
return currentBuffer.array();
}
@Override
public int getTagsOffset() {
if (tagCompressionContext != null) {
return 0;
}
return currentBuffer.arrayOffset() + tagsOffset;
}
@Override
public int getTagsLength() {
return tagsLength;
}
@Override
@Deprecated
public byte[] getValue() {
throw new UnsupportedOperationException("getValue() not supported");
}
@Override
@Deprecated
public byte[] getFamily() {
throw new UnsupportedOperationException("getFamily() not supported");
}
@Override
@Deprecated
public byte[] getQualifier() {
throw new UnsupportedOperationException("getQualifier() not supported");
}
@Override
@Deprecated
public byte[] getRow() {
throw new UnsupportedOperationException("getRow() not supported");
}
@Override
public String toString() {
return KeyValue.keyToString(this.keyBuffer, 0, KeyValueUtil.keyLength(this)) + "/vlen="
+ getValueLength() + "/seqid=" + memstoreTS;
}
public Cell shallowCopy() {
return new ClonedSeekerState(currentBuffer, keyBuffer, currentKey.getRowLength(),
currentKey.getFamilyOffset(), currentKey.getFamilyLength(), keyLength,
currentKey.getQualifierOffset(), currentKey.getQualifierLength(),
currentKey.getTimestamp(), currentKey.getTypeByte(), valueLength, valueOffset,
memstoreTS, tagsOffset, tagsLength, tagCompressionContext, tagsBuffer);
}
}
/**
* Copies only the key part of the keybuffer by doing a deep copy and passes the
* seeker state members for taking a clone.
* Note that the value byte[] part is still pointing to the currentBuffer and the
* represented by the valueOffset and valueLength
*/
// We return this as a Cell to the upper layers of read flow and might try setting a new SeqId
// there. So this has to be an instance of SettableSequenceId. SeekerState need not be
// SettableSequenceId as we never return that to top layers. When we have to, we make
// ClonedSeekerState from it.
protected static class ClonedSeekerState implements Cell, HeapSize, SettableSequenceId {
private static final long FIXED_OVERHEAD = ClassSize.align(ClassSize.OBJECT
+ (4 * ClassSize.REFERENCE) + (2 * Bytes.SIZEOF_LONG) + (7 * Bytes.SIZEOF_INT)
+ (Bytes.SIZEOF_SHORT) + (2 * Bytes.SIZEOF_BYTE) + (2 * ClassSize.ARRAY));
private byte[] keyOnlyBuffer;
private ByteBuffer currentBuffer;
private short rowLength;
private int familyOffset;
private byte familyLength;
private int qualifierOffset;
private int qualifierLength;
private long timestamp;
private byte typeByte;
private int valueOffset;
private int valueLength;
private int tagsLength;
private int tagsOffset;
private byte[] cloneTagsBuffer;
private long seqId;
private TagCompressionContext tagCompressionContext;
protected ClonedSeekerState(ByteBuffer currentBuffer, byte[] keyBuffer, short rowLength,
int familyOffset, byte familyLength, int keyLength, int qualOffset, int qualLength,
long timeStamp, byte typeByte, int valueLen, int valueOffset, long seqId,
int tagsOffset, int tagsLength, TagCompressionContext tagCompressionContext,
byte[] tagsBuffer) {
this.currentBuffer = currentBuffer;
keyOnlyBuffer = new byte[keyLength];
this.tagCompressionContext = tagCompressionContext;
this.rowLength = rowLength;
this.familyOffset = familyOffset;
this.familyLength = familyLength;
this.qualifierOffset = qualOffset;
this.qualifierLength = qualLength;
this.timestamp = timeStamp;
this.typeByte = typeByte;
this.valueLength = valueLen;
this.valueOffset = valueOffset;
this.tagsOffset = tagsOffset;
this.tagsLength = tagsLength;
System.arraycopy(keyBuffer, 0, keyOnlyBuffer, 0, keyLength);
if (tagCompressionContext != null) {
