libsoundio/src/jack.c

/*
 * Copyright (c) 2015 Andrew Kelley
 *
 * This file is part of libsoundio, which is MIT licensed.
 * See http://opensource.org/licenses/MIT
 */

#include "jack.h"
#include "soundio_private.h"
#include "list.h"

#include <stdio.h>

static struct SoundIoAtomicFlag global_msg_callback_flag = SOUNDIO_ATOMIC_FLAG_INIT;

struct SoundIoJackPort {
    const char *full_name;
    int full_name_len;
    const char *name;
    int name_len;
    enum SoundIoChannelId channel_id;
    jack_latency_range_t latency_range;
};

struct SoundIoJackClient {
    const char *name;
    int name_len;
    bool is_physical;
    enum SoundIoDeviceAim aim;
    int port_count;
    struct SoundIoJackPort ports[SOUNDIO_MAX_CHANNELS];
};

SOUNDIO_MAKE_LIST_STRUCT(struct SoundIoJackClient, SoundIoListJackClient, SOUNDIO_LIST_STATIC)
SOUNDIO_MAKE_LIST_DEF(struct SoundIoJackClient, SoundIoListJackClient, SOUNDIO_LIST_STATIC)

static void split_str(const char *input_str, int input_str_len, char c,
        const char **out_1, int *out_len_1, const char **out_2, int *out_len_2)
{
    *out_1 = input_str;
    while (*input_str) {
        if (*input_str == c) {
            *out_len_1 = input_str - *out_1;
            *out_2 = input_str + 1;
            *out_len_2 = input_str_len - 1 - *out_len_1;
            return;
        }
        input_str += 1;
    }
}

static struct SoundIoJackClient *find_or_create_client(struct SoundIoListJackClient *clients,
        enum SoundIoDeviceAim aim, bool is_physical, const char *client_name, int client_name_len)
{
    for (int i = 0; i < clients->length; i += 1) {
        struct SoundIoJackClient *client = SoundIoListJackClient_ptr_at(clients, i);
        if (client->is_physical == is_physical &&
            client->aim == aim &&
            soundio_streql(client->name, client->name_len, client_name, client_name_len))
        {
            return client;
        }
    }
    int err;
    if ((err = SoundIoListJackClient_add_one(clients)))
        return NULL;
    struct SoundIoJackClient *client = SoundIoListJackClient_last_ptr(clients);
    client->is_physical = is_physical;
    client->aim = aim;
    client->name = client_name;
    client->name_len = client_name_len;
    client->port_count = 0;
    return client;
}

static void destruct_device(struct SoundIoDevicePrivate *dp) {
    struct SoundIoDeviceJack *dj = &dp->backend_data.jack;
    for (int i = 0; i < dj->port_count; i += 1) {
        struct SoundIoDeviceJackPort *djp = &dj->ports[i];
        free(djp->full_name);
    }
    free(dj->ports);
}

static int refresh_devices_bare(struct SoundIoPrivate *si) {
    struct SoundIo *soundio = &si->pub;
    struct SoundIoJack *sij = &si->backend_data.jack;

    if (sij->is_shutdown)
        return SoundIoErrorBackendDisconnected;


    struct SoundIoDevicesInfo *devices_info = ALLOCATE(struct SoundIoDevicesInfo, 1);
    if (!devices_info)
        return SoundIoErrorNoMem;

    devices_info->default_output_index = -1;
    devices_info->default_input_index = -1;
    const char **port_names = jack_get_ports(sij->client, NULL, NULL, 0);
    if (!port_names) {
        soundio_destroy_devices_info(devices_info);
        return SoundIoErrorNoMem;
    }

    struct SoundIoListJackClient clients = {0};
    const char **port_name_ptr = port_names;
    for (; *port_name_ptr; port_name_ptr += 1) {
        const char *client_and_port_name = *port_name_ptr;
        int client_and_port_name_len = strlen(client_and_port_name);
        jack_port_t *jport = jack_port_by_name(sij->client, client_and_port_name);
        if (!jport) {
            // This refresh devices scan is already outdated. Just give up and
            // let refresh_devices be called again.
            jack_free(port_names);
            soundio_destroy_devices_info(devices_info);
            return SoundIoErrorInterrupted;
        }

