content: /*
   *
   * 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.bookkeeper.proto;
  
  import com.google.protobuf.ByteString;
  import io.netty.buffer.ByteBuf;
  import io.netty.util.ReferenceCountUtil;
  import java.io.IOException;
  import java.util.concurrent.TimeUnit;
  import org.apache.bookkeeper.bookie.Bookie;
  import org.apache.bookkeeper.bookie.BookieException;
  import org.apache.bookkeeper.common.util.MathUtils;
  import org.apache.bookkeeper.proto.BookkeeperProtocol.ReadLacRequest;
  import org.apache.bookkeeper.proto.BookkeeperProtocol.ReadLacResponse;
  import org.apache.bookkeeper.proto.BookkeeperProtocol.Request;
  import org.apache.bookkeeper.proto.BookkeeperProtocol.Response;
  import org.apache.bookkeeper.proto.BookkeeperProtocol.StatusCode;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * A read processor for v3 last add confirmed messages.
   */
  class ReadLacProcessorV3 extends PacketProcessorBaseV3 implements Runnable {
      private static final Logger logger = LoggerFactory.getLogger(ReadLacProcessorV3.class);
  
      public ReadLacProcessorV3(Request request, BookieRequestHandler requestHandler,
                               BookieRequestProcessor requestProcessor) {
          super(request, requestHandler, requestProcessor);
      }
  
      // Returns null if there is no exception thrown
      private ReadLacResponse getReadLacResponse() {
          final long startTimeNanos = MathUtils.nowInNano();
          ReadLacRequest readLacRequest = request.getReadLacRequest();
          long ledgerId = readLacRequest.getLedgerId();
  
          final ReadLacResponse.Builder readLacResponse = ReadLacResponse.newBuilder().setLedgerId(ledgerId);
  
          if (!isVersionCompatible()) {
              readLacResponse.setStatus(StatusCode.EBADVERSION);
              return readLacResponse.build();
          }
  
          logger.debug("Received ReadLac request: {}", request);
          StatusCode status = StatusCode.EOK;
          ByteBuf lastEntry = null;
          ByteBuf lac = null;
          try {
              lac = requestProcessor.bookie.getExplicitLac(ledgerId);
              if (lac != null) {
                  readLacResponse.setLacBody(ByteString.copyFrom(lac.nioBuffer()));
              }
          } catch (Bookie.NoLedgerException e) {
              status = StatusCode.ENOLEDGER;
              logger.debug("No ledger found while performing readLac from ledger: {}", ledgerId, e);
          } catch (BookieException.DataUnknownException e) {
              status = StatusCode.EUNKNOWNLEDGERSTATE;
              logger.error("Ledger {} in unknown state and cannot serve reacLac requests", ledgerId, e);
          } catch (BookieException | IOException e) {
              status = StatusCode.EIO;
              logger.error("IOException while performing readLac from ledger: {}", ledgerId, e);
          } finally {
              ReferenceCountUtil.release(lac);
          }
  
          try {
              lastEntry = requestProcessor.bookie.readEntry(ledgerId, BookieProtocol.LAST_ADD_CONFIRMED);
              if (lastEntry != null) {
                  readLacResponse.setLastEntryBody(ByteString.copyFrom(lastEntry.nioBuffer()));
              }
          } catch (Bookie.NoLedgerException e) {
              status = StatusCode.ENOLEDGER;
              logger.debug("No ledger found while trying to read last entry: {}", ledgerId, e);
          } catch (BookieException.DataUnknownException e) {
              status = StatusCode.EUNKNOWNLEDGERSTATE;
              logger.error("Ledger in an unknown state while trying to read last entry: {}", ledgerId, e);
          } catch (BookieException | IOException e) {
              status = StatusCode.EIO;
              logger.error("IOException while trying to read last entry: {}", ledgerId, e);
          } finally {
              ReferenceCountUtil.release(lastEntry);
          }
  
          if ((lac == null) && (lastEntry == null)) {
              status = StatusCode.ENOENTRY;
          }
  
          if (status == StatusCode.EOK) {
              requestProcessor.getRequestStats().getReadLacStats()
                  .registerSuccessfulEvent(MathUtils.elapsedNanos(startTimeNanos), TimeUnit.NANOSECONDS);
          } else {
              requestProcessor.getRequestStats().getReadLacStats()
                  .registerFailedEvent(MathUtils.elapsedNanos(startTimeNanos), TimeUnit.NANOSECONDS);
          }
          // Finally set the status and return
          readLacResponse.setStatus(status);
          return readLacResponse.build();
      }
  
      @Override
      public void run() {
          ReadLacResponse readLacResponse = getReadLacResponse();
          sendResponse(readLacResponse);
      }
  
      private void sendResponse(ReadLacResponse readLacResponse) {
          Response.Builder response = Response.newBuilder()
              .setHeader(getHeader())
              .setStatus(readLacResponse.getStatus())
              .setReadLacResponse(readLacResponse);
          sendResponse(response.getStatus(),
                  response.build(),
                  requestProcessor.getRequestStats().getReadLacRequestStats());
      }
  }
  