/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF 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
 *
 *      http://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 org.apache.coyote.ajp;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.net.InetAddress;
import java.nio.ByteBuffer;
import java.security.NoSuchProviderException;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;
import java.util.Iterator;
import java.util.concurrent.LinkedBlockingDeque;
import java.util.concurrent.atomic.AtomicBoolean;

import javax.servlet.RequestDispatcher;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpUpgradeHandler;

import org.apache.coyote.AbstractProcessor;
import org.apache.coyote.ActionCode;
import org.apache.coyote.AsyncContextCallback;
import org.apache.coyote.ByteBufferHolder;
import org.apache.coyote.ErrorState;
import org.apache.coyote.InputBuffer;
import org.apache.coyote.OutputBuffer;
import org.apache.coyote.Request;
import org.apache.coyote.RequestInfo;
import org.apache.coyote.Response;
import org.apache.tomcat.util.ExceptionUtils;
import org.apache.tomcat.util.buf.ByteChunk;
import org.apache.tomcat.util.buf.HexUtils;
import org.apache.tomcat.util.buf.MessageBytes;
import org.apache.tomcat.util.http.HttpMessages;
import org.apache.tomcat.util.http.MimeHeaders;
import org.apache.tomcat.util.net.AbstractEndpoint;
import org.apache.tomcat.util.net.AbstractEndpoint.Handler.SocketState;
import org.apache.tomcat.util.net.DispatchType;
import org.apache.tomcat.util.net.SSLSupport;
import org.apache.tomcat.util.net.SocketStatus;
import org.apache.tomcat.util.net.SocketWrapper;
import org.apache.tomcat.util.res.StringManager;

/**
 * Base class for AJP Processor implementations.
 */
public abstract class AbstractAjpProcessor<S> extends AbstractProcessor<S> {

    /**
     * The string manager for this package.
     */
    protected static final StringManager sm =
        StringManager.getManager(Constants.Package);


    /**
     * End message array.
     */
    protected static final byte[] endMessageArray;
    protected static final byte[] endAndCloseMessageArray;


    /**
     * Flush message array.
     */
    protected static final byte[] flushMessageArray;


    /**
     * Pong message array.
     */
    protected static final byte[] pongMessageArray;


    static {
        // Allocate the end message array
        AjpMessage endMessage = new AjpMessage(16);
        endMessage.reset();
        endMessage.appendByte(Constants.JK_AJP13_END_RESPONSE);
        endMessage.appendByte(1);
        endMessage.end();
        endMessageArray = new byte[endMessage.getLen()];
        System.arraycopy(endMessage.getBuffer(), 0, endMessageArray, 0,
                endMessage.getLen());

        // Allocate the end and close message array
        AjpMessage endAndCloseMessage = new AjpMessage(16);
        endAndCloseMessage.reset();
        endAndCloseMessage.appendByte(Constants.JK_AJP13_END_RESPONSE);
        endAndCloseMessage.appendByte(0);
        endAndCloseMessage.end();
        endAndCloseMessageArray = new byte[endAndCloseMessage.getLen()];
        System.arraycopy(endAndCloseMessage.getBuffer(), 0, endAndCloseMessageArray, 0,
                endAndCloseMessage.getLen());

        // Allocate the flush message array
        AjpMessage flushMessage = new AjpMessage(16);
        flushMessage.reset();
        flushMessage.appendByte(Constants.JK_AJP13_SEND_BODY_CHUNK);
        flushMessage.appendInt(0);
        flushMessage.appendByte(0);
        flushMessage.end();
        flushMessageArray = new byte[flushMessage.getLen()];
        System.arraycopy(flushMessage.getBuffer(), 0, flushMessageArray, 0,
                flushMessage.getLen());

        // Allocate the pong message array
        AjpMessage pongMessage = new AjpMessage(16);
        pongMessage.reset();
        pongMessage.appendByte(Constants.JK_AJP13_CPONG_REPLY);
        pongMessage.end();
        pongMessageArray = new byte[pongMessage.getLen()];
        System.arraycopy(pongMessage.getBuffer(), 0, pongMessageArray,
                0, pongMessage.getLen());
    }


    // ----------------------------------------------------- Instance Variables


    /**
     * GetBody message array. Not static like the other message arrays since the
     * message varies with packetSize and that can vary per connector.
     */
    protected final byte[] getBodyMessageArray;


    /**
     * AJP packet size.
     */
    private final int outputMaxChunkSize;

    /**
     * Header message. Note that this header is merely the one used during the
     * processing of the first message of a "request", so it might not be a
     * request header. It will stay unchanged during the processing of the whole
     * request.
     */
    protected final AjpMessage requestHeaderMessage;


    /**
     * Message used for response composition.
     */
    protected final AjpMessage responseMessage;


    /**
     * Location of next write of the response message (used withnon-blocking
     * writes when the message may not be written in a single write). Avalue of
     * -1 indicates that no message has been written to the buffer.
     */
    private int responseMsgPos = -1;


    /**
     * Body message.
     */
    protected final AjpMessage bodyMessage;


    /**
     * Body message.
     */
    protected final MessageBytes bodyBytes = MessageBytes.newInstance();


    /**
     * The max size of the buffered write buffer
     */
    private int bufferedWriteSize = 64*1024; //64k default write buffer


    /**
     * For "non-blocking" writes use an external set of buffers. Although the
     * API only allows one non-blocking write at a time, due to buffering and
     * the possible need to write HTTP headers, there may be more than one write
     * to the OutputBuffer.
     */
    private final LinkedBlockingDeque<ByteBufferHolder> bufferedWrites =
            new LinkedBlockingDeque<>();


    /**
     * Host name (used to avoid useless B2C conversion on the host name).
     */
    protected char[] hostNameC = new char[0];


    /**
     * Temp message bytes used for processing.
     */
    protected final MessageBytes tmpMB = MessageBytes.newInstance();


    /**
     * Byte chunk for certs.
     */
    protected final MessageBytes certificates = MessageBytes.newInstance();


    /**
     * End of stream flag.
     */
    protected boolean endOfStream = false;


    /**
     * Request body empty flag.
     */
    protected boolean empty = true;


    /**
     * First read.
     */
    protected boolean first = true;


    /**
     * Indicates that a 'get body chunk' message has been sent but the body
     * chunk has not yet been received.
     */
    private boolean waitingForBodyMessage = false;


    /**
     * Replay read.
     */
    protected boolean replay = false;


    /**
     * Should any response body be swallowed and not sent to the client.
     */
    private boolean swallowResponse = false;


    /**
     * Finished response.
     */
    protected boolean finished = false;


