tomcat coyote模块请求处理流程

以Http2.0协议,io方式为nio为例

时序图

  1. Connector启动时,启动其持有的EndPoint实例(NioEndPoint),EndPoint通过其持有的Acceptor轮询监听端口接收请求
 protected class Acceptor extends AbstractEndpoint.Acceptor {

        @Override
        public void run() {

            int errorDelay = 0;

            // Loop until we receive a shutdown command
            while (running) {

                // Loop if endpoint is paused
                while (paused && running) {
                    state = AcceptorState.PAUSED;
                    try {
                        Thread.sleep(50);
                    } catch (InterruptedException e) {
                        // Ignore
                    }
                }

                if (!running) {
                    break;
                }
                state = AcceptorState.RUNNING;

                try {
                    //if we have reached max connections, wait
                    countUpOrAwaitConnection();

                    SocketChannel socket = null;
                    try {
                        // Accept the next incoming connection from the server
                        // socket
                        socket = serverSock.accept();
                    } catch (IOException ioe) {
                        // We didn't get a socket
                        countDownConnection();
                        if (running) {
                            // Introduce delay if necessary
                            errorDelay = handleExceptionWithDelay(errorDelay);
                            // re-throw
                            throw ioe;
                        } else {
                            break;
                        }
                    }
                    // Successful accept, reset the error delay
                    errorDelay = 0;

                    // Configure the socket
                    if (running && !paused) {
                        // setSocketOptions() will hand the socket off to
                        // an appropriate processor if successful
                        if (!setSocketOptions(socket)) {
                            closeSocket(socket);
                        }
                    } else {
                        closeSocket(socket);
                    }
                } catch (Throwable t) {
                    ExceptionUtils.handleThrowable(t);
                    log.error(sm.getString("endpoint.accept.fail"), t);
                }
            }
            state = AcceptorState.ENDED;
        }


        private void closeSocket(SocketChannel socket) {
            countDownConnection();
            try {
                socket.socket().close();
            } catch (IOException ioe)  {
                if (log.isDebugEnabled()) {
                    log.debug(sm.getString("endpoint.err.close"), ioe);
                }
            }
            try {
                socket.close();
            } catch (IOException ioe) {
                if (log.isDebugEnabled()) {
                    log.debug(sm.getString("endpoint.err.close"), ioe);
                }
            }
        }
    }
  1. 监听到请求后且socket状态为running,将channel注册到poller上,唤醒selector
 protected boolean setSocketOptions(SocketChannel socket) {
        // Process the connection
        try {
            //disable blocking, APR style, we are gonna be polling it
            socket.configureBlocking(false);
            Socket sock = socket.socket();
            socketProperties.setProperties(sock);

            NioChannel channel = nioChannels.pop();
            if (channel == null) {
                SocketBufferHandler bufhandler = new SocketBufferHandler(
                        socketProperties.getAppReadBufSize(),
                        socketProperties.getAppWriteBufSize(),
                        socketProperties.getDirectBuffer());
                if (isSSLEnabled()) {
                    channel = new SecureNioChannel(socket, bufhandler, selectorPool, this);
                } else {
                    channel = new NioChannel(socket, bufhandler);
                }
            } else {
                channel.setIOChannel(socket);
                channel.reset();
            }
            getPoller0().register(channel);
        } catch (Throwable t) {
            ExceptionUtils.handleThrowable(t);
            try {
                log.error("",t);
            } catch (Throwable tt) {
                ExceptionUtils.handleThrowable(tt);
            }
            // Tell to close the socket
            return false;
        }
        return true;
    }

 private void addEvent(PollerEvent event) {
	  events.offer(event);
	  if ( wakeupCounter.incrementAndGet() == 0 ) selector.wakeup();
}
  1. poller实现了Runnable,在run方法中使用selector轮询socket状态,当轮询到可处理的请求时调用processKey进行处理
 @Override
 public void run() {
     // Loop until destroy() is called
     while (true) {

         boolean hasEvents = false;

