+++ /dev/null
-/*
- * Copyright 2017-present Open Networking Foundation
- *
- * Licensed 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 io.atomix.storage.journal;
-
-import com.esotericsoftware.kryo.KryoException;
-import io.atomix.storage.journal.index.JournalIndex;
-
-import java.io.IOException;
-import java.nio.BufferOverflowException;
-import java.nio.BufferUnderflowException;
-import java.nio.ByteBuffer;
-import java.nio.MappedByteBuffer;
-import java.util.zip.CRC32;
-
-/**
- * Segment writer.
- * <p>
- * The format of an entry in the log is as follows:
- * <ul>
- * <li>64-bit index</li>
- * <li>8-bit boolean indicating whether a term change is contained in the entry</li>
- * <li>64-bit optional term</li>
- * <li>32-bit signed entry length, including the entry type ID</li>
- * <li>8-bit signed entry type ID</li>
- * <li>n-bit entry bytes</li>
- * </ul>
- *
- * @author <a href="http://github.com/kuujo">Jordan Halterman</a>
- */
-class MappedJournalSegmentWriter<E> implements JournalWriter<E> {
- private final MappedByteBuffer mappedBuffer;
- private final ByteBuffer buffer;
- private final JournalSegment<E> segment;
- private final int maxEntrySize;
- private final JournalIndex index;
- private final JournalSerdes namespace;
- private final long firstIndex;
- private Indexed<E> lastEntry;
-
- MappedJournalSegmentWriter(
- MappedByteBuffer buffer,
- JournalSegment<E> segment,
- int maxEntrySize,
- JournalIndex index,
- JournalSerdes namespace) {
- this.mappedBuffer = buffer;
- this.buffer = buffer.slice();
- this.segment = segment;
- this.maxEntrySize = maxEntrySize;
- this.index = index;
- this.namespace = namespace;
- this.firstIndex = segment.index();
- reset(0);
- }
-
- /**
- * Returns the mapped buffer underlying the segment writer.
- *
- * @return the mapped buffer underlying the segment writer
- */
- MappedByteBuffer buffer() {
- return mappedBuffer;
- }
-
- @Override
- public void reset(long index) {
- long nextIndex = firstIndex;
-
- // Clear the buffer indexes.
- buffer.position(JournalSegmentDescriptor.BYTES);
-
- // Record the current buffer position.
- int position = buffer.position();
-
- // Read the entry length.
- buffer.mark();
-
- try {
- int length = buffer.getInt();
-
- // If the length is non-zero, read the entry.
- while (0 < length && length <= maxEntrySize && (index == 0 || nextIndex <= index)) {
-
- // Read the checksum of the entry.
- final long checksum = buffer.getInt() & 0xFFFFFFFFL;
-
- // Compute the checksum for the entry bytes.
- final CRC32 crc32 = new CRC32();
- ByteBuffer slice = buffer.slice();
- slice.limit(length);
- crc32.update(slice);
-
- // If the stored checksum equals the computed checksum, return the entry.
- if (checksum == crc32.getValue()) {
- slice.rewind();
- final E entry = namespace.deserialize(slice);
- lastEntry = new Indexed<>(nextIndex, entry, length);
- this.index.index(nextIndex, position);
- nextIndex++;
- } else {
- break;
- }
-
- // Update the current position for indexing.
- position = buffer.position() + length;
- buffer.position(position);
-
- buffer.mark();
- length = buffer.getInt();
- }
-
- // Reset the buffer to the previous mark.
- buffer.reset();
- } catch (BufferUnderflowException e) {
- buffer.reset();
- }
- }
-
- @Override
- public long getLastIndex() {
- return lastEntry != null ? lastEntry.index() : segment.index() - 1;
- }
-
- @Override
- public Indexed<E> getLastEntry() {
- return lastEntry;
- }
-
- @Override
- public long getNextIndex() {
- if (lastEntry != null) {
- return lastEntry.index() + 1;
- } else {
- return firstIndex;
- }
- }
-
- /**
- * Returns the size of the underlying buffer.
