| /** |
| * 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 com.twitter.distributedlog; |
| |
| import static com.twitter.distributedlog.LogRecordSet.COMPRESSION_CODEC_LZ4; |
| import static com.twitter.distributedlog.LogRecordSet.METADATA_COMPRESSION_MASK; |
| import static com.twitter.distributedlog.LogRecordSet.METADATA_VERSION_MASK; |
| import static com.twitter.distributedlog.LogRecordSet.NULL_OP_STATS_LOGGER; |
| import static com.twitter.distributedlog.LogRecordSet.VERSION; |
| |
| import com.twitter.distributedlog.io.CompressionCodec; |
| import com.twitter.distributedlog.io.CompressionUtils; |
| import java.io.DataInputStream; |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.nio.ByteBuffer; |
| |
| |
| /** |
| * Record reader to read records from an enveloped entry buffer. |
| */ |
| class EnvelopedRecordSetReader implements LogRecordSet.Reader { |
| |
| private final long logSegmentSeqNo; |
| private final long entryId; |
| private final long transactionId; |
| private final long startSequenceId; |
| private int numRecords; |
| private final ByteBuffer reader; |
| |
| // slot id |
| private long slotId; |
| private int position; |
| |
| EnvelopedRecordSetReader(long logSegmentSeqNo, |
| long entryId, |
| long transactionId, |
| long startSlotId, |
| int startPositionWithinLogSegment, |
| long startSequenceId, |
| InputStream in) |
| throws IOException { |
| this.logSegmentSeqNo = logSegmentSeqNo; |
| this.entryId = entryId; |
| this.transactionId = transactionId; |
| this.slotId = startSlotId; |
| this.position = startPositionWithinLogSegment; |
| this.startSequenceId = startSequenceId; |
| |
| // read data |
| DataInputStream src = new DataInputStream(in); |
| int metadata = src.readInt(); |
| int version = metadata & METADATA_VERSION_MASK; |
| if (version != VERSION) { |
| throw new IOException(String.format("Version mismatch while reading. Received: %d," |
| + " Required: %d", version, VERSION)); |
| } |
| int codecCode = metadata & METADATA_COMPRESSION_MASK; |
| this.numRecords = src.readInt(); |
| int originDataLen = src.readInt(); |
| int actualDataLen = src.readInt(); |
| byte[] compressedData = new byte[actualDataLen]; |
| src.readFully(compressedData); |
| |
| if (COMPRESSION_CODEC_LZ4 == codecCode) { |
| CompressionCodec codec = CompressionUtils.getCompressionCodec(CompressionCodec.Type.LZ4); |
| byte[] decompressedData = codec.decompress(compressedData, 0, actualDataLen, |
| originDataLen, NULL_OP_STATS_LOGGER); |
| this.reader = ByteBuffer.wrap(decompressedData); |
| } else { |
| if (originDataLen != actualDataLen) { |
| throw new IOException("Inconsistent data length found for a non-compressed record set : original = " |
| + originDataLen + ", actual = " + actualDataLen); |
| } |
| this.reader = ByteBuffer.wrap(compressedData); |
| } |
| } |
| |
| @Override |
| public LogRecordWithDLSN nextRecord() throws IOException { |
| if (numRecords <= 0) { |
| return null; |
| } |
| |
| int recordLen = reader.getInt(); |
| byte[] recordData = new byte[recordLen]; |
| reader.get(recordData); |
| DLSN dlsn = new DLSN(logSegmentSeqNo, entryId, slotId); |
| |
| LogRecordWithDLSN record = |
| new LogRecordWithDLSN(dlsn, startSequenceId); |
| record.setPositionWithinLogSegment(position); |
| record.setTransactionId(transactionId); |
| record.setPayload(recordData); |
| |
| ++slotId; |
| ++position; |
| --numRecords; |
| |
| return record; |
| } |
| |
| } |