Source/WebCore/Modules/mediastream/RTCDataChannel.cpp

/*
 * Copyright (C) 2012 Google Inc. All rights reserved.
 * Copyright (C) 2017 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:
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 *     notice, this list of conditions and the following disclaimer.
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 *     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 INC. AND ITS 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
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 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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#include "config.h"
#include "RTCDataChannel.h"

#if ENABLE(WEB_RTC)

#include "Blob.h"
#include "EventNames.h"
#include "ExceptionCode.h"
#include "MessageEvent.h"
#include "ScriptExecutionContext.h"
#include "SharedBuffer.h"
#include <JavaScriptCore/ArrayBufferView.h>
#include <wtf/IsoMallocInlines.h>
#include <wtf/NeverDestroyed.h>

namespace WebCore {

WTF_MAKE_ISO_ALLOCATED_IMPL(RTCDataChannel);

static const AtomString& blobKeyword()
{
    static MainThreadNeverDestroyed<const AtomString> blob("blob", AtomString::ConstructFromLiteral);
    return blob;
}

static const AtomString& arraybufferKeyword()
{
    static MainThreadNeverDestroyed<const AtomString> arraybuffer("arraybuffer", AtomString::ConstructFromLiteral);
    return arraybuffer;
}

Ref<RTCDataChannel> RTCDataChannel::create(Document& document, std::unique_ptr<RTCDataChannelHandler>&& handler, String&& label, RTCDataChannelInit&& options)
{
    ASSERT(handler);
    auto channel = adoptRef(*new RTCDataChannel(document, WTFMove(handler), WTFMove(label), WTFMove(options)));
    channel->suspendIfNeeded();
    channel->m_handler->setClient(channel.get());
    channel->setPendingActivity(channel.get());
    return channel;
}

NetworkSendQueue RTCDataChannel::createMessageQueue(Document& document, RTCDataChannel& channel)
{
    return { document, [&channel](auto& utf8) {
        if (!channel.m_handler->sendStringData(utf8))
            channel.scriptExecutionContext()->addConsoleMessage(MessageSource::JS, MessageLevel::Error, "Error sending string through RTCDataChannel."_s);
    }, [&channel](auto* data, size_t length) {
        if (!channel.m_handler->sendRawData(data, length))
            channel.scriptExecutionContext()->addConsoleMessage(MessageSource::JS, MessageLevel::Error, "Error sending binary data through RTCDataChannel."_s);
    }, [&channel](ExceptionCode errorCode) {
        if (auto* context = channel.scriptExecutionContext()) {
            auto code = static_cast<int>(errorCode);
            context->addConsoleMessage(MessageSource::JS, MessageLevel::Error, makeString("Error ", code, " in retrieving a blob data to be sent through RTCDataChannel."));
        }
        return NetworkSendQueue::Continue::Yes;
    } };
}

RTCDataChannel::RTCDataChannel(Document& document, std::unique_ptr<RTCDataChannelHandler>&& handler, String&& label, RTCDataChannelInit&& options)
    : ActiveDOMObject(document)
    , m_handler(WTFMove(handler))
    , m_label(WTFMove(label))
    , m_options(WTFMove(options))
    , m_messageQueue(createMessageQueue(document, *this))
{
}

const AtomString& RTCDataChannel::binaryType() const
{
    switch (m_binaryType) {
    case BinaryType::Blob:
        return blobKeyword();
    case BinaryType::ArrayBuffer:
        return arraybufferKeyword();
    }

    ASSERT_NOT_REACHED();
    return emptyAtom();
}

ExceptionOr<void> RTCDataChannel::setBinaryType(const AtomString& binaryType)
{
    if (binaryType == blobKeyword()) {
        m_binaryType = BinaryType::Blob;
        return { };
    }
    if (binaryType == arraybufferKeyword()) {
        m_binaryType = BinaryType::ArrayBuffer;
        return { };
    }
    return Exception { TypeMismatchError };
}