    /**
     * Bytes written to client for the current request.
     */
    protected long bytesWritten = 0;


    // ------------------------------------------------------------ Constructor

    public AbstractAjpProcessor(int packetSize, AbstractEndpoint<S> endpoint) {

        super(endpoint);

        // Calculate maximum chunk size as packetSize may have been changed from
        // the default (Constants.MAX_PACKET_SIZE)
        this.outputMaxChunkSize =
                Constants.MAX_SEND_SIZE + packetSize - Constants.MAX_PACKET_SIZE;

        request.setInputBuffer(new SocketInputBuffer());

        requestHeaderMessage = new AjpMessage(packetSize);
        responseMessage = new AjpMessage(packetSize);
        bodyMessage = new AjpMessage(packetSize);

        // Set the getBody message buffer
        AjpMessage getBodyMessage = new AjpMessage(16);
        getBodyMessage.reset();
        getBodyMessage.appendByte(Constants.JK_AJP13_GET_BODY_CHUNK);
        // Adjust read size if packetSize != default (Constants.MAX_PACKET_SIZE)
        getBodyMessage.appendInt(Constants.MAX_READ_SIZE + packetSize -
                Constants.MAX_PACKET_SIZE);
        getBodyMessage.end();
        getBodyMessageArray = new byte[getBodyMessage.getLen()];
        System.arraycopy(getBodyMessage.getBuffer(), 0, getBodyMessageArray,
                0, getBodyMessage.getLen());
    }


    // ------------------------------------------------------------- Properties


    /**
     * The number of milliseconds Tomcat will wait for a subsequent request
     * before closing the connection. The default is -1 which is an infinite
     * timeout.
     */
    protected int keepAliveTimeout = -1;
    public int getKeepAliveTimeout() { return keepAliveTimeout; }
    public void setKeepAliveTimeout(int timeout) { keepAliveTimeout = timeout; }


    /**
     * Use Tomcat authentication ?
     */
    protected boolean tomcatAuthentication = true;
    public boolean getTomcatAuthentication() { return tomcatAuthentication; }
    public void setTomcatAuthentication(boolean tomcatAuthentication) {
        this.tomcatAuthentication = tomcatAuthentication;
    }


    /**
     * Use Tomcat authorization ?
     */
    private boolean tomcatAuthorization = false;
    public boolean getTomcatAuthorization() { return tomcatAuthorization; }
    public void setTomcatAuthorization(boolean tomcatAuthorization) {
        this.tomcatAuthorization = tomcatAuthorization;
    }


    /**
     * Required secret.
     */
    protected String requiredSecret = null;
    public void setRequiredSecret(String requiredSecret) {
        this.requiredSecret = requiredSecret;
    }


    /**
     * When client certificate information is presented in a form other than
     * instances of {@link java.security.cert.X509Certificate} it needs to be
     * converted before it can be used and this property controls which JSSE
     * provider is used to perform the conversion. For example it is used with
     * the AJP connectors, the HTTP APR connector and with the
     * {@link org.apache.catalina.valves.SSLValve}. If not specified, the
     * default provider will be used.
     */
    protected String clientCertProvider = null;
    public String getClientCertProvider() { return clientCertProvider; }
    public void setClientCertProvider(String s) { this.clientCertProvider = s; }

    // --------------------------------------------------------- Public Methods


    /**
     * Send an action to the connector.
     *
     * @param actionCode Type of the action
     * @param param Action parameter
     */
    @Override
    public final void action(ActionCode actionCode, Object param) {

        switch (actionCode) {
        case CLOSE: {
            // End the processing of the current request, and stop any further
            // transactions with the client

            try {
                finish();
            } catch (IOException e) {
                setErrorState(ErrorState.CLOSE_NOW, e);
            }
            break;
        }
        case COMMIT: {
            if (response.isCommitted())
                return;

            // Validate and write response headers
            try {
                prepareResponse();
            } catch (IOException e) {
                setErrorState(ErrorState.CLOSE_NOW, e);
            }

            try {
                flush(false);
            } catch (IOException e) {
                setErrorState(ErrorState.CLOSE_NOW, e);
            }
            break;
        }
        case ACK: {
            // NO_OP for AJP
            break;
        }
        case CLIENT_FLUSH: {
            if (!response.isCommitted()) {
                // Validate and write response headers
                try {
                    prepareResponse();
                } catch (IOException e) {
                    setErrorState(ErrorState.CLOSE_NOW, e);
                    return;
                }
            }

