-->websocket的3種使用場景:

1)h5瀏覽器中websocket由瀏覽器提供

2)node.js中，可以使用ws模組寫伺服器

3)native app中，可以使用c++版本的websocket匯出c++介面給cocos creator客戶端使用

-->WebSocket的執行緒將訊息投遞給cocos主執行緒的過程:

websocket執行緒投遞給cocos主執行緒的訊息的執行緒安全的函式：

void WsThreadHelper::sendMessageToCocosThread(const std::function<void()>& cb)
{
    Director::getInstance()->getScheduler()->performFunctionInCocosThread(cb);
}
 

OPEN 連線狀態:

void WebSocket::onConnectionOpened()
{
    ...
    _readyState = State::OPEN;
    ...
    _wsHelper->sendMessageToCocosThread([this, isDestroyed](){
        if (*isDestroyed)
        {
            LOGD("WebSocket instance was destroyed!\n");
        }
        else
        {
            _delegate->onOpen(this);
        }
    });
}
 

收到訊息onClientReceivedData

void WebSocket::onClientReceivedData(void* in, ssize_t len)
{
    ...
        _wsHelper->sendMessageToCocosThread([this, frameData, frameSize, isBinary, isDestroyed](){
            // In UI thread
            LOGD("Notify data len %d to Cocos thread.\n", (int)frameSize);

            Data data;
            data.isBinary = isBinary;
            data.bytes = (char*)frameData->data();
            data.len = frameSize;

            if (*isDestroyed)
            {
                LOGD("WebSocket instance was destroyed!\n");
            }
            else
            {
                _delegate->onMessage(this, data);
            }

            delete frameData;
        });
    }
}
 

Error狀態

void WebSocket::onConnectionError()
{
    LOGD("WebSocket (%p) onConnectionError ...\n", this);

    _readStateMutex.lock();
    _readyState = State::CLOSING;
    _readStateMutex.unlock();

    std::shared_ptr<bool> isDestroyed = _isDestroyed;
    _wsHelper->sendMessageToCocosThread([this, isDestroyed](){
        if (*isDestroyed)
        {
            LOGD("WebSocket instance was destroyed!\n");
        }
        else
        {
            _delegate->onError(this, ErrorCode::CONNECTION_FAILURE);
        }
    });
}

Closed狀態

void WebSocket::onConnectionClosed()
{
    _readStateMutex.lock();
    if (_readyState == State::CLOSED)
    {
        LOGD("onConnectionClosed: WebSocket (%p) was closed, no need to close it again!\n", this);
        _readStateMutex.unlock();
        return;
    }

    LOGD("WebSocket (%p) onConnectionClosed ...\n", this);
    _readyState = State::CLOSED;
    _readStateMutex.unlock();

    _wsHelper->quitWebSocketThread();
    std::shared_ptr<bool> isDestroyed = _isDestroyed;
    _wsHelper->sendMessageToCocosThread([this, isDestroyed](){
        if (*isDestroyed)
        {
            LOGD("WebSocket instance was destroyed!\n");
        }
        else
        {
            // Waiting for the subThread safety exit
            _wsHelper->joinWebSocketThread();
            _delegate->onClose(this);
        }
    });
}

Send資料(傳送字串)

void WebSocket::send(const std::string& message)
{
    if (_readyState == State::OPEN)
    {
        // In main thread
        Data* data = new (std::nothrow) Data();
        data->bytes = (char*)malloc(message.length() + 1);
        // Make sure the last byte is '\0'
        data->bytes[message.length()] = '\0';
        strcpy(data->bytes, message.c_str());
        data->len = static_cast<ssize_t>(message.length());

        WsMessage* msg = new (std::nothrow) WsMessage();
        msg->what = WS_MSG_TO_SUBTRHEAD_SENDING_STRING;
        msg->obj = data;
        _wsHelper->sendMessageToWebSocketThread(msg);
    }
    else
    {
        LOGD("Couldn't send message since websocket wasn't opened!\n");
    }
}

最後看：Scheduler中update的渲染處理(_functionsToPerform變數)

