servers/midi/MidiServerApp.cpp

/*
 * Copyright (c) 2002-2004 Matthijs Hollemans
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */

#include <Alert.h>

#include "debug.h"
#include "MidiServerApp.h"
#include "PortDrivers.h"
#include "ServerDefs.h"
#include "protocol.h"

//------------------------------------------------------------------------------

MidiServerApp::MidiServerApp()
	: BApplication(MIDI_SERVER_SIGNATURE)
{
	TRACE(("Running OpenBeOS MIDI server"))

	nextId = 1;
	devWatcher.Start();
}

//------------------------------------------------------------------------------

MidiServerApp::~MidiServerApp()
{
	for (int32 t = 0; t < CountApps(); ++t)
	{
		delete AppAt(t);
	}

	for (int32 t = 0; t < CountEndpoints(); ++t)
	{
		delete EndpointAt(t);
	}
}

//------------------------------------------------------------------------------

void MidiServerApp::AboutRequested()
{
	(new BAlert(0,
		"OpenBeOS midi_server\n\n"
		"notes disguised as bytes\n"
		"propagating to endpoints,\n"
		"an aural delight",
		"Okay", 0, 0, B_WIDTH_AS_USUAL,
		B_INFO_ALERT))->Go();
}

//------------------------------------------------------------------------------

void MidiServerApp::MessageReceived(BMessage* msg)
{
	#ifdef DEBUG
	printf("IN "); msg->PrintToStream();
	#endif

	// About thread safety inside the midi_server: even though
	// multiple apps may be sending requests to the server at
	// the same time, the BLooper's thread handles passes them
	// to our MessageReceived() one after the other, so there
	// is no need to synchronize anything.

	switch (msg->what)
	{
		case MSG_REGISTER_APP:         OnRegisterApp(msg);       break;
		case MSG_CREATE_ENDPOINT:      OnCreateEndpoint(msg);    break;
		case MSG_DELETE_ENDPOINT:      OnDeleteEndpoint(msg);    break;
		case MSG_PURGE_ENDPOINT:       OnPurgeEndpoint(msg);     break;
		case MSG_CHANGE_ENDPOINT:      OnChangeEndpoint(msg);    break;
		case MSG_CONNECT_ENDPOINTS:    OnConnectDisconnect(msg); break;
		case MSG_DISCONNECT_ENDPOINTS: OnConnectDisconnect(msg); break;

		default: super::MessageReceived(msg); break;
	}
}

//------------------------------------------------------------------------------

void MidiServerApp::OnRegisterApp(BMessage* msg)
{
	TRACE(("MidiServerApp::OnRegisterApp"))

	// We only send the "app registered" message upon success,
	// so if anything goes wrong here, we do not let the app
	// know about it, and we consider it unregistered. (Most
	// likely, the app is dead. If not, it freezes forever
	// in anticipation of a message that will never arrive.)

	app_t* app = new app_t;

	if (msg->FindMessenger("midi:messenger", &app->messenger) == B_OK)
	{
		if (SendAllEndpoints(app))
		{
			if (SendAllConnections(app))
			{
				BMessage reply;
				reply.what = MSG_APP_REGISTERED;

				if (SendNotification(app, &reply))
				{
					apps.AddItem(app);

					#ifdef DEBUG
					DumpApps();
					#endif

					return;
				}
			}
		}
	}

	delete app;
}

//------------------------------------------------------------------------------

void MidiServerApp::OnCreateEndpoint(BMessage* msg)
{
	TRACE(("MidiServerApp::OnCreateEndpoint"))

	status_t err;

	endpoint_t* endp = new endpoint_t;

	endp->app = WhichApp(msg);
	if (endp->app == NULL)
	{
		err = B_ERROR;
	}
	else
	{
		err = B_BAD_VALUE;

		if ((msg->FindBool("midi:consumer", &endp->consumer) == B_OK)
		&&  (msg->FindBool("midi:registered", &endp->registered) == B_OK)
		&&  (msg->FindString("midi:name", &endp->name) == B_OK)
		&&  (msg->FindMessage("midi:properties", &endp->properties) == B_OK))
		{
			if (endp->consumer)
			{
				if ((msg->FindInt32("midi:port", &endp->port) == B_OK)
				&&  (msg->FindInt64("midi:latency", &endp->latency) == B_OK))
				{
					err = B_OK;
				}
			}
			else
			{
				err = B_OK;
			}
		}
	}