        int flags = jack_port_flags(jport);
        const char *port_type = jack_port_type(jport);
        if (strcmp(port_type, JACK_DEFAULT_AUDIO_TYPE) != 0) {
            // we don't know how to support such a port
            continue;
        }

        enum SoundIoDeviceAim aim = (flags & JackPortIsInput) ?
            SoundIoDeviceAimOutput : SoundIoDeviceAimInput;
        bool is_physical = flags & JackPortIsPhysical;

        const char *client_name = NULL;
        const char *port_name = NULL;
        int client_name_len;
        int port_name_len;
        split_str(client_and_port_name, client_and_port_name_len, ':',
                &client_name, &client_name_len, &port_name, &port_name_len);
        if (!client_name || !port_name) {
            // device does not have colon, skip it
            continue;
        }
        struct SoundIoJackClient *client = find_or_create_client(&clients, aim, is_physical,
                client_name, client_name_len);
        if (!client) {
            jack_free(port_names);
            soundio_destroy_devices_info(devices_info);
            return SoundIoErrorNoMem;
        }
        if (client->port_count >= SOUNDIO_MAX_CHANNELS) {
            // we hit the channel limit, skip the leftovers
            continue;
        }
        struct SoundIoJackPort *port = &client->ports[client->port_count++];
        port->full_name = client_and_port_name;
        port->full_name_len = client_and_port_name_len;
        port->name = port_name;
        port->name_len = port_name_len;
        port->channel_id = soundio_parse_channel_id(port_name, port_name_len);

        jack_latency_callback_mode_t latency_mode = (aim == SoundIoDeviceAimOutput) ?
            JackPlaybackLatency : JackCaptureLatency;
        jack_port_get_latency_range(jport, latency_mode, &port->latency_range);
    }

    for (int i = 0; i < clients.length; i += 1) {
        struct SoundIoJackClient *client = SoundIoListJackClient_ptr_at(&clients, i);
        if (client->port_count <= 0)
            continue;

        struct SoundIoDevicePrivate *dev = ALLOCATE(struct SoundIoDevicePrivate, 1);
        if (!dev) {
            jack_free(port_names);
            soundio_destroy_devices_info(devices_info);
            return SoundIoErrorNoMem;
        }
        struct SoundIoDevice *device = &dev->pub;
        struct SoundIoDeviceJack *dj = &dev->backend_data.jack;
        int description_len = client->name_len + 3 + 2 * client->port_count;
        for (int port_index = 0; port_index < client->port_count; port_index += 1) {
            struct SoundIoJackPort *port = &client->ports[port_index];

            description_len += port->name_len;
        }

        dev->destruct = destruct_device;

        device->ref_count = 1;
        device->soundio = soundio;
        device->is_raw = false;
        device->aim = client->aim;
        device->id = soundio_str_dupe(client->name, client->name_len);
        device->name = ALLOCATE(char, description_len);
        device->current_format = SoundIoFormatFloat32NE;
        device->sample_rate_count = 1;
        device->sample_rates = &dev->prealloc_sample_rate_range;
        device->sample_rates[0].min = sij->sample_rate;
        device->sample_rates[0].max = sij->sample_rate;
        device->sample_rate_current = sij->sample_rate;

        device->software_latency_current = sij->period_size / (double) sij->sample_rate;
        device->software_latency_min = sij->period_size / (double) sij->sample_rate;
        device->software_latency_max = sij->period_size / (double) sij->sample_rate;

        dj->port_count = client->port_count;
        dj->ports = ALLOCATE(struct SoundIoDeviceJackPort, dj->port_count);

        if (!device->id || !device->name || !dj->ports) {
            jack_free(port_names);
            soundio_device_unref(device);
            soundio_destroy_devices_info(devices_info);
            return SoundIoErrorNoMem;
        }

        for (int port_index = 0; port_index < client->port_count; port_index += 1) {
            struct SoundIoJackPort *port = &client->ports[port_index];
            struct SoundIoDeviceJackPort *djp = &dj->ports[port_index];
            djp->full_name = soundio_str_dupe(port->full_name, port->full_name_len);
            djp->full_name_len = port->full_name_len;
            djp->channel_id = port->channel_id;
            djp->latency_range = port->latency_range;