this.cloneTagsBuffer = new byte[tagsLength];
System.arraycopy(tagsBuffer, 0, this.cloneTagsBuffer, 0, tagsLength);
}
setSequenceId(seqId);
}
@Override
public byte[] getRowArray() {
return keyOnlyBuffer;
}
@Override
public byte[] getFamilyArray() {
return keyOnlyBuffer;
}
@Override
public byte[] getQualifierArray() {
return keyOnlyBuffer;
}
@Override
public int getRowOffset() {
return Bytes.SIZEOF_SHORT;
}
@Override
public short getRowLength() {
return rowLength;
}
@Override
public int getFamilyOffset() {
return familyOffset;
}
@Override
public byte getFamilyLength() {
return familyLength;
}
@Override
public int getQualifierOffset() {
return qualifierOffset;
}
@Override
public int getQualifierLength() {
return qualifierLength;
}
@Override
public long getTimestamp() {
return timestamp;
}
@Override
public byte getTypeByte() {
return typeByte;
}
@Override
@Deprecated
public long getMvccVersion() {
return getSequenceId();
}
@Override
public long getSequenceId() {
return seqId;
}
@Override
public byte[] getValueArray() {
return currentBuffer.array();
}
@Override
public int getValueOffset() {
return currentBuffer.arrayOffset() + valueOffset;
}
@Override
public int getValueLength() {
return valueLength;
}
@Override
public byte[] getTagsArray() {
if (tagCompressionContext != null) {
return cloneTagsBuffer;
}
return currentBuffer.array();
}
@Override
public int getTagsOffset() {
if (tagCompressionContext != null) {
return 0;
}
return currentBuffer.arrayOffset() + tagsOffset;
}
@Override
public int getTagsLength() {
return tagsLength;
}
@Override
@Deprecated
public byte[] getValue() {
return CellUtil.cloneValue(this);
}
@Override
@Deprecated
public byte[] getFamily() {
return CellUtil.cloneFamily(this);
}
@Override
@Deprecated
public byte[] getQualifier() {
return CellUtil.cloneQualifier(this);
}
@Override
@Deprecated
public byte[] getRow() {
return CellUtil.cloneRow(this);
}
@Override
public String toString() {
return KeyValue.keyToString(this.keyOnlyBuffer, 0, KeyValueUtil.keyLength(this)) + "/vlen="
+ getValueLength() + "/seqid=" + seqId;
}
@Override
public void setSequenceId(long seqId) {
this.seqId = seqId;
}
@Override
public long heapSize() {
return FIXED_OVERHEAD + rowLength + familyLength + qualifierLength + valueLength + tagsLength;
}
}
protected abstract static class
BufferedEncodedSeeker<STATE extends SeekerState>
implements EncodedSeeker {
protected HFileBlockDecodingContext decodingCtx;
protected final KVComparator comparator;
protected final SamePrefixComparator<byte[]> samePrefixComparator;
protected ByteBuffer currentBuffer;
protected STATE current = createSeekerState(); // always valid
protected STATE previous = createSeekerState(); // may not be valid
protected TagCompressionContext tagCompressionContext = null;
public BufferedEncodedSeeker(KVComparator comparator,
HFileBlockDecodingContext decodingCtx) {
this.comparator = comparator;
this.samePrefixComparator = comparator;
this.decodingCtx = decodingCtx;
if (decodingCtx.getHFileContext().isCompressTags()) {
try {
tagCompressionContext = new TagCompressionContext(LRUDictionary.class, Byte.MAX_VALUE);
} catch (Exception e) {
throw new RuntimeException("Failed to initialize TagCompressionContext", e);
}
}
}
protected boolean includesMvcc() {
return this.decodingCtx.getHFileContext().isIncludesMvcc();
}
protected boolean includesTags() {
return this.decodingCtx.getHFileContext().isIncludesTags();
}
@Override
public int compareKey(KVComparator comparator, byte[] key, int offset, int length) {