	BMessage reply;

	if (err == B_OK)
	{
		endp->id = nextId++;
		reply.AddInt32("midi:id", endp->id);
	}

	reply.AddInt32("midi:result", err);

	if (SendReply(endp->app, msg, &reply) && (err == B_OK))
	{
		AddEndpoint(msg, endp);
	}
	else
	{
		delete endp;
	}
}

//------------------------------------------------------------------------------

void MidiServerApp::OnDeleteEndpoint(BMessage* msg)
{
	TRACE(("MidiServerApp::OnDeleteEndpoint"))

	// Clients send the "delete endpoint" message from
	// the BMidiEndpoint destructor, so there is no point
	// sending a reply, because the endpoint object will
	// be destroyed no matter what.

	app_t* app = WhichApp(msg);
	if (app != NULL)
	{
		endpoint_t* endp = WhichEndpoint(msg, app);
		if (endp != NULL)
		{
			RemoveEndpoint(app, endp);
		}
	}
}

//------------------------------------------------------------------------------

void MidiServerApp::OnPurgeEndpoint(BMessage* msg)
{
	TRACE(("MidiServerApp::OnPurgeEndpoint"))

	// This performs the same task as OnDeleteEndpoint(),
	// except that this message was send by the midi_server
	// itself, so we don't check that the app that made the
	// request really is the owner of the endpoint. (But we
	// _do_ check that the message came from the server.)

	if (!msg->IsSourceRemote())
	{
		int32 id;
		if (msg->FindInt32("midi:id", &id) == B_OK)
		{
			endpoint_t* endp = FindEndpoint(id);
			if (endp != NULL)
			{
				RemoveEndpoint(NULL, endp);
			}
		}
	}
}

//------------------------------------------------------------------------------

void MidiServerApp::OnChangeEndpoint(BMessage* msg)
{
	TRACE(("MidiServerApp::OnChangeEndpoint"))

	endpoint_t* endp = NULL;
	status_t err;

	app_t* app = WhichApp(msg);
	if (app == NULL)
	{
		err = B_ERROR;
	}
	else
	{
		endp = WhichEndpoint(msg, app);
		if (endp == NULL)
		{
			err = B_BAD_VALUE;
		}
		else
		{
			err = B_OK;
		}
	}

	BMessage reply;
	reply.AddInt32("midi:result", err);

	if (SendReply(app, msg, &reply) && (err == B_OK))
	{
		TRACE(("Endpoint %ld (%p) changed", endp->id, endp))

		BMessage notify;
		notify.what = MSG_ENDPOINT_CHANGED;
		notify.AddInt32("midi:id", endp->id);

		bool registered;
		if (msg->FindBool("midi:registered", &registered) == B_OK)
		{
			notify.AddBool("midi:registered", registered);
			endp->registered = registered;
		}

		BString name;
		if (msg->FindString("midi:name", &name) == B_OK)
		{
			notify.AddString("midi:name", name);
			endp->name = name;
		}

		BMessage properties;
		if (msg->FindMessage("midi:properties", &properties) == B_OK)
		{
			notify.AddMessage("midi:properties", &properties);
			endp->properties = properties;
		}

		bigtime_t latency;
		if (msg->FindInt64("midi:latency", &latency) == B_OK)
		{
			notify.AddInt64("midi:latency", latency);
			endp->latency = latency;
		}

		NotifyAll(&notify, app);

		#ifdef DEBUG
		DumpEndpoints();
		#endif
	}
}

//------------------------------------------------------------------------------

void MidiServerApp::OnConnectDisconnect(BMessage* msg)
{
	TRACE(("MidiServerApp::OnConnectDisconnect"))

	bool mustConnect = (msg->what == MSG_CONNECT_ENDPOINTS);

	status_t err;
	endpoint_t* prod = NULL;
	endpoint_t* cons = NULL;

	app_t* app = WhichApp(msg);
	if (app == NULL)
	{
		err = B_ERROR;
	}
	else
	{
		err = B_BAD_VALUE;

		int32 prodId, consId;
		if ((msg->FindInt32("midi:producer", &prodId) == B_OK)
		&&  (msg->FindInt32("midi:consumer", &consId) == B_OK))
		{
			prod = FindEndpoint(prodId);
			cons = FindEndpoint(consId);

			if ((prod != NULL) && !prod->consumer)
			{
				if ((cons != NULL) && cons->consumer)
				{
					// It is an error to connect two endpoints that
					// are already connected, or to disconnect two
					// endpoints that are not connected at all.