            if (!djp->full_name) {
                jack_free(port_names);
                soundio_device_unref(device);
                soundio_destroy_devices_info(devices_info);
                return SoundIoErrorNoMem;
            }
        }

        memcpy(device->name, client->name, client->name_len);
        memcpy(&device->name[client->name_len], ": ", 2);
        int index = client->name_len + 2;
        for (int port_index = 0; port_index < client->port_count; port_index += 1) {
            struct SoundIoJackPort *port = &client->ports[port_index];
            memcpy(&device->name[index], port->name, port->name_len);
            index += port->name_len;
            if (port_index + 1 < client->port_count) {
                memcpy(&device->name[index], ", ", 2);
                index += 2;
            }
        }

        device->current_layout.channel_count = client->port_count;
        bool any_invalid = false;
        for (int port_index = 0; port_index < client->port_count; port_index += 1) {
            struct SoundIoJackPort *port = &client->ports[port_index];
            device->current_layout.channels[port_index] = port->channel_id;
            any_invalid = any_invalid || (port->channel_id == SoundIoChannelIdInvalid);
        }
        if (any_invalid) {
            const struct SoundIoChannelLayout *layout = soundio_channel_layout_get_default(client->port_count);
            if (layout)
                device->current_layout = *layout;
        } else {
            soundio_channel_layout_detect_builtin(&device->current_layout);
        }

        device->layout_count = 1;
        device->layouts = &device->current_layout;
        device->format_count = 1;
        device->formats = &dev->prealloc_format;
        device->formats[0] = device->current_format;

        struct SoundIoListDevicePtr *device_list;
        if (device->aim == SoundIoDeviceAimOutput) {
            device_list = &devices_info->output_devices;
            if (devices_info->default_output_index < 0 && client->is_physical)
                devices_info->default_output_index = device_list->length;
        } else {
            assert(device->aim == SoundIoDeviceAimInput);
            device_list = &devices_info->input_devices;
            if (devices_info->default_input_index < 0 && client->is_physical)
                devices_info->default_input_index = device_list->length;
        }

        if (SoundIoListDevicePtr_append(device_list, device)) {
            soundio_device_unref(device);
            soundio_destroy_devices_info(devices_info);
            return SoundIoErrorNoMem;
        }

    }
    jack_free(port_names);

    soundio_destroy_devices_info(si->safe_devices_info);
    si->safe_devices_info = devices_info;

    return 0;
}

static int refresh_devices(struct SoundIoPrivate *si) {
    int err = SoundIoErrorInterrupted;
    while (err == SoundIoErrorInterrupted)
        err = refresh_devices_bare(si);
    return err;
}

static void my_flush_events(struct SoundIoPrivate *si, bool wait) {
    struct SoundIo *soundio = &si->pub;
    struct SoundIoJack *sij = &si->backend_data.jack;
    int err;

    bool cb_shutdown = false;

    soundio_os_mutex_lock(sij->mutex);

    if (wait)
        soundio_os_cond_wait(sij->cond, sij->mutex);

    if (sij->is_shutdown && !sij->emitted_shutdown_cb) {
        sij->emitted_shutdown_cb = true;
        cb_shutdown = true;
    }

    soundio_os_mutex_unlock(sij->mutex);

    if (cb_shutdown) {
        soundio->on_backend_disconnect(soundio, SoundIoErrorBackendDisconnected);
    } else {
        if (!SOUNDIO_ATOMIC_FLAG_TEST_AND_SET(sij->refresh_devices_flag)) {
            if ((err = refresh_devices(si))) {
                SOUNDIO_ATOMIC_FLAG_CLEAR(sij->refresh_devices_flag);
            } else {
                soundio->on_devices_change(soundio);
            }
        }
    }
}

static void flush_events_jack(struct SoundIoPrivate *si) {
    my_flush_events(si, false);
}

static void wait_events_jack(struct SoundIoPrivate *si) {
    my_flush_events(si, false);
    my_flush_events(si, true);
}

static void wakeup_jack(struct SoundIoPrivate *si) {
    struct SoundIoJack *sij = &si->backend_data.jack;
    soundio_os_mutex_lock(sij->mutex);
    soundio_os_cond_signal(sij->cond, sij->mutex);
    soundio_os_mutex_unlock(sij->mutex);
}