         try {
             if (!close) {
                 hasEvents = events();
                 if (wakeupCounter.getAndSet(-1) > 0) {
                     //if we are here, means we have other stuff to do
                     //do a non blocking select
                     keyCount = selector.selectNow();
                 } else {
                     keyCount = selector.select(selectorTimeout);
                 }
                 wakeupCounter.set(0);
             }
             if (close) {
                 events();
                 timeout(0, false);
                 try {
                     selector.close();
                 } catch (IOException ioe) {
                     log.error(sm.getString("endpoint.nio.selectorCloseFail"), ioe);
                 }
                 break;
             }
         } catch (Throwable x) {
             ExceptionUtils.handleThrowable(x);
             log.error("",x);
             continue;
         }
         //either we timed out or we woke up, process events first
         if ( keyCount == 0 ) hasEvents = (hasEvents | events());

         Iterator<SelectionKey> iterator =
             keyCount > 0 ? selector.selectedKeys().iterator() : null;
         // Walk through the collection of ready keys and dispatch
         // any active event.
         while (iterator != null && iterator.hasNext()) {
             SelectionKey sk = iterator.next();
             NioSocketWrapper attachment = (NioSocketWrapper)sk.attachment();
             // Attachment may be null if another thread has called
             // cancelledKey()
             if (attachment == null) {
                 iterator.remove();
             } else {
                 iterator.remove();
                 processKey(sk, attachment);
             }
         }//while

         //process timeouts
         timeout(keyCount,hasEvents);
     }//while

     getStopLatch().countDown();
 }

protected void processKey(SelectionKey sk, NioSocketWrapper attachment) {
   try {
        if ( close ) {
            cancelledKey(sk);
        } else if ( sk.isValid() && attachment != null ) {
            if (sk.isReadable() || sk.isWritable() ) {
                if ( attachment.getSendfileData() != null ) {
                    processSendfile(sk,attachment, false);
                } else {
                    unreg(sk, attachment, sk.readyOps());
                    boolean closeSocket = false;
                    // Read goes before write
                    if (sk.isReadable()) {
                        if (!processSocket(attachment, SocketEvent.OPEN_READ, true)) {
                            closeSocket = true;
                        }
                    }
                    if (!closeSocket && sk.isWritable()) {
                        if (!processSocket(attachment, SocketEvent.OPEN_WRITE, true)) {
                            closeSocket = true;
                        }
                    }
                    if (closeSocket) {
                        cancelledKey(sk);
                    }
                }
            }
        } else {
            //invalid key
            cancelledKey(sk);
        }
    } catch ( CancelledKeyException ckx ) {
        cancelledKey(sk);
    } catch (Throwable t) {
        ExceptionUtils.handleThrowable(t);
        log.error("",t);
    }
}
  1. socket的处理方法processSocket在NioEndpoint的父类AbstractEndpoint中,将传入的SocketWrapper和SocketEnvent包装成一个可复用的SocketProcessor线程交给线程池执行,SocketProcessor的实际实现在每个EndPoint中
public boolean processSocket(SocketWrapperBase<S> socketWrapper,
            SocketEvent event, boolean dispatch) {
    try {
        if (socketWrapper == null) {
            return false;
        }
        SocketProcessorBase<S> sc = processorCache.pop();
        if (sc == null) {
            sc = createSocketProcessor(socketWrapper, event);
        } else {
            sc.reset(socketWrapper, event);
        }
        Executor executor = getExecutor();
        if (dispatch && executor != null) {
            executor.execute(sc);
        } else {
            sc.run();
        }
    } catch (RejectedExecutionException ree) {
        getLog().warn(sm.getString("endpoint.executor.fail", socketWrapper) , ree);
        return false;
    } catch (Throwable t) {
        ExceptionUtils.handleThrowable(t);
        // This means we got an OOM or similar creating a thread, or that
        // the pool and its queue are full
        getLog().error(sm.getString("endpoint.process.fail"), t);
        return false;
    }
    return true;
}

public abstract class SocketProcessorBase<S> implements Runnable {

    protected SocketWrapperBase<S> socketWrapper;
    protected SocketEvent event;

    public SocketProcessorBase(SocketWrapperBase<S> socketWrapper, SocketEvent event) {
        reset(socketWrapper, event);
    }


    public void reset(SocketWrapperBase<S> socketWrapper, SocketEvent event) {
        Objects.requireNonNull(event);
        this.socketWrapper = socketWrapper;
        this.event = event;
    }


