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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up with different versions on classes on the class path).

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/*
 * 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.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelPipeline;
import io.netty.handler.codec.ByteToMessageDecoder;
import io.netty.handler.codec.DecoderResult;
import io.netty.handler.codec.PrematureChannelClosureException;
import io.netty.handler.codec.TooLongFrameException;
import io.netty.util.AsciiString;
import io.netty.util.ByteProcessor;
import io.netty.util.internal.StringUtil;

import java.util.List;
import java.util.concurrent.atomic.AtomicBoolean;

import static io.netty.util.internal.ObjectUtil.checkNotNull;

/**
 * Decodes {@link ByteBuf}s into {@link HttpMessage}s and
 * {@link HttpContent}s.
 *
 * 
Parameters that prevents excessive memory consumption

 * 
 * 
 * 
 * 
 * 
 * 
 * 
 * 
 * 
 * 
 * 
 * 
 * 
 * 
 * 
 * 
 * 
 * 
 * 
 * 
NameDefault valueMeaning
{@code maxInitialLineLength}{@value #DEFAULT_MAX_INITIAL_LINE_LENGTH}The maximum length of the initial line
 *     (e.g. {@code "GET / HTTP/1.0"} or {@code "HTTP/1.0 200 OK"})
 *     If the length of the initial line exceeds this value, a
 *     {@link TooLongHttpLineException} will be raised.
{@code maxHeaderSize}{@value #DEFAULT_MAX_HEADER_SIZE}The maximum length of all headers.  If the sum of the length of each
 *     header exceeds this value, a {@link TooLongHttpHeaderException} will be raised.
{@code maxChunkSize}{@value #DEFAULT_MAX_CHUNK_SIZE}The maximum length of the content or each chunk.  If the content length
 *     (or the length of each chunk) exceeds this value, the content or chunk
 *     will be split into multiple {@link HttpContent}s whose length is
 *     {@code maxChunkSize} at maximum.

 *
 * 
Parameters that control parsing behavior

 * 
 * 
 * 
 * 
 * 
 * 
 * 
 * 
 * 
 * 
 * 
 * 
 * 
 * 
 * 
NameDefault valueMeaning
{@code allowDuplicateContentLengths}{@value #DEFAULT_ALLOW_DUPLICATE_CONTENT_LENGTHS}When set to {@code false}, will reject any messages that contain multiple Content-Length header fields.
 *     When set to {@code true}, will allow multiple Content-Length headers only if they are all the same decimal value.
 *     The duplicated field-values will be replaced with a single valid Content-Length field.
 *     See RFC 7230, Section 3.3.2.
{@code allowPartialChunks}{@value #DEFAULT_ALLOW_PARTIAL_CHUNKS}If the length of a chunk exceeds the {@link ByteBuf}s readable bytes and {@code allowPartialChunks}
 *     is set to {@code true}, the chunk will be split into multiple {@link HttpContent}s.
 *     Otherwise, if the chunk size does not exceed {@code maxChunkSize} and {@code allowPartialChunks}
 *     is set to {@code false}, the {@link ByteBuf} is not decoded into an {@link HttpContent} until
 *     the readable bytes are greater or equal to the chunk size.

 *
 * 
Chunked Content

 *
 * If the content of an HTTP message is greater than {@code maxChunkSize} or
 * the transfer encoding of the HTTP message is 'chunked', this decoder
 * generates one {@link HttpMessage} instance and its following
 * {@link HttpContent}s per single HTTP message to avoid excessive memory
 * consumption. For example, the following HTTP message:
 * 
 * GET / HTTP/1.1
 * Transfer-Encoding: chunked
 *
 * 1a
 * abcdefghijklmnopqrstuvwxyz
 * 10
 * 1234567890abcdef
 * 0
 * Content-MD5: ...
 * [blank line]
 * 

 * triggers {@link HttpRequestDecoder} to generate 3 objects:
 * 
    
 * 
  1. An {@link HttpRequest},
    2. 
 * 
  2. The first {@link HttpContent} whose content is {@code 'abcdefghijklmnopqrstuvwxyz'},
    3. 
 * 
  3. The second {@link LastHttpContent} whose content is {@code '1234567890abcdef'}, which marks
 * the end of the content.
    4. 
 * 

 *
 * If you prefer not to handle {@link HttpContent}s by yourself for your
 * convenience, insert {@link HttpObjectAggregator} after this decoder in the
 * {@link ChannelPipeline}.  However, please note that your server might not
 * be as memory efficient as without the aggregator.
 *
 * 
Extensibility

 *
 * Please note that this decoder is designed to be extended to implement
 * a protocol derived from HTTP, such as
 * RTSP and
 * ICAP.
 * To implement the decoder of such a derived protocol, extend this class and
 * implement all abstract methods properly.
 *
 * 
Header Validation

 *
 * It is recommended to always enable header validation.
 * 

 * Without header validation, your system can become vulnerable to
 * 
 *     CWE-113: Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Response Splitting')
 * .
 * 

