C++ BMediaRoster::GetNodeFor方法代码示例

// --------------------
// NodeHarnessWin implementation
NodeHarnessWin::NodeHarnessWin(BRect frame, const char *title)
    :	BWindow(frame, title, B_TITLED_WINDOW, B_NOT_RESIZABLE | B_ASYNCHRONOUS_CONTROLS),
      mToneNode(NULL), mIsConnected(false), mIsRunning(false)
{
    // build the UI
    BRect r(10, 10, 100, 40);
    mConnectButton = new BButton(r, "Connect", "Connect", new BMessage(BUTTON_CONNECT));
    mConnectButton->SetEnabled(true);
    AddChild(mConnectButton);
    r.OffsetBy(0, 40);
    mStartButton = new BButton(r, "Start", "Start", new BMessage(BUTTON_START));
    mStartButton->SetEnabled(false);
    AddChild(mStartButton);
    r.OffsetBy(0, 40);
    mStopButton = new BButton(r, "Stop", "Stop", new BMessage(BUTTON_STOP));
    mStopButton->SetEnabled(false);
    AddChild(mStopButton);

    // e.moon 2jun99: create the node
    BMediaRoster* roster = BMediaRoster::Roster();
    mToneNode = new ToneProducer();

    status_t err = roster->RegisterNode(mToneNode);
    ErrorCheck(err, "unable to register ToneProducer node!\n");
    // make sure the Media Roster knows that we're using the node
    roster->GetNodeFor(mToneNode->Node().node, &mConnection.producer);
}

void
MediaWindow::SmartNode::SetTo(const dormant_node_info* info)
{
	_FreeNode();
	if (!info)
		return;

	fNode = new media_node();
	BMediaRoster* roster = BMediaRoster::Roster();

	status_t status = B_OK;
	media_node_id node_id;
	if (roster->GetInstancesFor(info->addon, info->flavor_id, &node_id) == B_OK)
		status = roster->GetNodeFor(node_id, fNode);
	else
		status = roster->InstantiateDormantNode(*info, fNode, B_FLAVOR_IS_GLOBAL);

	if (status != B_OK) {
		fprintf(stderr, "SmartNode::SetTo error with node %" B_PRId32
			": %s\n", fNode->node, strerror(status));
	}

	status = roster->StartWatching(fMessenger, *fNode, B_MEDIA_WILDCARD);
	if (status != B_OK) {
		fprintf(stderr, "SmartNode::SetTo can't start watching for"
			" node %" B_PRId32 "\n", fNode->node);
	}
}

status_t
GameSoundBuffer::Connect(media_node * consumer)
{
	BMediaRoster* roster = BMediaRoster::Roster();
	status_t err = roster->RegisterNode(fNode);
	
	if (err != B_OK) 
		return err;
	
	// make sure the Media Roster knows that we're using the node
	err = roster->GetNodeFor(fNode->Node().node, &fConnection->producer);

	if (err != B_OK)
        	return err;
	
	// connect to the mixer
	fConnection->consumer = *consumer;

	// set the producer's time source to be the "default" time source, which
	// the Mixer uses too.
	err = roster->GetTimeSource(&fConnection->timeSource);
	if (err != B_OK)
                return err;	

	err = roster->SetTimeSourceFor(fConnection->producer.node, fConnection->timeSource.node);
        if (err != B_OK)
                return err;
	// got the nodes; now we find the endpoints of the connection
	media_input mixerInput;
	media_output soundOutput;
	int32 count = 1;
	err = roster->GetFreeOutputsFor(fConnection->producer, &soundOutput, 1, &count);
	if (err != B_OK) 
		return err;
	count = 1;
	err = roster->GetFreeInputsFor(fConnection->consumer, &mixerInput, 1, &count);
	if (err != B_OK) 
		return err;

	// got the endpoints; now we connect it!
	media_format format;
	format.type = B_MEDIA_RAW_AUDIO;	
	format.u.raw_audio = media_raw_audio_format::wildcard;
	err = roster->Connect(soundOutput.source, mixerInput.destination, &format, &soundOutput, &mixerInput);
	if (err != B_OK) 
		return err;
	