return comparator.compareFlatKey(key, offset, length,
current.keyBuffer, 0, current.keyLength);
}
@Override
public int compareKey(KVComparator comparator, Cell key) {
return comparator.compareOnlyKeyPortion(key,
new KeyValue.KeyOnlyKeyValue(current.keyBuffer, 0, current.keyLength));
}
@Override
public void setCurrentBuffer(ByteBuffer buffer) {
if (this.tagCompressionContext != null) {
this.tagCompressionContext.clear();
}
currentBuffer = buffer;
current.currentBuffer = currentBuffer;
if(tagCompressionContext != null) {
current.tagCompressionContext = tagCompressionContext;
}
decodeFirst();
current.setKey(current.keyBuffer, current.memstoreTS);
previous.invalidate();
}
@Override
public ByteBuffer getKeyDeepCopy() {
ByteBuffer keyBuffer = ByteBuffer.allocate(current.keyLength);
keyBuffer.put(current.keyBuffer, 0, current.keyLength);
return keyBuffer;
}
@Override
public ByteBuffer getValueShallowCopy() {
ByteBuffer dup = currentBuffer.duplicate();
dup.position(current.valueOffset);
dup.limit(current.valueOffset + current.valueLength);
return dup.slice();
}
@Override
public ByteBuffer getKeyValueBuffer() {
ByteBuffer kvBuffer = createKVBuffer();
kvBuffer.putInt(current.keyLength);
kvBuffer.putInt(current.valueLength);
kvBuffer.put(current.keyBuffer, 0, current.keyLength);
ByteBufferUtils.copyFromBufferToBuffer(kvBuffer, currentBuffer, current.valueOffset,
current.valueLength);
if (current.tagsLength > 0) {
// Put short as unsigned
kvBuffer.put((byte) (current.tagsLength >> 8 & 0xff));
kvBuffer.put((byte) (current.tagsLength & 0xff));
if (current.tagsOffset != -1) {
// the offset of the tags bytes in the underlying buffer is marked. So the temp
// buffer,tagsBuffer was not been used.
ByteBufferUtils.copyFromBufferToBuffer(kvBuffer, currentBuffer, current.tagsOffset,
current.tagsLength);
} else {
// When tagsOffset is marked as -1, tag compression was present and so the tags were
// uncompressed into temp buffer, tagsBuffer. Let us copy it from there
kvBuffer.put(current.tagsBuffer, 0, current.tagsLength);
}
}
return kvBuffer;
}
protected ByteBuffer createKVBuffer() {
int kvBufSize = (int) KeyValue.getKeyValueDataStructureSize(current.keyLength,
current.valueLength, current.tagsLength);
ByteBuffer kvBuffer = ByteBuffer.allocate(kvBufSize);
return kvBuffer;
}
@Override
public Cell getKeyValue() {
return current.shallowCopy();
}
@Override
public void rewind() {
currentBuffer.rewind();
if (tagCompressionContext != null) {
tagCompressionContext.clear();
}
decodeFirst();
current.setKey(current.keyBuffer, current.memstoreTS);
previous.invalidate();
}
@Override
public boolean next() {
if (!currentBuffer.hasRemaining()) {
return false;
}
decodeNext();
current.setKey(current.keyBuffer, current.memstoreTS);
previous.invalidate();
return true;
}
protected void decodeTags() {
current.tagsLength = ByteBufferUtils.readCompressedInt(currentBuffer);
if (tagCompressionContext != null) {
if (current.uncompressTags) {
// Tag compression is been used. uncompress it into tagsBuffer
current.ensureSpaceForTags();
try {
current.tagsCompressedLength = tagCompressionContext.uncompressTags(currentBuffer,
current.tagsBuffer, 0, current.tagsLength);
} catch (IOException e) {
throw new RuntimeException("Exception while uncompressing tags", e);
}
} else {
ByteBufferUtils.skip(currentBuffer, current.tagsCompressedLength);
current.uncompressTags = true;// Reset this.
}
current.tagsOffset = -1;
} else {
// When tag compress is not used, let us not do copying of tags bytes into tagsBuffer.