 * This recommendation stands even when both peers in the HTTP exchange are trusted,
 * as it helps with defence-in-depth.
 */
public abstract class HttpObjectDecoder extends ByteToMessageDecoder {
    public static final int DEFAULT_MAX_INITIAL_LINE_LENGTH = 4096;
    public static final int DEFAULT_MAX_HEADER_SIZE = 8192;
    public static final boolean DEFAULT_CHUNKED_SUPPORTED = true;
    public static final boolean DEFAULT_ALLOW_PARTIAL_CHUNKS = true;
    public static final int DEFAULT_MAX_CHUNK_SIZE = 8192;
    public static final boolean DEFAULT_VALIDATE_HEADERS = true;
    public static final int DEFAULT_INITIAL_BUFFER_SIZE = 128;
    public static final boolean DEFAULT_ALLOW_DUPLICATE_CONTENT_LENGTHS = false;
    private final int maxChunkSize;
    private final boolean chunkedSupported;
    private final boolean allowPartialChunks;
    /**
     * This field is no longer used. It is only kept around for backwards compatibility purpose.
     */
    @Deprecated
    protected final boolean validateHeaders;
    protected final HttpHeadersFactory headersFactory;
    protected final HttpHeadersFactory trailersFactory;
    private final boolean allowDuplicateContentLengths;
    private final ByteBuf parserScratchBuffer;
    private final HeaderParser headerParser;
    private final LineParser lineParser;

    private HttpMessage message;
    private long chunkSize;
    private long contentLength = Long.MIN_VALUE;
    private boolean chunked;
    private boolean isSwitchingToNonHttp1Protocol;

    private final AtomicBoolean resetRequested = new AtomicBoolean();

    // These will be updated by splitHeader(...)
    private AsciiString name;
    private String value;
    private LastHttpContent trailer;

    @Override
    protected void handlerRemoved0(ChannelHandlerContext ctx) throws Exception {
        try {
            parserScratchBuffer.release();
        } finally {
            super.handlerRemoved0(ctx);
        }
    }

    /**
     * The internal state of {@link HttpObjectDecoder}.
     * Internal use only.
     */
    private enum State {
        SKIP_CONTROL_CHARS,
        READ_INITIAL,
        READ_HEADER,
        READ_VARIABLE_LENGTH_CONTENT,
        READ_FIXED_LENGTH_CONTENT,
        READ_CHUNK_SIZE,
        READ_CHUNKED_CONTENT,
        READ_CHUNK_DELIMITER,
        READ_CHUNK_FOOTER,
        BAD_MESSAGE,
        UPGRADED
    }

    private State currentState = State.SKIP_CONTROL_CHARS;

    /**
     * Creates a new instance with the default
     * {@code maxInitialLineLength (4096)}, {@code maxHeaderSize (8192)}, and
     * {@code maxChunkSize (8192)}.
     */
    protected HttpObjectDecoder() {
        this(new HttpDecoderConfig());
    }

    /**
     * Creates a new instance with the specified parameters.
     *
     * @deprecated Use {@link #HttpObjectDecoder(HttpDecoderConfig)} instead.
     */
    @Deprecated
    protected HttpObjectDecoder(
            int maxInitialLineLength, int maxHeaderSize, int maxChunkSize, boolean chunkedSupported) {
        this(new HttpDecoderConfig()
                .setMaxInitialLineLength(maxInitialLineLength)
                .setMaxHeaderSize(maxHeaderSize)
                .setMaxChunkSize(maxChunkSize)
                .setChunkedSupported(chunkedSupported));
    }

    /**
     * Creates a new instance with the specified parameters.
     *
     * @deprecated Use {@link #HttpObjectDecoder(HttpDecoderConfig)} instead.
     */
    @Deprecated
    protected HttpObjectDecoder(
            int maxInitialLineLength, int maxHeaderSize, int maxChunkSize,
            boolean chunkedSupported, boolean validateHeaders) {
        this(new HttpDecoderConfig()
                .setMaxInitialLineLength(maxInitialLineLength)
                .setMaxHeaderSize(maxHeaderSize)
                .setMaxChunkSize(maxChunkSize)
                .setChunkedSupported(chunkedSupported)
                .setValidateHeaders(validateHeaders));
    }

    /**
     * Creates a new instance with the specified parameters.
     *
     * @deprecated Use {@link #HttpObjectDecoder(HttpDecoderConfig)} instead.
     */
    @Deprecated
    protected HttpObjectDecoder(
            int maxInitialLineLength, int maxHeaderSize, int maxChunkSize,
            boolean chunkedSupported, boolean validateHeaders, int initialBufferSize) {
        this(new HttpDecoderConfig()
                .setMaxInitialLineLength(maxInitialLineLength)
                .setMaxHeaderSize(maxHeaderSize)
                .setMaxChunkSize(maxChunkSize)
                .setChunkedSupported(chunkedSupported)
                .setValidateHeaders(validateHeaders)
                .setInitialBufferSize(initialBufferSize));
    }

    /**
     * Creates a new instance with the specified parameters.
     *
     * @deprecated Use {@link #HttpObjectDecoder(HttpDecoderConfig)} instead.
     */
    @Deprecated
    protected HttpObjectDecoder(
            int maxInitialLineLength, int maxHeaderSize, int maxChunkSize,
            boolean chunkedSupported, boolean validateHeaders, int initialBufferSize,
            boolean allowDuplicateContentLengths) {
        this(new HttpDecoderConfig()
                .setMaxInitialLineLength(maxInitialLineLength)
                .setMaxHeaderSize(maxHeaderSize)
                .setMaxChunkSize(maxChunkSize)
                .setChunkedSupported(chunkedSupported)
                .setValidateHeaders(validateHeaders)
                .setInitialBufferSize(initialBufferSize)
                .setAllowDuplicateContentLengths(allowDuplicateContentLengths));
    }

    /**
     * Creates a new instance with the specified parameters.
     *
     * @deprecated Use {@link #HttpObjectDecoder(HttpDecoderConfig)} instead.
     */
    @Deprecated
    protected HttpObjectDecoder(
            int maxInitialLineLength, int maxHeaderSize, int maxChunkSize,
            boolean chunkedSupported, boolean validateHeaders, int initialBufferSize,
            boolean allowDuplicateContentLengths, boolean allowPartialChunks) {
        this(new HttpDecoderConfig()
                .setMaxInitialLineLength(maxInitialLineLength)
                .setMaxHeaderSize(maxHeaderSize)
                .setMaxChunkSize(maxChunkSize)
                .setChunkedSupported(chunkedSupported)
                .setValidateHeaders(validateHeaders)
                .setInitialBufferSize(initialBufferSize)
                .setAllowDuplicateContentLengths(allowDuplicateContentLengths)
                .setAllowPartialChunks(allowPartialChunks));
    }

