kafka DefaultRecord 源码
kafka DefaultRecord 代码
文件路径：/clients/src/main/java/org/apache/kafka/common/record/DefaultRecord.java
/*
* 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.kafka.common.record;
import org.apache.kafka.common.InvalidRecordException;
import org.apache.kafka.common.header.Header;
import org.apache.kafka.common.header.internals.RecordHeader;
import org.apache.kafka.common.utils.ByteUtils;
import org.apache.kafka.common.utils.PrimitiveRef;
import org.apache.kafka.common.utils.PrimitiveRef.IntRef;
import org.apache.kafka.common.utils.Utils;
import java.io.DataInput;
import java.io.DataOutputStream;
import java.io.IOException;
import java.nio.BufferUnderflowException;
import java.nio.ByteBuffer;
import java.util.Arrays;
import java.util.Objects;
import static org.apache.kafka.common.record.RecordBatch.MAGIC_VALUE_V2;
/**
* This class implements the inner record format for magic 2 and above. The schema is as follows:
*
*
* Record =>
* Length => Varint
* Attributes => Int8
* TimestampDelta => Varlong
* OffsetDelta => Varint
* Key => Bytes
* Value => Bytes
* Headers => [HeaderKey HeaderValue]
* HeaderKey => String
* HeaderValue => Bytes
*
* Note that in this schema, the Bytes and String types use a variable length integer to represent
* the length of the field. The array type used for the headers also uses a Varint for the number of
* headers.
*
* The current record attributes are depicted below:
*
* ----------------
* | Unused (0-7) |
* ----------------
*
* The offset and timestamp deltas compute the difference relative to the base offset and
* base timestamp of the batch that this record is contained in.
*/
public class DefaultRecord implements Record {
// excluding key, value and headers: 5 bytes length + 10 bytes timestamp + 5 bytes offset + 1 byte attributes
public static final int MAX_RECORD_OVERHEAD = 21;
private static final int NULL_VARINT_SIZE_BYTES = ByteUtils.sizeOfVarint(-1);
private final int sizeInBytes;
private final byte attributes;
private final long offset;
private final long timestamp;
private final int sequence;
private final ByteBuffer key;
private final ByteBuffer value;
private final Header[] headers;
DefaultRecord(int sizeInBytes,
byte attributes,
long offset,
long timestamp,
int sequence,
ByteBuffer key,
ByteBuffer value,
Header[] headers) {
this.sizeInBytes = sizeInBytes;
this.attributes = attributes;
this.offset = offset;
this.timestamp = timestamp;
this.sequence = sequence;
this.key = key;
this.value = value;
this.headers = headers;
}
@Override
public long offset() {
return offset;
}
@Override
public int sequence() {
return sequence;
}
@Override
public int sizeInBytes() {
return sizeInBytes;
}
@Override
public long timestamp() {
return timestamp;
}
public byte attributes() {
return attributes;
}
@Override
public void ensureValid() {}
@Override
public int keySize() {
return key == null ? -1 : key.remaining();
}
@Override
public int valueSize() {
return value == null ? -1 : value.remaining();
}
@Override
public boolean hasKey() {
return key != null;
}
@Override
public ByteBuffer key() {
return key == null ? null : key.duplicate();
}
@Override
public boolean hasValue() {
return value != null;
}
@Override
public ByteBuffer value() {
return value == null ? null : value.duplicate();
}
@Override
public Header[] headers() {
return headers;
}
/**
* Write the record to `out` and return its size.
