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      1 /*
      2  * Copyright (C) 2017 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 /*
     18  * Copyright 2013 The Netty Project
     19  *
     20  * The Netty Project licenses this file to you under the Apache License,
     21  * version 2.0 (the "License"); you may not use this file except in compliance
     22  * with the License. You may obtain a copy of the License at:
     23  *
     24  *   http://www.apache.org/licenses/LICENSE-2.0
     25  *
     26  * Unless required by applicable law or agreed to in writing, software
     27  * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
     28  * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
     29  * License for the specific language governing permissions and limitations
     30  * under the License.
     31  */
     32 package org.conscrypt;
     33 
     34 import static org.conscrypt.Preconditions.checkNotNull;
     35 
     36 import java.nio.ByteBuffer;
     37 
     38 /**
     39  * A buffer that was allocated by a {@link BufferAllocator}.
     40  */
     41 @ExperimentalApi
     42 public abstract class AllocatedBuffer {
     43     /**
     44      * Returns the {@link ByteBuffer} that backs this buffer.
     45      */
     46     public abstract ByteBuffer nioBuffer();
     47 
     48     /**
     49      * Increases the reference count by {@code 1}.
     50      */
     51     public abstract AllocatedBuffer retain();
     52 
     53     /**
     54      * Decreases the reference count by {@code 1} and deallocates this object if the reference count
     55      * reaches at {@code 0}.
     56      *
     57      * @return {@code true} if and only if the reference count became {@code 0} and this object has
     58      * been deallocated
     59      */
     60     public abstract AllocatedBuffer release();
     61 
     62     /**
     63      * Creates a new {@link AllocatedBuffer} that is backed by the given {@link ByteBuffer}.
     64      */
     65     public static AllocatedBuffer wrap(final ByteBuffer buffer) {
     66         checkNotNull(buffer, "buffer");
     67 
     68         return new AllocatedBuffer() {
     69 
     70             @Override
     71             public ByteBuffer nioBuffer() {
     72                 return buffer;
     73             }
     74 
     75             @Override
     76             public AllocatedBuffer retain() {
     77                 // Do nothing.
     78                 return this;
     79             }
     80 
     81             @Override
     82             public AllocatedBuffer release() {
     83                 // Do nothing.
     84                 return this;
     85             }
     86         };
     87     }
     88 }
     89