    /**
     * Creates a new instance with the specified configuration.
     */
    protected HttpObjectDecoder(HttpDecoderConfig config) {
        checkNotNull(config, "config");

        parserScratchBuffer = Unpooled.buffer(config.getInitialBufferSize());
        lineParser = new LineParser(parserScratchBuffer, config.getMaxInitialLineLength());
        headerParser = new HeaderParser(parserScratchBuffer, config.getMaxHeaderSize());
        maxChunkSize = config.getMaxChunkSize();
        chunkedSupported = config.isChunkedSupported();
        headersFactory = config.getHeadersFactory();
        trailersFactory = config.getTrailersFactory();
        validateHeaders = isValidating(headersFactory);
        allowDuplicateContentLengths = config.isAllowDuplicateContentLengths();
        allowPartialChunks = config.isAllowPartialChunks();
    }

    protected boolean isValidating(HttpHeadersFactory headersFactory) {
        if (headersFactory instanceof DefaultHttpHeadersFactory) {
            DefaultHttpHeadersFactory builder = (DefaultHttpHeadersFactory) headersFactory;
            return builder.isValidatingHeaderNames() || builder.isValidatingHeaderValues();
        }
        return true; // We can't actually tell in this case, but we assume some validation is taking place.
    }

    @Override
    protected void decode(ChannelHandlerContext ctx, ByteBuf buffer, List out) throws Exception {
        if (resetRequested.get()) {
            resetNow();
        }

        switch (currentState) {
        case SKIP_CONTROL_CHARS:
            // Fall-through
        case READ_INITIAL: try {
            ByteBuf line = lineParser.parse(buffer);
            if (line == null) {
                return;
            }
            final String[] initialLine = splitInitialLine(line);
            assert initialLine.length == 3 : "initialLine::length must be 3";

            message = createMessage(initialLine);
            currentState = State.READ_HEADER;
            // fall-through
        } catch (Exception e) {
            out.add(invalidMessage(message, buffer, e));
            return;
        }
        case READ_HEADER: try {
            State nextState = readHeaders(buffer);
            if (nextState == null) {
                return;
            }
            currentState = nextState;
            switch (nextState) {
            case SKIP_CONTROL_CHARS:
                // fast-path
                // No content is expected.
                addCurrentMessage(out);
                out.add(LastHttpContent.EMPTY_LAST_CONTENT);
                resetNow();
                return;
            case READ_CHUNK_SIZE:
                if (!chunkedSupported) {
                    throw new IllegalArgumentException("Chunked messages not supported");
                }
                // Chunked encoding - generate HttpMessage first.  HttpChunks will follow.
                addCurrentMessage(out);
                return;
            default:
                /*
                 * RFC 7230, 3.3.3 (https://tools.ietf.org/html/rfc7230#section-3.3.3) states that if a
                 * request does not have either a transfer-encoding or a content-length header then the message body
                 * length is 0. However, for a response the body length is the number of octets received prior to the
                 * server closing the connection. So we treat this as variable length chunked encoding.
                 */
                if (contentLength == 0 || contentLength == -1 && isDecodingRequest()) {
                    addCurrentMessage(out);
                    out.add(LastHttpContent.EMPTY_LAST_CONTENT);
                    resetNow();
                    return;
                }

                assert nextState == State.READ_FIXED_LENGTH_CONTENT ||
                        nextState == State.READ_VARIABLE_LENGTH_CONTENT;

                addCurrentMessage(out);

                if (nextState == State.READ_FIXED_LENGTH_CONTENT) {
                    // chunkSize will be decreased as the READ_FIXED_LENGTH_CONTENT state reads data chunk by chunk.
                    chunkSize = contentLength;
                }

                // We return here, this forces decode to be called again where we will decode the content
                return;
            }
        } catch (Exception e) {
            out.add(invalidMessage(message, buffer, e));
            return;
        }
        case READ_VARIABLE_LENGTH_CONTENT: {
            // Keep reading data as a chunk until the end of connection is reached.
            int toRead = Math.min(buffer.readableBytes(), maxChunkSize);
            if (toRead > 0) {
                ByteBuf content = buffer.readRetainedSlice(toRead);
                out.add(new DefaultHttpContent(content));
            }
            return;
        }
        case READ_FIXED_LENGTH_CONTENT: {
            int readLimit = buffer.readableBytes();

            // Check if the buffer is readable first as we use the readable byte count
            // to create the HttpChunk. This is needed as otherwise we may end up with
            // create an HttpChunk instance that contains an empty buffer and so is
            // handled like it is the last HttpChunk.
            //
            // See https://github.com/netty/netty/issues/433
            if (readLimit == 0) {
                return;
            }

            int toRead = Math.min(readLimit, maxChunkSize);
            if (toRead > chunkSize) {
                toRead = (int) chunkSize;
            }
            ByteBuf content = buffer.readRetainedSlice(toRead);
            chunkSize -= toRead;