*/
public static int writeTo(DataOutputStream out,
int offsetDelta,
long timestampDelta,
ByteBuffer key,
ByteBuffer value,
Header[] headers) throws IOException {
int sizeInBytes = sizeOfBodyInBytes(offsetDelta, timestampDelta, key, value, headers);
ByteUtils.writeVarint(sizeInBytes, out);
byte attributes = 0; // there are no used record attributes at the moment
out.write(attributes);
ByteUtils.writeVarlong(timestampDelta, out);
ByteUtils.writeVarint(offsetDelta, out);
if (key == null) {
ByteUtils.writeVarint(-1, out);
} else {
int keySize = key.remaining();
ByteUtils.writeVarint(keySize, out);
Utils.writeTo(out, key, keySize);
}
if (value == null) {
ByteUtils.writeVarint(-1, out);
} else {
int valueSize = value.remaining();
ByteUtils.writeVarint(valueSize, out);
Utils.writeTo(out, value, valueSize);
}
if (headers == null)
throw new IllegalArgumentException("Headers cannot be null");
ByteUtils.writeVarint(headers.length, out);
for (Header header : headers) {
String headerKey = header.key();
if (headerKey == null)
throw new IllegalArgumentException("Invalid null header key found in headers");
byte[] utf8Bytes = Utils.utf8(headerKey);
ByteUtils.writeVarint(utf8Bytes.length, out);
out.write(utf8Bytes);
byte[] headerValue = header.value();
if (headerValue == null) {
ByteUtils.writeVarint(-1, out);
} else {
ByteUtils.writeVarint(headerValue.length, out);
out.write(headerValue);
}
}
return ByteUtils.sizeOfVarint(sizeInBytes) + sizeInBytes;
}
@Override
public boolean hasMagic(byte magic) {
return magic >= MAGIC_VALUE_V2;
}
@Override
public boolean isCompressed() {
return false;
}
@Override
public boolean hasTimestampType(TimestampType timestampType) {
return false;
}
@Override
public String toString() {
return String.format("DefaultRecord(offset=%d, timestamp=%d, key=%d bytes, value=%d bytes)",
offset,
timestamp,
key == null ? 0 : key.limit(),
value == null ? 0 : value.limit());
}
@Override
public boolean equals(Object o) {
if (this == o)
return true;
if (o == null || getClass() != o.getClass())
return false;
DefaultRecord that = (DefaultRecord) o;
return sizeInBytes == that.sizeInBytes &&
attributes == that.attributes &&
offset == that.offset &&
timestamp == that.timestamp &&
sequence == that.sequence &&
Objects.equals(key, that.key) &&
Objects.equals(value, that.value) &&
Arrays.equals(headers, that.headers);
}
@Override
public int hashCode() {
int result = sizeInBytes;
result = 31 * result + (int) attributes;
result = 31 * result + Long.hashCode(offset);
result = 31 * result + Long.hashCode(timestamp);
result = 31 * result + sequence;
result = 31 * result + (key != null ? key.hashCode() : 0);
result = 31 * result + (value != null ? value.hashCode() : 0);
result = 31 * result + Arrays.hashCode(headers);
return result;
}
public static DefaultRecord readFrom(DataInput input,
long baseOffset,
long baseTimestamp,
int baseSequence,
Long logAppendTime) throws IOException {
int sizeOfBodyInBytes = ByteUtils.readVarint(input);
ByteBuffer recordBuffer = ByteBuffer.allocate(sizeOfBodyInBytes);
input.readFully(recordBuffer.array(), 0, sizeOfBodyInBytes);
int totalSizeInBytes = ByteUtils.sizeOfVarint(sizeOfBodyInBytes) + sizeOfBodyInBytes;
return readFrom(recordBuffer, totalSizeInBytes, sizeOfBodyInBytes, baseOffset, baseTimestamp,
baseSequence, logAppendTime);
}
public static DefaultRecord readFrom(ByteBuffer buffer,
long baseOffset,
long baseTimestamp,
int baseSequence,
Long logAppendTime) {
int sizeOfBodyInBytes = ByteUtils.readVarint(buffer);
if (buffer.remaining() < sizeOfBodyInBytes)
throw new InvalidRecordException("Invalid record size: expected " + sizeOfBodyInBytes +
" bytes in record payload, but instead the buffer has only " + buffer.remaining() +
" remaining bytes.");
int totalSizeInBytes = ByteUtils.sizeOfVarint(sizeOfBodyInBytes) + sizeOfBodyInBytes;
return readFrom(buffer, totalSizeInBytes, sizeOfBodyInBytes, baseOffset, baseTimestamp,
baseSequence, logAppendTime);
}
private static DefaultRecord readFrom(ByteBuffer buffer,
int sizeInBytes,
int sizeOfBodyInBytes,
long baseOffset,
long baseTimestamp,
int baseSequence,
Long logAppendTime) {
try {
int recordStart = buffer.position();
byte attributes = buffer.get();
long timestampDelta = ByteUtils.readVarlong(buffer);
long timestamp = baseTimestamp + timestampDelta;
if (logAppendTime != null)
timestamp = logAppendTime;
int offsetDelta = ByteUtils.readVarint(buffer);
long offset = baseOffset + offsetDelta;
int sequence = baseSequence >= 0 ?