            try {
                flush(true);
            } catch (IOException e) {
                setErrorState(ErrorState.CLOSE_NOW, e);
            }
            break;
        }
        case IS_ERROR: {
            ((AtomicBoolean) param).set(getErrorState().isError());
            break;
        }
        case DISABLE_SWALLOW_INPUT: {
            // TODO: Do not swallow request input but
            // make sure we are closing the connection
            setErrorState(ErrorState.CLOSE_CLEAN, null);
            break;
        }
        case RESET: {
            // NO-OP
            break;
        }
        case REQ_SSL_ATTRIBUTE: {
            if (!certificates.isNull()) {
                ByteChunk certData = certificates.getByteChunk();
                X509Certificate jsseCerts[] = null;
                ByteArrayInputStream bais =
                    new ByteArrayInputStream(certData.getBytes(),
                            certData.getStart(),
                            certData.getLength());
                // Fill the  elements.
                try {
                    CertificateFactory cf;
                    if (clientCertProvider == null) {
                        cf = CertificateFactory.getInstance("X.509");
                    } else {
                        cf = CertificateFactory.getInstance("X.509",
                                clientCertProvider);
                    }
                    while(bais.available() > 0) {
                        X509Certificate cert = (X509Certificate)
                        cf.generateCertificate(bais);
                        if(jsseCerts == null) {
                            jsseCerts = new X509Certificate[1];
                            jsseCerts[0] = cert;
                        } else {
                            X509Certificate [] temp = new X509Certificate[jsseCerts.length+1];
                            System.arraycopy(jsseCerts,0,temp,0,jsseCerts.length);
                            temp[jsseCerts.length] = cert;
                            jsseCerts = temp;
                        }
                    }
                } catch (java.security.cert.CertificateException e) {
                    getLog().error(sm.getString("ajpprocessor.certs.fail"), e);
                    return;
                } catch (NoSuchProviderException e) {
                    getLog().error(sm.getString("ajpprocessor.certs.fail"), e);
                    return;
                }
                request.setAttribute(SSLSupport.CERTIFICATE_KEY, jsseCerts);
            }
            break;
        }
        case REQ_SSL_CERTIFICATE: {
            // NO-OP. Can't force a new SSL handshake with the client when using
            // AJP as the reverse proxy controls that connection.
            break;
        }
        case REQ_HOST_ATTRIBUTE: {
            // Get remote host name using a DNS resolution
            if (request.remoteHost().isNull()) {
                try {
                    request.remoteHost().setString(InetAddress.getByName
                            (request.remoteAddr().toString()).getHostName());
                } catch (IOException iex) {
                    // Ignore
                }
            }
            break;
        }
        case REQ_HOST_ADDR_ATTRIBUTE: {
            // NO-OP
            // Automatically populated during prepareRequest()
            break;
        }
        case REQ_LOCAL_NAME_ATTRIBUTE: {
            // NO-OP
            // Automatically populated during prepareRequest()
            break;
        }
        case REQ_LOCAL_ADDR_ATTRIBUTE: {
            // Automatically populated during prepareRequest() when using
            // modern AJP forwarder, otherwise copy from local name
            if (request.localAddr().isNull()) {
                request.localAddr().setString(request.localName().toString());
            }
            break;
        }
        case REQ_REMOTEPORT_ATTRIBUTE: {
            // NO-OP
            // Automatically populated during prepareRequest() when using
            // modern AJP forwarder, otherwise not available
            break;
        }
        case REQ_LOCALPORT_ATTRIBUTE: {
            // NO-OP
            // Automatically populated during prepareRequest()
            break;
        }
        case REQ_SET_BODY_REPLAY: {
            // Set the given bytes as the content
            ByteChunk bc = (ByteChunk) param;
            int length = bc.getLength();
            bodyBytes.setBytes(bc.getBytes(), bc.getStart(), length);
            request.setContentLength(length);
            first = false;
            empty = false;
            replay = true;
            endOfStream = false;
            break;
        }
        case ASYNC_START: {
            asyncStateMachine.asyncStart((AsyncContextCallback) param);
            // Async time out is based on SocketWrapper access time
            getSocketWrapper().access();
            break;
        }
        case ASYNC_COMPLETE: {
            socketWrapper.clearDispatches();
            if (asyncStateMachine.asyncComplete()) {
                endpoint.processSocket(socketWrapper, SocketStatus.OPEN_READ, true);
            }
            break;
        }
        case ASYNC_DISPATCH: {
            if (asyncStateMachine.asyncDispatch()) {
                endpoint.processSocket(socketWrapper, SocketStatus.OPEN_READ, true);
            }
            break;
        }
        case ASYNC_DISPATCHED: {
            asyncStateMachine.asyncDispatched();
            break;
        }
        case ASYNC_SETTIMEOUT: {
            if (param == null) return;
            long timeout = ((Long)param).longValue();
            socketWrapper.setTimeout(timeout);
            break;
        }
        case ASYNC_TIMEOUT: {
            AtomicBoolean result = (AtomicBoolean) param;
            result.set(asyncStateMachine.asyncTimeout());
            break;
        }
        case ASYNC_RUN: {
            asyncStateMachine.asyncRun((Runnable) param);
            break;
        }
        case ASYNC_ERROR: {
            asyncStateMachine.asyncError();
            break;
        }
        case ASYNC_IS_STARTED: {
            ((AtomicBoolean) param).set(asyncStateMachine.isAsyncStarted());
            break;
        }
        case ASYNC_IS_COMPLETING: {
            ((AtomicBoolean) param).set(asyncStateMachine.isCompleting());
            break;
        }
        case ASYNC_IS_DISPATCHING: {
            ((AtomicBoolean) param).set(asyncStateMachine.isAsyncDispatching());
            break;
        }
        case ASYNC_IS_ASYNC: {
            ((AtomicBoolean) param).set(asyncStateMachine.isAsync());
            break;
        }
        case ASYNC_IS_TIMINGOUT: {
            ((AtomicBoolean) param).set(asyncStateMachine.isAsyncTimingOut());
            break;
        }
        case ASYNC_IS_ERROR: {
            ((AtomicBoolean) param).set(asyncStateMachine.isAsyncError());
            break;
        }
        case UPGRADE: {
            // HTTP connections only. Unsupported for AJP.
            throw new UnsupportedOperationException(
                    sm.getString("ajpprocessor.httpupgrade.notsupported"));
        }
        case COMET_BEGIN: {
            // HTTP connections only. Unsupported for AJP.
            throw new UnsupportedOperationException(
                    sm.getString("ajpprocessor.comet.notsupported"));
        }
        case COMET_END: {
            // HTTP connections only. Unsupported for AJP.
            throw new UnsupportedOperationException(
                    sm.getString("ajpprocessor.comet.notsupported"));
        }
        case COMET_CLOSE: {
            // HTTP connections only. Unsupported for AJP.
            throw new UnsupportedOperationException(
                    sm.getString("ajpprocessor.comet.notsupported"));
        }
        case COMET_SETTIMEOUT: {
            // HTTP connections only. Unsupported for AJP.
            throw new UnsupportedOperationException(
                    sm.getString("ajpprocessor.comet.notsupported"));
        }
        case AVAILABLE: {
            if (available()) {
                request.setAvailable(1);
            } else {
                request.setAvailable(0);
            }
            break;
        }
        case NB_READ_INTEREST: {
            if (!endOfStream) {
                registerForEvent(true, false);
            }
            break;
        }
        case NB_WRITE_INTEREST: {
            AtomicBoolean isReady = (AtomicBoolean)param;
            boolean result = bufferedWrites.size() == 0 && responseMsgPos == -1;
            isReady.set(result);
            if (!result) {
                registerForEvent(false, true);
            }
            break;
        }
        case REQUEST_BODY_FULLY_READ: {
            AtomicBoolean result = (AtomicBoolean) param;
            result.set(endOfStream);
            break;
        }
        case DISPATCH_READ: {
            socketWrapper.addDispatch(DispatchType.NON_BLOCKING_READ);
            break;
        }
        case DISPATCH_WRITE: {
            socketWrapper.addDispatch(DispatchType.NON_BLOCKING_WRITE);
            break;
        }
        case DISPATCH_EXECUTE: {
            getEndpoint().executeNonBlockingDispatches(socketWrapper);
            break;
        }
        case CLOSE_NOW: {
            // Prevent further writes to the response
            swallowResponse = true;
            setErrorState(ErrorState.CLOSE_NOW, null);
            break;
        }
        case END_REQUEST: {
            // NO-OP for AJP
            break;
        }
       }
    }