					if (mustConnect == prod->connections.HasItem(cons))
					{
						err = B_ERROR;
					}
					else
					{
						err = B_OK;
					}
				}
			}
		}
	}

	BMessage reply;
	reply.AddInt32("midi:result", err);

	if (SendReply(app, msg, &reply) && (err == B_OK))
	{
		if (mustConnect)
		{
			TRACE(("Connection made: %ld ---> %ld", prod->id, cons->id))

			prod->connections.AddItem(cons);
		}
		else
		{
			TRACE(("Connection broken: %ld -X-> %ld", prod->id, cons->id))

			prod->connections.RemoveItem(cons);
		}

		BMessage notify;
		MakeConnectedNotification(&notify, prod, cons, mustConnect);
		NotifyAll(&notify, app);

		#ifdef DEBUG
		DumpEndpoints();
		#endif
	}
}

//------------------------------------------------------------------------------

bool MidiServerApp::SendAllEndpoints(app_t* app)
{
	ASSERT(app != NULL)

	BMessage notify;

	for (int32 t = 0; t < CountEndpoints(); ++t)
	{
		endpoint_t* endp = EndpointAt(t);

		MakeCreatedNotification(&notify, endp);

		if (!SendNotification(app, &notify)) { return false; }
	}

	return true;
}

//------------------------------------------------------------------------------

bool MidiServerApp::SendAllConnections(app_t* app)
{
	ASSERT(app != NULL)

	BMessage notify;

	for (int32 t = 0; t < CountEndpoints(); ++t)
	{
		endpoint_t* prod = EndpointAt(t);
		if (!prod->consumer)
		{
			for (int32 k = 0; k < CountConnections(prod); ++k)
			{
				endpoint_t* cons = ConnectionAt(prod, k);

				MakeConnectedNotification(&notify, prod, cons, true);

				if (!SendNotification(app, &notify)) { return false; }
			}
		}
	}

	return true;
}

//------------------------------------------------------------------------------

void MidiServerApp::AddEndpoint(BMessage* msg, endpoint_t* endp)
{
	ASSERT(msg != NULL)
	ASSERT(endp != NULL)
	ASSERT(!endpoints.HasItem(endp))

	TRACE(("Endpoint %ld (%p) added", endp->id, endp))

	endpoints.AddItem(endp);

	BMessage notify;
	MakeCreatedNotification(&notify, endp);
	NotifyAll(&notify, endp->app);

	#ifdef DEBUG
	DumpEndpoints();
	#endif
}

//------------------------------------------------------------------------------

void MidiServerApp::RemoveEndpoint(app_t* app, endpoint_t* endp)
{
	ASSERT(endp != NULL)
	ASSERT(endpoints.HasItem(endp))

	TRACE(("Endpoint %ld (%p) removed", endp->id, endp))

	endpoints.RemoveItem(endp);

	if (endp->consumer)
	{
		DisconnectDeadConsumer(endp);
	}

	BMessage notify;
	notify.what = MSG_ENDPOINT_DELETED;
	notify.AddInt32("midi:id", endp->id);
	NotifyAll(&notify, app);

	delete endp;

	#ifdef DEBUG
	DumpEndpoints();
	#endif
}

//------------------------------------------------------------------------------

void MidiServerApp::DisconnectDeadConsumer(endpoint_t* cons)
{
	ASSERT(cons != NULL)
	ASSERT(cons->consumer)

	for (int32 t = 0; t < CountEndpoints(); ++t)
	{
		endpoint_t* prod = EndpointAt(t);
		if (!prod->consumer)
		{
			prod->connections.RemoveItem(cons);
		}
	}
}