ExceptionOr<void> RTCDataChannel::send(const String& data)
{
    if (m_readyState != RTCDataChannelState::Open)
        return Exception { InvalidStateError };

    // FIXME: We might want to use strict conversion like WebSocket.
    auto utf8 = data.utf8();
    m_bufferedAmount += utf8.length();
    m_messageQueue.enqueue(WTFMove(utf8));
    return { };
}

ExceptionOr<void> RTCDataChannel::send(ArrayBuffer& data)
{
    if (m_readyState != RTCDataChannelState::Open)
        return Exception { InvalidStateError };

    m_bufferedAmount += data.byteLength();
    m_messageQueue.enqueue(data, 0, data.byteLength());
    return { };
}

ExceptionOr<void> RTCDataChannel::send(ArrayBufferView& data)
{
    if (m_readyState != RTCDataChannelState::Open)
        return Exception { InvalidStateError };

    m_bufferedAmount += data.byteLength();
    m_messageQueue.enqueue(*data.unsharedBuffer(), data.byteOffset(), data.byteLength());
    return { };
}

ExceptionOr<void> RTCDataChannel::send(Blob& blob)
{
    if (m_readyState != RTCDataChannelState::Open)
        return Exception { InvalidStateError };

    m_bufferedAmount += blob.size();
    m_messageQueue.enqueue(blob);
    return { };
}

void RTCDataChannel::close()
{
    if (m_stopped)
        return;

    m_stopped = true;
    m_readyState = RTCDataChannelState::Closed;

    m_messageQueue.clear();

    m_handler->close();
    m_handler = nullptr;
    unsetPendingActivity(*this);
}

void RTCDataChannel::didChangeReadyState(RTCDataChannelState newState)
{
    if (m_stopped || m_readyState == RTCDataChannelState::Closed || m_readyState == newState)
        return;

    m_readyState = newState;

    switch (m_readyState) {
    case RTCDataChannelState::Open:
        scheduleDispatchEvent(Event::create(eventNames().openEvent, Event::CanBubble::No, Event::IsCancelable::No));
        break;
    case RTCDataChannelState::Closed:
        scheduleDispatchEvent(Event::create(eventNames().closeEvent, Event::CanBubble::No, Event::IsCancelable::No));
        break;
    default:
        break;
    }
}

void RTCDataChannel::didReceiveStringData(const String& text)
{
    scheduleDispatchEvent(MessageEvent::create(text));
}

void RTCDataChannel::didReceiveRawData(const char* data, size_t dataLength)
{
    switch (m_binaryType) {
    case BinaryType::Blob:
        scheduleDispatchEvent(MessageEvent::create(Blob::create(SharedBuffer::create(data, dataLength), emptyString()), { }));
        return;
    case BinaryType::ArrayBuffer:
        scheduleDispatchEvent(MessageEvent::create(ArrayBuffer::create(data, dataLength)));
        return;
    }
    ASSERT_NOT_REACHED();
}

void RTCDataChannel::didDetectError()
{
    scheduleDispatchEvent(Event::create(eventNames().errorEvent, Event::CanBubble::No, Event::IsCancelable::No));
}

void RTCDataChannel::bufferedAmountIsDecreasing(size_t amount)
{
    auto previousBufferedAmount = m_bufferedAmount;
    m_bufferedAmount -= amount;
    if (previousBufferedAmount > m_bufferedAmountLowThreshold && m_bufferedAmount <= m_bufferedAmountLowThreshold)
        scheduleDispatchEvent(Event::create(eventNames().bufferedamountlowEvent, Event::CanBubble::No, Event::IsCancelable::No));
}

void RTCDataChannel::stop()
{
    close();
}

void RTCDataChannel::scheduleDispatchEvent(Ref<Event>&& event)
{
    if (m_stopped)
        return;

    // https://w3c.github.io/webrtc-pc/#operation
    queueTaskToDispatchEvent(*this, TaskSource::Networking, WTFMove(event));
}

} // namespace WebCore

#endif // ENABLE(WEB_RTC)