// main loop
void Scheduler::update(float dt)
{
    

    // updates with priority < 0
    DL_FOREACH_SAFE(_updatesNegList, entry, tmp)
    {
        if ((! entry->paused) && (! entry->markedForDeletion))
        {
            entry->callback(dt);
        }
    }

    // updates with priority == 0
    DL_FOREACH_SAFE(_updates0List, entry, tmp)
    {
        if ((! entry->paused) && (! entry->markedForDeletion))
        {
            entry->callback(dt);
        }
    }

    // updates with priority > 0
    DL_FOREACH_SAFE(_updatesPosList, entry, tmp)
    {
        if ((! entry->paused) && (! entry->markedForDeletion))
        {
            entry->callback(dt);
        }
    }

    // Iterate over all the custom selectors
    for (tHashTimerEntry *elt = _hashForTimers; elt != nullptr; )
    {
        _currentTarget = elt;
        _currentTargetSalvaged = false;

        if (! _currentTarget->paused)
        {
            // The 'timers' array may change while inside this loop
            for (elt->timerIndex = 0; elt->timerIndex < elt->timers->num; ++(elt->timerIndex))
            {
                elt->currentTimer = (Timer*)(elt->timers->arr[elt->timerIndex]);
                elt->currentTimerSalvaged = false;

                elt->currentTimer->update(dt);

                if (elt->currentTimerSalvaged)
                {
                    // The currentTimer told the remove itself. To prevent the timer from
                    // accidentally deallocating itself before finishing its step, we retained
                    // it. Now that step is done, it's safe to release it.
                    elt->currentTimer->release();
                }

                elt->currentTimer = nullptr;
            }
        }

        // elt, at this moment, is still valid
        // so it is safe to ask this here (issue #490)
        elt = (tHashTimerEntry *)elt->hh.next;

        // only delete currentTarget if no actions were scheduled during the cycle (issue #481)
        if (_currentTargetSalvaged && _currentTarget->timers->num == 0)
        {
            removeHashElement(_currentTarget);
        }
    }

    // delete all updates that are marked for deletion
    // updates with priority < 0
    DL_FOREACH_SAFE(_updatesNegList, entry, tmp)
    {
        if (entry->markedForDeletion)
        {
            this->removeUpdateFromHash(entry);
        }
    }

    // updates with priority == 0
    DL_FOREACH_SAFE(_updates0List, entry, tmp)
    {
        if (entry->markedForDeletion)
        {
            this->removeUpdateFromHash(entry);
        }
    }

    // updates with priority > 0
    DL_FOREACH_SAFE(_updatesPosList, entry, tmp)
    {
        if (entry->markedForDeletion)
        {
            this->removeUpdateFromHash(entry);
        }
    }

    _updateHashLocked = false;
    _currentTarget = nullptr;

#if CC_ENABLE_SCRIPT_BINDING
    //
    // Script callbacks
    //

    // Iterate over all the script callbacks
    if (!_scriptHandlerEntries.empty())
    {
        for (auto i = _scriptHandlerEntries.size() - 1; i >= 0; i--)
        {
            SchedulerScriptHandlerEntry* eachEntry = _scriptHandlerEntries.at(i);
            if (eachEntry->isMarkedForDeletion())
            {
                _scriptHandlerEntries.erase(i);
            }
            else if (!eachEntry->isPaused())
            {
                eachEntry->getTimer()->update(dt);
            }
        }
    }
#endif
    //
    // Functions allocated from another thread
    //

    // Testing size is faster than locking / unlocking.
    // And almost never there will be functions scheduled to be called.
    //----就是這了，投遞過來之後，在update的最後面進行處理
    if( !_functionsToPerform.empty() ) {
        _performMutex.lock();
        // fixed #4123: Save the callback functions, they must be invoked after '_performMutex.unlock()', otherwise if new functions are added in callback, it will cause thread deadlock.
        auto temp = _functionsToPerform;
        _functionsToPerform.clear();
        _performMutex.unlock();
        for( const auto &function : temp ) {
            function();
        }
        
    }
}