//------------------------------------------------------------------------------

void MidiServerApp::MakeCreatedNotification(BMessage* msg, endpoint_t* endp)
{
	ASSERT(msg != NULL)
	ASSERT(endp != NULL)

	msg->MakeEmpty();
	msg->what = MSG_ENDPOINT_CREATED;
	msg->AddInt32("midi:id", endp->id);
	msg->AddBool("midi:consumer", endp->consumer);
	msg->AddBool("midi:registered", endp->registered);
	msg->AddString("midi:name", endp->name);
	msg->AddMessage("midi:properties", &endp->properties);

	if (endp->consumer)
	{
		msg->AddInt32("midi:port", endp->port);
		msg->AddInt64("midi:latency", endp->latency);
	}
}

//------------------------------------------------------------------------------

void MidiServerApp::MakeConnectedNotification(
	BMessage* msg, endpoint_t* prod, endpoint_t* cons, bool mustConnect)
{
	ASSERT(msg != NULL)
	ASSERT(prod != NULL)
	ASSERT(cons != NULL)
	ASSERT(!prod->consumer)
	ASSERT(cons->consumer)

	msg->MakeEmpty();

	if (mustConnect)
	{
		msg->what = MSG_ENDPOINTS_CONNECTED;
	}
	else
	{
		msg->what = MSG_ENDPOINTS_DISCONNECTED;
	}

	msg->AddInt32("midi:producer", prod->id);
	msg->AddInt32("midi:consumer", cons->id);
}

//------------------------------------------------------------------------------

app_t* MidiServerApp::WhichApp(BMessage* msg)
{
	ASSERT(msg != NULL)

	BMessenger retadr = msg->ReturnAddress();

	for (int32 t = 0; t < CountApps(); ++t)
	{
		app_t* app = AppAt(t);
		if (app->messenger.Team() == retadr.Team())
		{
			return app;
		}
	}

	TRACE(("Application %ld is not registered", retadr.Team()))

	return NULL;
}

//------------------------------------------------------------------------------

endpoint_t* MidiServerApp::WhichEndpoint(BMessage* msg, app_t* app)
{
	ASSERT(msg != NULL)
	ASSERT(app != NULL)

	int32 id;
	if (msg->FindInt32("midi:id", &id) == B_OK)
	{
		endpoint_t* endp = FindEndpoint(id);
		if ((endp != NULL) && (endp->app == app))
		{
			return endp;
		}
	}

	TRACE(("Endpoint not found or wrong app"))

	return NULL;
}

//------------------------------------------------------------------------------

endpoint_t* MidiServerApp::FindEndpoint(int32 id)
{
	if (id > 0)
	{
		for (int32 t = 0; t < CountEndpoints(); ++t)
		{
			endpoint_t* endp = EndpointAt(t);
			if (endp->id == id)
			{
				return endp;
			}
		}
	}

	TRACE(("Endpoint %ld not found", id))

	return NULL;
}

//------------------------------------------------------------------------------

void MidiServerApp::NotifyAll(BMessage* msg, app_t* except)
{
	ASSERT(msg != NULL)

	for (int32 t = CountApps() - 1; t >= 0; --t)
	{
		app_t* app = AppAt(t);
		if (app != except)
		{
			if (!SendNotification(app, msg))
			{
				delete (app_t*) apps.RemoveItem(t);

				#ifdef DEBUG
				DumpApps();
				#endif
			}
		}
	}
}

//------------------------------------------------------------------------------

bool MidiServerApp::SendNotification(app_t* app, BMessage* msg)
{
	ASSERT(app != NULL)
	ASSERT(msg != NULL)

	status_t err = app->messenger.SendMessage(msg, (BHandler*) NULL, TIMEOUT);

	if (err != B_OK)
	{
		DeliveryError(app);
	}

	return (err == B_OK);
}

//------------------------------------------------------------------------------

bool MidiServerApp::SendReply(app_t* app, BMessage* msg, BMessage* reply)
{
	ASSERT(msg != NULL)
	ASSERT(reply != NULL)

	status_t err = msg->SendReply(reply, (BHandler*) NULL, TIMEOUT);

	if ((err != B_OK) && (app != NULL))
	{
		DeliveryError(app);
		apps.RemoveItem(app);
		delete app;

		#ifdef DEBUG
		DumpApps();
		#endif
	}

	return (err == B_OK);
}

//------------------------------------------------------------------------------

void MidiServerApp::DeliveryError(app_t* app)
{
	ASSERT(app != NULL)

	// We cannot communicate with the app, so we assume it's
	// dead. We need to remove its endpoints from the roster,
	// but we cannot do that right away; removing endpoints
	// triggers a bunch of new notifications and we don't want
	// those to get in the way of the notifications we are
	// currently sending out. Instead, we consider the death
	// of an app as a separate event, and pretend that the
	// now-dead app sent us delete requests for its endpoints.

