code: /*
   * Copyright 2012-2018 Chronicle Map Contributors
   *
   * Licensed 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 net.openhft.chronicle.hash.impl.stage.query;
  
  import net.openhft.chronicle.hash.Data;
  import net.openhft.chronicle.hash.impl.VanillaChronicleHashHolder;
  import net.openhft.chronicle.hash.impl.stage.entry.HashEntryStages;
  import net.openhft.chronicle.hash.impl.stage.entry.HashLookupPos;
  import net.openhft.chronicle.hash.impl.stage.entry.HashLookupSearch;
  import net.openhft.chronicle.hash.impl.stage.entry.SegmentStages;
  import net.openhft.chronicle.hash.impl.stage.hash.CheckOnEachPublicOperation;
  import net.openhft.chronicle.hash.serialization.DataAccess;
  import net.openhft.chronicle.set.SetEntry;
  import net.openhft.sg.Stage;
  import net.openhft.sg.StageRef;
  import net.openhft.sg.Staged;
  
  import static net.openhft.chronicle.hash.impl.stage.query.KeySearch.SearchState.ABSENT;
  
  @Staged
  public abstract class HashQuery<K> implements SetEntry<K> {
  
      @StageRef
      public VanillaChronicleHashHolder<K> hh;
      final DataAccess<K> innerInputKeyDataAccess = hh.h().keyDataAccess.copy();
      @StageRef
      public SegmentStages s;
      @StageRef
      public HashEntryStages<K> entry;
      @StageRef
      public HashLookupSearch hashLookupSearch;
      @StageRef
      public CheckOnEachPublicOperation checkOnEachPublicOperation;
      @StageRef
      public HashLookupPos hlp;
      @StageRef
      public KeySearch<K> ks;
      /**
       * This stage exists for hooking {@link #innerInputKeyDataAccess} usage, to trigger {@link
       * DataAccess#uninit()} on context exit
       */
      @Stage("InputKeyDataAccess")
      private boolean inputKeyDataAccessInitialized = false;
      @Stage("PresenceOfEntry")
      private EntryPresence entryPresence = null;
  
      void initInputKeyDataAccess() {
          inputKeyDataAccessInitialized = true;
      }
  
      void closeInputKeyDataAccess() {
          innerInputKeyDataAccess.uninit();
          inputKeyDataAccessInitialized = false;
      }
  
      public DataAccess<K> inputKeyDataAccess() {
          initInputKeyDataAccess();
          return innerInputKeyDataAccess;
      }
  
      public void dropSearchIfNestedContextsAndPresentHashLookupSlotCheckFailed() {
          if (s.locksInit()) {
              if (s.nestedContextsLockedOnSameSegment &&
                      s.rootContextLockedOnThisSegment.latestSameThreadSegmentModCount() !=
                              s.contextModCount) {
                  if (ks.keySearchInit() && ks.searchStatePresent() &&
                          !hashLookupSearch.checkSlotContainsExpectedKeyAndValue(entry.pos)) {
                      hlp.closeHashLookupPos();
                  }
              }
          }
      }
  
      public Data<K> queriedKey() {
          checkOnEachPublicOperation.checkOnEachPublicOperation();
          return ks.inputKey;
      }
  
      private void initPresenceOfEntry() {
          if (ks.searchStatePresent() || tieredEntryPresent()) {
              entryPresence = EntryPresence.PRESENT;
          } else {
              entryPresence = EntryPresence.ABSENT;
          }
      }
  
      public void initPresenceOfEntry(EntryPresence entryPresence) {
          this.entryPresence = entryPresence;
      }
  
      private boolean tieredEntryPresent() {
          int firstTier = s.tier;
          long firstTierBaseAddr = s.tierBaseAddr;
          while (true) {
              if (s.hasNextTier()) {
                  s.nextTier();
              } else {
                  if (s.tier != 0)
                      s.initSegmentTier(); // loop to the root tier
              }
              if (s.tierBaseAddr == firstTierBaseAddr)
                  break;
              if (ks.searchStatePresent())
                  return true;
          }
          // not found
          if (firstTier != 0) {
              // key is absent; probably are going to allocate a new entry;
              // start trying from the root tier
              s.initSegmentTier();
          }
          return false;
      }
  
      public boolean entryPresent() {
          return entryPresence == EntryPresence.PRESENT;
      }
  
      @Override
      public void doRemove() {
          checkOnEachPublicOperation.checkOnEachPublicOperation();
          s.innerWriteLock.lock();
          if (ks.searchStatePresent()) {
              entry.innerRemoveEntryExceptHashLookupUpdate();
              hashLookupSearch.remove();
              ks.setSearchState(ABSENT);
              initPresenceOfEntry(EntryPresence.ABSENT);
          } else {
              throw new IllegalStateException(
                      hh.h().toIdentityString() + ": Entry is absent when doRemove() is called");
          }
      }
  
      public enum EntryPresence {PRESENT, ABSENT}
  }
  