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.streams.state.internals;
  
  import org.apache.kafka.streams.processor.internals.ProcessorRecordContext;
  
  import java.nio.ByteBuffer;
  import java.util.Arrays;
  import java.util.Objects;
  
  import static org.apache.kafka.common.utils.Utils.getNullableArray;
  import static org.apache.kafka.common.utils.Utils.getNullableSizePrefixedArray;
  
  public final class BufferValue {
      private static final int NULL_VALUE_SENTINEL = -1;
      private static final int OLD_PREV_DUPLICATE_VALUE_SENTINEL = -2;
      private final byte[] priorValue;
      private final byte[] oldValue;
      private final byte[] newValue;
      private final ProcessorRecordContext recordContext;
  
      BufferValue(final byte[] priorValue,
                  final byte[] oldValue,
                  final byte[] newValue,
                  final ProcessorRecordContext recordContext) {
          this.oldValue = oldValue;
          this.newValue = newValue;
          this.recordContext = recordContext;
  
          // This de-duplicates the prior and old references.
          // If they were already the same reference, the comparison is trivially fast, so we don't specifically check
          // for that case.
          if (Arrays.equals(priorValue, oldValue)) {
              this.priorValue = oldValue;
          } else {
              this.priorValue = priorValue;
          }
      }
  
      byte[] priorValue() {
          return priorValue;
      }
  
      byte[] oldValue() {
          return oldValue;
      }
  
      byte[] newValue() {
          return newValue;
      }
  
      ProcessorRecordContext context() {
          return recordContext;
      }
  
      static BufferValue deserialize(final ByteBuffer buffer) {
          final ProcessorRecordContext context = ProcessorRecordContext.deserialize(buffer);
  
          final byte[] priorValue = getNullableSizePrefixedArray(buffer);
  
          final byte[] oldValue;
          final int oldValueLength = buffer.getInt();
          if (oldValueLength == OLD_PREV_DUPLICATE_VALUE_SENTINEL) {
              oldValue = priorValue;
          } else {
              oldValue = getNullableArray(buffer, oldValueLength);
          }
  
          final byte[] newValue = getNullableSizePrefixedArray(buffer);
  
          return new BufferValue(priorValue, oldValue, newValue, context);
      }
  
      ByteBuffer serialize(final int endPadding) {
  
          final int sizeOfValueLength = Integer.BYTES;
  
          final int sizeOfPriorValue = priorValue == null ? 0 : priorValue.length;
          final int sizeOfOldValue = oldValue == null || priorValue == oldValue ? 0 : oldValue.length;
          final int sizeOfNewValue = newValue == null ? 0 : newValue.length;
  
          final byte[] serializedContext = recordContext.serialize();
  
          final ByteBuffer buffer = ByteBuffer.allocate(
              serializedContext.length
                  + sizeOfValueLength + sizeOfPriorValue
                  + sizeOfValueLength + sizeOfOldValue
                  + sizeOfValueLength + sizeOfNewValue
                  + endPadding
          );
  
          buffer.put(serializedContext);
  
          addValue(buffer, priorValue);
  
          if (oldValue == null) {
              buffer.putInt(NULL_VALUE_SENTINEL);
          } else if (Arrays.equals(priorValue, oldValue)) {
              buffer.putInt(OLD_PREV_DUPLICATE_VALUE_SENTINEL);
          } else {
              buffer.putInt(sizeOfOldValue);
              buffer.put(oldValue);
          }
  
          addValue(buffer, newValue);
  
          return buffer;
      }
  
      private static void addValue(final ByteBuffer buffer, final byte[] value) {
          if (value == null) {
              buffer.putInt(NULL_VALUE_SENTINEL);
          } else {
              buffer.putInt(value.length);
              buffer.put(value);
          }
      }
  
      long residentMemorySizeEstimate() {
          return (priorValue == null ? 0 : priorValue.length)
              + (oldValue == null || priorValue == oldValue ? 0 : oldValue.length)
              + (newValue == null ? 0 : newValue.length)
              + recordContext.residentMemorySizeEstimate();
      }
  
      @Override
      public boolean equals(final Object o) {
          if (this == o) return true;
          if (o == null || getClass() != o.getClass()) return false;
          final BufferValue that = (BufferValue) o;
          return Arrays.equals(priorValue, that.priorValue) &&
              Arrays.equals(oldValue, that.oldValue) &&
              Arrays.equals(newValue, that.newValue) &&
              Objects.equals(recordContext, that.recordContext);
      }
  
      @Override
      public int hashCode() {
          int result = Objects.hash(recordContext);
          result = 31 * result + Arrays.hashCode(priorValue);
          result = 31 * result + Arrays.hashCode(oldValue);
          result = 31 * result + Arrays.hashCode(newValue);
          return result;
      }
  
      @Override
      public String toString() {
          return "BufferValue{" +
              "priorValue=" + Arrays.toString(priorValue) +
              ", oldValue=" + Arrays.toString(oldValue) +
              ", newValue=" + Arrays.toString(newValue) +
              ", recordContext=" + recordContext +
              '}';
      }
  }
  