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   /*
    * Copyright 2013 The Netty Project
    *
    * The Netty Project 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:
    *
    *   https://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 io.netty.buffer;
  
  import io.netty.util.internal.ObjectUtil;
  
  import java.nio.ByteOrder;
  
  /**
   * A {@link ByteBuf} implementation that wraps another buffer to prevent a user from increasing or decreasing the
   * wrapped buffer's reference count.
   */
  final class UnreleasableByteBuf extends WrappedByteBuf {
  
      private SwappedByteBuf swappedBuf;
  
      UnreleasableByteBuf(ByteBuf buf) {
          super(buf instanceof UnreleasableByteBuf ? buf.unwrap() : buf);
      }
  
      @Override
      public ByteBuf order(ByteOrder endianness) {
          if (ObjectUtil.checkNotNull(endianness, "endianness") == order()) {
              return this;
          }
  
          SwappedByteBuf swappedBuf = this.swappedBuf;
          if (swappedBuf == null) {
              this.swappedBuf = swappedBuf = new SwappedByteBuf(this);
          }
          return swappedBuf;
      }
  
      @Override
      public ByteBuf asReadOnly() {
          return buf.isReadOnly() ? this : new UnreleasableByteBuf(buf.asReadOnly());
      }
  
      @Override
      public ByteBuf readSlice(int length) {
          return new UnreleasableByteBuf(buf.readSlice(length));
      }
  
      @Override
      public ByteBuf readRetainedSlice(int length) {
          // We could call buf.readSlice(..), and then call buf.release(). However this creates a leak in unit tests
          // because the release method on UnreleasableByteBuf will never allow the leak record to be cleaned up.
          // So we just use readSlice(..) because the end result should be logically equivalent.
          return readSlice(length);
      }
  
      @Override
      public ByteBuf slice() {
          return new UnreleasableByteBuf(buf.slice());
      }
  
      @Override
      public ByteBuf retainedSlice() {
          // We could call buf.retainedSlice(), and then call buf.release(). However this creates a leak in unit tests
          // because the release method on UnreleasableByteBuf will never allow the leak record to be cleaned up.
          // So we just use slice() because the end result should be logically equivalent.
          return slice();
      }
  
      @Override
      public ByteBuf slice(int index, int length) {
          return new UnreleasableByteBuf(buf.slice(index, length));
      }
  
      @Override
      public ByteBuf retainedSlice(int index, int length) {
          // We could call buf.retainedSlice(..), and then call buf.release(). However this creates a leak in unit tests
          // because the release method on UnreleasableByteBuf will never allow the leak record to be cleaned up.
          // So we just use slice(..) because the end result should be logically equivalent.
          return slice(index, length);
      }
  
      @Override
      public ByteBuf duplicate() {
          return new UnreleasableByteBuf(buf.duplicate());
      }
  
      @Override
      public ByteBuf retainedDuplicate() {
          // We could call buf.retainedDuplicate(), and then call buf.release(). However this creates a leak in unit tests
          // because the release method on UnreleasableByteBuf will never allow the leak record to be cleaned up.
         // So we just use duplicate() because the end result should be logically equivalent.
         return duplicate();
     }
 
     @Override
     public ByteBuf retain(int increment) {
         return this;
     }
 
     @Override
     public ByteBuf retain() {
         return this;
     }
 
     @Override
     public ByteBuf touch() {
         return this;
     }
 
     @Override
     public ByteBuf touch(Object hint) {
         return this;
     }
 
     @Override
     public boolean release() {
         return false;
     }
 
     @Override
     public boolean release(int decrement) {
         return false;
     }
 }