DefaultRecordBatch.incrementSequence(baseSequence, offsetDelta) :
RecordBatch.NO_SEQUENCE;
ByteBuffer key = null;
int keySize = ByteUtils.readVarint(buffer);
if (keySize >= 0) {
key = buffer.slice();
key.limit(keySize);
buffer.position(buffer.position() + keySize);
}
ByteBuffer value = null;
int valueSize = ByteUtils.readVarint(buffer);
if (valueSize >= 0) {
value = buffer.slice();
value.limit(valueSize);
buffer.position(buffer.position() + valueSize);
}
int numHeaders = ByteUtils.readVarint(buffer);
if (numHeaders < 0)
throw new InvalidRecordException("Found invalid number of record headers " + numHeaders);
if (numHeaders > buffer.remaining())
throw new InvalidRecordException("Found invalid number of record headers. " + numHeaders + " is larger than the remaining size of the buffer");
final Header[] headers;
if (numHeaders == 0)
headers = Record.EMPTY_HEADERS;
else
headers = readHeaders(buffer, numHeaders);
// validate whether we have read all header bytes in the current record
if (buffer.position() - recordStart != sizeOfBodyInBytes)
throw new InvalidRecordException("Invalid record size: expected to read " + sizeOfBodyInBytes +
" bytes in record payload, but instead read " + (buffer.position() - recordStart));
return new DefaultRecord(sizeInBytes, attributes, offset, timestamp, sequence, key, value, headers);
} catch (BufferUnderflowException | IllegalArgumentException e) {
throw new InvalidRecordException("Found invalid record structure", e);
}
}
public static PartialDefaultRecord readPartiallyFrom(DataInput input,
byte[] skipArray,
long baseOffset,
long baseTimestamp,
int baseSequence,
Long logAppendTime) throws IOException {
int sizeOfBodyInBytes = ByteUtils.readVarint(input);
int totalSizeInBytes = ByteUtils.sizeOfVarint(sizeOfBodyInBytes) + sizeOfBodyInBytes;
return readPartiallyFrom(input, skipArray, totalSizeInBytes, sizeOfBodyInBytes, baseOffset, baseTimestamp,
baseSequence, logAppendTime);
}
private static PartialDefaultRecord readPartiallyFrom(DataInput input,
byte[] skipArray,
int sizeInBytes,
int sizeOfBodyInBytes,
long baseOffset,
long baseTimestamp,
int baseSequence,
Long logAppendTime) throws IOException {
ByteBuffer skipBuffer = ByteBuffer.wrap(skipArray);
// set its limit to 0 to indicate no bytes readable yet
skipBuffer.limit(0);
try {
// reading the attributes / timestamp / offset and key-size does not require
// any byte array allocation and therefore we can just read them straight-forwardly
IntRef bytesRemaining = PrimitiveRef.ofInt(sizeOfBodyInBytes);
byte attributes = readByte(skipBuffer, input, bytesRemaining);
long timestampDelta = readVarLong(skipBuffer, input, bytesRemaining);
long timestamp = baseTimestamp + timestampDelta;
if (logAppendTime != null)
timestamp = logAppendTime;
int offsetDelta = readVarInt(skipBuffer, input, bytesRemaining);
long offset = baseOffset + offsetDelta;
int sequence = baseSequence >= 0 ?