	// the inputs and outputs might have been reassigned during the
	// nodes' negotiation of the Connect().  That's why we wait until
	// after Connect() finishes to save their contents.
	fConnection->format = format;
	fConnection->source = soundOutput.source;
	fConnection->destination = mixerInput.destination;

	fIsConnected = true;
	return B_OK;
}

MediaNodeControlApp::MediaNodeControlApp(
	const char* pAppSignature,
	media_node_id nodeID) :
	BApplication(pAppSignature) {

	BMediaRoster* r = BMediaRoster::Roster();
	
	// get the node	
	status_t err = r->GetNodeFor(nodeID, &m_node);
	if(err < B_OK) {
		char buffer[512];
		sprintf(buffer,
			"MediaNodeControlApp: couldn't find node (%ld):\n%s\n",
			nodeID, strerror(err));
		(new BAlert("error", buffer, "OK"))->Go();
		return;
	}
	
	// fetch info (name)
	live_node_info nInfo;
	err = r->GetLiveNodeInfo(m_node, &nInfo);
	if(err < B_OK) {
		char buffer[512];
		sprintf(buffer,
			"MediaNodeControlApp: couldn't get node info (%ld):\n%s\n",
			nodeID, strerror(err));
		(new BAlert("error", buffer, "OK"))->Go();
		return;
	}
	
	BString windowTitle;
	windowTitle << nInfo.name << '(' << nodeID << ") controls";		
	
	// get parameter web
	BParameterWeb* pWeb;
	err = r->GetParameterWebFor(m_node, &pWeb);
	if(err < B_OK) {
		char buffer[512];
		sprintf(buffer,
			"MediaNodeControlApp: no parameters for node (%ld):\n%s\n",
			nodeID, strerror(err));
		(new BAlert("error", buffer, "OK"))->Go();
		return;
	}
	
	// build & show control window
	BView* pView = BMediaTheme::ViewFor(pWeb);
	BWindow* pWnd = new PanelWindow();
	pWnd->AddChild(pView);
	pWnd->ResizeTo(pView->Bounds().Width(), pView->Bounds().Height());
	pWnd->SetTitle(windowTitle.String());
	pWnd->Show();
	
	// release the node
	//r->ReleaseNode(m_node);	
}

void
AudioSettingsView::_FillChannelMenu(const dormant_node_info* nodeInfo)
{
	_EmptyMenu(fChannelMenu);

	BMediaRoster* roster = BMediaRoster::Roster();
	media_node node;
	media_node_id node_id;

	status_t err = roster->GetInstancesFor(nodeInfo->addon,
		nodeInfo->flavor_id, &node_id);
	if (err != B_OK) {
		err = roster->InstantiateDormantNode(*nodeInfo, &node,
			B_FLAVOR_IS_GLOBAL);
	} else {
		err = roster->GetNodeFor(node_id, &node);
	}

	if (err == B_OK) {
		int32 inputCount = 4;
		media_input* inputs = new media_input[inputCount];
		BPrivate::ArrayDeleter<media_input> inputDeleter(inputs);

		while (true) {
			int32 realInputCount = 0;
			err = roster->GetAllInputsFor(node, inputs,
				inputCount, &realInputCount);
			if (realInputCount > inputCount) {
				inputCount *= 2;
				inputs = new media_input[inputCount];
				inputDeleter.SetTo(inputs);
			} else {
				inputCount = realInputCount;
				break;
			}
		}

		if (err == B_OK) {
			BMessage message(ML_DEFAULT_CHANNEL_CHANGED);

			for (int32 i = 0; i < inputCount; i++) {
				media_input* input = new media_input();
				memcpy(input, &inputs[i], sizeof(*input));
				ChannelMenuItem* channelItem = new ChannelMenuItem(input,
					new BMessage(message));
				fChannelMenu->AddItem(channelItem);

				if (channelItem->DestinationID() == 0)
					channelItem->SetMarked(true);
			}
		}
	}

	if (Window())
		fChannelMenu->SetTargetForItems(BMessenger(this));
}

void
MediaWindow::SmartNode::SetTo(const dormant_node_info* info)
{
	_FreeNode();
	if (!info)
		return;

	fNode = new media_node();
	BMediaRoster* roster = BMediaRoster::Roster();

	// TODO: error codes
	media_node_id node_id;
	if (roster->GetInstancesFor(info->addon, info->flavor_id, &node_id) == B_OK)
		roster->GetNodeFor(node_id, fNode);
	else
		roster->InstantiateDormantNode(*info, fNode, B_FLAVOR_IS_GLOBAL);
	roster->StartWatching(fMessenger, *fNode, B_MEDIA_WILDCARD);
}

void
NodeHarnessWin::MessageReceived(BMessage *msg)
{
	status_t err;

	switch (msg->what)
	{
	case BUTTON_CONNECT:
		mIsConnected = true;

