/*

 * Copyright (C) 2008 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.

 *

 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``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 APPLE COMPUTER, INC. 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"

#include "MessagePort.h"

#include "AtomicString.h"

#include "DOMWindow.h"

#include "Document.h"

#include "EventException.h"

#include "EventNames.h"

#include "MessageEvent.h"

#include "SecurityOrigin.h"

#include "Timer.h"

namespace WebCore {

MessagePort::MessagePort(ScriptExecutionContext& scriptExecutionContext)

    : m_entangledChannel(0)

    , m_started(false)

    , m_closed(false)

    , m_scriptExecutionContext(&scriptExecutionContext)

{

    m_scriptExecutionContext->createdMessagePort(this);

    // Don't need to call processMessagePortMessagesSoon() here, because the port will not be opened until start() is invoked.

}

MessagePort::~MessagePort()

{

    close();

    if (m_scriptExecutionContext)

        m_scriptExecutionContext->destroyedMessagePort(this);

}

// FIXME: remove this when we update the ObjC bindings (bug #28774).

void MessagePort::postMessage(PassRefPtr<SerializedScriptValue> message, MessagePort* port, ExceptionCode& ec)

{

    MessagePortArray ports;

    if (port)

        ports.append(port);

    postMessage(message, &ports, ec);

}

void MessagePort::postMessage(PassRefPtr<SerializedScriptValue> message, ExceptionCode& ec)

{

    postMessage(message, static_cast<MessagePortArray*>(0), ec);

}

void MessagePort::postMessage(PassRefPtr<SerializedScriptValue> message, const MessagePortArray* ports, ExceptionCode& ec)

{

    if (!m_entangledChannel)

        return;

    ASSERT(m_scriptExecutionContext);

    OwnPtr<MessagePortChannelArray> channels;

    // Make sure we aren't connected to any of the passed-in ports.

    if (ports) {

        for (unsigned int i = 0; i < ports->size(); ++i) {

            MessagePort* dataPort = (*ports)[i].get();

            if (dataPort == this || m_entangledChannel->isConnectedTo(dataPort)) {

                ec = INVALID_STATE_ERR;

                return;

            }

        }

        channels = MessagePort::disentanglePorts(ports, ec);

        if (ec)

            return;

    }

    m_entangledChannel->postMessageToRemote(MessagePortChannel::EventData::create(message, channels.release()));

}

PassOwnPtr<MessagePortChannel> MessagePort::disentangle(ExceptionCode& ec)

{

    if (!m_entangledChannel)

        ec = INVALID_STATE_ERR;

    else {

        m_entangledChannel->disentangle();

        // We can't receive any messages or generate any events, so remove ourselves from the list of active ports.

        ASSERT(m_scriptExecutionContext);

        m_scriptExecutionContext->destroyedMessagePort(this);

        m_scriptExecutionContext = 0;

    }

    return m_entangledChannel.release();

}

// Invoked to notify us that there are messages available for this port.

// This code may be called from another thread, and so should not call any non-threadsafe APIs (i.e. should not call into the entangled channel or access mutable variables).

void MessagePort::messageAvailable()

{

    ASSERT(m_scriptExecutionContext);

    m_scriptExecutionContext->processMessagePortMessagesSoon();

}

void MessagePort::start()

{

    // Do nothing if we've been cloned

    if (!m_entangledChannel)

        return;

    ASSERT(m_scriptExecutionContext);

    if (m_started)

        return;

    m_started = true;

    m_scriptExecutionContext->processMessagePortMessagesSoon();

}

void MessagePort::close()

{

    m_closed = true;

    if (!m_entangledChannel)

        return;

    m_entangledChannel->close();

}

void MessagePort::entangle(PassOwnPtr<MessagePortChannel> remote)

{

    // Only invoked to set our initial entanglement.