static void force_device_scan_jack(struct SoundIoPrivate *si) {
    struct SoundIo *soundio = &si->pub;
    struct SoundIoJack *sij = &si->backend_data.jack;
    SOUNDIO_ATOMIC_FLAG_CLEAR(sij->refresh_devices_flag);
    soundio_os_mutex_lock(sij->mutex);
    soundio_os_cond_signal(sij->cond, sij->mutex);
    soundio->on_events_signal(soundio);
    soundio_os_mutex_unlock(sij->mutex);
}

static int outstream_process_callback(jack_nframes_t nframes, void *arg) {
    struct SoundIoOutStreamPrivate *os = (struct SoundIoOutStreamPrivate *)arg;
    struct SoundIoOutStreamJack *osj = &os->backend_data.jack;
    struct SoundIoOutStream *outstream = &os->pub;
    osj->frames_left = nframes;
    for (int ch = 0; ch < outstream->layout.channel_count; ch += 1) {
        struct SoundIoOutStreamJackPort *osjp = &osj->ports[ch];
        osj->areas[ch].ptr = (char*)jack_port_get_buffer(osjp->source_port, nframes);
        osj->areas[ch].step = outstream->bytes_per_sample;
    }
    outstream->write_callback(outstream, osj->frames_left, osj->frames_left);
    return 0;
}

static void outstream_destroy_jack(struct SoundIoPrivate *is, struct SoundIoOutStreamPrivate *os) {
    struct SoundIoOutStreamJack *osj = &os->backend_data.jack;

    jack_client_close(osj->client);
    osj->client = NULL;
}

static struct SoundIoDeviceJackPort *find_port_matching_channel(struct SoundIoDevice *device, enum SoundIoChannelId id) {
    struct SoundIoDevicePrivate *dev = (struct SoundIoDevicePrivate *)device;
    struct SoundIoDeviceJack *dj = &dev->backend_data.jack;

    for (int ch = 0; ch < device->current_layout.channel_count; ch += 1) {
        enum SoundIoChannelId chan_id = device->current_layout.channels[ch];
        if (chan_id == id)
            return &dj->ports[ch];
    }

    return NULL;
}

static int outstream_xrun_callback(void *arg) {
    struct SoundIoOutStreamPrivate *os = (struct SoundIoOutStreamPrivate *)arg;
    struct SoundIoOutStream *outstream = &os->pub;
    outstream->underflow_callback(outstream);
    return 0;
}

static int outstream_buffer_size_callback(jack_nframes_t nframes, void *arg) {
    struct SoundIoOutStreamPrivate *os = (struct SoundIoOutStreamPrivate *)arg;
    struct SoundIoOutStreamJack *osj = &os->backend_data.jack;
    struct SoundIoOutStream *outstream = &os->pub;
    if ((jack_nframes_t)osj->period_size == nframes) {
        return 0;
    } else {
        outstream->error_callback(outstream, SoundIoErrorStreaming);
        return -1;
    }
}

static int outstream_sample_rate_callback(jack_nframes_t nframes, void *arg) {
    struct SoundIoOutStreamPrivate *os = (struct SoundIoOutStreamPrivate *)arg;
    struct SoundIoOutStream *outstream = &os->pub;
    if (nframes == (jack_nframes_t)outstream->sample_rate) {
        return 0;
    } else {
        outstream->error_callback(outstream, SoundIoErrorStreaming);
        return -1;
    }
}

static void outstream_shutdown_callback(void *arg) {
    struct SoundIoOutStreamPrivate *os = (struct SoundIoOutStreamPrivate *)arg;
    struct SoundIoOutStream *outstream = &os->pub;
    outstream->error_callback(outstream, SoundIoErrorStreaming);
}

static inline jack_nframes_t nframes_max(jack_nframes_t a, jack_nframes_t b) {
    return (a >= b) ? a : b;
}

static int outstream_open_jack(struct SoundIoPrivate *si, struct SoundIoOutStreamPrivate *os) {
    struct SoundIoJack *sij = &si->backend_data.jack;
    struct SoundIoOutStreamJack *osj = &os->backend_data.jack;
    struct SoundIoOutStream *outstream = &os->pub;
    struct SoundIoDevice *device = outstream->device;
    struct SoundIoDevicePrivate *dev = (struct SoundIoDevicePrivate *)device;
    struct SoundIoDeviceJack *dj = &dev->backend_data.jack;

