X-Git-Url: https://git.opendaylight.org/gerrit/gitweb?a=blobdiff_plain;f=atomix-storage%2Fsrc%2Fmain%2Fjava%2Fio%2Fatomix%2Fstorage%2Fjournal%2FMappedJournalSegmentWriter.java;h=99180c5840321165696796a45234f5dcfcbb237e;hb=479ecb0109aaa1c8682dd083600b777cbd68dc07;hp=6ca6ab30dd72cce4a8952782375d83a2e17b3c67;hpb=c15f343c9fdf01aaff0170c58398d0b8a7259822;p=controller.git

diff --git a/atomix-storage/src/main/java/io/atomix/storage/journal/MappedJournalSegmentWriter.java b/atomix-storage/src/main/java/io/atomix/storage/journal/MappedJournalSegmentWriter.java
index 6ca6ab30dd..99180c5840 100644
--- a/atomix-storage/src/main/java/io/atomix/storage/journal/MappedJournalSegmentWriter.java
+++ b/atomix-storage/src/main/java/io/atomix/storage/journal/MappedJournalSegmentWriter.java
@@ -1,5 +1,6 @@
 /*
- * Copyright 2017-present Open Networking Foundation
+ * 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.
@@ -15,15 +16,18 @@
  */
 package io.atomix.storage.journal;
 
+import static io.atomix.storage.journal.SegmentEntry.HEADER_BYTES;
+
 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;
+import org.eclipse.jdt.annotation.NonNull;
 
 /**
  * Segment writer.
@@ -40,43 +44,58 @@ import java.util.zip.CRC32;
  *
  * @author <a href="http://github.com/kuujo">Jordan Halterman</a>
  */
-class MappedJournalSegmentWriter<E> implements JournalWriter<E> {
-  private final MappedByteBuffer mappedBuffer;
+final class MappedJournalSegmentWriter<E> extends JournalSegmentWriter<E> {
+  private final @NonNull 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,
+      FileChannel channel,
       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();
+    super(channel, segment, maxEntrySize, index, namespace);
+    mappedBuffer = mapBuffer(channel, maxSegmentSize);
+    buffer = mappedBuffer.slice();
     reset(0);
   }
 
-  /**
-   * Returns the mapped buffer underlying the segment writer.
-   *
-   * @return the mapped buffer underlying the segment writer
-   */
-  MappedByteBuffer buffer() {
+  MappedJournalSegmentWriter(JournalSegmentWriter<E> previous, int position) {
+    super(previous);
+    mappedBuffer = mapBuffer(channel, maxSegmentSize);
+    buffer = mappedBuffer.slice().position(position);
+    lastEntry = previous.getLastEntry();
+  }
+
+  private static @NonNull MappedByteBuffer mapBuffer(FileChannel channel, int maxSegmentSize) {
+    try {
+      return channel.map(FileChannel.MapMode.READ_WRITE, 0, maxSegmentSize);
+    } catch (IOException e) {
+      throw new StorageException(e);
+    }
+  }
+
+  @Override
+  @NonNull MappedByteBuffer buffer() {
     return mappedBuffer;
   }
 
   @Override
-  public void reset(long index) {
+  MappedJournalSegmentWriter<E> toMapped() {
+    return this;
+  }
+
+  @Override
+  DiskJournalSegmentWriter<E> toFileChannel() {
+    final int position = buffer.position();
+    close();
+    return new DiskJournalSegmentWriter<>(this, position);
+  }
+
+  @Override
+  void reset(long index) {
     long nextIndex = firstIndex;
 
     // Clear the buffer indexes.
@@ -97,29 +116,30 @@ class MappedJournalSegmentWriter<E> implements JournalWriter<E> {
         // Read the checksum of the entry.
         final long checksum = buffer.getInt() & 0xFFFFFFFFL;
 
+        // Slice off the entry's bytes
+        final ByteBuffer entryBytes = buffer.slice();
+        entryBytes.limit(length);
+
         // 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 {
+        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, position);
+        nextIndex++;
+
         // Update the current position for indexing.
         position = buffer.position() + length;
         buffer.position(position);
 
-        buffer.mark();
-        length = buffer.getInt();
+        length = buffer.mark().getInt();
       }
 
       // Reset the buffer to the previous mark.
@@ -130,53 +150,23 @@ class MappedJournalSegmentWriter<E> implements JournalWriter<E> {
   }
 
   @Override
-  public long getLastIndex() {
-    return lastEntry != null ? lastEntry.index() : segment.index() - 1;
-  }
-
-  @Override
-  public Indexed<E> getLastEntry() {
+  Indexed<E> getLastEntry() {
     return lastEntry;
   }
 
-  @Override
-  public long getNextIndex() {
-    if (lastEntry != null) {
-      return lastEntry.index() + 1;
-    } else {
-      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) {
+  <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()) {
+    if (position + HEADER_BYTES > buffer.limit()) {
       throw new BufferOverflowException();
     }
 
-    buffer.position(position + Integer.BYTES + Integer.BYTES);
+    buffer.position(position + HEADER_BYTES);
 
     try {
       namespace.serialize(entry, buffer);
@@ -184,7 +174,7 @@ class MappedJournalSegmentWriter<E> implements JournalWriter<E> {
       throw new BufferOverflowException();
     }
 
-    final int length = buffer.position() - (position + Integer.BYTES + Integer.BYTES);
+    final int length = buffer.position() - (position + HEADER_BYTES);
 
     // If the entry length exceeds the maximum entry size then throw an exception.
     if (length > maxEntrySize) {
@@ -195,17 +185,14 @@ class MappedJournalSegmentWriter<E> implements JournalWriter<E> {
 
     // Compute the checksum for the entry.
     final CRC32 crc32 = new CRC32();
-    buffer.position(position + Integer.BYTES + Integer.BYTES);
+    buffer.position(position + HEADER_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);
+    buffer.position(position).putInt(length).putInt((int) checksum).position(position + HEADER_BYTES + length);
 
     // Update the last entry with the correct index/term/length.
     Indexed<E> indexedEntry = new Indexed<>(index, entry, length);
@@ -215,12 +202,7 @@ class MappedJournalSegmentWriter<E> implements JournalWriter<E> {
   }
 
   @Override
-  public void commit(long index) {
-
-  }
-
-  @Override
-  public void truncate(long index) {
+  void truncate(long index) {
     // If the index is greater than or equal to the last index, skip the truncate.
     if (index >= getLastIndex()) {
       return;
@@ -232,30 +214,27 @@ class MappedJournalSegmentWriter<E> implements JournalWriter<E> {
     // Truncate the index.
     this.index.truncate(index);
 
-    if (index < segment.index()) {
-      buffer.position(JournalSegmentDescriptor.BYTES);
-      buffer.putInt(0);
-      buffer.putInt(0);
+    if (index < firstIndex) {
+      // Reset the writer to the first entry.
       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);
     }
+
+    // Zero the entry header at current buffer position.
+    int position = buffer.position();
+    // Note: we issue a single putLong() instead of two putInt()s.
+    buffer.putLong(0).position(position);
   }
 
   @Override
-  public void flush() {
+  void flush() {
     mappedBuffer.force();
   }
 
   @Override
-  public void close() {
+  void close() {
     flush();
     try {
       BufferCleaner.freeBuffer(mappedBuffer);