pa_jack.c

一个开源的sip源代码

    PaJackStream *stream = (PaJackStream *)s;

    long bytesRead;
    char *p = (char *) data;
    long numBytes = stream->bytesPerFrame * numFrames;
    while( numBytes > 0 )
    {
        bytesRead = PaUtil_ReadRingBuffer( &stream->inFIFO, p, numBytes );
        numBytes -= bytesRead;
        p += bytesRead;
        if( numBytes > 0 )
        {
            /* see write for an explanation */
            if( stream->data_available )
                stream->data_available = 0;
            else
                sem_wait( &stream->data_semaphore );
        }
    }

    return result;
}

static PaError BlockingWriteStream( PaStream* s, const void *data, unsigned long numFrames )
{
    PaError result = paNoError;
    PaJackStream *stream = (PaJackStream *)s;
    long bytesWritten;
    char *p = (char *) data;
    long numBytes = stream->bytesPerFrame * numFrames;
    while( numBytes > 0 )
    {
        bytesWritten = PaUtil_WriteRingBuffer( &stream->outFIFO, p, numBytes );
        numBytes -= bytesWritten;
        p += bytesWritten;
        if( numBytes > 0 ) 
        {
            /* we use the following algorithm: 
             *   (1) write data
             *   (2) if some data didn't fit into the ringbuffer, set data_available to 0
             *       to indicate to the audio that if space becomes available, we want to know
             *   (3) retry to write data (because it might be that between (1) and (2)
             *       new space in the buffer became available)
             *   (4) if this failed, we are sure that the buffer is really empty and
             *       we will definitely receive a notification when it becomes available
             *       thus we can safely sleep
             *
             * if the algorithm bailed out in step (3) before, it leaks a count of 1
             * on the semaphore; however, it doesn't matter, because if we block in (4),
             * we also do it in a loop
             */
            if( stream->data_available )
                stream->data_available = 0;
            else
                sem_wait( &stream->data_semaphore );
        }
    }

    return result;
}

static signed long
BlockingGetStreamReadAvailable( PaStream* s )
{
    PaJackStream *stream = (PaJackStream *)s;

    int bytesFull = PaUtil_GetRingBufferReadAvailable( &stream->inFIFO );
    return bytesFull / stream->bytesPerFrame;
}

static signed long
BlockingGetStreamWriteAvailable( PaStream* s )
{
    PaJackStream *stream = (PaJackStream *)s;

    int bytesEmpty = PaUtil_GetRingBufferWriteAvailable( &stream->outFIFO );
    return bytesEmpty / stream->bytesPerFrame;
}

static PaError
BlockingWaitEmpty( PaStream *s )
{
    PaJackStream *stream = (PaJackStream *)s;

    while( PaUtil_GetRingBufferReadAvailable( &stream->outFIFO ) > 0 )
    {
        stream->data_available = 0;
        sem_wait( &stream->data_semaphore );
    }
    return 0;
}

/* ---- jack driver ---- */

/* BuildDeviceList():
 *
 * The process of determining a list of PortAudio "devices" from
 * JACK's client/port system is fairly involved, so it is separated
 * into its own routine.
 */

static PaError BuildDeviceList( PaJackHostApiRepresentation *jackApi )
{
    /* Utility macros for the repetitive process of allocating memory */

    /* JACK has no concept of a device.  To JACK, there are clients
     * which have an arbitrary number of ports.  To make this
     * intelligible to PortAudio clients, we will group each JACK client
     * into a device, and make each port of that client a channel */

    PaError result = paNoError;
    PaUtilHostApiRepresentation *commonApi = &jackApi->commonHostApiRep;

    const char **jack_ports = NULL;
    char **client_names = NULL;
    char *regex_pattern = NULL;
    int port_index, client_index, i;
    double globalSampleRate;
    regex_t port_regex;
    unsigned long numClients = 0, numPorts = 0;
    char *tmp_client_name = NULL;

    commonApi->info.defaultInputDevice = paNoDevice;
    commonApi->info.defaultOutputDevice = paNoDevice;
    commonApi->info.deviceCount = 0;

    /* Parse the list of ports, using a regex to grab the client names */
    ASSERT_CALL( regcomp( &port_regex, "^[^:]*", REG_EXTENDED ), 0 );

    /* since we are rebuilding the list of devices, free all memory
     * associated with the previous list */
    PaUtil_FreeAllAllocations( jackApi->deviceInfoMemory );

    regex_pattern = PaUtil_GroupAllocateMemory( jackApi->deviceInfoMemory, jack_client_name_size() + 3 );
    tmp_client_name = PaUtil_GroupAllocateMemory( jackApi->deviceInfoMemory, jack_client_name_size() );