    if (sij->is_shutdown)
        return SoundIoErrorBackendDisconnected;

    if (!outstream->name)
        outstream->name = "SoundIoOutStream";

    outstream->software_latency = device->software_latency_current;
    osj->period_size = sij->period_size;

    jack_status_t status;
    osj->client = jack_client_open(outstream->name, JackNoStartServer, &status);
    if (!osj->client) {
        outstream_destroy_jack(si, os);
        assert(!(status & JackInvalidOption));
        if (status & JackShmFailure)
            return SoundIoErrorSystemResources;
        if (status & JackNoSuchClient)
            return SoundIoErrorNoSuchClient;
        return SoundIoErrorOpeningDevice;
    }

    int err;
    if ((err = jack_set_process_callback(osj->client, outstream_process_callback, os))) {
        outstream_destroy_jack(si, os);
        return SoundIoErrorOpeningDevice;
    }
    if ((err = jack_set_buffer_size_callback(osj->client, outstream_buffer_size_callback, os))) {
        outstream_destroy_jack(si, os);
        return SoundIoErrorOpeningDevice;
    }
    if ((err = jack_set_sample_rate_callback(osj->client, outstream_sample_rate_callback, os))) {
        outstream_destroy_jack(si, os);
        return SoundIoErrorOpeningDevice;
    }
    if ((err = jack_set_xrun_callback(osj->client, outstream_xrun_callback, os))) {
        outstream_destroy_jack(si, os);
        return SoundIoErrorOpeningDevice;
    }
    jack_on_shutdown(osj->client, outstream_shutdown_callback, os);


    jack_nframes_t max_port_latency = 0;

    // register ports and map channels
    int connected_count = 0;
    for (int ch = 0; ch < outstream->layout.channel_count; ch += 1) {
        enum SoundIoChannelId my_channel_id = outstream->layout.channels[ch];
        const char *channel_name = soundio_get_channel_name(my_channel_id);
        unsigned long flags = JackPortIsOutput;
        if (!outstream->non_terminal_hint)
            flags |= JackPortIsTerminal;
        jack_port_t *jport = jack_port_register(osj->client, channel_name, JACK_DEFAULT_AUDIO_TYPE, flags, 0);
        if (!jport) {
            outstream_destroy_jack(si, os);
            return SoundIoErrorOpeningDevice;
        }
        struct SoundIoOutStreamJackPort *osjp = &osj->ports[ch];
        osjp->source_port = jport;
        // figure out which dest port this connects to
        struct SoundIoDeviceJackPort *djp = find_port_matching_channel(device, my_channel_id);
        if (djp) {
            osjp->dest_port_name = djp->full_name;
            osjp->dest_port_name_len = djp->full_name_len;
            connected_count += 1;
            max_port_latency = nframes_max(max_port_latency, djp->latency_range.max);
        }
    }
    // If nothing got connected, channel layouts aren't working. Just send the
    // data in the order of the ports.
    if (connected_count == 0) {
        max_port_latency = 0;
        outstream->layout_error = SoundIoErrorIncompatibleDevice;

        int ch_count = soundio_int_min(outstream->layout.channel_count, dj->port_count);
        for (int ch = 0; ch < ch_count; ch += 1) {
            struct SoundIoOutStreamJackPort *osjp = &osj->ports[ch];
            struct SoundIoDeviceJackPort *djp = &dj->ports[ch];
            osjp->dest_port_name = djp->full_name;
            osjp->dest_port_name_len = djp->full_name_len;
            max_port_latency = nframes_max(max_port_latency, djp->latency_range.max);
        }
    }

    osj->hardware_latency = max_port_latency / (double)outstream->sample_rate;

    return 0;
}

static int outstream_pause_jack(struct SoundIoPrivate *si, struct SoundIoOutStreamPrivate *os, bool pause) {
    struct SoundIoJack *sij = &si->backend_data.jack;

    if (sij->is_shutdown)
        return SoundIoErrorBackendDisconnected;