// Just mark the tags Offset so as to create the KV buffer later in getKeyValueBuffer()
current.tagsOffset = currentBuffer.position();
ByteBufferUtils.skip(currentBuffer, current.tagsLength);
}
}
@Override
public int seekToKeyInBlock(byte[] key, int offset, int length, boolean seekBefore) {
return seekToKeyInBlock(new KeyValue.KeyOnlyKeyValue(key, offset, length), seekBefore);
}
@Override
public int seekToKeyInBlock(Cell seekCell, boolean seekBefore) {
int rowCommonPrefix = 0;
int familyCommonPrefix = 0;
int qualCommonPrefix = 0;
previous.invalidate();
KeyValue.KeyOnlyKeyValue currentCell = new KeyValue.KeyOnlyKeyValue();
do {
int comp;
if (samePrefixComparator != null) {
currentCell.setKey(current.keyBuffer, 0, current.keyLength);
if (current.lastCommonPrefix != 0) {
// The KV format has row key length also in the byte array. The
// common prefix
// includes it. So we need to subtract to find out the common prefix
// in the
// row part alone
rowCommonPrefix = Math.min(rowCommonPrefix, current.lastCommonPrefix - 2);
}
if (current.lastCommonPrefix <= 2) {
rowCommonPrefix = 0;
}
rowCommonPrefix += CellComparator.findCommonPrefixInRowPart(seekCell, currentCell,
rowCommonPrefix);
comp = CellComparator.compareCommonRowPrefix(seekCell, currentCell, rowCommonPrefix);
if (comp == 0) {
comp = compareTypeBytes(seekCell, currentCell);
if (comp == 0) {
// Subtract the fixed row key length and the family key fixed length
familyCommonPrefix = Math.max(
0,
Math.min(familyCommonPrefix,
current.lastCommonPrefix - (3 + currentCell.getRowLength())));
familyCommonPrefix += CellComparator.findCommonPrefixInFamilyPart(seekCell,
currentCell, familyCommonPrefix);
comp = CellComparator.compareCommonFamilyPrefix(seekCell, currentCell,
familyCommonPrefix);
if (comp == 0) {
// subtract the rowkey fixed length and the family key fixed
// length
qualCommonPrefix = Math.max(
0,
Math.min(
qualCommonPrefix,
current.lastCommonPrefix
- (3 + currentCell.getRowLength() + currentCell.getFamilyLength())));
qualCommonPrefix += CellComparator.findCommonPrefixInQualifierPart(seekCell,
currentCell, qualCommonPrefix);
comp = CellComparator.compareCommonQualifierPrefix(seekCell, currentCell,
qualCommonPrefix);
if (comp == 0) {
comp = CellComparator.compareTimestamps(seekCell, currentCell);
if (comp == 0) {
// Compare types. Let the delete types sort ahead of puts;
// i.e. types
// of higher numbers sort before those of lesser numbers.
// Maximum
// (255)
// appears ahead of everything, and minimum (0) appears
// after
// everything.
comp = (0xff & currentCell.getTypeByte()) - (0xff & seekCell.getTypeByte());
}
}
}
}
}
} else {
Cell r = new KeyValue.KeyOnlyKeyValue(current.keyBuffer, 0, current.keyLength);
comp = comparator.compareOnlyKeyPortion(seekCell, r);
}
if (comp == 0) { // exact match
if (seekBefore) {
if (!previous.isValid()) {
// The caller (seekBefore) has to ensure that we are not at the
// first key in the block.
throw new IllegalStateException("Cannot seekBefore if "
+ "positioned at the first key in the block: key="
+ Bytes.toStringBinary(seekCell.getRowArray()));
}
moveToPrevious();
return 1;
}
return 0;
}
if (comp < 0) { // already too large, check previous
if (previous.isValid()) {
moveToPrevious();
} else {
return HConstants.INDEX_KEY_MAGIC; // using optimized index key
}
return 1;
}
// move to next, if more data is available
if (currentBuffer.hasRemaining()) {
previous.copyFromNext(current);
decodeNext();
current.setKey(current.keyBuffer, current.memstoreTS);
} else {
break;
}
} while (true);
// we hit the end of the block, not an exact match
return 1;
}
private int compareTypeBytes(Cell key, Cell right) {
if (key.getFamilyLength() + key.getQualifierLength() == 0
&& key.getTypeByte() == Type.Minimum.getCode()) {
// left is "bigger", i.e. it appears later in the sorted order
return 1;
}
if (right.getFamilyLength() + right.getQualifierLength() == 0
&& right.getTypeByte() == Type.Minimum.getCode()) {
return -1;
}
return 0;
}
private void moveToPrevious() {
if (!previous.isValid()) {
throw new IllegalStateException(
"Can move back only once and not in first key in the block.");
}
STATE tmp = previous;
previous = current;
current = tmp;
// move after last key value
currentBuffer.position(current.nextKvOffset);
// Already decoded the tag bytes. We cache this tags into current state and also the total
// compressed length of the tags bytes. For the next time decodeNext() we don't need to decode
// the tags again. This might pollute the Data Dictionary what we use for the compression.