            if (chunkSize == 0) {
                // Read all content.
                out.add(new DefaultLastHttpContent(content, trailersFactory));
                resetNow();
            } else {
                out.add(new DefaultHttpContent(content));
            }
            return;
        }
        /*
         * everything else after this point takes care of reading chunked content. basically, read chunk size,
         * read chunk, read and ignore the CRLF and repeat until 0
         */
        case READ_CHUNK_SIZE: try {
            ByteBuf line = lineParser.parse(buffer);
            if (line == null) {
                return;
            }
            int chunkSize = getChunkSize(line.array(), line.arrayOffset() + line.readerIndex(), line.readableBytes());
            this.chunkSize = chunkSize;
            if (chunkSize == 0) {
                currentState = State.READ_CHUNK_FOOTER;
                return;
            }
            currentState = State.READ_CHUNKED_CONTENT;
            // fall-through
        } catch (Exception e) {
            out.add(invalidChunk(buffer, e));
            return;
        }
        case READ_CHUNKED_CONTENT: {
            assert chunkSize <= Integer.MAX_VALUE;
            int toRead = Math.min((int) chunkSize, maxChunkSize);
            if (!allowPartialChunks && buffer.readableBytes() < toRead) {
                return;
            }
            toRead = Math.min(toRead, buffer.readableBytes());
            if (toRead == 0) {
                return;
            }
            HttpContent chunk = new DefaultHttpContent(buffer.readRetainedSlice(toRead));
            chunkSize -= toRead;

            out.add(chunk);

            if (chunkSize != 0) {
                return;
            }
            currentState = State.READ_CHUNK_DELIMITER;
            // fall-through
        }
        case READ_CHUNK_DELIMITER: {
            final int wIdx = buffer.writerIndex();
            int rIdx = buffer.readerIndex();
            while (wIdx > rIdx) {
                byte next = buffer.getByte(rIdx++);
                if (next == HttpConstants.LF) {
                    currentState = State.READ_CHUNK_SIZE;
                    break;
                }
            }
            buffer.readerIndex(rIdx);
            return;
        }
        case READ_CHUNK_FOOTER: try {
            LastHttpContent trailer = readTrailingHeaders(buffer);
            if (trailer == null) {
                return;
            }
            out.add(trailer);
            resetNow();
            return;
        } catch (Exception e) {
            out.add(invalidChunk(buffer, e));
            return;
        }
        case BAD_MESSAGE: {
            // Keep discarding until disconnection.
            buffer.skipBytes(buffer.readableBytes());
            break;
        }
        case UPGRADED: {
            int readableBytes = buffer.readableBytes();
            if (readableBytes > 0) {
                // Keep on consuming as otherwise we may trigger an DecoderException,
                // other handler will replace this codec with the upgraded protocol codec to
                // take the traffic over at some point then.
                // See https://github.com/netty/netty/issues/2173
                out.add(buffer.readBytes(readableBytes));
            }
            break;
        }
        default:
            break;
        }
    }

    @Override
    protected void decodeLast(ChannelHandlerContext ctx, ByteBuf in, List out) throws Exception {
        super.decodeLast(ctx, in, out);

        if (resetRequested.get()) {
            // If a reset was requested by decodeLast() we need to do it now otherwise we may produce a
            // LastHttpContent while there was already one.
            resetNow();
        }

        // Handle the last unfinished message.
        switch (currentState) {
            case READ_VARIABLE_LENGTH_CONTENT:
                if (!chunked && !in.isReadable()) {
                    // End of connection.
                    out.add(LastHttpContent.EMPTY_LAST_CONTENT);
                    resetNow();
                }
                return;
            case READ_HEADER:
                // If we are still in the state of reading headers we need to create a new invalid message that
                // signals that the connection was closed before we received the headers.
                out.add(invalidMessage(message, Unpooled.EMPTY_BUFFER,
                        new PrematureChannelClosureException("Connection closed before received headers")));
                resetNow();
                return;
            case READ_CHUNK_DELIMITER: // fall-trough
            case READ_CHUNK_FOOTER: // fall-trough
            case READ_CHUNKED_CONTENT: // fall-trough
            case READ_CHUNK_SIZE: // fall-trough
            case READ_FIXED_LENGTH_CONTENT:
                // Check if the closure of the connection signifies the end of the content.
                boolean prematureClosure;
                if (isDecodingRequest() || chunked) {
                    // The last request did not wait for a response.
                    prematureClosure = true;
                } else {
                    // Compare the length of the received content and the 'Content-Length' header.
                    // If the 'Content-Length' header is absent, the length of the content is determined by the end of
                    // the connection, so it is perfectly fine.
                    prematureClosure = contentLength > 0;
                }
                if (!prematureClosure) {
                    out.add(LastHttpContent.EMPTY_LAST_CONTENT);
                }
                resetNow();
                return;
            case SKIP_CONTROL_CHARS: // fall-trough
            case READ_INITIAL:// fall-trough
            case BAD_MESSAGE: // fall-trough
            case UPGRADED: // fall-trough
                // Do nothing
                break;
            default:
                throw new IllegalStateException("Unhandled state " + currentState);
        }
    }

    @Override
    public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
        if (evt instanceof HttpExpectationFailedEvent) {
            switch (currentState) {
            case READ_FIXED_LENGTH_CONTENT:
            case READ_VARIABLE_LENGTH_CONTENT:
            case READ_CHUNK_SIZE:
                reset();
                break;
            default:
                break;
            }
        }
        super.userEventTriggered(ctx, evt);
    }

    private void addCurrentMessage(List out) {
        HttpMessage message = this.message;
        assert message != null;
        this.message = null;
        out.add(message);
    }

    protected boolean isContentAlwaysEmpty(HttpMessage msg) {
        if (msg instanceof HttpResponse) {
            HttpResponse res = (HttpResponse) msg;
            final HttpResponseStatus status = res.status();
            final int code = status.code();
            final HttpStatusClass statusClass = status.codeClass();

            // Correctly handle return codes of 1xx.
            //
            // See:
            //     - https://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html Section 4.4
            //     - https://github.com/netty/netty/issues/222
            if (statusClass == HttpStatusClass.INFORMATIONAL) {
                // One exception: Hixie 76 websocket handshake response
                return !(code == 101 && !res.headers().contains(HttpHeaderNames.SEC_WEBSOCKET_ACCEPT)
                         && res.headers().contains(HttpHeaderNames.UPGRADE, HttpHeaderValues.WEBSOCKET, true));
            }

            switch (code) {
            case 204: case 304:
                return true;
            default:
                return false;
            }
        }
        return false;
    }