    @Override
    public final void run() {
        synchronized (socketWrapper) {
            // It is possible that processing may be triggered for read and
            // write at the same time. The sync above makes sure that processing
            // does not occur in parallel. The test below ensures that if the
            // first event to be processed results in the socket being closed,
            // the subsequent events are not processed.
            if (socketWrapper.isClosed()) {
                return;
            }
            doRun();
        }
    }


    protected abstract void doRun();
}
  1. NioEndpoint中SocketProcessor的实现,先判断socket的状态然后提交到ConnectionHandler处理
protected class SocketProcessor extends SocketProcessorBase<NioChannel> {

        public SocketProcessor(SocketWrapperBase<NioChannel> socketWrapper, SocketEvent event) {
            super(socketWrapper, event);
        }

        @Override
        protected void doRun() {
            NioChannel socket = socketWrapper.getSocket();
            SelectionKey key = socket.getIOChannel().keyFor(socket.getPoller().getSelector());

            try {
                int handshake = -1;

                try {
                    if (key != null) {
                        if (socket.isHandshakeComplete()) {
                            // No TLS handshaking required. Let the handler
                            // process this socket / event combination.
                            handshake = 0;
                        } else if (event == SocketEvent.STOP || event == SocketEvent.DISCONNECT ||
                                event == SocketEvent.ERROR) {
                            // Unable to complete the TLS handshake. Treat it as
                            // if the handshake failed.
                            handshake = -1;
                        } else {
                            handshake = socket.handshake(key.isReadable(), key.isWritable());
                            // The handshake process reads/writes from/to the
                            // socket. status may therefore be OPEN_WRITE once
                            // the handshake completes. However, the handshake
                            // happens when the socket is opened so the status
                            // must always be OPEN_READ after it completes. It
                            // is OK to always set this as it is only used if
                            // the handshake completes.
                            event = SocketEvent.OPEN_READ;
                        }
                    }
                } catch (IOException x) {
                    handshake = -1;
                    if (log.isDebugEnabled()) log.debug("Error during SSL handshake",x);
                } catch (CancelledKeyException ckx) {
                    handshake = -1;
                }
                if (handshake == 0) {
                    SocketState state = SocketState.OPEN;
                    // Process the request from this socket
                    if (event == null) {
                        state = getHandler().process(socketWrapper, SocketEvent.OPEN_READ);
                    } else {
                        state = getHandler().process(socketWrapper, event);
                    }
                    if (state == SocketState.CLOSED) {
                        close(socket, key);
                    }
                } else if (handshake == -1 ) {
                    getHandler().process(socketWrapper, SocketEvent.CONNECT_FAIL);
                    close(socket, key);
                } else if (handshake == SelectionKey.OP_READ){
                    socketWrapper.registerReadInterest();
                } else if (handshake == SelectionKey.OP_WRITE){
                    socketWrapper.registerWriteInterest();
                }
            } catch (CancelledKeyException cx) {
                socket.getPoller().cancelledKey(key);
            } catch (VirtualMachineError vme) {
                ExceptionUtils.handleThrowable(vme);
            } catch (Throwable t) {
                log.error("", t);
                socket.getPoller().cancelledKey(key);
            } finally {
                socketWrapper = null;
                event = null;
                //return to cache
                if (running && !paused) {
                    processorCache.push(this);
                }
            }
        }
    }
  1. ConnectionHandler是AbstractProtocal的一个内部类,用于为socket链接选择一个合适的Processor进行处理,协议的升级也是在ConnectionHandler中做的
@Override
public SocketState process(SocketWrapperBase<S> wrapper, SocketEvent status) {
    if (getLog().isDebugEnabled()) {
        getLog().debug(sm.getString("abstractConnectionHandler.process",
                wrapper.getSocket(), status));
    }
    if (wrapper == null) {
        // Nothing to do. Socket has been closed.
        return SocketState.CLOSED;
    }

