--- /dev/null
+/*
+ * Copyright 2017-2022 Open Networking Foundation and others. All rights reserved.
+ * Copyright (c) 2024 PANTHEON.tech, s.r.o.
+ *
+ * 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.nio.channels.FileChannel;
+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>
+ */
+final class DiskJournalSegmentWriter<E> extends JournalSegmentWriter<E> {
+ private static final ByteBuffer ZERO_ENTRY_HEADER = ByteBuffer.wrap(new byte[ENTRY_HEADER_BYTES]);
+
+ private final ByteBuffer memory;
+ private Indexed<E> lastEntry;
+ private long currentPosition;
+
+ DiskJournalSegmentWriter(
+ FileChannel channel,
+ JournalSegment<E> segment,
+ int maxEntrySize,
+ JournalIndex index,
+ JournalSerdes namespace) {
+ super(channel, segment, maxEntrySize, index, namespace);
+ memory = allocMemory(maxEntrySize);
+ reset(0);
+ }
+
+ DiskJournalSegmentWriter(JournalSegmentWriter<E> previous, int position) {
+ super(previous);
+ memory = allocMemory(maxEntrySize);
+ lastEntry = previous.getLastEntry();
+ currentPosition = position;
+ }
+
+ private static ByteBuffer allocMemory(int maxEntrySize) {
+ final var buf = ByteBuffer.allocate((maxEntrySize + ENTRY_HEADER_BYTES) * 2);
+ buf.limit(0);
+ return buf;
+ }
+
+ @Override
+ MappedByteBuffer buffer() {
+ return null;
+ }
+
+ @Override
+ MappedJournalSegmentWriter<E> toMapped() {
+ return new MappedJournalSegmentWriter<>(this, (int) currentPosition);
+ }
+
+ @Override
+ DiskJournalSegmentWriter<E> toFileChannel() {
+ return this;
+ }
+
+ @Override
+ void reset(long index) {
+ long nextIndex = firstIndex;
+
+ // Clear the buffer indexes.
+ currentPosition = JournalSegmentDescriptor.BYTES;
+
+ try {
+ // Clear memory buffer and read fist chunk
+ channel.read(memory.clear(), JournalSegmentDescriptor.BYTES);
+ memory.flip();
+
+ // Read the entry length.
+ 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;
+
+ // Slice off the entry's bytes
+ final ByteBuffer entryBytes = memory.slice();
+ entryBytes.limit(length);
+
+ // Compute the checksum for the entry bytes.
+ final CRC32 crc32 = new CRC32();
+ crc32.update(entryBytes);
+
+ // If the stored checksum does not equal the computed checksum, do not proceed further
+ if (checksum != crc32.getValue()) {
+ break;
+ }
+
+ entryBytes.rewind();
+ final E entry = namespace.deserialize(entryBytes);
+ lastEntry = new Indexed<>(nextIndex, entry, length);
+ this.index.index(nextIndex, (int) currentPosition);
+ nextIndex++;
+
+ // Update the current position for indexing.
+ currentPosition = currentPosition + ENTRY_HEADER_BYTES + length;
+ memory.position(memory.position() + length);
+
+ // Read more bytes from the segment if necessary.
+ if (memory.remaining() < maxEntrySize) {
+ channel.read(memory.compact());
+ memory.flip();
+ }
+
+ length = memory.getInt();
+ }
+ } catch (BufferUnderflowException e) {
+ // No-op, position is only updated on success
+ } catch (IOException e) {
+ throw new StorageException(e);
+ }
+ }
+
+ @Override
+ Indexed<E> getLastEntry() {
+ return lastEntry;
+ }
+
+ @Override
+ @SuppressWarnings("unchecked")
+ <T extends E> Indexed<T> append(T entry) {
+ // Store the entry index.
+ final long index = getNextIndex();
+
+ // Serialize the entry.
+ try {
+ namespace.serialize(entry, memory.clear().position(ENTRY_HEADER_BYTES));
+ } catch (KryoException e) {
+ throw new StorageException.TooLarge("Entry size exceeds maximum allowed bytes (" + maxEntrySize + ")");
+ }
+ memory.flip();
+
+ final int length = memory.limit() - ENTRY_HEADER_BYTES;
+
+ // Ensure there's enough space left in the buffer to store the entry.
+ if (maxSegmentSize - currentPosition < length + ENTRY_HEADER_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 CRC32 crc32 = new CRC32();
+ crc32.update(memory.array(), ENTRY_HEADER_BYTES, memory.limit() - ENTRY_HEADER_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).putInt(Integer.BYTES, (int) checksum);
+ try {
+ channel.write(memory, currentPosition);
+ } catch (IOException e) {
+ throw new StorageException(e);
+ }
+
+ // 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) currentPosition);
+
+ currentPosition = currentPosition + ENTRY_HEADER_BYTES + length;
+ return (Indexed<T>) indexedEntry;
+ }
+
+ @Override
+ 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);
+
+ try {
+ if (index < firstIndex) {
+ // Reset the writer to the first entry.
+ currentPosition = JournalSegmentDescriptor.BYTES;
+ } else {
+ // Reset the writer to the given index.
+ reset(index);
+ }
+
+ // Zero the entry header at current channel position.
+ channel.write(ZERO_ENTRY_HEADER.asReadOnlyBuffer(), currentPosition);
+ } catch (IOException e) {
+ throw new StorageException(e);
+ }
+ }
+
+ @Override
+ void flush() {
+ try {
+ if (channel.isOpen()) {
+ channel.force(true);
+ }
+ } catch (IOException e) {
+ throw new StorageException(e);
+ }
+ }
+
+ @Override
+ void close() {
+ flush();
+ }
+}
Code Review / controller.git / blobdiff