    /**
     * Returns true if the server switched to a different protocol than HTTP/1.0 or HTTP/1.1, e.g. HTTP/2 or Websocket.
     * Returns false if the upgrade happened in a different layer, e.g. upgrade from HTTP/1.1 to HTTP/1.1 over TLS.
     */
    protected boolean isSwitchingToNonHttp1Protocol(HttpResponse msg) {
        if (msg.status().code() != HttpResponseStatus.SWITCHING_PROTOCOLS.code()) {
            return false;
        }
        String newProtocol = msg.headers().get(HttpHeaderNames.UPGRADE);
        return newProtocol == null ||
                !newProtocol.contains(HttpVersion.HTTP_1_0.text()) &&
                !newProtocol.contains(HttpVersion.HTTP_1_1.text());
    }

    /**
     * Resets the state of the decoder so that it is ready to decode a new message.
     * This method is useful for handling a rejected request with {@code Expect: 100-continue} header.
     */
    public void reset() {
        resetRequested.lazySet(true);
    }

    private void resetNow() {
        message = null;
        name = null;
        value = null;
        contentLength = Long.MIN_VALUE;
        chunked = false;
        lineParser.reset();
        headerParser.reset();
        trailer = null;
        if (isSwitchingToNonHttp1Protocol) {
            isSwitchingToNonHttp1Protocol = false;
            currentState = State.UPGRADED;
            return;
        }

        resetRequested.lazySet(false);
        currentState = State.SKIP_CONTROL_CHARS;
    }

    private HttpMessage invalidMessage(HttpMessage current, ByteBuf in, Exception cause) {
        currentState = State.BAD_MESSAGE;
        message = null;
        trailer = null;

        // Advance the readerIndex so that ByteToMessageDecoder does not complain
        // when we produced an invalid message without consuming anything.
        in.skipBytes(in.readableBytes());

        if (current == null) {
            current = createInvalidMessage();
        }
        current.setDecoderResult(DecoderResult.failure(cause));

        return current;
    }

    private HttpContent invalidChunk(ByteBuf in, Exception cause) {
        currentState = State.BAD_MESSAGE;
        message = null;
        trailer = null;

        // Advance the readerIndex so that ByteToMessageDecoder does not complain
        // when we produced an invalid message without consuming anything.
        in.skipBytes(in.readableBytes());

        HttpContent chunk = new DefaultLastHttpContent(Unpooled.EMPTY_BUFFER);
        chunk.setDecoderResult(DecoderResult.failure(cause));
        return chunk;
    }

    private State readHeaders(ByteBuf buffer) {
        final HttpMessage message = this.message;
        final HttpHeaders headers = message.headers();

        final HeaderParser headerParser = this.headerParser;

        ByteBuf line = headerParser.parse(buffer);
        if (line == null) {
            return null;
        }
        int lineLength = line.readableBytes();
        while (lineLength > 0) {
            final byte[] lineContent = line.array();
            final int startLine = line.arrayOffset() + line.readerIndex();
            final byte firstChar = lineContent[startLine];
            if (name != null && (firstChar == ' ' || firstChar == '\t')) {
                //please do not make one line from below code
                //as it breaks +XX:OptimizeStringConcat optimization
                String trimmedLine = langAsciiString(lineContent, startLine, lineLength).trim();
                String valueStr = value;
                value = valueStr + ' ' + trimmedLine;
            } else {
                if (name != null) {
                    headers.add(name, value);
                }
                splitHeader(lineContent, startLine, lineLength);
            }

            line = headerParser.parse(buffer);
            if (line == null) {
                return null;
            }
            lineLength = line.readableBytes();
        }

        // Add the last header.
        if (name != null) {
            headers.add(name, value);
        }

        // reset name and value fields
        name = null;
        value = null;

        // Done parsing initial line and headers. Set decoder result.
        HttpMessageDecoderResult decoderResult = new HttpMessageDecoderResult(lineParser.size, headerParser.size);
        message.setDecoderResult(decoderResult);

        List contentLengthFields = headers.getAll(HttpHeaderNames.CONTENT_LENGTH);
        if (!contentLengthFields.isEmpty()) {
            HttpVersion version = message.protocolVersion();
            boolean isHttp10OrEarlier = version.majorVersion() < 1 || (version.majorVersion() == 1
                    && version.minorVersion() == 0);
            // Guard against multiple Content-Length headers as stated in
            // https://tools.ietf.org/html/rfc7230#section-3.3.2:
            contentLength = HttpUtil.normalizeAndGetContentLength(contentLengthFields,
                    isHttp10OrEarlier, allowDuplicateContentLengths);
            if (contentLength != -1) {
                String lengthValue = contentLengthFields.get(0).trim();
                if (contentLengthFields.size() > 1 || // don't unnecessarily re-order headers
                        !lengthValue.equals(Long.toString(contentLength))) {
                    headers.set(HttpHeaderNames.CONTENT_LENGTH, contentLength);
                }
            }
        } else {
            // We know the content length if it's a Web Socket message even if
            // Content-Length header is missing.
            contentLength = HttpUtil.getWebSocketContentLength(message);
        }
        if (!isDecodingRequest() && message instanceof HttpResponse) {
            HttpResponse res = (HttpResponse) message;
            this.isSwitchingToNonHttp1Protocol = isSwitchingToNonHttp1Protocol(res);
        }
        if (isContentAlwaysEmpty(message)) {
            HttpUtil.setTransferEncodingChunked(message, false);
            return State.SKIP_CONTROL_CHARS;
        }
        if (HttpUtil.isTransferEncodingChunked(message)) {
            this.chunked = true;
            if (!contentLengthFields.isEmpty() && message.protocolVersion() == HttpVersion.HTTP_1_1) {
                handleTransferEncodingChunkedWithContentLength(message);
            }
            return State.READ_CHUNK_SIZE;
        }
        if (contentLength >= 0) {
            return State.READ_FIXED_LENGTH_CONTENT;
        }
        return State.READ_VARIABLE_LENGTH_CONTENT;
    }