    @Override
    public SocketState asyncDispatch(SocketStatus status) {

        if (status == SocketStatus.OPEN_WRITE && response.getWriteListener() != null) {
            try {
                asyncStateMachine.asyncOperation();
                try {
                    if (hasDataToWrite()) {
                        flushBufferedData();
                        if (hasDataToWrite()) {
                            // There is data to write but go via Response to
                            // maintain a consistent view of non-blocking state
                            response.checkRegisterForWrite();
                            return SocketState.LONG;
                        }
                    }
                } catch (IOException x) {
                    if (getLog().isDebugEnabled()) {
                        getLog().debug("Unable to write async data.",x);
                    }
                    status = SocketStatus.ASYNC_WRITE_ERROR;
                    request.setAttribute(RequestDispatcher.ERROR_EXCEPTION, x);
                }
            } catch (IllegalStateException x) {
                registerForEvent(false, true);
            }
        } else if (status == SocketStatus.OPEN_READ && request.getReadListener() != null) {
            try {
                if (available()) {
                    asyncStateMachine.asyncOperation();
                }
            } catch (IllegalStateException x) {
                registerForEvent(true, false);
            }
        }

        RequestInfo rp = request.getRequestProcessor();
        try {
            rp.setStage(org.apache.coyote.Constants.STAGE_SERVICE);
            if(!getAdapter().asyncDispatch(request, response, status)) {
                setErrorState(ErrorState.CLOSE_NOW, null);
            }
            resetTimeouts();
        } catch (InterruptedIOException e) {
            setErrorState(ErrorState.CLOSE_NOW, e);
        } catch (Throwable t) {
            ExceptionUtils.handleThrowable(t);
            setErrorState(ErrorState.CLOSE_NOW, t);
            getLog().error(sm.getString("http11processor.request.process"), t);
        }

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

        if (isAsync()) {
            if (getErrorState().isError()) {
                request.updateCounters();
                return SocketState.CLOSED;
            } else {
                return SocketState.LONG;
            }
        } else {
            request.updateCounters();
            if (getErrorState().isError()) {
                return SocketState.CLOSED;
            } else {
                return SocketState.OPEN;
            }
        }
    }


    /**
     * Process pipelined HTTP requests using the specified input and output
     * streams.
     *
     * @throws IOException error during an I/O operation
     */
    @Override
    public SocketState process(SocketWrapper<S> socket) throws IOException {

        RequestInfo rp = request.getRequestProcessor();
        rp.setStage(org.apache.coyote.Constants.STAGE_PARSE);

        // Setting up the socket
        this.socketWrapper = socket;

        setupSocket(socket);

        int soTimeout = endpoint.getSoTimeout();
        boolean cping = false;

        boolean keptAlive = false;

        while (!getErrorState().isError() && !endpoint.isPaused()) {
            // Parsing the request header
            try {
                // Get first message of the request
                if (!readMessage(requestHeaderMessage, !keptAlive)) {
                    break;
                }
                // Set back timeout if keep alive timeout is enabled
                if (keepAliveTimeout > 0) {
                    setTimeout(socketWrapper, soTimeout);
                }
                // Check message type, process right away and break if
                // not regular request processing
                int type = requestHeaderMessage.getByte();
                if (type == Constants.JK_AJP13_CPING_REQUEST) {
                    if (endpoint.isPaused()) {
                        recycle(true);
                        break;
                    }
                    cping = true;
                    try {
                        output(pongMessageArray, 0, pongMessageArray.length, true);
                    } catch (IOException e) {
                        setErrorState(ErrorState.CLOSE_NOW, e);
                    }
                    recycle(false);
                    continue;
                } else if(type != Constants.JK_AJP13_FORWARD_REQUEST) {
                    // Unexpected packet type. Unread body packets should have
                    // been swallowed in finish().
                    if (getLog().isDebugEnabled()) {
                        getLog().debug("Unexpected message: " + type);
                    }
                    setErrorState(ErrorState.CLOSE_NOW, null);
                    break;
                }
                keptAlive = true;
                request.setStartTime(System.currentTimeMillis());
            } catch (IOException e) {
                setErrorState(ErrorState.CLOSE_NOW, e);
                break;
            } catch (Throwable t) {
                ExceptionUtils.handleThrowable(t);
                getLog().debug(sm.getString("ajpprocessor.header.error"), t);
                // 400 - Bad Request
                response.setStatus(400);
                setErrorState(ErrorState.CLOSE_CLEAN, t);
                getAdapter().log(request, response, 0);
            }

            if (!getErrorState().isError()) {
                // Setting up filters, and parse some request headers
                rp.setStage(org.apache.coyote.Constants.STAGE_PREPARE);
                try {
                    prepareRequest();
                } catch (Throwable t) {
                    ExceptionUtils.handleThrowable(t);
                    getLog().debug(sm.getString("ajpprocessor.request.prepare"), t);
                    // 500 - Internal Server Error
                    response.setStatus(500);
                    setErrorState(ErrorState.CLOSE_CLEAN, t);
                    getAdapter().log(request, response, 0);
                }
            }

            if (!getErrorState().isError() && !cping && endpoint.isPaused()) {
                // 503 - Service unavailable
                response.setStatus(503);
                setErrorState(ErrorState.CLOSE_CLEAN, null);
                getAdapter().log(request, response, 0);
            }
            cping = false;

            // Process the request in the adapter
            if (!getErrorState().isError()) {
                try {
                    rp.setStage(org.apache.coyote.Constants.STAGE_SERVICE);
                    getAdapter().service(request, response);
                } catch (InterruptedIOException e) {
                    setErrorState(ErrorState.CLOSE_NOW, e);
                } catch (Throwable t) {
                    ExceptionUtils.handleThrowable(t);
                    getLog().error(sm.getString("ajpprocessor.request.process"), t);
                    // 500 - Internal Server Error
                    response.setStatus(500);
                    setErrorState(ErrorState.CLOSE_CLEAN, t);
                    getAdapter().log(request, response, 0);
                }
            }

            if (isAsync() && !getErrorState().isError()) {
                break;
            }

            // Finish the response if not done yet
            if (!finished && getErrorState().isIoAllowed()) {
                try {
                    finish();
                } catch (Throwable t) {
                    ExceptionUtils.handleThrowable(t);
                    setErrorState(ErrorState.CLOSE_NOW, t);
                }
            }

            // 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);
            }
            request.updateCounters();

            rp.setStage(org.apache.coyote.Constants.STAGE_KEEPALIVE);
            // Set keep alive timeout if enabled
            if (keepAliveTimeout > 0) {
                setTimeout(socketWrapper, keepAliveTimeout);
            }

            recycle(false);
        }

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

        if (getErrorState().isError() || endpoint.isPaused()) {
            return SocketState.CLOSED;
        } else {
            if (isAsync()) {
                return SocketState.LONG;
            } else {
                return SocketState.OPEN;
            }
        }
    }