    return SoundIoErrorIncompatibleBackend;
}

static int outstream_start_jack(struct SoundIoPrivate *si, struct SoundIoOutStreamPrivate *os) {
    struct SoundIoOutStreamJack *osj = &os->backend_data.jack;
    struct SoundIoOutStream *outstream = &os->pub;
    struct SoundIoJack *sij = &si->backend_data.jack;
    int err;

    if (sij->is_shutdown)
        return SoundIoErrorBackendDisconnected;

    if ((err = jack_activate(osj->client)))
        return SoundIoErrorStreaming;

    for (int ch = 0; ch < outstream->layout.channel_count; ch += 1) {
        struct SoundIoOutStreamJackPort *osjp = &osj->ports[ch];
        const char *dest_port_name = osjp->dest_port_name;
        // allow unconnected ports
        if (!dest_port_name)
            continue;
        const char *source_port_name = jack_port_name(osjp->source_port);
        if ((err = jack_connect(osj->client, source_port_name, dest_port_name)))
            return SoundIoErrorStreaming;
    }

    return 0;
}

static int outstream_begin_write_jack(struct SoundIoPrivate *si, struct SoundIoOutStreamPrivate *os,
        struct SoundIoChannelArea **out_areas, int *frame_count)
{
    struct SoundIoOutStreamJack *osj = &os->backend_data.jack;

    if (*frame_count != osj->frames_left)
        return SoundIoErrorInvalid;

    *out_areas = osj->areas;

    return 0;
}

static int outstream_end_write_jack(struct SoundIoPrivate *si, struct SoundIoOutStreamPrivate *os) {
    struct SoundIoOutStreamJack *osj = &os->backend_data.jack;
    osj->frames_left = 0;
    return 0;
}

static int outstream_clear_buffer_jack(struct SoundIoPrivate *si, struct SoundIoOutStreamPrivate *os) {
    return SoundIoErrorIncompatibleBackend;
}

static int outstream_get_latency_jack(struct SoundIoPrivate *si, struct SoundIoOutStreamPrivate *os,
        double *out_latency)
{
    struct SoundIoOutStreamJack *osj = &os->backend_data.jack;
    *out_latency = osj->hardware_latency;
    return 0;
}


static void instream_destroy_jack(struct SoundIoPrivate *si, struct SoundIoInStreamPrivate *is) {
    struct SoundIoInStreamJack *isj = &is->backend_data.jack;

    jack_client_close(isj->client);
    isj->client = NULL;
}

static int instream_xrun_callback(void *arg) {
    struct SoundIoInStreamPrivate *is = (struct SoundIoInStreamPrivate *)arg;
    struct SoundIoInStream *instream = &is->pub;
    instream->overflow_callback(instream);
    return 0;
}

static int instream_buffer_size_callback(jack_nframes_t nframes, void *arg) {
    struct SoundIoInStreamPrivate *is = (struct SoundIoInStreamPrivate *)arg;
    struct SoundIoInStreamJack *isj = &is->backend_data.jack;
    struct SoundIoInStream *instream = &is->pub;

    if ((jack_nframes_t)isj->period_size == nframes) {
        return 0;
    } else {
        instream->error_callback(instream, SoundIoErrorStreaming);
        return -1;
    }
}

static int instream_sample_rate_callback(jack_nframes_t nframes, void *arg) {
    struct SoundIoInStreamPrivate *is = (struct SoundIoInStreamPrivate *)arg;
    struct SoundIoInStream *instream = &is->pub;
    if (nframes == (jack_nframes_t)instream->sample_rate) {
        return 0;
    } else {
        instream->error_callback(instream, SoundIoErrorStreaming);
        return -1;
    }
}

static void instream_shutdown_callback(void *arg) {
    struct SoundIoInStreamPrivate *is = (struct SoundIoInStreamPrivate *)arg;
    struct SoundIoInStream *instream = &is->pub;
    instream->error_callback(instream, SoundIoErrorStreaming);
}