    /* We can only retrieve the list of clients indirectly, by first
     * asking for a list of all ports, then parsing the port names
     * according to the client_name:port_name convention (which is
     * enforced by jackd)
     * A: If jack_get_ports returns NULL, there's nothing for us to do */
    UNLESS( (jack_ports = jack_get_ports( jackApi->jack_client, "", "", 0 )) && jack_ports[0], paNoError );
    /* Find number of ports */
    while( jack_ports[numPorts] )
        ++numPorts;
    /* At least there will be one port per client :) */
    UNLESS( client_names = PaUtil_GroupAllocateMemory( jackApi->deviceInfoMemory, numPorts *
                sizeof (char *) ), paInsufficientMemory );

    /* Build a list of clients from the list of ports */
    for( numClients = 0, port_index = 0; jack_ports[port_index] != NULL; port_index++ )
    {
        int client_seen = FALSE;
        regmatch_t match_info;
        const char *port = jack_ports[port_index];

        /* extract the client name from the port name, using a regex
         * that parses the clientname:portname syntax */
        UNLESS( !regexec( &port_regex, port, 1, &match_info, 0 ), paInternalError );
        assert(match_info.rm_eo - match_info.rm_so < jack_client_name_size());
        memcpy( tmp_client_name, port + match_info.rm_so,
                match_info.rm_eo - match_info.rm_so );
        tmp_client_name[match_info.rm_eo - match_info.rm_so] = '\0';

        /* do we know about this port's client yet? */
        for( i = 0; i < numClients; i++ )
        {
            if( strcmp( tmp_client_name, client_names[i] ) == 0 )
                client_seen = TRUE;
        }

        if (client_seen)
            continue;   /* A: Nothing to see here, move along */

        UNLESS( client_names[numClients] = (char*)PaUtil_GroupAllocateMemory( jackApi->deviceInfoMemory,
                    strlen(tmp_client_name) + 1), paInsufficientMemory );

        /* The alsa_pcm client should go in spot 0.  If this
         * is the alsa_pcm client AND we are NOT about to put
         * it in spot 0 put it in spot 0 and move whatever
         * was already in spot 0 to the end. */
        if( strcmp( "alsa_pcm", tmp_client_name ) == 0 && numClients > 0 )
        {
            /* alsa_pcm goes in spot 0 */
            strcpy( client_names[ numClients ], client_names[0] );
            strcpy( client_names[0], tmp_client_name );
        }
        else
        {
            /* put the new client at the end of the client list */
            strcpy( client_names[ numClients ], tmp_client_name );
        }
        ++numClients;
    }

    /* Now we have a list of clients, which will become the list of
     * PortAudio devices. */

    /* there is one global sample rate all clients must conform to */

    globalSampleRate = jack_get_sample_rate( jackApi->jack_client );
    UNLESS( commonApi->deviceInfos = (PaDeviceInfo**)PaUtil_GroupAllocateMemory( jackApi->deviceInfoMemory,
                sizeof(PaDeviceInfo*) * numClients ), paInsufficientMemory );

    assert( commonApi->info.deviceCount == 0 );

    /* Create a PaDeviceInfo structure for every client */
    for( client_index = 0; client_index < numClients; client_index++ )
    {
        PaDeviceInfo *curDevInfo;
        const char **clientPorts = NULL;

        UNLESS( curDevInfo = (PaDeviceInfo*)PaUtil_GroupAllocateMemory( jackApi->deviceInfoMemory,
                    sizeof(PaDeviceInfo) ), paInsufficientMemory );
        UNLESS( curDevInfo->name = (char*)PaUtil_GroupAllocateMemory( jackApi->deviceInfoMemory,
                    strlen(client_names[client_index]) + 1 ), paInsufficientMemory );
        strcpy( (char *)curDevInfo->name, client_names[client_index] );

        curDevInfo->structVersion = 2;
        curDevInfo->hostApi = jackApi->hostApiIndex;

        /* JACK is very inflexible: there is one sample rate the whole
         * system must run at, and all clients must speak IEEE float. */
        curDevInfo->defaultSampleRate = globalSampleRate;

        /* To determine how many input and output channels are available,
         * we re-query jackd with more specific parameters. */

        sprintf( regex_pattern, "%s:.*", client_names[client_index] );