    /**
     * Invoked when a message with both a "Transfer-Encoding: chunked" and a "Content-Length" header field is detected.
     * The default behavior is to remove the Content-Length field, but this method could be overridden
     * to change the behavior (to, e.g., throw an exception and produce an invalid message).
     * 

     * See: https://tools.ietf.org/html/rfc7230#section-3.3.3
     * 
     *     If a message is received with both a Transfer-Encoding and a
     *     Content-Length header field, the Transfer-Encoding overrides the
     *     Content-Length.  Such a message might indicate an attempt to
     *     perform request smuggling (Section 9.5) or response splitting
     *     (Section 9.4) and ought to be handled as an error.  A sender MUST
     *     remove the received Content-Length field prior to forwarding such
     *     a message downstream.
     * 

     * Also see:
     * https://github.com/apache/tomcat/blob/b693d7c1981fa7f51e58bc8c8e72e3fe80b7b773/
     * java/org/apache/coyote/http11/Http11Processor.java#L747-L755
     * https://github.com/nginx/nginx/blob/0ad4393e30c119d250415cb769e3d8bc8dce5186/
     * src/http/ngx_http_request.c#L1946-L1953
     */
    protected void handleTransferEncodingChunkedWithContentLength(HttpMessage message) {
        message.headers().remove(HttpHeaderNames.CONTENT_LENGTH);
        contentLength = Long.MIN_VALUE;
    }

    private LastHttpContent readTrailingHeaders(ByteBuf buffer) {
        final HeaderParser headerParser = this.headerParser;
        ByteBuf line = headerParser.parse(buffer);
        if (line == null) {
            return null;
        }
        LastHttpContent trailer = this.trailer;
        int lineLength = line.readableBytes();
        if (lineLength == 0 && trailer == null) {
            // We have received the empty line which signals the trailer is complete and did not parse any trailers
            // before. Just return an empty last content to reduce allocations.
            return LastHttpContent.EMPTY_LAST_CONTENT;
        }

        CharSequence lastHeader = null;
        if (trailer == null) {
            trailer = this.trailer = new DefaultLastHttpContent(Unpooled.EMPTY_BUFFER, trailersFactory);
        }
        while (lineLength > 0) {
            final byte[] lineContent = line.array();
            final int startLine = line.arrayOffset() + line.readerIndex();
            final byte firstChar = lineContent[startLine];
            if (lastHeader != null && (firstChar == ' ' || firstChar == '\t')) {
                List current = trailer.trailingHeaders().getAll(lastHeader);
                if (!current.isEmpty()) {
                    int lastPos = current.size() - 1;
                    //please do not make one line from below code
                    //as it breaks +XX:OptimizeStringConcat optimization
                    String lineTrimmed = langAsciiString(lineContent, startLine, line.readableBytes()).trim();
                    String currentLastPos = current.get(lastPos);
                    current.set(lastPos, currentLastPos + lineTrimmed);
                }
            } else {
                splitHeader(lineContent, startLine, lineLength);
                AsciiString headerName = name;
                if (!HttpHeaderNames.CONTENT_LENGTH.contentEqualsIgnoreCase(headerName) &&
                        !HttpHeaderNames.TRANSFER_ENCODING.contentEqualsIgnoreCase(headerName) &&
                        !HttpHeaderNames.TRAILER.contentEqualsIgnoreCase(headerName)) {
                    trailer.trailingHeaders().add(headerName, value);
                }
                lastHeader = name;
                // reset name and value fields
                name = null;
                value = null;
            }
            line = headerParser.parse(buffer);
            if (line == null) {
                return null;
            }
            lineLength = line.readableBytes();
        }

        this.trailer = null;
        return trailer;
    }

    protected abstract boolean isDecodingRequest();
    protected abstract HttpMessage createMessage(String[] initialLine) throws Exception;
    protected abstract HttpMessage createInvalidMessage();

    /**
     * It skips any whitespace char and return the number of skipped bytes.
     */
    private static int skipWhiteSpaces(byte[] hex, int start, int length) {
        for (int i = 0; i < length; i++) {
            if (!isWhitespace(hex[start + i])) {
                return i;
            }
        }
        return length;
    }

    private static int getChunkSize(byte[] hex, int start, int length) {
        // trim the leading bytes if white spaces, if any
        final int skipped = skipWhiteSpaces(hex, start, length);
        if (skipped == length) {
            // empty case
            throw new NumberFormatException();
        }
        start += skipped;
        length -= skipped;
        int result = 0;
        for (int i = 0; i < length; i++) {
            final int digit = StringUtil.decodeHexNibble(hex[start + i]);
            if (digit == -1) {
                // uncommon path
                final byte b = hex[start + i];
                if (b == ';' || isControlOrWhitespaceAsciiChar(b)) {
                    if (i == 0) {
                        // empty case
                        throw new NumberFormatException("Empty chunk size");
                    }
                    return result;
                }
                // non-hex char fail-fast path
                throw new NumberFormatException("Invalid character in chunk size");
            }
            result *= 16;
            result += digit;
            if (result < 0) {
                throw new NumberFormatException("Chunk size overflow: " + result);
            }
        }
        return result;
    }

    private String[] splitInitialLine(ByteBuf asciiBuffer) {
        final byte[] asciiBytes = asciiBuffer.array();

        final int arrayOffset = asciiBuffer.arrayOffset();