- *
- * @return The size of the underlying buffer.
- */
- public long size() {
- return buffer.position() + JournalSegmentDescriptor.BYTES;
- }
-
- /**
- * Returns a boolean indicating whether the segment is empty.
- *
- * @return Indicates whether the segment is empty.
- */
- public boolean isEmpty() {
- return lastEntry == null;
- }
-
- @Override
- public void append(Indexed<E> entry) {
- final long nextIndex = getNextIndex();
-
- // If the entry's index is greater than the next index in the segment, skip some entries.
- if (entry.index() > nextIndex) {
- throw new IndexOutOfBoundsException("Entry index is not sequential");
- }
-
- // If the entry's index is less than the next index, truncate the segment.
- if (entry.index() < nextIndex) {
- truncate(entry.index() - 1);
- }
- append(entry.entry());
- }
-
- @Override
- @SuppressWarnings("unchecked")
- public <T extends E> Indexed<T> append(T entry) {
- // Store the entry index.
- final long index = getNextIndex();
-
- // Serialize the entry.
- int position = buffer.position();
- if (position + Integer.BYTES + Integer.BYTES > buffer.limit()) {
- throw new BufferOverflowException();
- }
-
- buffer.position(position + Integer.BYTES + Integer.BYTES);
-
- try {
- namespace.serialize(entry, buffer);
- } catch (KryoException e) {
- throw new BufferOverflowException();
- }
-
- final int length = buffer.position() - (position + Integer.BYTES + Integer.BYTES);
-
- // If the entry length exceeds the maximum entry size then throw an exception.
- if (length > maxEntrySize) {
- // Just reset the buffer. There's no need to zero the bytes since we haven't written the length or checksum.
- buffer.position(position);
- throw new StorageException.TooLarge("Entry size " + length + " exceeds maximum allowed bytes (" + maxEntrySize + ")");
- }
-
- // Compute the checksum for the entry.
- final CRC32 crc32 = new CRC32();
- buffer.position(position + Integer.BYTES + Integer.BYTES);
- ByteBuffer slice = buffer.slice();
- slice.limit(length);
- crc32.update(slice);
- final long checksum = crc32.getValue();
-
- // Create a single byte[] in memory for the entire entry and write it as a batch to the underlying buffer.
- buffer.position(position);
- buffer.putInt(length);
- buffer.putInt((int) checksum);
- buffer.position(position + Integer.BYTES + Integer.BYTES + length);
-
- // Update the last entry with the correct index/term/length.
- Indexed<E> indexedEntry = new Indexed<>(index, entry, length);
- this.lastEntry = indexedEntry;
- this.index.index(index, position);
- return (Indexed<T>) indexedEntry;
- }
-
- @Override
- public void commit(long index) {
-
- }
-
- @Override
- public void truncate(long index) {
- // If the index is greater than or equal to the last index, skip the truncate.
- if (index >= getLastIndex()) {
- return;
- }
-
- // Reset the last entry.
- lastEntry = null;
-
- // Truncate the index.
- this.index.truncate(index);
-
- if (index < segment.index()) {
- buffer.position(JournalSegmentDescriptor.BYTES);
- buffer.putInt(0);
- buffer.putInt(0);
- buffer.position(JournalSegmentDescriptor.BYTES);
- } else {
- // Reset the writer to the given index.
- reset(index);
-
- // Zero entries after the given index.
- int position = buffer.position();
- buffer.putInt(0);
- buffer.putInt(0);
- buffer.position(position);
- }
- }
-
- @Override
- public void flush() {
- mappedBuffer.force();
- }
-
- @Override
- public void close() {
- flush();
- try {
- BufferCleaner.freeBuffer(mappedBuffer);
- } catch (IOException e) {
- throw new StorageException(e);
- }
- }
-}
Code Review / controller.git / blobdiff