        /* ... what are your output ports (that we could input from)? */
        clientPorts = jack_get_ports( jackApi->jack_client, regex_pattern,
                                     NULL, JackPortIsOutput);
        curDevInfo->maxInputChannels = 0;
        curDevInfo->defaultLowInputLatency = 0.;
        curDevInfo->defaultHighInputLatency = 0.;
        if( clientPorts )
        {
            jack_port_t *p = jack_port_by_name( jackApi->jack_client, clientPorts[0] );
            curDevInfo->defaultLowInputLatency = curDevInfo->defaultHighInputLatency =
                jack_port_get_latency( p ) / globalSampleRate;

            for( i = 0; clientPorts[i] != NULL; i++)
            {
                /* The number of ports returned is the number of output channels.
                 * We don't care what they are, we just care how many */
                curDevInfo->maxInputChannels++;
            }
            free(clientPorts);
        }

        /* ... what are your input ports (that we could output to)? */
        clientPorts = jack_get_ports( jackApi->jack_client, regex_pattern,
                                     NULL, JackPortIsInput);
        curDevInfo->maxOutputChannels = 0;
        curDevInfo->defaultLowOutputLatency = 0.;
        curDevInfo->defaultHighOutputLatency = 0.;
        if( clientPorts )
        {
            jack_port_t *p = jack_port_by_name( jackApi->jack_client, clientPorts[0] );
            curDevInfo->defaultLowOutputLatency = curDevInfo->defaultHighOutputLatency =
                jack_port_get_latency( p ) / globalSampleRate;

            for( i = 0; clientPorts[i] != NULL; i++)
            {
                /* The number of ports returned is the number of input channels.
                 * We don't care what they are, we just care how many */
                curDevInfo->maxOutputChannels++;
            }
            free(clientPorts);
        }

        /* Add this client to the list of devices */
        commonApi->deviceInfos[client_index] = curDevInfo;
        ++commonApi->info.deviceCount;
        if( commonApi->info.defaultInputDevice == paNoDevice && curDevInfo->maxInputChannels > 0 )
            commonApi->info.defaultInputDevice = client_index;
        if( commonApi->info.defaultOutputDevice == paNoDevice && curDevInfo->maxOutputChannels > 0 )
            commonApi->info.defaultOutputDevice = client_index;
    }

error:
    regfree( &port_regex );
    free( jack_ports );
    return result;
}

static void UpdateSampleRate( PaJackStream *stream, double sampleRate )
{
    /* XXX: Maybe not the cleanest way of going about this? */
    stream->cpuLoadMeasurer.samplingPeriod = stream->bufferProcessor.samplePeriod = 1. / sampleRate;
    stream->streamRepresentation.streamInfo.sampleRate = sampleRate;
}

static void JackErrorCallback( const char *msg )
{
    if( pthread_self() == mainThread_ )
    {
        assert( msg );
        jackErr_ = realloc( jackErr_, strlen( msg ) + 1 );
        strcpy( jackErr_, msg );
    }
}

static void JackOnShutdown( void *arg )
{
    PaJackHostApiRepresentation *jackApi = (PaJackHostApiRepresentation *)arg;
    PaJackStream *stream = jackApi->processQueue;

    PA_DEBUG(( "%s: JACK server is shutting down\n", __FUNCTION__ ));
    for( ; stream; stream = stream->next )
    {
        stream->is_active = 0;
    }

    /* Make sure that the main thread doesn't get stuck waiting on the condition */
    ASSERT_CALL( pthread_mutex_lock( &jackApi->mtx ), 0 );
    jackApi->jackIsDown = 1;
    ASSERT_CALL( pthread_cond_signal( &jackApi->cond ), 0 );
    ASSERT_CALL( pthread_mutex_unlock( &jackApi->mtx ), 0 );

}

static int JackSrCb( jack_nframes_t nframes, void *arg )
{
    PaJackHostApiRepresentation *jackApi = (PaJackHostApiRepresentation *)arg;
    double sampleRate = (double)nframes;
    PaJackStream *stream = jackApi->processQueue;

    /* Update all streams in process queue */
    PA_DEBUG(( "%s: Acting on change in JACK samplerate: %f\n", __FUNCTION__, sampleRate ));
    for( ; stream; stream = stream->next )
    {
        if( stream->streamRepresentation.streamInfo.sampleRate != sampleRate )
        {
            PA_DEBUG(( "%s: Updating samplerate\n", __FUNCTION__ ));
            UpdateSampleRate( stream, sampleRate );
        }
    }

    return 0;
}

static int JackXRunCb(void *arg) {
    PaJackHostApiRepresentation *hostApi = (PaJackHostApiRepresentation *)arg;
    assert( hostApi );
    hostApi->xrun = TRUE;
    PA_DEBUG(( "%s: JACK signalled xrun\n", __FUNCTION__ ));