static int instream_process_callback(jack_nframes_t nframes, void *arg) {
    struct SoundIoInStreamPrivate *is = (struct SoundIoInStreamPrivate *)arg;
    struct SoundIoInStream *instream = &is->pub;
    struct SoundIoInStreamJack *isj = &is->backend_data.jack;
    isj->frames_left = nframes;
    for (int ch = 0; ch < instream->layout.channel_count; ch += 1) {
        struct SoundIoInStreamJackPort *isjp = &isj->ports[ch];
        isj->areas[ch].ptr = (char*)jack_port_get_buffer(isjp->dest_port, nframes);
        isj->areas[ch].step = instream->bytes_per_sample;
    }
    instream->read_callback(instream, isj->frames_left, isj->frames_left);
    return 0;
}

static int instream_open_jack(struct SoundIoPrivate *si, struct SoundIoInStreamPrivate *is) {
    struct SoundIoInStream *instream = &is->pub;
    struct SoundIoInStreamJack *isj = &is->backend_data.jack;
    struct SoundIoJack *sij = &si->backend_data.jack;
    struct SoundIoDevice *device = instream->device;
    struct SoundIoDevicePrivate *dev = (struct SoundIoDevicePrivate *)device;
    struct SoundIoDeviceJack *dj = &dev->backend_data.jack;

    if (sij->is_shutdown)
        return SoundIoErrorBackendDisconnected;

    if (!instream->name)
        instream->name = "SoundIoInStream";

    instream->software_latency = device->software_latency_current;
    isj->period_size = sij->period_size;

    jack_status_t status;
    isj->client = jack_client_open(instream->name, JackNoStartServer, &status);
    if (!isj->client) {
        instream_destroy_jack(si, is);
        assert(!(status & JackInvalidOption));
        if (status & JackShmFailure)
            return SoundIoErrorSystemResources;
        if (status & JackNoSuchClient)
            return SoundIoErrorNoSuchClient;
        return SoundIoErrorOpeningDevice;
    }

    int err;
    if ((err = jack_set_process_callback(isj->client, instream_process_callback, is))) {
        instream_destroy_jack(si, is);
        return SoundIoErrorOpeningDevice;
    }
    if ((err = jack_set_buffer_size_callback(isj->client, instream_buffer_size_callback, is))) {
        instream_destroy_jack(si, is);
        return SoundIoErrorOpeningDevice;
    }
    if ((err = jack_set_sample_rate_callback(isj->client, instream_sample_rate_callback, is))) {
        instream_destroy_jack(si, is);
        return SoundIoErrorOpeningDevice;
    }
    if ((err = jack_set_xrun_callback(isj->client, instream_xrun_callback, is))) {
        instream_destroy_jack(si, is);
        return SoundIoErrorOpeningDevice;
    }
    jack_on_shutdown(isj->client, instream_shutdown_callback, is);

    jack_nframes_t max_port_latency = 0;

    // register ports and map channels
    int connected_count = 0;
    for (int ch = 0; ch < instream->layout.channel_count; ch += 1) {
        enum SoundIoChannelId my_channel_id = instream->layout.channels[ch];
        const char *channel_name = soundio_get_channel_name(my_channel_id);
        unsigned long flags = JackPortIsInput;
        if (!instream->non_terminal_hint)
            flags |= JackPortIsTerminal;
        jack_port_t *jport = jack_port_register(isj->client, channel_name, JACK_DEFAULT_AUDIO_TYPE, flags, 0);
        if (!jport) {
            instream_destroy_jack(si, is);
            return SoundIoErrorOpeningDevice;
        }
        struct SoundIoInStreamJackPort *isjp = &isj->ports[ch];
        isjp->dest_port = jport;
        // figure out which source port this connects to
        struct SoundIoDeviceJackPort *djp = find_port_matching_channel(device, my_channel_id);
        if (djp) {
            isjp->source_port_name = djp->full_name;
            isjp->source_port_name_len = djp->full_name_len;
            connected_count += 1;
            max_port_latency = nframes_max(max_port_latency, djp->latency_range.max);
        }
    }
    // If nothing got connected, channel layouts aren't working. Just send the
    // data in the order of the ports.
    if (connected_count == 0) {
        max_port_latency = 0;
        instream->layout_error = SoundIoErrorIncompatibleDevice;

