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Add a simple event server #759

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Add a simple event server #759

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209 changes: 208 additions & 1 deletion BlackHole/BlackHole.c
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Original file line number Diff line number Diff line change
Expand Up @@ -13,14 +13,19 @@
//==================================================================================================

#include <CoreAudio/AudioServerPlugIn.h>
#include <arpa/inet.h>
#include <dispatch/dispatch.h>
#include <mach/mach_time.h>
#include <pthread.h>
#include <stdint.h>
#include <sys/socket.h>
#include <sys/syslog.h>
#include <sys/types.h>
#include <sys/un.h>
#include <Accelerate/Accelerate.h>
#include <Availability.h>


//==================================================================================================
#pragma mark -
#pragma mark Macros
Expand Down Expand Up @@ -225,7 +230,13 @@ struct ObjectInfo {
#define kDevice2_HasOutput true
#endif

#ifndef kEventSeverEnabled
#define kEventSeverEnabled false
#endif

#ifndef kEventSeverPort
#define kEventSeverPort 25192
#endif

#ifndef kManufacturer_Name
#define kManufacturer_Name "Existential Audio Inc."
Expand Down Expand Up @@ -392,6 +403,10 @@ static OSStatus BlackHole_GetControlPropertyDataSize(AudioServerPlugInDri
static OSStatus BlackHole_GetControlPropertyData(AudioServerPlugInDriverRef inDriver, AudioObjectID inObjectID, pid_t inClientProcessID, const AudioObjectPropertyAddress* inAddress, UInt32 inQualifierDataSize, const void* inQualifierData, UInt32 inDataSize, UInt32* outDataSize, void* outData);
static OSStatus BlackHole_SetControlPropertyData(AudioServerPlugInDriverRef inDriver, AudioObjectID inObjectID, pid_t inClientProcessID, const AudioObjectPropertyAddress* inAddress, UInt32 inQualifierDataSize, const void* inQualifierData, UInt32 inDataSize, const void* inData, UInt32* outNumberPropertiesChanged, AudioObjectPropertyAddress outChangedAddresses[2]);

// BlackHole Event Server prototypes
static void BlackHole_onDeviceStateUpdated(void);
static void BlackHole_Server_Start(void);

#pragma mark The Interface

static AudioServerPlugInDriverInterface gAudioServerPlugInDriverInterface =
Expand Down Expand Up @@ -781,7 +796,8 @@ static OSStatus BlackHole_Initialize(AudioServerPlugInDriverRef inDriver, AudioS
gDevice_AdjustedTicksPerFrame = gDevice_HostTicksPerFrame - gDevice_HostTicksPerFrame/100.0 * 2.0*(gPitch_Adjust - 0.5);

// DebugMsg("BlackHole theTimeBaseInfo.numer: %u \t theTimeBaseInfo.denom: %u", theTimeBaseInfo.numer, theTimeBaseInfo.denom);


BlackHole_Server_Start();
Done:
return theAnswer;
}
Expand Down Expand Up @@ -4331,6 +4347,7 @@ static OSStatus BlackHole_StartIO(AudioServerPlugInDriverRef inDriver, AudioObje
gRingBuffer = calloc(kRing_Buffer_Frame_Size * kNumber_Of_Channels, sizeof(Float32));
}

BlackHole_onDeviceStateUpdated();

// unlock the state lock
pthread_mutex_unlock(&gPlugIn_StateMutex);
Expand Down Expand Up @@ -4368,6 +4385,8 @@ static OSStatus BlackHole_StopIO(AudioServerPlugInDriverRef inDriver, AudioObjec
free(gRingBuffer);
gRingBuffer = NULL;
}

BlackHole_onDeviceStateUpdated();

// unlock the state lock
pthread_mutex_unlock(&gPlugIn_StateMutex);
Expand Down Expand Up @@ -4610,3 +4629,191 @@ static OSStatus BlackHole_EndIOOperation(AudioServerPlugInDriverRef inDriver, Au
Done:
return theAnswer;
}

//==================================================================================================
#pragma mark -
#pragma mark Black Hole Event Server
//==================================================================================================
/*
* Event server communicates device related events to all conected clients.
* Can be used, for example, to autimatically start some application when microphone is used.
*
* Event message is exactly 1 byte long and consists of device id (2 bits) and event id (6 bits).
*
* | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
* | Device ID | Device Event |
*/

#pragma mark Interface

enum DeviceEvent
{
DeviceEventNone = 0, // No event. Can be used for pings, etc.
DeviceEventStarted = 1,
DeviceEventStopped = 62,
DeviceEventMax = 63, // Maximum possible value of device event
};

#pragma mark State

static pthread_t gServerThread = 0;
static UInt64 gServer_Device1IsRunning = 0;
static UInt64 gServer_Device2IsRunning = 0;
static pthread_mutex_t gClients_Mutex = PTHREAD_MUTEX_INITIALIZER;
static CFMutableArrayRef gClients = NULL;