		// set the button states appropriately
		mConnectButton->SetEnabled(false);
		mStartButton->SetEnabled(true);

		// set up the node network
		{
			BMediaRoster* r = BMediaRoster::Roster();

			// find a node that can handle an audio file
#if TEST_WITH_AUDIO
			entry_ref inRef;
			dormant_node_info info;

			::get_ref_for_path("/boot/optional/sound/virtual (void)", &inRef);
			err = r->SniffRef(inRef, B_BUFFER_PRODUCER | B_FILE_INTERFACE, &info);
			ErrorCheck(err, "couldn't find file reader node\n");

			err = r->InstantiateDormantNode(info, &mConnection.producer, B_FLAVOR_IS_LOCAL);
			ErrorCheck(err, "couldn't instantiate file reader node\n");

			bigtime_t dummy_length;			// output = media length; we don't use it
			err = r->SetRefFor(mConnection.producer, inRef, false, &dummy_length);
			ErrorCheck(err, "unable to SetRefFor() to read that sound file!\n");
#else
			r->GetVideoInput(&mConnection.producer);
#endif

			entry_ref logRef;
			::get_ref_for_path("/tmp/node_log", &logRef);

			mLogNode = new LoggingConsumer(logRef);
			err = r->RegisterNode(mLogNode);
			ErrorCheck(err, "unable to register LoggingConsumer node!\n");
			// make sure the Media Roster knows that we're using the node
			r->GetNodeFor(mLogNode->Node().node, &mConnection.consumer);

			// trim down the log's verbosity a touch
			mLogNode->SetEnabled(LOG_HANDLE_EVENT, false);

			// fire off a window with the LoggingConsumer's controls in it
			BParameterWeb* web;
			r->GetParameterWebFor(mConnection.consumer, &web);
			BView* view = BMediaTheme::ViewFor(web);
			BWindow* win = new BWindow(BRect(250, 200, 300, 300), "Controls",
				B_TITLED_WINDOW, B_ASYNCHRONOUS_CONTROLS);
			win->AddChild(view);
			win->ResizeTo(view->Bounds().Width(), view->Bounds().Height());
			win->Show();

			// set the nodes' time sources
			r->GetTimeSource(&mTimeSource);
			r->SetTimeSourceFor(mConnection.consumer.node, mTimeSource.node);
			r->SetTimeSourceFor(mConnection.producer.node, mTimeSource.node);

			// got the nodes; now we find the endpoints of the connection
			media_input logInput;
			media_output soundOutput;
			int32 count;
			err = r->GetFreeOutputsFor(mConnection.producer, &soundOutput, 1, &count);
			ErrorCheck(err, "unable to get a free output from the producer node");
			err = r->GetFreeInputsFor(mConnection.consumer, &logInput, 1, &count);
			ErrorCheck(err, "unable to get a free input to the LoggingConsumer");

			// fill in the rest of the Connection object
			mConnection.source = soundOutput.source;
			mConnection.destination = logInput.destination;

			// got the endpoints; now we connect it!
			media_format format;
#if TEST_WITH_AUDIO
			format.type = B_MEDIA_RAW_AUDIO;			// !!! hmmm.. how to fully wildcard this?
			format.u.raw_audio = media_raw_audio_format::wildcard;
#else
			format.type = B_MEDIA_RAW_VIDEO;			// !!! hmmm.. how to fully wildcard this?
			format.u.raw_video = media_raw_video_format::wildcard;
#endif
			err = r->Connect(mConnection.source, mConnection.destination, &format, &soundOutput, &logInput);
			ErrorCheck(err, "unable to connect nodes");
			mConnection.format = format;

			// for video input, we need to set the downstream latency for record -> playback
			bigtime_t latency;
			r->GetLatencyFor(mConnection.producer, &latency);
			printf("Setting producer run mode latency to %" B_PRIdBIGTIME "\n", latency);
			r->SetProducerRunModeDelay(mConnection.producer, latency + 6000);

			// preroll first, to be a good citizen
			r->PrerollNode(mConnection.consumer);
			r->PrerollNode(mConnection.producer);

//.........这里部分代码省略.........