DefaultRecordBatch.incrementSequence(baseSequence, offsetDelta) :
RecordBatch.NO_SEQUENCE;
// first skip key
int keySize = skipLengthDelimitedField(skipBuffer, input, bytesRemaining);
// then skip value
int valueSize = skipLengthDelimitedField(skipBuffer, input, bytesRemaining);
// then skip header
int numHeaders = readVarInt(skipBuffer, input, bytesRemaining);
if (numHeaders < 0)
throw new InvalidRecordException("Found invalid number of record headers " + numHeaders);
for (int i = 0; i < numHeaders; i++) {
int headerKeySize = skipLengthDelimitedField(skipBuffer, input, bytesRemaining);
if (headerKeySize < 0)
throw new InvalidRecordException("Invalid negative header key size " + headerKeySize);
// headerValueSize
skipLengthDelimitedField(skipBuffer, input, bytesRemaining);
}
if (bytesRemaining.value > 0 || skipBuffer.remaining() > 0)
throw new InvalidRecordException("Invalid record size: expected to read " + sizeOfBodyInBytes +
" bytes in record payload, but there are still bytes remaining");
return new PartialDefaultRecord(sizeInBytes, attributes, offset, timestamp, sequence, keySize, valueSize);
} catch (BufferUnderflowException | IllegalArgumentException e) {
throw new InvalidRecordException("Found invalid record structure", e);
}
}
private static byte readByte(ByteBuffer buffer, DataInput input, IntRef bytesRemaining) throws IOException {
if (buffer.remaining() < 1 && bytesRemaining.value > 0) {
readMore(buffer, input, bytesRemaining);
}
return buffer.get();
}
private static long readVarLong(ByteBuffer buffer, DataInput input, IntRef bytesRemaining) throws IOException {
if (buffer.remaining() < 10 && bytesRemaining.value > 0) {
readMore(buffer, input, bytesRemaining);
}
return ByteUtils.readVarlong(buffer);
}
private static int readVarInt(ByteBuffer buffer, DataInput input, IntRef bytesRemaining) throws IOException {
if (buffer.remaining() < 5 && bytesRemaining.value > 0) {
readMore(buffer, input, bytesRemaining);
}
return ByteUtils.readVarint(buffer);
}
private static int skipLengthDelimitedField(ByteBuffer buffer, DataInput input, IntRef bytesRemaining) throws IOException {
boolean needMore = false;
int sizeInBytes = -1;
int bytesToSkip = -1;
while (true) {
if (needMore) {
readMore(buffer, input, bytesRemaining);
needMore = false;
}
if (bytesToSkip < 0) {
if (buffer.remaining() < 5 && bytesRemaining.value > 0) {
needMore = true;
} else {
sizeInBytes = ByteUtils.readVarint(buffer);
if (sizeInBytes <= 0)
return sizeInBytes;
else
bytesToSkip = sizeInBytes;
}
} else {
if (bytesToSkip > buffer.remaining()) {
bytesToSkip -= buffer.remaining();
buffer.position(buffer.limit());
needMore = true;
} else {
buffer.position(buffer.position() + bytesToSkip);
return sizeInBytes;
}
}
}
}
private static void readMore(ByteBuffer buffer, DataInput input, IntRef bytesRemaining) throws IOException {
if (bytesRemaining.value > 0) {
byte[] array = buffer.array();
// first copy the remaining bytes to the beginning of the array;
// at most 4 bytes would be shifted here
int stepsToLeftShift = buffer.position();
int bytesToLeftShift = buffer.remaining();
for (int i = 0; i < bytesToLeftShift; i++) {
array[i] = array[i + stepsToLeftShift];
}
// then try to read more bytes to the remaining of the array
int bytesRead = Math.min(bytesRemaining.value, array.length - bytesToLeftShift);
input.readFully(array, bytesToLeftShift, bytesRead);
buffer.rewind();