#pragma mark Event Server Implementationt

static size_t BlackHole_WriteEvent(int socket, uint8_t deviceId, uint8_t event)
{
uint8_t message = (deviceId << 6) | event;
return send(socket, &message, sizeof(message), MSG_NOSIGNAL);
}

static size_t BlackHole_WriteCurrentDevicesState(int socket)
{
size_t result = 0;
result = BlackHole_WriteEvent(socket, 1, gServer_Device1IsRunning > 0 ? DeviceEventStarted : DeviceEventStopped);
if (result < 0) {
return result;
}

result = BlackHole_WriteEvent(socket, 2, gServer_Device2IsRunning > 0 ? DeviceEventStarted : DeviceEventStopped);
if (result < 0) {
return result;
}

return 2; // Two bytes written
}

static void BlackHole_BroadcastDeviceEvent(uint8_t deviceId, uint8_t event)
{
pthread_mutex_lock(&gClients_Mutex);

CFIndex count = CFArrayGetCount(gClients);

// Traverse all clients in backwards order
// so we can remove the from array if client's socket is closed
for (CFIndex i = count - 1; i >= 0; i--) {
CFNumberRef socketNumber = CFArrayGetValueAtIndex(gClients, i);
DebugMsg("BlackHole: serving client %li", (long)i);

int clientSocket;
if (!CFNumberGetValue(socketNumber, kCFNumberIntType, &clientSocket)) {
DebugMsg("BlackHole: Couldn't get soket fd from CFNumber");
continue;
}
DebugMsg("BlackHole: writing to %i", clientSocket);

// If write failed socket is probably closed.
// Remove it from the array of clients
if (BlackHole_WriteEvent(clientSocket, deviceId, event) < 0) {
DebugMsg("BlackHole: Write failed. Socket is closed (%i)", clientSocket);
CFArrayRemoveValueAtIndex(gClients, i);
}
}

pthread_mutex_unlock(&gClients_Mutex);
}

static void BlackHole_onDeviceStateUpdated(void)
{
bool device1StateHasChanged = gServer_Device1IsRunning != gDevice_IOIsRunning;
bool device2StateHasChanged = gServer_Device2IsRunning != gDevice2_IOIsRunning;

gServer_Device1IsRunning = gDevice_IOIsRunning;
gServer_Device2IsRunning = gDevice2_IOIsRunning;

if (device1StateHasChanged) {
uint8_t event = gServer_Device1IsRunning > 0 ? DeviceEventStarted : DeviceEventStopped;
BlackHole_BroadcastDeviceEvent(1, event);
}

if (device2StateHasChanged) {
uint8_t event = gServer_Device2IsRunning > 0 ? DeviceEventStarted : DeviceEventStopped;
BlackHole_BroadcastDeviceEvent(2, event);
}
}

static void BlackHole_Server_Main(void)
{
syslog(LOG_NOTICE, "Server: Server thread started");
int server_socket;
int client_socket;
int result = 0;

server_socket = socket(AF_INET, SOCK_STREAM, 0);
struct sockaddr_in servaddr, client_addr;
bzero(&servaddr, sizeof(servaddr));

// assign IP, PORT
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = inet_addr("127.0.0.1");
servaddr.sin_port = htons(kEventSeverPort);

int bindAttempts = 10;
while (bindAttempts > 0) {
result = bind(server_socket, (struct sockaddr*)&servaddr, sizeof(servaddr));
if (result == 0) {
break;
}
bindAttempts--;
if (bindAttempts > 0) {
DebugMsg("Server: Failed to bind socket (%i) retrying", result);
}
sleep(1);
}

if (result != 0) {
DebugMsg("Server: Failed to bind socket (%i) stopping", result);
return;
}

result = listen(server_socket, 5);
if (result != 0) {
DebugMsg("Server: Failed to start listening socket (%i)", result);
return;
}

while(1){
unsigned int clen = sizeof(client_addr);
client_socket = accept(server_socket, (struct sockaddr *) &client_addr, &clen);

// Update newly connected client with the device statuses
BlackHole_WriteCurrentDevicesState(client_socket);

// lock the clients lock
pthread_mutex_lock(&gClients_Mutex);
CFNumberRef socketNumber = CFNumberCreate(kCFAllocatorDefault, kCFNumberIntType, &client_socket);
CFArrayAppendValue(gClients, socketNumber);
CFRelease(socketNumber);
// unlock the clients lock
pthread_mutex_unlock(&gClients_Mutex);
}
}

static void BlackHole_Server_Start(void)
{
if (!kEventSeverEnabled) {
return;
}

int result;
// lock the clients lock
pthread_mutex_lock(&gClients_Mutex);
if (gClients == NULL) {
gClients = CFArrayCreateMutable(kCFAllocatorDefault, 10, &kCFTypeArrayCallBacks);
}
// unlock the clients lock
pthread_mutex_unlock(&gClients_Mutex);

if (gServerThread != 0) {
DebugMsg("Server: Server's already running");
return;
}

result = pthread_create(&gServerThread, NULL, (void*)&BlackHole_Server_Main, NULL) ;
if(result != 0) {
DebugMsg("Server: Failed to start server thread (%i)", result);
}
}