// When current.uncompressTags is false, we will just reuse the current.tagsBuffer and skip
// 'tagsCompressedLength' bytes of source stream.
// See in decodeTags()
current.tagsBuffer = previous.tagsBuffer;
current.tagsCompressedLength = previous.tagsCompressedLength;
current.uncompressTags = false;
previous.invalidate();
}
@SuppressWarnings("unchecked")
protected STATE createSeekerState() {
// This will fail for non-default seeker state if the subclass does not
// override this method.
return (STATE) new SeekerState();
}
abstract protected void decodeFirst();
abstract protected void decodeNext();
}
/**
* @param cell
* @param out
* @param encodingCtx
* @return unencoded size added
* @throws IOException
*/
protected final int afterEncodingKeyValue(Cell cell, DataOutputStream out,
HFileBlockDefaultEncodingContext encodingCtx) throws IOException {
int size = 0;
if (encodingCtx.getHFileContext().isIncludesTags()) {
int tagsLength = cell.getTagsLength();
ByteBufferUtils.putCompressedInt(out, tagsLength);
// There are some tags to be written
if (tagsLength > 0) {
TagCompressionContext tagCompressionContext = encodingCtx.getTagCompressionContext();
// When tag compression is enabled, tagCompressionContext will have a not null value. Write
// the tags using Dictionary compression in such a case
if (tagCompressionContext != null) {
tagCompressionContext
.compressTags(out, cell.getTagsArray(), cell.getTagsOffset(), tagsLength);
} else {
out.write(cell.getTagsArray(), cell.getTagsOffset(), tagsLength);
}
}
size += tagsLength + KeyValue.TAGS_LENGTH_SIZE;
}
if (encodingCtx.getHFileContext().isIncludesMvcc()) {
// Copy memstore timestamp from the byte buffer to the output stream.
long memstoreTS = cell.getSequenceId();
WritableUtils.writeVLong(out, memstoreTS);
// TODO use a writeVLong which returns the #bytes written so that 2 time parsing can be
// avoided.
size += WritableUtils.getVIntSize(memstoreTS);
}
return size;
}
protected final void afterDecodingKeyValue(DataInputStream source,
ByteBuffer dest, HFileBlockDefaultDecodingContext decodingCtx) throws IOException {
if (decodingCtx.getHFileContext().isIncludesTags()) {
int tagsLength = ByteBufferUtils.readCompressedInt(source);
// Put as unsigned short
dest.put((byte) ((tagsLength >> 8) & 0xff));
dest.put((byte) (tagsLength & 0xff));
if (tagsLength > 0) {
TagCompressionContext tagCompressionContext = decodingCtx.getTagCompressionContext();
// When tag compression is been used in this file, tagCompressionContext will have a not
// null value passed.
if (tagCompressionContext != null) {
tagCompressionContext.uncompressTags(source, dest, tagsLength);
} else {
ByteBufferUtils.copyFromStreamToBuffer(dest, source, tagsLength);
}
}
}
if (decodingCtx.getHFileContext().isIncludesMvcc()) {
long memstoreTS = -1;
try {
// Copy memstore timestamp from the data input stream to the byte
// buffer.