    S socket = wrapper.getSocket();

    Processor processor = connections.get(socket);
    if (getLog().isDebugEnabled()) {
        getLog().debug(sm.getString("abstractConnectionHandler.connectionsGet",
                processor, socket));
    }

    // Timeouts are calculated on a dedicated thread and then
    // dispatched. Because of delays in the dispatch process, the
    // timeout may no longer be required. Check here and avoid
    // unnecessary processing.
    if (SocketEvent.TIMEOUT == status &&
            (processor == null ||
            !processor.isAsync() && !processor.isUpgrade() ||
            processor.isAsync() && !processor.checkAsyncTimeoutGeneration())) {
        // This is effectively a NO-OP
        return SocketState.OPEN;
    }

    if (processor != null) {
        // Make sure an async timeout doesn't fire
        getProtocol().removeWaitingProcessor(processor);
    } else if (status == SocketEvent.DISCONNECT || status == SocketEvent.ERROR) {
        // Nothing to do. Endpoint requested a close and there is no
        // longer a processor associated with this socket.
        return SocketState.CLOSED;
    }

    ContainerThreadMarker.set();

    try {
        if (processor == null) {
            String negotiatedProtocol = wrapper.getNegotiatedProtocol();
            // OpenSSL typically returns null whereas JSSE typically
            // returns "" when no protocol is negotiated
            if (negotiatedProtocol != null && negotiatedProtocol.length() > 0) {
                UpgradeProtocol upgradeProtocol = getProtocol().getNegotiatedProtocol(negotiatedProtocol);
                if (upgradeProtocol != null) {
                    processor = upgradeProtocol.getProcessor(wrapper, getProtocol().getAdapter());
                    if (getLog().isDebugEnabled()) {
                        getLog().debug(sm.getString("abstractConnectionHandler.processorCreate", processor));
                    }
                } else if (negotiatedProtocol.equals("http/1.1")) {
                    // Explicitly negotiated the default protocol.
                    // Obtain a processor below.
                } else {
                    // TODO:
                    // OpenSSL 1.0.2's ALPN callback doesn't support
                    // failing the handshake with an error if no
                    // protocol can be negotiated. Therefore, we need to
                    // fail the connection here. Once this is fixed,
                    // replace the code below with the commented out
                    // block.
                    if (getLog().isDebugEnabled()) {
                        getLog().debug(sm.getString("abstractConnectionHandler.negotiatedProcessor.fail",
                                negotiatedProtocol));
                    }
                    return SocketState.CLOSED;
                    /*
                     * To replace the code above once OpenSSL 1.1.0 is
                     * used.
                    // Failed to create processor. This is a bug.
                    throw new IllegalStateException(sm.getString(
                            "abstractConnectionHandler.negotiatedProcessor.fail",
                            negotiatedProtocol));
                    */
                }
            }
        }
        if (processor == null) {
            processor = recycledProcessors.pop();
            if (getLog().isDebugEnabled()) {
                getLog().debug(sm.getString("abstractConnectionHandler.processorPop", processor));
            }
        }
        if (processor == null) {
            processor = getProtocol().createProcessor();
            register(processor);
            if (getLog().isDebugEnabled()) {
                getLog().debug(sm.getString("abstractConnectionHandler.processorCreate", processor));
            }
        }

        processor.setSslSupport(
                wrapper.getSslSupport(getProtocol().getClientCertProvider()));

        // Associate the processor with the connection
        connections.put(socket, processor);

        SocketState state = SocketState.CLOSED;
        do {
            state = processor.process(wrapper, status);