	TRACE(("Delivery error; unregistering app (%p)", app))

	BMessage msg;

	for (int32 t = 0; t < CountEndpoints(); ++t)
	{
		endpoint_t* endp = EndpointAt(t);
		if (endp->app == app)
		{
			msg.MakeEmpty();
			msg.what = MSG_PURGE_ENDPOINT;
			msg.AddInt32("midi:id", endp->id);

			// It is not safe to post a message to your own
			// looper's message queue, because you risk a
			// deadlock if the queue is full. The chance of
			// that happening is fairly small, but just in
			// case, we catch it with a timeout. Because this
			// situation is so unlikely, I decided to simply
			// forget about the whole "purge" message then.

			if (be_app_messenger.SendMessage(
					&msg, (BHandler*) NULL, TIMEOUT) != B_OK)
			{
				WARN("Could not deliver purge message")
			}
		}
	}
}

//------------------------------------------------------------------------------

int32 MidiServerApp::CountApps()
{
	return apps.CountItems();
}

//------------------------------------------------------------------------------

app_t* MidiServerApp::AppAt(int32 index)
{
	ASSERT(index >= 0 && index < CountApps())

	return (app_t*) apps.ItemAt(index);
}

//------------------------------------------------------------------------------

int32 MidiServerApp::CountEndpoints()
{
	return endpoints.CountItems();
}

//------------------------------------------------------------------------------

endpoint_t* MidiServerApp::EndpointAt(int32 index)
{
	ASSERT(index >= 0 && index < CountEndpoints())

	return (endpoint_t*) endpoints.ItemAt(index);
}

//------------------------------------------------------------------------------

int32 MidiServerApp::CountConnections(endpoint_t* prod)
{
	ASSERT(prod != NULL)
	ASSERT(!prod->consumer)

	return prod->connections.CountItems();
}

//------------------------------------------------------------------------------

endpoint_t* MidiServerApp::ConnectionAt(endpoint_t* prod, int32 index)
{
	ASSERT(prod != NULL)
	ASSERT(!prod->consumer)
	ASSERT(index >= 0 && index < CountConnections(prod))

	return (endpoint_t*) prod->connections.ItemAt(index);
}

//------------------------------------------------------------------------------

#ifdef DEBUG
void MidiServerApp::DumpApps()
{
	printf("*** START DumpApps\n");

	for (int32 t = 0; t < CountApps(); ++t)
	{
		app_t* app = AppAt(t);

		printf("\tapp %ld (%p): team %ld\n", t, app, app->messenger.Team());
	}

	printf("*** END DumpApps\n");
}
#endif

//------------------------------------------------------------------------------

#ifdef DEBUG
void MidiServerApp::DumpEndpoints()
{
	printf("*** START DumpEndpoints\n");

	for (int32 t = 0; t < CountEndpoints(); ++t)
	{
		endpoint_t* endp = EndpointAt(t);

		printf("\tendpoint %ld (%p):\n", t, endp);

		printf("\t\tid %ld, name '%s', %s, %s, app %p\n",
			endp->id, endp->name.String(),
			endp->consumer ? "consumer" : "producer",
			endp->registered ? "registered" : "unregistered",
			endp->app);

		printf("\t\tproperties: "); endp->properties.PrintToStream();

		if (endp->consumer)
		{
			printf("\t\tport %ld, latency %Ld\n", endp->port, endp->latency);
		}
		else
		{
			printf("\t\tconnections:\n");
			for (int32 k = 0; k < CountConnections(endp); ++k)
			{
				endpoint_t* cons = ConnectionAt(endp, k);
				printf("\t\t\tid %ld (%p)\n", cons->id, cons);
			}
		}
	}

	printf("*** END DumpEndpoints\n");
}
#endif

//------------------------------------------------------------------------------

int main()
{
	MidiServerApp app;
	app.Run();
	return 0;
}

//------------------------------------------------------------------------------