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 io.netty.buffer;
  
  import org.apache.arrow.memory.BufferAllocator;
  
  /**
   * Allows us to decorate ArrowBuf to make it expandable so that we can use them in the context of
   * the Netty framework (thus supporting RPC level memory accounting).
   */
  public class ExpandableByteBuf extends MutableWrappedByteBuf {
  
    private final BufferAllocator allocator;
  
    public ExpandableByteBuf(ByteBuf buffer, BufferAllocator allocator) {
      super(buffer);
      this.allocator = allocator;
    }
  
    @Override
    public ByteBuf copy(int index, int length) {
      return new ExpandableByteBuf(buffer.copy(index, length), allocator);
    }
  
    @Override
    public ByteBuf capacity(int newCapacity) {
      if (newCapacity > capacity()) {
        ByteBuf newBuf = NettyArrowBuf.unwrapBuffer(allocator.buffer(newCapacity));
        newBuf.writeBytes(buffer, 0, buffer.capacity());
        newBuf.readerIndex(buffer.readerIndex());
        newBuf.writerIndex(buffer.writerIndex());
        buffer.release();
        buffer = newBuf;
        return newBuf;
      } else {
        return super.capacity(newCapacity);
      }
    }
  }
  