            if (state == SocketState.UPGRADING) {
                // Get the HTTP upgrade handler
                UpgradeToken upgradeToken = processor.getUpgradeToken();
                // Retrieve leftover input
                ByteBuffer leftOverInput = processor.getLeftoverInput();
                if (upgradeToken == null) {
                    // Assume direct HTTP/2 connection
                    UpgradeProtocol upgradeProtocol = getProtocol().getUpgradeProtocol("h2c");
                    if (upgradeProtocol != null) {
                        processor = upgradeProtocol.getProcessor(
                                wrapper, getProtocol().getAdapter());
                        wrapper.unRead(leftOverInput);
                        // Associate with the processor with the connection
                        connections.put(socket, processor);
                    } else {
                        if (getLog().isDebugEnabled()) {
                            getLog().debug(sm.getString(
                                "abstractConnectionHandler.negotiatedProcessor.fail",
                                "h2c"));
                        }
                        return SocketState.CLOSED;
                    }
                } else {
                    HttpUpgradeHandler httpUpgradeHandler = upgradeToken.getHttpUpgradeHandler();
                    // Release the Http11 processor to be re-used
                    release(processor);
                    // Create the upgrade processor
                    processor = getProtocol().createUpgradeProcessor(wrapper, upgradeToken);
                    if (getLog().isDebugEnabled()) {
                        getLog().debug(sm.getString("abstractConnectionHandler.upgradeCreate",
                                processor, wrapper));
                    }
                    wrapper.unRead(leftOverInput);
                    // Mark the connection as upgraded
                    wrapper.setUpgraded(true);
                    // Associate with the processor with the connection
                    connections.put(socket, processor);
                    // Initialise the upgrade handler (which may trigger
                    // some IO using the new protocol which is why the lines
                    // above are necessary)
                    // This cast should be safe. If it fails the error
                    // handling for the surrounding try/catch will deal with
                    // it.
                    if (upgradeToken.getInstanceManager() == null) {
                        httpUpgradeHandler.init((WebConnection) processor);
                    } else {
                        ClassLoader oldCL = upgradeToken.getContextBind().bind(false, null);
                        try {
                            httpUpgradeHandler.init((WebConnection) processor);
                        } finally {
                            upgradeToken.getContextBind().unbind(false, oldCL);
                        }
                    }
                }
            }
        } while ( state == SocketState.UPGRADING);

        if (state == SocketState.LONG) {
            // In the middle of processing a request/response. Keep the
            // socket associated with the processor. Exact requirements
            // depend on type of long poll
            longPoll(wrapper, processor);
            if (processor.isAsync()) {
                getProtocol().addWaitingProcessor(processor);
            }
        } else if (state == SocketState.OPEN) {
            // In keep-alive but between requests. OK to recycle
            // processor. Continue to poll for the next request.
            connections.remove(socket);
            release(processor);
            wrapper.registerReadInterest();
        } else if (state == SocketState.SENDFILE) {
            // Sendfile in progress. If it fails, the socket will be
            // closed. If it works, the socket either be added to the
            // poller (or equivalent) to await more data or processed
            // if there are any pipe-lined requests remaining.
        } else if (state == SocketState.UPGRADED) {
            // Don't add sockets back to the poller if this was a
            // non-blocking write otherwise the poller may trigger
            // multiple read events which may lead to thread starvation
            // in the connector. The write() method will add this socket
            // to the poller if necessary.
            if (status != SocketEvent.OPEN_WRITE) {
                longPoll(wrapper, processor);
                getProtocol().addWaitingProcessor(processor);
            }
        } else if (state == SocketState.SUSPENDED) {
            // Don't add sockets back to the poller.
            // The resumeProcessing() method will add this socket
            // to the poller.
        } else {
            // Connection closed. OK to recycle the processor.
            // Processors handling upgrades require additional clean-up
            // before release.
            connections.remove(socket);
            if (processor.isUpgrade()) {
                UpgradeToken upgradeToken = processor.getUpgradeToken();
                HttpUpgradeHandler httpUpgradeHandler = upgradeToken.getHttpUpgradeHandler();
                InstanceManager instanceManager = upgradeToken.getInstanceManager();
                if (instanceManager == null) {
                    httpUpgradeHandler.destroy();
                } else {
                    ClassLoader oldCL = upgradeToken.getContextBind().bind(false, null);
                    try {
                        httpUpgradeHandler.destroy();
                    } finally {
                        try {
                            instanceManager.destroyInstance(httpUpgradeHandler);
                        } catch (Throwable e) {
                            ExceptionUtils.handleThrowable(e);
                            getLog().error(sm.getString("abstractConnectionHandler.error"), e);
                        }
                        upgradeToken.getContextBind().unbind(false, oldCL);
                    }
                }
            }
            release(processor);
        }
        return state;
    } catch(java.net.SocketException e) {
        // SocketExceptions are normal
        getLog().debug(sm.getString(
                "abstractConnectionHandler.socketexception.debug"), e);
    } catch (java.io.IOException e) {
        // IOExceptions are normal
        getLog().debug(sm.getString(
                "abstractConnectionHandler.ioexception.debug"), e);
    } catch (ProtocolException e) {
        // Protocol exceptions normally mean the client sent invalid or
        // incomplete data.
        getLog().debug(sm.getString(
                "abstractConnectionHandler.protocolexception.debug"), e);
    }
    // Future developers: if you discover any other
    // rare-but-nonfatal exceptions, catch them here, and log as
    // above.
    catch (OutOfMemoryError oome) {
        // Try and handle this here to give Tomcat a chance to close the
        // connection and prevent clients waiting until they time out.
        // Worst case, it isn't recoverable and the attempt at logging
        // will trigger another OOME.
        getLog().error(sm.getString("abstractConnectionHandler.oome"), oome);
    } catch (Throwable e) {
        ExceptionUtils.handleThrowable(e);
        // any other exception or error is odd. Here we log it
        // with "ERROR" level, so it will show up even on
        // less-than-verbose logs.
        getLog().error(sm.getString("abstractConnectionHandler.error"), e);
    } finally {
        ContainerThreadMarker.clear();
    }

