+++ /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.channels.FileChannel;
-import java.util.zip.CRC32;
-import java.util.zip.Checksum;
-
-/**
- * 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 FileChannelJournalSegmentWriter<E> implements JournalWriter<E> {
- private final FileChannel channel;
- private final JournalSegment<E> segment;
- private final int maxEntrySize;
- private final JournalIndex index;
- private final JournalSerdes namespace;
- private final ByteBuffer memory;
- private final long firstIndex;
- private Indexed<E> lastEntry;
-
- FileChannelJournalSegmentWriter(
- FileChannel channel,
- JournalSegment<E> segment,
- int maxEntrySize,
- JournalIndex index,
- JournalSerdes namespace) {
- this.channel = channel;
- this.segment = segment;
- this.maxEntrySize = maxEntrySize;
- this.index = index;
- this.memory = ByteBuffer.allocate((maxEntrySize + Integer.BYTES + Integer.BYTES) * 2);
- memory.limit(0);
- this.namespace = namespace;
- this.firstIndex = segment.index();
- reset(0);
- }
-
- @Override
- public void reset(long index) {
- long nextIndex = firstIndex;
-
- // Clear the buffer indexes.
- try {
- channel.position(JournalSegmentDescriptor.BYTES);
- memory.clear().flip();
-
- // Record the current buffer position.
- long position = channel.position();
-
- // Read more bytes from the segment if necessary.
- if (memory.remaining() < maxEntrySize) {
- memory.clear();
- channel.read(memory);
- channel.position(position);
- memory.flip();
- }
-
- // Read the entry length.
- memory.mark();
- int length = memory.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 = memory.getInt() & 0xFFFFFFFFL;
-
- // Compute the checksum for the entry bytes.
- final Checksum crc32 = new CRC32();
- crc32.update(memory.array(), memory.position(), length);
-
- // If the stored checksum equals the computed checksum, return the entry.
- if (checksum == crc32.getValue()) {
- int limit = memory.limit();
- memory.limit(memory.position() + length);
- final E entry = namespace.deserialize(memory);
- memory.limit(limit);
- lastEntry = new Indexed<>(nextIndex, entry, length);
- this.index.index(nextIndex, (int) position);
- nextIndex++;
- } else {
- break;
- }
-
- // Update the current position for indexing.
- position = channel.position() + memory.position();
-
- // Read more bytes from the segment if necessary.
- if (memory.remaining() < maxEntrySize) {
- channel.position(position);
- memory.clear();
- channel.read(memory);
- channel.position(position);
- memory.flip();
- }
-
- memory.mark();
- length = memory.getInt();
- }
-
- // Reset the buffer to the previous mark.
- channel.position(channel.position() + memory.reset().position());
- } catch (BufferUnderflowException e) {
- try {
- channel.position(channel.position() + memory.reset().position());
- } catch (IOException e2) {
- throw new StorageException(e2);
- }
- } catch (IOException e) {
- throw new StorageException(e);
- }
- }
-
- @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() {
- try {
- return channel.position();
- } catch (IOException e) {
- throw new StorageException(e);
- }
- }
-
- /**
- * Returns a boolean indicating whether the segment is empty.
- *
- * @return Indicates whether the segment is empty.
- */
- public boolean isEmpty() {
- return lastEntry == null;
- }
-
- /**
- * Returns a boolean indicating whether the segment is full.
- *
- * @return Indicates whether the segment is full.
- */
- public boolean isFull() {
- return size() >= segment.descriptor().maxSegmentSize()
- || getNextIndex() - firstIndex >= segment.descriptor().maxEntries();
- }
-
- /**
- * Returns the first index written to the segment.
- */
- public long firstIndex() {
- return firstIndex;
- }
-
- @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();
-
- try {
- // Serialize the entry.
- memory.clear();
- memory.position(Integer.BYTES + Integer.BYTES);
- try {
- namespace.serialize(entry, memory);
- } catch (KryoException e) {
- throw new StorageException.TooLarge("Entry size exceeds maximum allowed bytes (" + maxEntrySize + ")");
- }
- memory.flip();
-
- final int length = memory.limit() - (Integer.BYTES + Integer.BYTES);
-
- // Ensure there's enough space left in the buffer to store the entry.
- long position = channel.position();
- if (segment.descriptor().maxSegmentSize() - position < length + Integer.BYTES + Integer.BYTES) {
- throw new BufferOverflowException();
- }
-
- // If the entry length exceeds the maximum entry size then throw an exception.
- if (length > maxEntrySize) {
- throw new StorageException.TooLarge("Entry size " + length + " exceeds maximum allowed bytes (" + maxEntrySize + ")");
- }
-
- // Compute the checksum for the entry.
- final Checksum crc32 = new CRC32();
- crc32.update(memory.array(), Integer.BYTES + Integer.BYTES, memory.limit() - (Integer.BYTES + Integer.BYTES));
- 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.
- memory.putInt(0, length);
- memory.putInt(Integer.BYTES, (int) checksum);
- channel.write(memory);
-
- // 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, (int) position);
- return (Indexed<T>) indexedEntry;
- } catch (IOException e) {
- throw new StorageException(e);
- }
- }
-
- @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;
-
- try {
- // Truncate the index.
- this.index.truncate(index);
-
- if (index < segment.index()) {
- channel.position(JournalSegmentDescriptor.BYTES);
- channel.write(zero());
- channel.position(JournalSegmentDescriptor.BYTES);
- } else {
- // Reset the writer to the given index.
- reset(index);
-
- // Zero entries after the given index.
- long position = channel.position();
- channel.write(zero());
- channel.position(position);
- }
- } catch (IOException e) {
- throw new StorageException(e);
- }
- }
-
- /**
- * Returns a zeroed out byte buffer.
- */
- private ByteBuffer zero() {
- memory.clear();
- for (int i = 0; i < memory.limit(); i++) {
- memory.put(i, (byte) 0);
- }
- return memory;
- }
-
- @Override
- public void flush() {
- try {
- if (channel.isOpen()) {
- channel.force(true);
- }
- } catch (IOException e) {
- throw new StorageException(e);
- }
- }
-
- @Override
- public void close() {
- flush();
- }
-}
Code Review / controller.git / blobdiff