/*

 * Copyright (C) 2009 Ericsson AB

 * All rights reserved.

 * Copyright (C) 2010 Apple Inc. All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer

 *    in the documentation and/or other materials provided with the

 *    distribution.

 * 3. Neither the name of Ericsson nor the names of its contributors

 *    may be used to endorse or promote products derived from this

 *    software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

#include "config.h"

#if ENABLE(EVENTSOURCE)

#include "EventSource.h"

#include "Cache.h"

#include "DOMWindow.h"

#include "Event.h"

#include "EventException.h"

#include "PlatformString.h"

#include "MessageEvent.h"

#include "ResourceError.h"

#include "ResourceRequest.h"

#include "ResourceResponse.h"

#include "ScriptExecutionContext.h"

#include "SerializedScriptValue.h"

#include "TextResourceDecoder.h"

#include "ThreadableLoader.h"

namespace WebCore {

const unsigned long long EventSource::defaultReconnectDelay = 3000;

inline EventSource::EventSource(const KURL& url, ScriptExecutionContext* context)

    : ActiveDOMObject(context, this)

    , m_url(url)

    , m_state(CONNECTING)

    , m_decoder(TextResourceDecoder::create("text/plain", "UTF-8"))

    , m_reconnectTimer(this, &EventSource::reconnectTimerFired)

    , m_discardTrailingNewline(false)

    , m_failSilently(false)

    , m_requestInFlight(false)

    , m_reconnectDelay(defaultReconnectDelay)

    , m_origin(context->securityOrigin()->toString())

{

}

PassRefPtr<EventSource> EventSource::create(const String& url, ScriptExecutionContext* context, ExceptionCode& ec)

{

    if (url.isEmpty()) {

        ec = SYNTAX_ERR;

        return 0;

    }

    KURL fullURL = context->completeURL(url);

    if (!fullURL.isValid()) {

        ec = SYNTAX_ERR;

        return 0;

    }

    // FIXME: Should support at least some cross-origin requests.

    if (!context->securityOrigin()->canRequest(fullURL)) {

        ec = SECURITY_ERR;

        return 0;

    }

    RefPtr<EventSource> source = adoptRef(new EventSource(fullURL, context));

    source->setPendingActivity(source.get());

    source->connect();

    return source.release();

}

EventSource::~EventSource()

{

}

void EventSource::connect()

{

    ResourceRequest request(m_url);

    request.setHTTPMethod("GET");

    request.setHTTPHeaderField("Accept", "text/event-stream");

    request.setHTTPHeaderField("Cache-Control", "no-cache");

    if (!m_lastEventId.isEmpty())

        request.setHTTPHeaderField("Last-Event-ID", m_lastEventId);

    ThreadableLoaderOptions options;

    options.sendLoadCallbacks = true;

    options.sniffContent = false;

    options.allowCredentials = true;

    m_loader = ThreadableLoader::create(scriptExecutionContext(), this, request, options);

    m_requestInFlight = true;

    if (!scriptExecutionContext()->isWorkerContext())

        cache()->loader()->nonCacheRequestInFlight(m_url);

}

void EventSource::endRequest()

{

    m_requestInFlight = false;

    if (!m_failSilently)

        dispatchEvent(Event::create(eventNames().errorEvent, false, false));

    if (!scriptExecutionContext()->isWorkerContext())

        cache()->loader()->nonCacheRequestComplete(m_url);

    if (m_state != CLOSED)

        scheduleReconnect();

    else

        unsetPendingActivity(this);

}

void EventSource::scheduleReconnect()

{

    m_state = CONNECTING;

    m_reconnectTimer.startOneShot(m_reconnectDelay / 1000);

}

void EventSource::reconnectTimerFired(Timer<EventSource>*)

{

    connect();

}

String EventSource::url() const

{

    return m_url.string();

}

EventSource::State EventSource::readyState() const

{

    return m_state;

}

void EventSource::close()

{

    if (m_state == CLOSED)

        return;

    if (m_reconnectTimer.isActive()) {

        m_reconnectTimer.stop();

        unsetPendingActivity(this);

    }

    m_state = CLOSED;

    m_failSilently = true;

    if (m_requestInFlight)

        m_loader->cancel();

}

ScriptExecutionContext* EventSource::scriptExecutionContext() const

{

    return ActiveDOMObject::scriptExecutionContext();

}

void EventSource::didReceiveResponse(const ResourceResponse& response)