memstoreTS = WritableUtils.readVLong(source);
ByteBufferUtils.writeVLong(dest, memstoreTS);
} catch (IOException ex) {
throw new RuntimeException("Unable to copy memstore timestamp " +
memstoreTS + " after decoding a key/value");
}
}
}
@Override
public HFileBlockEncodingContext newDataBlockEncodingContext(DataBlockEncoding encoding,
byte[] header, HFileContext meta) {
return new HFileBlockDefaultEncodingContext(encoding, header, meta);
}
@Override
public HFileBlockDecodingContext newDataBlockDecodingContext(HFileContext meta) {
return new HFileBlockDefaultDecodingContext(meta);
}
protected abstract ByteBuffer internalDecodeKeyValues(DataInputStream source,
int allocateHeaderLength, int skipLastBytes, HFileBlockDefaultDecodingContext decodingCtx)
throws IOException;
/**
* Asserts that there is at least the given amount of unfilled space
* remaining in the given buffer.
* @param out typically, the buffer we are writing to
* @param length the required space in the buffer
* @throws EncoderBufferTooSmallException If there are no enough bytes.
*/
protected static void ensureSpace(ByteBuffer out, int length)
throws EncoderBufferTooSmallException {
if (out.position() + length > out.limit()) {
throw new EncoderBufferTooSmallException(
"Buffer position=" + out.position() +
", buffer limit=" + out.limit() +
", length to be written=" + length);
}
}
@Override
public void startBlockEncoding(HFileBlockEncodingContext blkEncodingCtx, DataOutputStream out)
throws IOException {
if (blkEncodingCtx.getClass() != HFileBlockDefaultEncodingContext.class) {
throw new IOException (this.getClass().getName() + " only accepts "
+ HFileBlockDefaultEncodingContext.class.getName() + " as the " +
"encoding context.");
}
HFileBlockDefaultEncodingContext encodingCtx =
(HFileBlockDefaultEncodingContext) blkEncodingCtx;
encodingCtx.prepareEncoding(out);
if (encodingCtx.getHFileContext().isIncludesTags()
&& encodingCtx.getHFileContext().isCompressTags()) {
if (encodingCtx.getTagCompressionContext() != null) {
// It will be overhead to create the TagCompressionContext again and again for every block
// encoding.
encodingCtx.getTagCompressionContext().clear();
} else {
try {
TagCompressionContext tagCompressionContext = new TagCompressionContext(
LRUDictionary.class, Byte.MAX_VALUE);
encodingCtx.setTagCompressionContext(tagCompressionContext);
} catch (Exception e) {
throw new IOException("Failed to initialize TagCompressionContext", e);
}
}
}
ByteBufferUtils.putInt(out, 0); // DUMMY length. This will be updated in endBlockEncoding()
blkEncodingCtx.setEncodingState(new BufferedDataBlockEncodingState());
}
private static class BufferedDataBlockEncodingState extends EncodingState {
int unencodedDataSizeWritten = 0;
}
@Override
public int encode(Cell cell, HFileBlockEncodingContext encodingCtx, DataOutputStream out)
throws IOException {
BufferedDataBlockEncodingState state = (BufferedDataBlockEncodingState) encodingCtx
.getEncodingState();
int encodedKvSize = internalEncode(cell, (HFileBlockDefaultEncodingContext) encodingCtx, out);
state.unencodedDataSizeWritten += encodedKvSize;
return encodedKvSize;
}
public abstract int internalEncode(Cell cell, HFileBlockDefaultEncodingContext encodingCtx,
DataOutputStream out) throws IOException;
@Override
public void endBlockEncoding(HFileBlockEncodingContext encodingCtx, DataOutputStream out,
byte[] uncompressedBytesWithHeader) throws IOException {
BufferedDataBlockEncodingState state = (BufferedDataBlockEncodingState) encodingCtx
.getEncodingState();
// Write the unencodedDataSizeWritten (with header size)
Bytes.putInt(uncompressedBytesWithHeader, HConstants.HFILEBLOCK_HEADER_SIZE
+ DataBlockEncoding.ID_SIZE, state.unencodedDataSizeWritten
);
if (encodingCtx.getDataBlockEncoding() != DataBlockEncoding.NONE) {
encodingCtx.postEncoding(BlockType.ENCODED_DATA);
} else {
encodingCtx.postEncoding(BlockType.DATA);
}
}
}