    @Override
    public void setSslSupport(SSLSupport sslSupport) {
        // Should never reach this code but in case we do...
        throw new IllegalStateException(
                sm.getString("ajpprocessor.ssl.notsupported"));
    }


    @Override
    public SocketState event(SocketStatus status) throws IOException {
        // Should never reach this code but in case we do...
        throw new IOException(
                sm.getString("ajpprocessor.comet.notsupported"));
    }


    @Override
    public SocketState upgradeDispatch(SocketStatus status) throws IOException {
        // Should never reach this code but in case we do...
        throw new IOException(
                sm.getString("ajpprocessor.httpupgrade.notsupported"));
    }


    @Override
    public HttpUpgradeHandler getHttpUpgradeHandler() {
        // Should never reach this code but in case we do...
        throw new IllegalStateException(
                sm.getString("ajpprocessor.httpupgrade.notsupported"));
    }


    /**
     * Recycle the processor, ready for the next request which may be on the
     * same connection or a different connection.
     *
     * @param socketClosing Indicates if the socket is about to be closed
     *                      allowing the processor to perform any additional
     *                      clean-up that may be required
     */
    @Override
    public void recycle(boolean socketClosing) {
        getAdapter().checkRecycled(request, response);

        asyncStateMachine.recycle();

        // Recycle Request object
        first = true;
        endOfStream = false;
        waitingForBodyMessage = false;
        empty = true;
        replay = false;
        finished = false;
        request.recycle();
        response.recycle();
        certificates.recycle();
        swallowResponse = false;
        bytesWritten = 0;
        resetErrorState();
        bufferedWrites.clear();
    }


    // ------------------------------------------------------ Protected Methods

    // Methods called by asyncDispatch
    /**
     * Provides a mechanism for those connector implementations (currently only
     * NIO) that need to reset timeouts from Async timeouts to standard HTTP
     * timeouts once async processing completes.
     */
    protected abstract void resetTimeouts();

    // Methods called by prepareResponse()
    protected abstract int output(byte[] src, int offset, int length,
            boolean block) throws IOException;

    // Methods called by process()
    protected abstract void setupSocket(SocketWrapper<S> socketWrapper)
            throws IOException;

    protected abstract void setTimeout(SocketWrapper<S> socketWrapper,
            int timeout) throws IOException;

    // Methods used by readMessage
    /**
     * Read at least the specified amount of bytes, and place them
     * in the input buffer. Note that if any data is available to read then this
     * method will always block until at least the specified number of bytes
     * have been read.
     *
     * @param buf   Buffer to read data into
     * @param pos   Start position
     * @param n     The minimum number of bytes to read
     * @param block If there is no data available to read when this method is
     *              called, should this call block until data becomes available?
     * @return  <code>true</code> if the requested number of bytes were read
     *          else <code>false</code>
     * @throws IOException
     */
    protected abstract boolean read(byte[] buf, int pos, int n, boolean block)
            throws IOException;

    // Methods used by SocketInputBuffer
    /**
     * Read an AJP body message. Used to read both the 'special' packet in ajp13
     * and to receive the data after we send a GET_BODY packet.
     *
     * @param block If there is no data available to read when this method is
     *              called, should this call block until data becomes available?
     *
     * @return <code>true</code> if at least one body byte was read, otherwise
     *         <code>false</code>
     */
    protected boolean receive(boolean block) throws IOException {

        bodyMessage.reset();

        if (!readMessage(bodyMessage, block)) {
            return false;
        }

        waitingForBodyMessage = false;

        // No data received.
        if (bodyMessage.getLen() == 0) {
            // just the header
            return false;
        }
        int blen = bodyMessage.peekInt();
        if (blen == 0) {
            return false;
        }

        bodyMessage.getBodyBytes(bodyBytes);
        empty = false;
        return true;
    }


    /**
     * Read an AJP message.
     *
     * @param message   The message to populate
     * @param block If there is no data available to read when this method is
     *              called, should this call block until data becomes available?

     * @return true if the message has been read, false if no data was read
     *
     * @throws IOException any other failure, including incomplete reads
     */
    protected boolean readMessage(AjpMessage message, boolean block)
        throws IOException {

        byte[] buf = message.getBuffer();
        int headerLength = message.getHeaderLength();

        if (!read(buf, 0, headerLength, block)) {
            return false;
        }

        int messageLength = message.processHeader(true);
        if (messageLength < 0) {
            // Invalid AJP header signature
            throw new IOException(sm.getString("ajpmessage.invalidLength",
                    Integer.valueOf(messageLength)));
        }
        else if (messageLength == 0) {
            // Zero length message.
            return true;
        }
        else {
            if (messageLength > message.getBuffer().length) {
                // Message too long for the buffer
                // Need to trigger a 400 response
                throw new IllegalArgumentException(sm.getString(
                        "ajpprocessor.header.tooLong",
                        Integer.valueOf(messageLength),
                        Integer.valueOf(buf.length)));
            }
            read(buf, headerLength, messageLength, true);
            return true;
        }
    }


    @Override
    public final boolean isComet() {
        // AJP does not support Comet
        return false;
    }


    @Override
    public final boolean isUpgrade() {
        // AJP does not support HTTP upgrade
        return false;
    }


    @Override
    public ByteBuffer getLeftoverInput() {
        return null;
    }


    /**
     * Get more request body data from the web server and store it in the
     * internal buffer.
     *
     * @return true if there is more data, false if not.
     */
    protected boolean refillReadBuffer(boolean block) throws IOException {
        // When using replay (e.g. after FORM auth) all the data to read has
        // been buffered so there is no opportunity to refill the buffer.
        if (replay) {
            endOfStream = true; // we've read everything there is
        }
        if (endOfStream) {
            return false;
        }

        if (first) {
            first = false;
            long contentLength = request.getContentLengthLong();
            // - When content length > 0, AJP sends the first body message
            //   automatically.
            // - When content length == 0, AJP does not send a body message.
            // - When content length is unknown, AJP does not send the first
            //   body message automatically.
            if (contentLength > 0) {
                waitingForBodyMessage = true;
            } else if (contentLength == 0) {
                endOfStream = true;
                return false;
            }
        }

        // Request more data immediately
        if (!waitingForBodyMessage) {
            output(getBodyMessageArray, 0, getBodyMessageArray.length, true);
            waitingForBodyMessage = true;
        }

        boolean moreData = receive(block);
        if (!moreData && !waitingForBodyMessage) {
            endOfStream = true;
        }
        return moreData;
    }


