/**
* 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.hadoop.hdfs.protocol.datatransfer;
import static org.apache.hadoop.hdfs.protocolPB.PBHelper.vintPrefixed;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import com.google.common.collect.Lists;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.hdfs.HdfsConfiguration;
import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_DATANODE_OOB_TIMEOUT_KEY;
import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_DATANODE_OOB_TIMEOUT_DEFAULT;
import org.apache.hadoop.hdfs.protocol.proto.DataTransferProtos.PipelineAckProto;
import org.apache.hadoop.hdfs.protocol.proto.DataTransferProtos.Status;
import com.google.protobuf.TextFormat;
import org.apache.hadoop.hdfs.util.LongBitFormat;
/** Pipeline Acknowledgment **/
@InterfaceAudience.Private
@InterfaceStability.Evolving
public class PipelineAck {
PipelineAckProto proto;
public final static long UNKOWN_SEQNO = -2;
final static int OOB_START = Status.OOB_RESTART_VALUE; // the first OOB type
final static int OOB_END = Status.OOB_RESERVED3_VALUE; // the last OOB type
final static int NUM_OOB_TYPES = OOB_END - OOB_START + 1;
// place holder for timeout value of each OOB type
final static long[] OOB_TIMEOUT;
public enum ECN {
DISABLED(0),
SUPPORTED(1),
SUPPORTED2(2),
CONGESTED(3);
private final int value;
private static final ECN[] VALUES = values();
static ECN valueOf(int value) {
return VALUES[value];
}
ECN(int value) {
this.value = value;
}
public int getValue() {
return value;
}
}
private enum StatusFormat {
STATUS(null, 4),
RESERVED(STATUS.BITS, 1),
ECN_BITS(RESERVED.BITS, 2);
private final LongBitFormat BITS;
StatusFormat(LongBitFormat prev, int bits) {
BITS = new LongBitFormat(name(), prev, bits, 0);
}
static Status getStatus(int header) {
return Status.valueOf((int) STATUS.BITS.retrieve(header));
}
static ECN getECN(int header) {
return ECN.valueOf((int) ECN_BITS.BITS.retrieve(header));
}
public static int setStatus(int old, Status status) {
return (int) STATUS.BITS.combine(status.getNumber(), old);
}
public static int setECN(int old, ECN ecn) {
return (int) ECN_BITS.BITS.combine(ecn.getValue(), old);
}
}
static {
OOB_TIMEOUT = new long[NUM_OOB_TYPES];
HdfsConfiguration conf = new HdfsConfiguration();
String[] ele = conf.get(DFS_DATANODE_OOB_TIMEOUT_KEY,
DFS_DATANODE_OOB_TIMEOUT_DEFAULT).split(",");
for (int i = 0; i < NUM_OOB_TYPES; i++) {
OOB_TIMEOUT[i] = (i < ele.length) ? Long.parseLong(ele[i]) : 0;
}
}
/** default constructor **/
public PipelineAck() {
}
/**
* Constructor assuming no next DN in pipeline
* @param seqno sequence number
* @param replies an array of replies
*/
public PipelineAck(long seqno, int[] replies) {
this(seqno, replies, 0L);
}
/**
* Constructor
* @param seqno sequence number
* @param replies an array of replies
* @param downstreamAckTimeNanos ack RTT in nanoseconds, 0 if no next DN in pipeline
*/
public PipelineAck(long seqno, int[] replies,
long downstreamAckTimeNanos) {
ArrayList<Status> statusList = Lists.newArrayList();
ArrayList<Integer> flagList = Lists.newArrayList();
for (int r : replies) {
statusList.add(StatusFormat.getStatus(r));
flagList.add(r);
}
proto = PipelineAckProto.newBuilder()
.setSeqno(seqno)
.addAllReply(statusList)
.addAllFlag(flagList)
.setDownstreamAckTimeNanos(downstreamAckTimeNanos)
.build();
}
/**
* Get the sequence number
* @return the sequence number
*/
public long getSeqno() {
return proto.getSeqno();
}
/**
* Get the number of replies
* @return the number of replies
*/
public short getNumOfReplies() {
return (short)proto.getReplyCount();
}
/**
* get the header flag of ith reply
*/
public int getHeaderFlag(int i) {
if (proto.getFlagCount() > 0) {
return proto.getFlag(i);
} else {
return combineHeader(ECN.DISABLED, proto.getReply(i));
}
}
public int getFlag(int i) {
return proto.getFlag(i);
}
/**
* Get the time elapsed for downstream ack RTT in nanoseconds
* @return time elapsed for downstream ack in nanoseconds, 0 if no next DN in pipeline
*/
public long getDownstreamAckTimeNanos() {
return proto.getDownstreamAckTimeNanos();
}
/**
* Check if this ack contains error status
* @return true if all statuses are SUCCESS
*/
public boolean isSuccess() {
for (Status s : proto.getReplyList()) {
if (s != Status.SUCCESS) {
return false;
}
}
return true;
}
/**
* Returns the OOB status if this ack contains one.
* @return null if it is not an OOB ack.
*/
public Status getOOBStatus() {
// Normal data transfer acks will have a valid sequence number, so
// this will return right away in most cases.
if (getSeqno() != UNKOWN_SEQNO) {
return null;
}
for (Status s : proto.getReplyList()) {
// The following check is valid because protobuf guarantees to
// preserve the ordering of enum elements.
if (s.getNumber() >= OOB_START && s.getNumber() <= OOB_END) {
return s;
}
}
return null;
}
/**
* Get the timeout to be used for transmitting the OOB type
* @return the timeout in milliseconds
*/
public static long getOOBTimeout(Status status) throws IOException {
int index = status.getNumber() - OOB_START;
if (index >= 0 && index < NUM_OOB_TYPES) {
return OOB_TIMEOUT[index];
}
// Not an OOB.
throw new IOException("Not an OOB status: " + status);
}
/** Get the Restart OOB ack status */
public static Status getRestartOOBStatus() {
return Status.OOB_RESTART;
}
/** return true if it is the restart OOB status code */
public static boolean isRestartOOBStatus(Status st) {
return st.equals(Status.OOB_RESTART);
}
/**** Writable interface ****/
public void readFields(InputStream in) throws IOException {
proto = PipelineAckProto.parseFrom(vintPrefixed(in));
}
public void write(OutputStream out) throws IOException {
proto.writeDelimitedTo(out);
}
@Override //Object
public String toString() {
return TextFormat.shortDebugString(proto);
}
public static Status getStatusFromHeader(int header) {
return StatusFormat.getStatus(header);
}
public static ECN getECNFromHeader(int header) {
return StatusFormat.getECN(header);
}
public static int setStatusForHeader(int old, Status status) {
return StatusFormat.setStatus(old, status);
}
public static int combineHeader(ECN ecn, Status status) {
int header = 0;
header = StatusFormat.setStatus(header, status);
header = StatusFormat.setECN(header, ecn);
return header;
}
}