HttpObjectEncoder.java — netty Source File

Source Code

/*
 * Copyright 2012 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.handler.codec.http;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufUtil;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelPromise;
import io.netty.channel.FileRegion;
import io.netty.handler.codec.EncoderException;
import io.netty.handler.codec.MessageToMessageEncoder;
import io.netty.util.CharsetUtil;
import io.netty.util.LeakPresenceDetector;
import io.netty.util.ReferenceCountUtil;
import io.netty.util.concurrent.PromiseCombiner;
import io.netty.util.internal.StringUtil;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map.Entry;

import static io.netty.buffer.Unpooled.directBuffer;
import static io.netty.buffer.Unpooled.unreleasableBuffer;
import static io.netty.handler.codec.http.HttpConstants.CR;
import static io.netty.handler.codec.http.HttpConstants.LF;

/**
 * Encodes an {@link HttpMessage} or an {@link HttpContent} into
 * a {@link ByteBuf}.
 *
 * <h3>Extensibility</h3>
 *
 * Please note that this encoder is designed to be extended to implement
 * a protocol derived from HTTP, such as
 * <a href="https://en.wikipedia.org/wiki/Real_Time_Streaming_Protocol">RTSP</a> and
 * <a href="https://en.wikipedia.org/wiki/Internet_Content_Adaptation_Protocol">ICAP</a>.
 * To implement the encoder of such a derived protocol, extend this class and
 * implement all abstract methods properly.
 */
public abstract class HttpObjectEncoder<H extends HttpMessage> extends MessageToMessageEncoder<Object> {

    // this is a constant to decide when it is appropriate to copy the data content into the header buffer
    private static final int COPY_CONTENT_THRESHOLD = 128;
    static final int CRLF_SHORT = (CR << 8) | LF;
    private static final int ZERO_CRLF_MEDIUM = ('0' << 16) | CRLF_SHORT;
// ... (559 more lines)