1 /*
2 * Copyright 2025 The Netty Project
3 *
4 * The Netty Project licenses this file to you under the Apache License,
5 * version 2.0 (the "License"); you may not use this file except in compliance
6 * with the License. You may obtain a copy of the License at:
7 *
8 * https://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, WITHOUT
12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13 * License for the specific language governing permissions and limitations
14 * under the License.
15 */
16 package io.netty.util.internal;
17
18 import java.nio.ByteBuffer;
19
20 /**
21 * Encapsulates a direct {@link ByteBuffer} and its mechanism for immediate deallocation, if any.
22 */
23 public interface CleanableDirectBuffer {
24 /**
25 * Get the buffer instance.
26 * <p>
27 * Note: the buffer must not be accessed after the {@link #clean()} method has been called.
28 *
29 * @return The {@link ByteBuffer} instance.
30 */
31 ByteBuffer buffer();
32
33 /**
34 * Deallocate the buffer. This method can only be called once per instance,
35 * and all usages of the buffer must have ceased before this method is called,
36 * and the buffer must not be accessed again after this method has been called.
37 */
38 void clean();
39
40 /**
41 * @return {@code true} if the {@linkplain #memoryAddress() native memory address} is available,
42 * otherwise {@code false}.
43 */
44 default boolean hasMemoryAddress() {
45 return false;
46 }
47
48 /**
49 * Get the native memory address, but only if {@link #hasMemoryAddress()} returns true,
50 * otherwise this may return an unspecified value or throw an exception.
51 * @return The native memory address of this buffer, if available.
52 */
53 default long memoryAddress() {
54 return 0;
55 }
56 }