    /**
     * After reading the request headers, we have to setup the request filters.
     */
    protected void prepareRequest() {

        // Translate the HTTP method code to a String.
        byte methodCode = requestHeaderMessage.getByte();
        if (methodCode != Constants.SC_M_JK_STORED) {
            String methodName = Constants.getMethodForCode(methodCode - 1);
            request.method().setString(methodName);
        }

        requestHeaderMessage.getBytes(request.protocol());
        requestHeaderMessage.getBytes(request.requestURI());

        requestHeaderMessage.getBytes(request.remoteAddr());
        requestHeaderMessage.getBytes(request.remoteHost());
        requestHeaderMessage.getBytes(request.localName());
        request.setLocalPort(requestHeaderMessage.getInt());

        boolean isSSL = requestHeaderMessage.getByte() != 0;
        if (isSSL) {
            request.scheme().setString("https");
        }

        // Decode headers
        MimeHeaders headers = request.getMimeHeaders();

        // Set this every time in case limit has been changed via JMX
        headers.setLimit(endpoint.getMaxHeaderCount());

        boolean contentLengthSet = false;
        int hCount = requestHeaderMessage.getInt();
        for(int i = 0 ; i < hCount ; i++) {
            String hName = null;

            // Header names are encoded as either an integer code starting
            // with 0xA0, or as a normal string (in which case the first
            // two bytes are the length).
            int isc = requestHeaderMessage.peekInt();
            int hId = isc & 0xFF;

            MessageBytes vMB = null;
            isc &= 0xFF00;
            if(0xA000 == isc) {
                requestHeaderMessage.getInt(); // To advance the read position
                hName = Constants.getHeaderForCode(hId - 1);
                vMB = headers.addValue(hName);
            } else {
                // reset hId -- if the header currently being read
                // happens to be 7 or 8 bytes long, the code below
                // will think it's the content-type header or the
                // content-length header - SC_REQ_CONTENT_TYPE=7,
                // SC_REQ_CONTENT_LENGTH=8 - leading to unexpected
                // behaviour.  see bug 5861 for more information.
                hId = -1;
                requestHeaderMessage.getBytes(tmpMB);
                ByteChunk bc = tmpMB.getByteChunk();
                vMB = headers.addValue(bc.getBuffer(),
                        bc.getStart(), bc.getLength());
            }

            requestHeaderMessage.getBytes(vMB);

            if (hId == Constants.SC_REQ_CONTENT_LENGTH ||
                    (hId == -1 && tmpMB.equalsIgnoreCase("Content-Length"))) {
                long cl = vMB.getLong();
                if (contentLengthSet) {
                    response.setStatus(HttpServletResponse.SC_BAD_REQUEST);
                    setErrorState(ErrorState.CLOSE_CLEAN, null);
                } else {
                    contentLengthSet = true;
                    // Set the content-length header for the request
                    request.setContentLength(cl);
                }
            } else if (hId == Constants.SC_REQ_CONTENT_TYPE ||
                    (hId == -1 && tmpMB.equalsIgnoreCase("Content-Type"))) {
                // just read the content-type header, so set it
                ByteChunk bchunk = vMB.getByteChunk();
                request.contentType().setBytes(bchunk.getBytes(),
                        bchunk.getOffset(),
                        bchunk.getLength());
            }
        }

        // Decode extra attributes
        boolean secret = false;
        byte attributeCode;
        while ((attributeCode = requestHeaderMessage.getByte())
                != Constants.SC_A_ARE_DONE) {

            switch (attributeCode) {

            case Constants.SC_A_REQ_ATTRIBUTE :
                requestHeaderMessage.getBytes(tmpMB);
                String n = tmpMB.toString();
                requestHeaderMessage.getBytes(tmpMB);
                String v = tmpMB.toString();
                /*
                 * AJP13 misses to forward the local IP address and the
                 * remote port. Allow the AJP connector to add this info via
                 * private request attributes.
                 * We will accept the forwarded data and remove it from the
                 * public list of request attributes.
                 */
                if(n.equals(Constants.SC_A_REQ_LOCAL_ADDR)) {
                    request.localAddr().setString(v);
                } else if(n.equals(Constants.SC_A_REQ_REMOTE_PORT)) {
                    try {
                        request.setRemotePort(Integer.parseInt(v));
                    } catch (NumberFormatException nfe) {
                        // Ignore invalid value
                    }
                } else if(n.equals(Constants.SC_A_SSL_PROTOCOL)) {
                    request.setAttribute(SSLSupport.PROTOCOL_VERSION_KEY, v);
                } else {
                    request.setAttribute(n, v );
                }
                break;

            case Constants.SC_A_CONTEXT :
                requestHeaderMessage.getBytes(tmpMB);
                // nothing
                break;

            case Constants.SC_A_SERVLET_PATH :
                requestHeaderMessage.getBytes(tmpMB);
                // nothing
                break;

            case Constants.SC_A_REMOTE_USER :
                if (tomcatAuthorization || !tomcatAuthentication) {
                    // Implies tomcatAuthentication == false
                    requestHeaderMessage.getBytes(request.getRemoteUser());
                    request.setRemoteUserNeedsAuthorization(tomcatAuthorization);
                } else {
                    // Ignore user information from reverse proxy
                    requestHeaderMessage.getBytes(tmpMB);
                }
                break;

            case Constants.SC_A_AUTH_TYPE :
                if (tomcatAuthentication) {
                    // ignore server
                    requestHeaderMessage.getBytes(tmpMB);
                } else {
                    requestHeaderMessage.getBytes(request.getAuthType());
                }
                break;

            case Constants.SC_A_QUERY_STRING :
                requestHeaderMessage.getBytes(request.queryString());
                break;

            case Constants.SC_A_JVM_ROUTE :
                requestHeaderMessage.getBytes(request.instanceId());
                break;

            case Constants.SC_A_SSL_CERT :
                // SSL certificate extraction is lazy, moved to JkCoyoteHandler
                requestHeaderMessage.getBytes(certificates);
                break;

            case Constants.SC_A_SSL_CIPHER :
                requestHeaderMessage.getBytes(tmpMB);
                request.setAttribute(SSLSupport.CIPHER_SUITE_KEY,
                        tmpMB.toString());
                break;

            case Constants.SC_A_SSL_SESSION :
                requestHeaderMessage.getBytes(tmpMB);
                request.setAttribute(SSLSupport.SESSION_ID_KEY,
                        tmpMB.toString());
                break;

            case Constants.SC_A_SSL_KEY_SIZE :
                request.setAttribute(SSLSupport.KEY_SIZE_KEY,
                        Integer.valueOf(requestHeaderMessage.getInt()));
                break;

            case Constants.SC_A_STORED_METHOD:
                requestHeaderMessage.getBytes(request.method());
                break;

            case Constants.SC_A_SECRET:
                requestHeaderMessage.getBytes(tmpMB);
                if (requiredSecret != null) {
                    secret = true;
                    if (!tmpMB.equals(requiredSecret)) {
                        response.setStatus(403);
                        setErrorState(ErrorState.CLOSE_CLEAN, null);
                    }
                }
                break;

            default:
                // Ignore unknown attribute for backward compatibility
                break;