        final int startContent = arrayOffset + asciiBuffer.readerIndex();

        final int end = startContent + asciiBuffer.readableBytes();

        final int aStart = findNonSPLenient(asciiBytes, startContent, end);
        final int aEnd = findSPLenient(asciiBytes, aStart, end);

        final int bStart = findNonSPLenient(asciiBytes, aEnd, end);
        final int bEnd = findSPLenient(asciiBytes, bStart, end);

        final int cStart = findNonSPLenient(asciiBytes, bEnd, end);
        final int cEnd = findEndOfString(asciiBytes, Math.max(cStart - 1, startContent), end);

        return new String[]{
                splitFirstWordInitialLine(asciiBytes, aStart, aEnd - aStart),
                splitSecondWordInitialLine(asciiBytes, bStart, bEnd - bStart),
                cStart < cEnd ? splitThirdWordInitialLine(asciiBytes, cStart, cEnd - cStart) : StringUtil.EMPTY_STRING};
    }

    protected String splitFirstWordInitialLine(final byte[] asciiContent, int start, int length) {
        return langAsciiString(asciiContent, start, length);
    }

    protected String splitSecondWordInitialLine(final byte[] asciiContent, int start, int length) {
        return langAsciiString(asciiContent, start, length);
    }

    protected String splitThirdWordInitialLine(final byte[] asciiContent, int start, int length) {
        return langAsciiString(asciiContent, start, length);
    }

    /**
     * This method shouldn't exist: look at https://bugs.openjdk.org/browse/JDK-8295496 for more context
     */
    private static String langAsciiString(final byte[] asciiContent, int start, int length) {
        if (length == 0) {
            return StringUtil.EMPTY_STRING;
        }
        // DON'T REMOVE: it helps JIT to use a simpler intrinsic stub for System::arrayCopy based on the call-site
        if (start == 0) {
            if (length == asciiContent.length) {
                return new String(asciiContent, 0, 0, asciiContent.length);
            }
            return new String(asciiContent, 0, 0, length);
        }
        return new String(asciiContent, 0, start, length);
    }

    private void splitHeader(byte[] line, int start, int length) {
        final int end = start + length;
        int nameEnd;
        final int nameStart = findNonWhitespace(line, start, end);
        // hoist this load out of the loop, because it won't change!
        final boolean isDecodingRequest = isDecodingRequest();
        for (nameEnd = nameStart; nameEnd < end; nameEnd ++) {
            byte ch = line[nameEnd];
            // https://tools.ietf.org/html/rfc7230#section-3.2.4
            //
            // No whitespace is allowed between the header field-name and colon. In
            // the past, differences in the handling of such whitespace have led to
            // security vulnerabilities in request routing and response handling. A
            // server MUST reject any received request message that contains
            // whitespace between a header field-name and colon with a response code
            // of 400 (Bad Request). A proxy MUST remove any such whitespace from a
            // response message before forwarding the message downstream.
            if (ch == ':' ||
                    // In case of decoding a request we will just continue processing and header validation
                    // is done in the DefaultHttpHeaders implementation.
                    //
                    // In the case of decoding a response we will "skip" the whitespace.
                    (!isDecodingRequest && isOWS(ch))) {
                break;
            }
        }

        if (nameEnd == end) {
            // There was no colon present at all.
            throw new IllegalArgumentException("No colon found");
        }
        int colonEnd;
        for (colonEnd = nameEnd; colonEnd < end; colonEnd ++) {
            if (line[colonEnd] == ':') {
                colonEnd ++;
                break;
            }
        }
        name = splitHeaderName(line, nameStart, nameEnd - nameStart);
        final int valueStart = findNonWhitespace(line, colonEnd, end);
        if (valueStart == end) {
            value = StringUtil.EMPTY_STRING;
        } else {
            final int valueEnd = findEndOfString(line, start, end);
            // no need to make uses of the ByteBuf's toString ASCII method here, and risk to get JIT confused
            value = langAsciiString(line, valueStart, valueEnd - valueStart);
        }
    }

    protected AsciiString splitHeaderName(byte[] sb, int start, int length) {
        return new AsciiString(sb, start, length, true);
    }

    private static int findNonSPLenient(byte[] sb, int offset, int end) {
        for (int result = offset; result < end; ++result) {
            byte c = sb[result];
            // See https://tools.ietf.org/html/rfc7230#section-3.5
            if (isSPLenient(c)) {
                continue;
            }
            if (isWhitespace(c)) {
                // Any other whitespace delimiter is invalid
                throw new IllegalArgumentException("Invalid separator");
            }
            return result;
        }
        return end;
    }

    private static int findSPLenient(byte[] sb, int offset, int end) {
        for (int result = offset; result < end; ++result) {
            if (isSPLenient(sb[result])) {
                return result;
            }
        }
        return end;
    }

    private static final boolean[] SP_LENIENT_BYTES;
    private static final boolean[] LATIN_WHITESPACE;

    static {
        // See https://tools.ietf.org/html/rfc7230#section-3.5
        SP_LENIENT_BYTES = new boolean[256];
        SP_LENIENT_BYTES[128 + ' '] = true;
        SP_LENIENT_BYTES[128 + 0x09] = true;
        SP_LENIENT_BYTES[128 + 0x0B] = true;
        SP_LENIENT_BYTES[128 + 0x0C] = true;
        SP_LENIENT_BYTES[128 + 0x0D] = true;
        // TO SAVE PERFORMING Character::isWhitespace ceremony
        LATIN_WHITESPACE = new boolean[256];
        for (byte b = Byte.MIN_VALUE; b < Byte.MAX_VALUE; b++) {
            LATIN_WHITESPACE[128 + b] = Character.isWhitespace(b);
        }
    }