    // Make sure socket/processor is removed from the list of current
    // connections
    connections.remove(socket);
    release(processor);
    return SocketState.CLOSED;
}
  1. 协议升级完成后,当SocketEvent变为OPEN_READ后,将会调用AbstractProcessorLight的service方法,此时会选择具体的协议处理
@Override
public SocketState process(SocketWrapperBase<?> socketWrapper, SocketEvent status)
        throws IOException {

    SocketState state = SocketState.CLOSED;
    Iterator<DispatchType> dispatches = null;
    do {
        if (dispatches != null) {
            DispatchType nextDispatch = dispatches.next();
            if (getLog().isDebugEnabled()) {
                getLog().debug("Processing dispatch type: [" + nextDispatch + "]");
            }
            state = dispatch(nextDispatch.getSocketStatus());
            if (!dispatches.hasNext()) {
                state = checkForPipelinedData(state, socketWrapper);
            }
        } else if (status == SocketEvent.DISCONNECT) {
            // Do nothing here, just wait for it to get recycled
        } else if (isAsync() || isUpgrade() || state == SocketState.ASYNC_END) {
            state = dispatch(status);
            state = checkForPipelinedData(state, socketWrapper);
        } else if (status == SocketEvent.OPEN_WRITE) {
            // Extra write event likely after async, ignore
            state = SocketState.LONG;
        } else if (status == SocketEvent.OPEN_READ) {
            state = service(socketWrapper);
        } else if (status == SocketEvent.CONNECT_FAIL) {
            logAccess(socketWrapper);
        } else {
            // Default to closing the socket if the SocketEvent passed in
            // is not consistent with the current state of the Processor
            state = SocketState.CLOSED;
        }

        if (getLog().isDebugEnabled()) {
            getLog().debug("Socket: [" + socketWrapper +
                    "], Status in: [" + status +
                    "], State out: [" + state + "]");
        }

        if (isAsync()) {
            state = asyncPostProcess();
            if (getLog().isDebugEnabled()) {
                getLog().debug("Socket: [" + socketWrapper +
                        "], State after async post processing: [" + state + "]");
            }
        }

        if (dispatches == null || !dispatches.hasNext()) {
            // Only returns non-null iterator if there are
            // dispatches to process.
            dispatches = getIteratorAndClearDispatches();
        }
    } while (state == SocketState.ASYNC_END ||
            dispatches != null && state != SocketState.CLOSED);

    return state;
}

tomcat coyote模块请求处理流程_第1张图片
8. 在具体的协议中会对socket处理做coyoteRequest和coyoteResponse的转换,最后交给Coyote模块和catalina模块的连接器CoyoteAdapter处理,处理过程可以参考catalina模块请求处理过程
以Http11Processor的service实现为例