{

    int statusCode = response.httpStatusCode();

    if (statusCode == 200 && response.httpHeaderField("Content-Type") == "text/event-stream") {

        m_state = OPEN;

        dispatchEvent(Event::create(eventNames().openEvent, false, false));

    } else {

        if (statusCode <= 200 || statusCode > 299)

            m_state = CLOSED;

        m_loader->cancel();

    }

}

void EventSource::didReceiveData(const char* data, int length)

{

    append(m_receiveBuf, m_decoder->decode(data, length));

    parseEventStream();

}

void EventSource::didFinishLoading(unsigned long)

{

    if (m_receiveBuf.size() > 0 || m_data.size() > 0) {

        append(m_receiveBuf, "\n\n");

        parseEventStream();

    }

    m_state = CONNECTING;

    endRequest();

}

void EventSource::didFail(const ResourceError& error)

{

    int canceled = error.isCancellation();

    if (((m_state == CONNECTING) && !canceled) || ((m_state == OPEN) && canceled))

        m_state = CLOSED;

    endRequest();

}

void EventSource::didFailRedirectCheck()

{

    m_state = CLOSED;

    m_loader->cancel();

}

void EventSource::parseEventStream()

{

    unsigned int bufPos = 0;

    unsigned int bufSize = m_receiveBuf.size();

    while (bufPos < bufSize) {

        if (m_discardTrailingNewline) {

            if (m_receiveBuf[bufPos] == '\n')

                bufPos++;

            m_discardTrailingNewline = false;

        }

        int lineLength = -1;

        int fieldLength = -1;

        for (unsigned int i = bufPos; lineLength < 0 && i < bufSize; i++) {

            switch (m_receiveBuf[i]) {

            case ':':

                if (fieldLength < 0)

                    fieldLength = i - bufPos;

                break;

            case '\r':

                m_discardTrailingNewline = true;

            case '\n':

                lineLength = i - bufPos;

                break;

            }

        }

        if (lineLength < 0)

            break;

        parseEventStreamLine(bufPos, fieldLength, lineLength);

        bufPos += lineLength + 1;

    }

    if (bufPos == bufSize)

        m_receiveBuf.clear();

    else if (bufPos)

        m_receiveBuf.remove(0, bufPos);

}

void EventSource::parseEventStreamLine(unsigned int bufPos, int fieldLength, int lineLength)

{

    if (!lineLength) {

        if (!m_data.isEmpty()) {

            m_data.removeLast();

            dispatchEvent(createMessageEvent());

        }

        if (!m_eventName.isEmpty())

            m_eventName = "";

    } else if (fieldLength) {

        bool noValue = fieldLength < 0;

        String field(&m_receiveBuf[bufPos], noValue ? lineLength : fieldLength);

        int step;

        if (noValue)

            step = lineLength;

        else if (m_receiveBuf[bufPos + fieldLength + 1] != ' ')

            step = fieldLength + 1;

        else

            step = fieldLength + 2;

        bufPos += step;

        int valueLength = lineLength - step;

        if (field == "data") {

            if (valueLength)

                m_data.append(&m_receiveBuf[bufPos], valueLength);

            m_data.append('\n');

        } else if (field == "event")

            m_eventName = valueLength ? String(&m_receiveBuf[bufPos], valueLength) : "";

        else if (field == "id")

            m_lastEventId = valueLength ? String(&m_receiveBuf[bufPos], valueLength) : "";

        else if (field == "retry") {

            if (!valueLength)

                m_reconnectDelay = defaultReconnectDelay;

            else {

                String value(&m_receiveBuf[bufPos], valueLength);

                bool ok;

                unsigned long long retry = value.toUInt64(&ok);

                if (ok)

                    m_reconnectDelay = retry;

            }

        }

    }

}

void EventSource::stop()

{

    close();

}

PassRefPtr<MessageEvent> EventSource::createMessageEvent()

{

    RefPtr<MessageEvent> event = MessageEvent::create();

    event->initMessageEvent(m_eventName.isEmpty() ? eventNames().messageEvent : AtomicString(m_eventName), false, false, SerializedScriptValue::create(String::adopt(m_data)), m_origin, m_lastEventId, 0, 0);

    return event.release();

}

EventTargetData* EventSource::eventTargetData()

{

    return &m_eventTargetData;

}

EventTargetData* EventSource::ensureEventTargetData()

{

    return &m_eventTargetData;

}

} // namespace WebCore

#endif // ENABLE(EVENTSOURCE)