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.client;
  
  import io.netty.buffer.ByteBuf;
  import java.util.List;
  import org.apache.bookkeeper.client.ReadLastConfirmedOp.LastConfirmedDataCallback;
  import org.apache.bookkeeper.net.BookieId;
  import org.apache.bookkeeper.proto.BookieClient;
  import org.apache.bookkeeper.proto.BookieProtocol;
  import org.apache.bookkeeper.proto.BookkeeperInternalCallbacks.ReadEntryCallback;
  import org.apache.bookkeeper.proto.checksum.DigestManager.RecoveryData;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * This op is try to read last confirmed without involving quorum coverage checking.
   * Use {@link ReadLastConfirmedOp} if you need quorum coverage checking.
   */
  class TryReadLastConfirmedOp implements ReadEntryCallback {
  
      static final Logger LOG = LoggerFactory.getLogger(TryReadLastConfirmedOp.class);
  
      final LedgerHandle lh;
      final BookieClient bookieClient;
      final LastConfirmedDataCallback cb;
  
      int numResponsesPending;
      volatile boolean hasValidResponse = false;
      volatile boolean completed = false;
      RecoveryData maxRecoveredData;
      final List<BookieId> currentEnsemble;
  
      TryReadLastConfirmedOp(LedgerHandle lh, BookieClient bookieClient,
                             List<BookieId> ensemble, LastConfirmedDataCallback cb, long lac) {
          this.lh = lh;
          this.bookieClient = bookieClient;
          this.cb = cb;
          this.maxRecoveredData = new RecoveryData(lac, 0);
          this.numResponsesPending = lh.getLedgerMetadata().getEnsembleSize();
          this.currentEnsemble = ensemble;
      }
  
      public void initiate() {
          for (int i = 0; i < currentEnsemble.size(); i++) {
              bookieClient.readEntry(currentEnsemble.get(i),
                                     lh.ledgerId,
                                     BookieProtocol.LAST_ADD_CONFIRMED,
                                     this, i, BookieProtocol.FLAG_NONE);
          }
      }
  
      @Override
      public void readEntryComplete(int rc, long ledgerId, long entryId, ByteBuf buffer, Object ctx) {
          if (LOG.isTraceEnabled()) {
              LOG.trace("TryReadLastConfirmed received response for (lid={}, eid={}) : {}",
                      ledgerId, entryId, rc);
          }
  
          int bookieIndex = (Integer) ctx;
          numResponsesPending--;
          if (BKException.Code.OK == rc) {
              try {
                  RecoveryData recoveryData = lh.macManager.verifyDigestAndReturnLastConfirmed(buffer);
                  if (LOG.isTraceEnabled()) {
                      LOG.trace("Received lastAddConfirmed (lac={}, length={}) from bookie({}) for (lid={}).",
                              recoveryData.getLastAddConfirmed(), recoveryData.getLength(), bookieIndex, ledgerId);
                  }
                  if (recoveryData.getLastAddConfirmed() > maxRecoveredData.getLastAddConfirmed()) {
                      maxRecoveredData = recoveryData;
                      // callback immediately
                      cb.readLastConfirmedDataComplete(BKException.Code.OK, maxRecoveredData);
                  }
                  hasValidResponse = true;
              } catch (BKException.BKDigestMatchException e) {
                  LOG.error("Mac mismatch for ledger: " + ledgerId + ", entry: " + entryId
                            + " while reading last entry from bookie: "
                            + currentEnsemble.get(bookieIndex));
              }
          } else if (BKException.Code.UnauthorizedAccessException == rc && !completed) {
              cb.readLastConfirmedDataComplete(rc, maxRecoveredData);
              completed = true;
          } else if (BKException.Code.NoSuchLedgerExistsException == rc || BKException.Code.NoSuchEntryException == rc) {
              hasValidResponse = true;
          }
          if (numResponsesPending == 0 && !completed) {
              if (!hasValidResponse) {
                  // no success called
                  cb.readLastConfirmedDataComplete(BKException.Code.LedgerRecoveryException, maxRecoveredData);
              } else {
                  // callback
                  cb.readLastConfirmedDataComplete(BKException.Code.OK, maxRecoveredData);
              }
              completed = true;
          }
      }
  }
  