// only those many bytes are readable
buffer.limit(bytesToLeftShift + bytesRead);
bytesRemaining.value -= bytesRead;
} else {
throw new InvalidRecordException("Invalid record size: expected to read more bytes in record payload");
}
}
private static Header[] readHeaders(ByteBuffer buffer, int numHeaders) {
Header[] headers = new Header[numHeaders];
for (int i = 0; i < numHeaders; i++) {
int headerKeySize = ByteUtils.readVarint(buffer);
if (headerKeySize < 0)
throw new InvalidRecordException("Invalid negative header key size " + headerKeySize);
ByteBuffer headerKeyBuffer = buffer.slice();
headerKeyBuffer.limit(headerKeySize);
buffer.position(buffer.position() + headerKeySize);
ByteBuffer headerValue = null;
int headerValueSize = ByteUtils.readVarint(buffer);
if (headerValueSize >= 0) {
headerValue = buffer.slice();
headerValue.limit(headerValueSize);
buffer.position(buffer.position() + headerValueSize);
}
headers[i] = new RecordHeader(headerKeyBuffer, headerValue);
}
return headers;
}
public static int sizeInBytes(int offsetDelta,
long timestampDelta,
ByteBuffer key,
ByteBuffer value,
Header[] headers) {
int bodySize = sizeOfBodyInBytes(offsetDelta, timestampDelta, key, value, headers);
return bodySize + ByteUtils.sizeOfVarint(bodySize);
}
public static int sizeInBytes(int offsetDelta,
long timestampDelta,
int keySize,
int valueSize,
Header[] headers) {
int bodySize = sizeOfBodyInBytes(offsetDelta, timestampDelta, keySize, valueSize, headers);
return bodySize + ByteUtils.sizeOfVarint(bodySize);
}
private static int sizeOfBodyInBytes(int offsetDelta,
long timestampDelta,
ByteBuffer key,
ByteBuffer value,
Header[] headers) {
int keySize = key == null ? -1 : key.remaining();
int valueSize = value == null ? -1 : value.remaining();
return sizeOfBodyInBytes(offsetDelta, timestampDelta, keySize, valueSize, headers);
}
public static int sizeOfBodyInBytes(int offsetDelta,
long timestampDelta,
int keySize,
int valueSize,
Header[] headers) {
int size = 1; // always one byte for attributes
size += ByteUtils.sizeOfVarint(offsetDelta);
size += ByteUtils.sizeOfVarlong(timestampDelta);
size += sizeOf(keySize, valueSize, headers);
return size;
}
private static int sizeOf(int keySize, int valueSize, Header[] headers) {
int size = 0;
if (keySize < 0)
size += NULL_VARINT_SIZE_BYTES;
else
size += ByteUtils.sizeOfVarint(keySize) + keySize;
if (valueSize < 0)
size += NULL_VARINT_SIZE_BYTES;
else
size += ByteUtils.sizeOfVarint(valueSize) + valueSize;
if (headers == null)
throw new IllegalArgumentException("Headers cannot be null");
size += ByteUtils.sizeOfVarint(headers.length);
for (Header header : headers) {
String headerKey = header.key();
if (headerKey == null)
throw new IllegalArgumentException("Invalid null header key found in headers");
int headerKeySize = Utils.utf8Length(headerKey);
size += ByteUtils.sizeOfVarint(headerKeySize) + headerKeySize;
byte[] headerValue = header.value();
if (headerValue == null) {
size += NULL_VARINT_SIZE_BYTES;
} else {
size += ByteUtils.sizeOfVarint(headerValue.length) + headerValue.length;
}
}
return size;
}
static int recordSizeUpperBound(ByteBuffer key, ByteBuffer value, Header[] headers) {
int keySize = key == null ? -1 : key.remaining();
int valueSize = value == null ? -1 : value.remaining();
return MAX_RECORD_OVERHEAD + sizeOf(keySize, valueSize, headers);
}
}
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