    ASSERT(!m_entangledChannel);

    ASSERT(m_scriptExecutionContext);

    // Don't entangle the ports if the channel is closed.

    if (remote->entangleIfOpen(this))

        m_entangledChannel = remote;

}

void MessagePort::contextDestroyed()

{

    ASSERT(m_scriptExecutionContext);

    // Must close port before blowing away the cached context, to ensure that we get no more calls to messageAvailable().

    close();

    m_scriptExecutionContext = 0;

}

ScriptExecutionContext* MessagePort::scriptExecutionContext() const

{

    return m_scriptExecutionContext;

}

void MessagePort::dispatchMessages()

{

    // Messages for contexts that are not fully active get dispatched too, but JSAbstractEventListener::handleEvent() doesn't call handlers for these.

    // The HTML5 spec specifies that any messages sent to a document that is not fully active should be dropped, so this behavior is OK.

    ASSERT(started());

    OwnPtr<MessagePortChannel::EventData> eventData;

    while (m_entangledChannel && m_entangledChannel->tryGetMessageFromRemote(eventData)) {

        OwnPtr<MessagePortArray> ports = MessagePort::entanglePorts(*m_scriptExecutionContext, eventData->channels());

        RefPtr<Event> evt = MessageEvent::create(ports.release(), eventData->message());

        ExceptionCode ec = 0;

        dispatchEvent(evt.release(), ec);

        ASSERT(!ec);

    }

}

bool MessagePort::hasPendingActivity()

{

    // The spec says that entangled message ports should always be treated as if they have a strong reference.

    // We'll also stipulate that the queue needs to be open (if the app drops its reference to the port before start()-ing it, then it's not really entangled as it's unreachable).

    return m_started && m_entangledChannel && m_entangledChannel->hasPendingActivity();

}

MessagePort* MessagePort::locallyEntangledPort()

{

    return m_entangledChannel ? m_entangledChannel->locallyEntangledPort(m_scriptExecutionContext) : 0;

}

PassOwnPtr<MessagePortChannelArray> MessagePort::disentanglePorts(const MessagePortArray* ports, ExceptionCode& ec)

{

    if (!ports || !ports->size())

        return 0;

    // HashSet used to efficiently check for duplicates in the passed-in array.

    HashSet<MessagePort*> portSet;

    // Walk the incoming array - if there are any duplicate ports, or null ports or cloned ports, throw an error (per section 8.3.3 of the HTML5 spec).

    for (unsigned int i = 0; i < ports->size(); ++i) {

        MessagePort* port = (*ports)[i].get();

        if (!port || port->isCloned() || portSet.contains(port)) {

            ec = INVALID_STATE_ERR;

            return 0;

        }

        portSet.add(port);

    }

    // Passed-in ports passed validity checks, so we can disentangle them.

    MessagePortChannelArray* portArray = new MessagePortChannelArray(ports->size());

    for (unsigned int i = 0 ; i < ports->size() ; ++i) {

        OwnPtr<MessagePortChannel> channel = (*ports)[i]->disentangle(ec);

        ASSERT(!ec); // Can't generate exception here if passed above checks.

        (*portArray)[i] = channel.release();

    }

    return portArray;

}

PassOwnPtr<MessagePortArray> MessagePort::entanglePorts(ScriptExecutionContext& context, PassOwnPtr<MessagePortChannelArray> channels)

{

    if (!channels || !channels->size())

        return 0;

    MessagePortArray* portArray = new MessagePortArray(channels->size());

    for (unsigned int i = 0; i < channels->size(); ++i) {

        RefPtr<MessagePort> port = MessagePort::create(context);

        port->entangle((*channels)[i].release());

        (*portArray)[i] = port.release();

    }

    return portArray;

}

EventTargetData* MessagePort::eventTargetData()

{

    return &m_eventTargetData;

}

EventTargetData* MessagePort::ensureEventTargetData()

{

    return &m_eventTargetData;

}

} // namespace WebCore