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.kafka.image;
  
  import org.apache.kafka.common.Uuid;
  import org.apache.kafka.common.metadata.AccessControlEntryRecord;
  import org.apache.kafka.common.metadata.RemoveAccessControlEntryRecord;
  import org.apache.kafka.metadata.authorizer.StandardAcl;
  import org.apache.kafka.metadata.authorizer.StandardAclWithId;
  import org.apache.kafka.server.common.MetadataVersion;
  
  import java.util.HashMap;
  import java.util.LinkedHashMap;
  import java.util.Map;
  import java.util.Map.Entry;
  import java.util.Optional;
  import java.util.stream.Collectors;
  
  
  /**
   * Represents changes to the ACLs in the metadata image.
   */
  public final class AclsDelta {
      private final AclsImage image;
      private final Map<Uuid, Optional<StandardAcl>> changes = new LinkedHashMap<>();
  
      public AclsDelta(AclsImage image) {
          this.image = image;
      }
  
      /**
       * Returns a Map of deltas from ACL ID to optional StandardAcl. An empty optional value indicates the ACL
       * is for removal. An optional with a value indicates the ACL is to be added.
       *
       * @return Map of deltas.
       */
      public Map<Uuid, Optional<StandardAcl>> changes() {
          return changes;
      }
  
      void finishSnapshot() {
          for (Entry<Uuid, StandardAcl> entry : image.acls().entrySet()) {
              if (!changes.containsKey(entry.getKey())) {
                  changes.put(entry.getKey(), Optional.empty());
              }
          }
      }
  
      public void handleMetadataVersionChange(MetadataVersion newVersion) {
          // no-op
      }
  
      public void replay(AccessControlEntryRecord record) {
          StandardAclWithId aclWithId = StandardAclWithId.fromRecord(record);
          changes.put(aclWithId.id(), Optional.of(aclWithId.acl()));
      }
  
      /**
       * This method replays a RemoveAccessControlEntryRecord record. If the current image contains the ACL
       * the removal is stored as an Optional.empty() value in the Map. If the changes Map contains the ACL
       * it means the ACL was recently applied and isn't in the image yet, in which case the ACL can be totally removed
       * from the Map because there is no need to add it then delete it when the changes are applied.
       *
       * @param record Log metadata record to replay.
       */
      public void replay(RemoveAccessControlEntryRecord record) {
          if (image.acls().containsKey(record.id())) {
              changes.put(record.id(), Optional.empty());
          } else if (changes.containsKey(record.id())) {
              changes.remove(record.id());
              // No need to track a ACL that was added and deleted within the same delta
          } else {
              throw new IllegalStateException("Failed to find existing ACL with ID " + record.id() + " in either image or changes");
          }
      }
  
      public AclsImage apply() {
          Map<Uuid, StandardAcl> newAcls = new HashMap<>();
          for (Entry<Uuid, StandardAcl> entry : image.acls().entrySet()) {
              Optional<StandardAcl> change = changes.get(entry.getKey());
              if (change == null) {
                  newAcls.put(entry.getKey(), entry.getValue());
              } else if (change.isPresent()) {
                  newAcls.put(entry.getKey(), change.get());
              }
          }
          for (Entry<Uuid, Optional<StandardAcl>> entry : changes.entrySet()) {
              if (!newAcls.containsKey(entry.getKey())) {
                  if (entry.getValue().isPresent()) {
                      newAcls.put(entry.getKey(), entry.getValue().get());
                  }
              }
          }
          return new AclsImage(newAcls);
      }
  
      @Override
      public String toString() {
          return "AclsDelta(" +
              ", changes=" + changes.entrySet().stream().
                  map(e -> e.getKey() + "=" + e.getValue()).
                  collect(Collectors.joining(", ")) + ")";
      }
  }
  