            }

        }

        // Check if secret was submitted if required
        if ((requiredSecret != null) && !secret) {
            response.setStatus(403);
            setErrorState(ErrorState.CLOSE_CLEAN, null);
        }

        // Check for a full URI (including protocol://host:port/)
        ByteChunk uriBC = request.requestURI().getByteChunk();
        if (uriBC.startsWithIgnoreCase("http", 0)) {

            int pos = uriBC.indexOf("://", 0, 3, 4);
            int uriBCStart = uriBC.getStart();
            int slashPos = -1;
            if (pos != -1) {
                byte[] uriB = uriBC.getBytes();
                slashPos = uriBC.indexOf('/', pos + 3);
                if (slashPos == -1) {
                    slashPos = uriBC.getLength();
                    // Set URI as "/"
                    request.requestURI().setBytes
                    (uriB, uriBCStart + pos + 1, 1);
                } else {
                    request.requestURI().setBytes
                    (uriB, uriBCStart + slashPos,
                            uriBC.getLength() - slashPos);
                }
                MessageBytes hostMB = headers.setValue("host");
                hostMB.setBytes(uriB, uriBCStart + pos + 3,
                        slashPos - pos - 3);
            }

        }

        MessageBytes valueMB = request.getMimeHeaders().getValue("host");
        parseHost(valueMB);

        if (getErrorState().isError()) {
            getAdapter().log(request, response, 0);
        }
    }


    /**
     * Parse host.
     */
    protected void parseHost(MessageBytes valueMB) {

        if (valueMB == null || valueMB.isNull()) {
            // HTTP/1.0
            request.setServerPort(request.getLocalPort());
            try {
                request.serverName().duplicate(request.localName());
            } catch (IOException e) {
                response.setStatus(400);
                setErrorState(ErrorState.CLOSE_CLEAN, e);
            }
            return;
        }

        ByteChunk valueBC = valueMB.getByteChunk();
        byte[] valueB = valueBC.getBytes();
        int valueL = valueBC.getLength();
        int valueS = valueBC.getStart();
        int colonPos = -1;
        if (hostNameC.length < valueL) {
            hostNameC = new char[valueL];
        }

        boolean ipv6 = (valueB[valueS] == '[');
        boolean bracketClosed = false;
        for (int i = 0; i < valueL; i++) {
            char b = (char) valueB[i + valueS];
            hostNameC[i] = b;
            if (b == ']') {
                bracketClosed = true;
            } else if (b == ':') {
                if (!ipv6 || bracketClosed) {
                    colonPos = i;
                    break;
                }
            }
        }

        if (colonPos < 0) {
            if (request.scheme().equalsIgnoreCase("https")) {
                // 443 - Default HTTPS port
                request.setServerPort(443);
            } else {
                // 80 - Default HTTTP port
                request.setServerPort(80);
            }
            request.serverName().setChars(hostNameC, 0, valueL);
        } else {

            request.serverName().setChars(hostNameC, 0, colonPos);

            int port = 0;
            int mult = 1;
            for (int i = valueL - 1; i > colonPos; i--) {
                int charValue = HexUtils.getDec(valueB[i + valueS]);
                if (charValue == -1) {
                    // Invalid character
                    // 400 - Bad request
                    response.setStatus(400);
                    setErrorState(ErrorState.CLOSE_CLEAN, null);
                    break;
                }
                port = port + (charValue * mult);
                mult = 10 * mult;
            }
            request.setServerPort(port);
        }
    }


    /**
     * When committing the response, we have to validate the set of headers, as
     * well as setup the response filters.
     */
    protected void prepareResponse() throws IOException {

        response.setCommitted(true);

        tmpMB.recycle();
        responseMsgPos = -1;
        responseMessage.reset();
        responseMessage.appendByte(Constants.JK_AJP13_SEND_HEADERS);

        // Responses with certain status codes are not permitted to include a
        // response body.
        int statusCode = response.getStatus();
        if (statusCode < 200 || statusCode == 204 || statusCode == 205 ||
                statusCode == 304) {
            // No entity body
            swallowResponse = true;
        }

        // Responses to HEAD requests are not permitted to include a response
        // body.
        MessageBytes methodMB = request.method();
        if (methodMB.equals("HEAD")) {
            // No entity body
            swallowResponse = true;
        }

        // HTTP header contents
        responseMessage.appendInt(statusCode);
        String message = null;
        if (org.apache.coyote.Constants.USE_CUSTOM_STATUS_MSG_IN_HEADER &&
                HttpMessages.isSafeInHttpHeader(response.getMessage())) {
            message = response.getMessage();
        }
        if (message == null){
            message = HttpMessages.getInstance(
                    response.getLocale()).getMessage(response.getStatus());
        }
        if (message == null) {
            // mod_jk + httpd 2.x fails with a null status message - bug 45026
            message = Integer.toString(response.getStatus());
        }
        tmpMB.setString(message);
        responseMessage.appendBytes(tmpMB);

        // Special headers
        MimeHeaders headers = response.getMimeHeaders();
        String contentType = response.getContentType();
        if (contentType != null) {
            headers.setValue("Content-Type").setString(contentType);
        }
        String contentLanguage = response.getContentLanguage();
        if (contentLanguage != null) {
            headers.setValue("Content-Language").setString(contentLanguage);
        }
        long contentLength = response.getContentLengthLong();
        if (contentLength >= 0) {
            headers.setValue("Content-Length").setLong(contentLength);
        }

        // Other headers
        int numHeaders = headers.size();
        responseMessage.appendInt(numHeaders);
        for (int i = 0; i < numHeaders; i++) {
            MessageBytes hN = headers.getName(i);
            int hC = Constants.getResponseAjpIndex(hN.toString());
            if (hC > 0) {
                responseMessage.appendInt(hC);
            }
            else {
                responseMessage.appendBytes(hN);
            }
            MessageBytes hV=headers.getValue(i);
            responseMessage.appendBytes(hV);
        }