@Override
public SocketState service(SocketWrapperBase<?> socketWrapper)
    throws IOException {
    RequestInfo rp = request.getRequestProcessor();
    rp.setStage(org.apache.coyote.Constants.STAGE_PARSE);

    // Setting up the I/O
    setSocketWrapper(socketWrapper);

    // Flags
    keepAlive = true;
    openSocket = false;
    readComplete = true;
    boolean keptAlive = false;
    SendfileState sendfileState = SendfileState.DONE;

    while (!getErrorState().isError() && keepAlive && !isAsync() && upgradeToken == null &&
            sendfileState == SendfileState.DONE && !endpoint.isPaused()) {

        // Parsing the request header
        try {
            if (!inputBuffer.parseRequestLine(keptAlive)) {
                if (inputBuffer.getParsingRequestLinePhase() == -1) {
                    return SocketState.UPGRADING;
                } else if (handleIncompleteRequestLineRead()) {
                    break;
                }
            }

            // Process the Protocol component of the request line
            // Need to know if this is an HTTP 0.9 request before trying to
            // parse headers.
            prepareRequestProtocol();

            if (endpoint.isPaused()) {
                // 503 - Service unavailable
                response.setStatus(503);
                setErrorState(ErrorState.CLOSE_CLEAN, null);
            } else {
                keptAlive = true;
                // Set this every time in case limit has been changed via JMX
                request.getMimeHeaders().setLimit(endpoint.getMaxHeaderCount());
                // Don't parse headers for HTTP/0.9
                if (!http09 && !inputBuffer.parseHeaders()) {
                    // We've read part of the request, don't recycle it
                    // instead associate it with the socket
                    openSocket = true;
                    readComplete = false;
                    break;
                }
                if (!disableUploadTimeout) {
                    socketWrapper.setReadTimeout(connectionUploadTimeout);
                }
            }
        } catch (IOException e) {
            if (log.isDebugEnabled()) {
                log.debug(sm.getString("http11processor.header.parse"), e);
            }
            setErrorState(ErrorState.CLOSE_CONNECTION_NOW, e);
            break;
        } catch (Throwable t) {
            ExceptionUtils.handleThrowable(t);
            UserDataHelper.Mode logMode = userDataHelper.getNextMode();
            if (logMode != null) {
                String message = sm.getString("http11processor.header.parse");
                switch (logMode) {
                    case INFO_THEN_DEBUG:
                        message += sm.getString("http11processor.fallToDebug");
                        //$FALL-THROUGH$
                    case INFO:
                        log.info(message, t);
                        break;
                    case DEBUG:
                        log.debug(message, t);
                }
            }
            // 400 - Bad Request
            response.setStatus(400);
            setErrorState(ErrorState.CLOSE_CLEAN, t);
        }

        // Has an upgrade been requested?
        if (isConnectionToken(request.getMimeHeaders(), "upgrade")) {
            // Check the protocol
            String requestedProtocol = request.getHeader("Upgrade");

            UpgradeProtocol upgradeProtocol = protocol.getUpgradeProtocol(requestedProtocol);
            if (upgradeProtocol != null) {
                if (upgradeProtocol.accept(request)) {
                    // TODO Figure out how to handle request bodies at this
                    // point.
                    response.setStatus(HttpServletResponse.SC_SWITCHING_PROTOCOLS);
                    response.setHeader("Connection", "Upgrade");
                    response.setHeader("Upgrade", requestedProtocol);
                    action(ActionCode.CLOSE,  null);
                    getAdapter().log(request, response, 0);