    private static boolean isSPLenient(byte c) {
        // See https://tools.ietf.org/html/rfc7230#section-3.5
        return SP_LENIENT_BYTES[c + 128];
    }

    private static boolean isWhitespace(byte b) {
        return LATIN_WHITESPACE[b + 128];
    }

    private static int findNonWhitespace(byte[] sb, int offset, int end) {
        for (int result = offset; result < end; ++result) {
            byte c = sb[result];
            if (!isWhitespace(c)) {
                return result;
            } else if (!isOWS(c)) {
                // Only OWS is supported for whitespace
                throw new IllegalArgumentException("Invalid separator, only a single space or horizontal tab allowed," +
                        " but received a '" + c + "' (0x" + Integer.toHexString(c) + ")");
            }
        }
        return end;
    }

    private static int findEndOfString(byte[] sb, int start, int end) {
        for (int result = end - 1; result > start; --result) {
            if (!isWhitespace(sb[result])) {
                return result + 1;
            }
        }
        return 0;
    }

    private static boolean isOWS(byte ch) {
        return ch == ' ' || ch == 0x09;
    }

    private static class HeaderParser {
        protected final ByteBuf seq;
        protected final int maxLength;
        int size;

        HeaderParser(ByteBuf seq, int maxLength) {
            this.seq = seq;
            this.maxLength = maxLength;
        }

        public ByteBuf parse(ByteBuf buffer) {
            final int readableBytes = buffer.readableBytes();
            final int readerIndex = buffer.readerIndex();
            final int maxBodySize = maxLength - size;
            assert maxBodySize >= 0;
            // adding 2 to account for both CR (if present) and LF
            // don't remove 2L: it's key to cover maxLength = Integer.MAX_VALUE
            final long maxBodySizeWithCRLF = maxBodySize + 2L;
            final int toProcess = (int) Math.min(maxBodySizeWithCRLF, readableBytes);
            final int toIndexExclusive = readerIndex + toProcess;
            assert toIndexExclusive >= readerIndex;
            final int indexOfLf = buffer.indexOf(readerIndex, toIndexExclusive, HttpConstants.LF);
            if (indexOfLf == -1) {
                if (readableBytes > maxBodySize) {
                    // TODO: Respond with Bad Request and discard the traffic
                    //    or close the connection.
                    //       No need to notify the upstream handlers - just log.
                    //       If decoding a response, just throw an exception.
                    throw newException(maxLength);
                }
                return null;
            }
            final int endOfSeqIncluded;
            if (indexOfLf > readerIndex && buffer.getByte(indexOfLf - 1) == HttpConstants.CR) {
                // Drop CR if we had a CRLF pair
                endOfSeqIncluded = indexOfLf - 1;
            } else {
                endOfSeqIncluded = indexOfLf;
            }
            final int newSize = endOfSeqIncluded - readerIndex;
            if (newSize == 0) {
                seq.clear();
                buffer.readerIndex(indexOfLf + 1);
                return seq;
            }
            int size = this.size + newSize;
            if (size > maxLength) {
                throw newException(maxLength);
            }
            this.size = size;
            seq.clear();
            seq.writeBytes(buffer, readerIndex, newSize);
            buffer.readerIndex(indexOfLf + 1);
            return seq;
        }

        public void reset() {
            size = 0;
        }

        protected TooLongFrameException newException(int maxLength) {
            return new TooLongHttpHeaderException("HTTP header is larger than " + maxLength + " bytes.");
        }
    }

    private final class LineParser extends HeaderParser {

        LineParser(ByteBuf seq, int maxLength) {
            super(seq, maxLength);
        }

        @Override
        public ByteBuf parse(ByteBuf buffer) {
            // Suppress a warning because HeaderParser.reset() is supposed to be called
            reset();
            final int readableBytes = buffer.readableBytes();
            if (readableBytes == 0) {
                return null;
            }
            final int readerIndex = buffer.readerIndex();
            if (currentState == State.SKIP_CONTROL_CHARS && skipControlChars(buffer, readableBytes, readerIndex)) {
                return null;
            }
            return super.parse(buffer);
        }

        private boolean skipControlChars(ByteBuf buffer, int readableBytes, int readerIndex) {
            assert currentState == State.SKIP_CONTROL_CHARS;
            final int maxToSkip = Math.min(maxLength, readableBytes);
            final int firstNonControlIndex = buffer.forEachByte(readerIndex, maxToSkip, SKIP_CONTROL_CHARS_BYTES);
            if (firstNonControlIndex == -1) {
                buffer.skipBytes(maxToSkip);
                if (readableBytes > maxLength) {
                    throw newException(maxLength);
                }
                return true;
            }
            // from now on we don't care about control chars
            buffer.readerIndex(firstNonControlIndex);
            currentState = State.READ_INITIAL;
            return false;
        }

        @Override
        protected TooLongFrameException newException(int maxLength) {
            return new TooLongHttpLineException("An HTTP line is larger than " + maxLength + " bytes.");
        }
    }

    private static final boolean[] ISO_CONTROL_OR_WHITESPACE;

    static {
        ISO_CONTROL_OR_WHITESPACE = new boolean[256];
        for (byte b = Byte.MIN_VALUE; b < Byte.MAX_VALUE; b++) {
            ISO_CONTROL_OR_WHITESPACE[128 + b] = Character.isISOControl(b) || isWhitespace(b);
        }
    }

    private static final ByteProcessor SKIP_CONTROL_CHARS_BYTES = new ByteProcessor() {

        @Override
        public boolean process(byte value) {
            return ISO_CONTROL_OR_WHITESPACE[128 + value];
        }
    };

    private static boolean isControlOrWhitespaceAsciiChar(byte b) {
        return ISO_CONTROL_OR_WHITESPACE[128 + b];
    }
}
    

    

    

            

    

            



    
    






    
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