        // Write to buffer
        responseMessage.end();
        output(responseMessage.getBuffer(), 0, responseMessage.getLen(), true);
    }


    /**
     * Callback to write data from the buffer.
     */
    protected void flush(boolean explicit) throws IOException {
        // Calling code should ensure that there is no data in the buffers for
        // non-blocking writes.
        // TODO Validate the assertion above
        if (explicit && !finished) {
            // Send the flush message
            output(flushMessageArray, 0, flushMessageArray.length, true);
        }
    }


    /**
     * Finish AJP response.
     */
    protected void finish() throws IOException {

        if (!response.isCommitted()) {
            // Validate and write response headers
            try {
                prepareResponse();
            } catch (IOException e) {
                setErrorState(ErrorState.CLOSE_NOW, e);
                return;
            }
        }

        if (finished)
            return;

        finished = true;

        // Swallow the unread body packet if present
        if (waitingForBodyMessage || first && request.getContentLengthLong() > 0) {
            refillReadBuffer(true);
        }

        // Add the end message
        if (getErrorState().isError()) {
            output(endAndCloseMessageArray, 0, endAndCloseMessageArray.length, true);
        } else {
            output(endMessageArray, 0, endMessageArray.length, true);
        }
    }


    private boolean available() {
        if (endOfStream) {
            return false;
        }
        if (empty) {
            try {
                refillReadBuffer(false);
            } catch (IOException timeout) {
                // Not ideal. This will indicate that data is available
                // which should trigger a read which in turn will trigger
                // another IOException and that one can be thrown.
                return true;
            }
        }
        return !empty;
    }


    private void writeData(ByteChunk chunk) throws IOException {
        // Prevent timeout
        socketWrapper.access();

        boolean blocking = (response.getWriteListener() == null);
        if (!blocking) {
            flushBufferedData();
        }

        int len = chunk.getLength();
        int off = 0;

        // Write this chunk
        while (responseMsgPos == -1 && len > 0) {
            int thisTime = len;
            if (thisTime > outputMaxChunkSize) {
                thisTime = outputMaxChunkSize;
            }
            responseMessage.reset();
            responseMessage.appendByte(Constants.JK_AJP13_SEND_BODY_CHUNK);
            responseMessage.appendBytes(chunk.getBytes(), chunk.getOffset() + off, thisTime);
            responseMessage.end();
            writeResponseMessage(blocking);

            len -= thisTime;
            off += thisTime;
        }

        bytesWritten += off;

        if (len > 0 && !blocking) {
            // Add this chunk to the buffer
            addToBuffers(chunk.getBuffer(), off, len);
        }
    }


    private void addToBuffers(byte[] buf, int offset, int length) {
        ByteBufferHolder holder = bufferedWrites.peekLast();
        if (holder == null || holder.isFlipped() || holder.getBuf().remaining() < length) {
            ByteBuffer buffer = ByteBuffer.allocate(Math.max(bufferedWriteSize,length));
            holder = new ByteBufferHolder(buffer, false);
            bufferedWrites.add(holder);
        }
        holder.getBuf().put(buf, offset, length);
    }


    private boolean hasDataToWrite() {
        return responseMsgPos != -1 || bufferedWrites.size() > 0;
    }


    private void flushBufferedData() throws IOException {

        if (responseMsgPos > -1) {
            // Must be using non-blocking IO
            // Partially written response message. Try and complete it.
            writeResponseMessage(false);
        }

        while (responseMsgPos == -1 && bufferedWrites.size() > 0) {
            // Try and write any remaining buffer data
            Iterator<ByteBufferHolder> holders = bufferedWrites.iterator();
            ByteBufferHolder holder = holders.next();
            holder.flip();
            ByteBuffer buffer = holder.getBuf();
            int initialBufferSize = buffer.remaining();
            while (responseMsgPos == -1 && buffer.remaining() > 0) {
                transferToResponseMsg(buffer);
                writeResponseMessage(false);
            }
            bytesWritten += (initialBufferSize - buffer.remaining());
            if (buffer.remaining() == 0) {
                holders.remove();
            }
        }
    }


    private void transferToResponseMsg(ByteBuffer buffer) {

        int thisTime = buffer.remaining();
        if (thisTime > outputMaxChunkSize) {
            thisTime = outputMaxChunkSize;
        }

        responseMessage.reset();
        responseMessage.appendByte(Constants.JK_AJP13_SEND_BODY_CHUNK);
        buffer.get(responseMessage.getBuffer(), responseMessage.pos, thisTime);
        responseMessage.end();
    }


    private void writeResponseMessage(boolean block) throws IOException {
        int len = responseMessage.getLen();
        int written = 1;
        if (responseMsgPos == -1) {
            // New message. Advance the write position to the beginning
            responseMsgPos = 0;
        }

        while (written > 0 && responseMsgPos < len) {
            written = output(
                    responseMessage.getBuffer(), responseMsgPos, len - responseMsgPos, block);
            responseMsgPos += written;
        }

        // Message fully written, reset the position for a new message.
        if (responseMsgPos == len) {
            responseMsgPos = -1;
        }
    }

    // ------------------------------------- InputStreamInputBuffer Inner Class


    /**
     * This class is an input buffer which will read its data from an input
     * stream.
     */
    protected class SocketInputBuffer implements InputBuffer {

        /**
         * Read bytes into the specified chunk.
         */
        @Override
        public int doRead(ByteChunk chunk, Request req) throws IOException {

            if (endOfStream) {
                return -1;
            }
            if (empty) {
                if (!refillReadBuffer(true)) {
                    return -1;
                }
            }
            ByteChunk bc = bodyBytes.getByteChunk();
            chunk.setBytes(bc.getBuffer(), bc.getStart(), bc.getLength());
            empty = true;
            return chunk.getLength();
        }
    }


    // ----------------------------------- OutputStreamOutputBuffer Inner Class

    /**
     * This class is an output buffer which will write data to an output
     * stream.
     */
    protected class SocketOutputBuffer implements OutputBuffer {

        /**
         * Write chunk.
         */
        @Override
        public int doWrite(ByteChunk chunk, Response res) throws IOException {

            if (!response.isCommitted()) {
                // Validate and write response headers
                try {
                    prepareResponse();
                } catch (IOException e) {
                    setErrorState(ErrorState.CLOSE_NOW, e);
                }
            }

            if (!swallowResponse) {
                writeData(chunk);
            }
            return chunk.getLength();
        }

        @Override
        public long getBytesWritten() {
            return bytesWritten;
        }
    }
}