                    InternalHttpUpgradeHandler upgradeHandler =
                            upgradeProtocol.getInternalUpgradeHandler(
                                    getAdapter(), cloneRequest(request));
                    UpgradeToken upgradeToken = new UpgradeToken(upgradeHandler, null, null);
                    action(ActionCode.UPGRADE, upgradeToken);
                    return SocketState.UPGRADING;
                }
            }
        }

        if (getErrorState().isIoAllowed()) {
            // Setting up filters, and parse some request headers
            rp.setStage(org.apache.coyote.Constants.STAGE_PREPARE);
            try {
                prepareRequest();
            } catch (Throwable t) {
                ExceptionUtils.handleThrowable(t);
                if (log.isDebugEnabled()) {
                    log.debug(sm.getString("http11processor.request.prepare"), t);
                }
                // 500 - Internal Server Error
                response.setStatus(500);
                setErrorState(ErrorState.CLOSE_CLEAN, t);
            }
        }

        if (maxKeepAliveRequests == 1) {
            keepAlive = false;
        } else if (maxKeepAliveRequests > 0 &&
                socketWrapper.decrementKeepAlive() <= 0) {
            keepAlive = false;
        }

        // Process the request in the adapter
        if (getErrorState().isIoAllowed()) {
            try {
                rp.setStage(org.apache.coyote.Constants.STAGE_SERVICE);
                getAdapter().service(request, response);
                // Handle when the response was committed before a serious
                // error occurred.  Throwing a ServletException should both
                // set the status to 500 and set the errorException.
                // If we fail here, then the response is likely already
                // committed, so we can't try and set headers.
                if(keepAlive && !getErrorState().isError() && !isAsync() &&
                        statusDropsConnection(response.getStatus())) {
                    setErrorState(ErrorState.CLOSE_CLEAN, null);
                }
            } catch (InterruptedIOException e) {
                setErrorState(ErrorState.CLOSE_CONNECTION_NOW, e);
            } catch (HeadersTooLargeException e) {
                log.error(sm.getString("http11processor.request.process"), e);
                // The response should not have been committed but check it
                // anyway to be safe
                if (response.isCommitted()) {
                    setErrorState(ErrorState.CLOSE_NOW, e);
                } else {
                    response.reset();
                    response.setStatus(500);
                    setErrorState(ErrorState.CLOSE_CLEAN, e);
                    response.setHeader("Connection", "close"); // TODO: Remove
                }
            } catch (Throwable t) {
                ExceptionUtils.handleThrowable(t);
                log.error(sm.getString("http11processor.request.process"), t);
                // 500 - Internal Server Error
                response.setStatus(500);
                setErrorState(ErrorState.CLOSE_CLEAN, t);
                getAdapter().log(request, response, 0);
            }
        }

        // Finish the handling of the request
        rp.setStage(org.apache.coyote.Constants.STAGE_ENDINPUT);
        if (!isAsync()) {
            // If this is an async request then the request ends when it has
            // been completed. The AsyncContext is responsible for calling
            // endRequest() in that case.
            endRequest();
        }
        rp.setStage(org.apache.coyote.Constants.STAGE_ENDOUTPUT);

        // If there was an error, make sure the request is counted as
        // and error, and update the statistics counter
        if (getErrorState().isError()) {
            response.setStatus(500);
        }

        if (!isAsync() || getErrorState().isError()) {
            request.updateCounters();
            if (getErrorState().isIoAllowed()) {
                inputBuffer.nextRequest();
                outputBuffer.nextRequest();
            }
        }

        if (!disableUploadTimeout) {
            int soTimeout = endpoint.getConnectionTimeout();
            if(soTimeout > 0) {
                socketWrapper.setReadTimeout(soTimeout);
            } else {
                socketWrapper.setReadTimeout(0);
            }
        }

        rp.setStage(org.apache.coyote.Constants.STAGE_KEEPALIVE);

        sendfileState = processSendfile(socketWrapper);
    }

    rp.setStage(org.apache.coyote.Constants.STAGE_ENDED);

    if (getErrorState().isError() || (endpoint.isPaused() && !isAsync())) {
        return SocketState.CLOSED;
    } else if (isAsync()) {
        return SocketState.LONG;
    } else if (isUpgrade()) {
        return SocketState.UPGRADING;
    } else {
        if (sendfileState == SendfileState.PENDING) {
            return SocketState.SENDFILE;
        } else {
            if (openSocket) {
                if (readComplete) {
                    return SocketState.OPEN;
                } else {
                    return SocketState.LONG;
                }
            } else {
                return SocketState.CLOSED;
            }
        }
    }
}

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