89 lines
2.9 KiB
Java
89 lines
2.9 KiB
Java
/*
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* Copyright 2020 The Netty Project
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*
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* The Netty Project licenses this file to you under the Apache License,
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* version 2.0 (the "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at:
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*
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* https://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*/
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package io.netty.buffer.api;
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import java.lang.invoke.VarHandle;
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/**
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* A mutable reference to a buffer.
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*/
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public final class BufferRef extends BufferHolder<BufferRef> {
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/**
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* Create a reference to the given {@linkplain Buffer buffer}.
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* This increments the reference count of the buffer.
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*
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* @param buf The buffer to reference.
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*/
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public BufferRef(Buffer buf) {
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super(buf);
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// BufferRef is meant to be atomic, so we need to add a fence to get the semantics of a volatile store.
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VarHandle.fullFence();
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}
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/**
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* Create a reference that holds the exclusive ownership of the sent buffer.
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*
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* @param send The {@linkplain Send sent} buffer to take ownership of.
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*/
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public BufferRef(Send<Buffer> send) {
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super(send);
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// BufferRef is meant to be atomic, so we need to add a fence to get the semantics of a volatile store.
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VarHandle.fullFence();
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}
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@Override
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protected BufferRef receive(Buffer buf) {
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return new BufferRef(buf);
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}
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/**
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* Replace the underlying referenced buffer with the given buffer.
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* <p>
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* <strong>Note:</strong> this method decreases the reference count of the current buffer,
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* and increases the reference count of the new buffer.
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* <p>
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* The buffer assignment is performed using a volatile store.
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*
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* @param newBuf The new {@link Buffer} instance that is replacing the currently held buffer.
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*/
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public void replace(Buffer newBuf) {
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replaceBufVolatile(newBuf);
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}
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/**
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* Replace the underlying referenced buffer with the given buffer.
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* <p>
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* <strong>Note:</strong> this method decreases the reference count of the current buffer,
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* and takes exclusive ownership of the sent buffer.
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* <p>
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* The buffer assignment is performed using a volatile store.
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*
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* @param send The {@link Send} with the new {@link Buffer} instance that is replacing the currently held buffer.
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*/
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public void replace(Send<Buffer> send) {
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replaceBufVolatile(send);
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}
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/**
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* Access the buffer in this reference.
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*
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* @return The buffer held by the reference.
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*/
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public Buffer contents() {
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return getBufVolatile();
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}
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}
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