jsancio commented on a change in pull request #10085: URL: https://github.com/apache/kafka/pull/10085#discussion_r623367561
########## File path: raft/src/main/java/org/apache/kafka/raft/internals/RecordsIterator.java ########## @@ -0,0 +1,238 @@ +/* + * 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.raft.internals; + +import java.io.IOException; +import java.nio.ByteBuffer; +import java.util.ArrayList; +import java.util.Collections; +import java.util.Iterator; +import java.util.List; +import java.util.NoSuchElementException; +import java.util.Optional; +import org.apache.kafka.common.protocol.DataInputStreamReadable; +import org.apache.kafka.common.protocol.Readable; +import org.apache.kafka.common.record.DefaultRecordBatch; +import org.apache.kafka.common.record.FileRecords; +import org.apache.kafka.common.record.MemoryRecords; +import org.apache.kafka.common.record.MutableRecordBatch; +import org.apache.kafka.common.record.Records; +import org.apache.kafka.common.utils.BufferSupplier; +import org.apache.kafka.raft.BatchReader.Batch; +import org.apache.kafka.raft.RecordSerde; + +public final class RecordsIterator<T> implements Iterator<Batch<T>>, AutoCloseable { + private final Records records; + private final RecordSerde<T> serde; + private final BufferSupplier bufferSupplier; + private final int batchSize; + + private Iterator<MutableRecordBatch> nextBatches = Collections.emptyIterator(); + private Optional<Batch<T>> nextBatch = Optional.empty(); + // Buffer used as the backing store for nextBatches if needed + private Optional<ByteBuffer> allocatedBuffer = Optional.empty(); + // Number of bytes from records read up to now + private int bytesRead = 0; + private boolean isClosed = false; + + public RecordsIterator( + Records records, + RecordSerde<T> serde, + BufferSupplier bufferSupplier, + int batchSize + ) { + this.records = records; + this.serde = serde; + this.bufferSupplier = bufferSupplier; + this.batchSize = Math.max(batchSize, Records.HEADER_SIZE_UP_TO_MAGIC); + } + + @Override + public boolean hasNext() { + ensureOpen(); + + if (!nextBatch.isPresent()) { + nextBatch = nextBatch(); + } + + return nextBatch.isPresent(); + } + + @Override + public Batch<T> next() { + if (!hasNext()) { + throw new NoSuchElementException("Batch iterator doesn't have any more elements"); + } + + Batch<T> batch = nextBatch.get(); + nextBatch = Optional.empty(); + + return batch; + } + + @Override + public void close() { + isClosed = true; + allocatedBuffer.ifPresent(bufferSupplier::release); + allocatedBuffer = Optional.empty(); + } + + private void ensureOpen() { + if (isClosed) { + throw new IllegalStateException("Serde record batch itererator was closed"); + } + } + + private MemoryRecords readFileRecords(FileRecords fileRecords, ByteBuffer buffer) { + int start = buffer.position(); + try { + fileRecords.readInto(buffer, bytesRead); + } catch (IOException e) { + throw new RuntimeException("Failed to read records into memory", e); + } + + bytesRead += buffer.limit() - start; + return MemoryRecords.readableRecords(buffer.slice()); + } + + private MemoryRecords createMemoryRecords(FileRecords fileRecords) { + final ByteBuffer buffer; + if (allocatedBuffer.isPresent()) { + buffer = allocatedBuffer.get(); + buffer.compact(); + } else { + buffer = bufferSupplier.get(Math.min(batchSize, records.sizeInBytes())); + allocatedBuffer = Optional.of(buffer); + } + + MemoryRecords memoryRecords = readFileRecords(fileRecords, buffer); + + if (memoryRecords.firstBatchSize() < buffer.remaining()) { Review comment: Yes. Added a comment. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org