        int ch_count = soundio_int_min(instream->layout.channel_count, dj->port_count);
        for (int ch = 0; ch < ch_count; ch += 1) {
            struct SoundIoInStreamJackPort *isjp = &isj->ports[ch];
            struct SoundIoDeviceJackPort *djp = &dj->ports[ch];
            isjp->source_port_name = djp->full_name;
            isjp->source_port_name_len = djp->full_name_len;
            max_port_latency = nframes_max(max_port_latency, djp->latency_range.max);
        }
    }

    isj->hardware_latency = max_port_latency / (double)instream->sample_rate;

    return 0;
}

static int instream_pause_jack(struct SoundIoPrivate *si, struct SoundIoInStreamPrivate *is, bool pause) {
    struct SoundIoJack *sij = &si->backend_data.jack;

    if (sij->is_shutdown)
        return SoundIoErrorBackendDisconnected;

    return SoundIoErrorIncompatibleBackend;
}

static int instream_start_jack(struct SoundIoPrivate *si, struct SoundIoInStreamPrivate *is) {
    struct SoundIoInStreamJack *isj = &is->backend_data.jack;
    struct SoundIoInStream *instream = &is->pub;
    struct SoundIoJack *sij = &si->backend_data.jack;
    int err;

    if (sij->is_shutdown)
        return SoundIoErrorBackendDisconnected;

    if ((err = jack_activate(isj->client)))
        return SoundIoErrorStreaming;

    for (int ch = 0; ch < instream->layout.channel_count; ch += 1) {
        struct SoundIoInStreamJackPort *isjp = &isj->ports[ch];
        const char *source_port_name = isjp->source_port_name;
        // allow unconnected ports
        if (!source_port_name)
            continue;
        const char *dest_port_name = jack_port_name(isjp->dest_port);
        if ((err = jack_connect(isj->client, source_port_name, dest_port_name)))
            return SoundIoErrorStreaming;
    }

    return 0;
}

static int instream_begin_read_jack(struct SoundIoPrivate *si, struct SoundIoInStreamPrivate *is,
        struct SoundIoChannelArea **out_areas, int *frame_count)
{
    struct SoundIoInStreamJack *isj = &is->backend_data.jack;

    if (*frame_count != isj->frames_left)
        return SoundIoErrorInvalid;

    *out_areas = isj->areas;

    return 0;
}

static int instream_end_read_jack(struct SoundIoPrivate *si, struct SoundIoInStreamPrivate *is) {
    struct SoundIoInStreamJack *isj = &is->backend_data.jack;
    isj->frames_left = 0;
    return 0;
}

static int instream_get_latency_jack(struct SoundIoPrivate *si, struct SoundIoInStreamPrivate *is,
        double *out_latency)
{
    struct SoundIoInStreamJack *isj = &is->backend_data.jack;
    *out_latency = isj->hardware_latency;
    return 0;
}

static void notify_devices_change(struct SoundIoPrivate *si) {
    struct SoundIo *soundio = &si->pub;
    struct SoundIoJack *sij = &si->backend_data.jack;
    SOUNDIO_ATOMIC_FLAG_CLEAR(sij->refresh_devices_flag);
    soundio_os_mutex_lock(sij->mutex);
    soundio_os_cond_signal(sij->cond, sij->mutex);
    soundio->on_events_signal(soundio);
    soundio_os_mutex_unlock(sij->mutex);
}

static int buffer_size_callback(jack_nframes_t nframes, void *arg) {
    struct SoundIoPrivate *si = (struct SoundIoPrivate *)arg;
    struct SoundIoJack *sij = &si->backend_data.jack;
    sij->period_size = nframes;
    notify_devices_change(si);
    return 0;
}

static int sample_rate_callback(jack_nframes_t nframes, void *arg) {
    struct SoundIoPrivate *si = (struct SoundIoPrivate *)arg;
    struct SoundIoJack *sij = &si->backend_data.jack;
    sij->sample_rate = nframes;
    notify_devices_change(si);
    return 0;
}

static void port_registration_callback(jack_port_id_t port_id, int reg, void *arg) {
    struct SoundIoPrivate *si = (struct SoundIoPrivate *)arg;
    notify_devices_change(si);
}

static void port_rename_calllback(jack_port_id_t port_id,
        const char *old_name, const char *new_name, void *arg)
{
    struct SoundIoPrivate *si = (struct SoundIoPrivate *)arg;
    notify_devices_change(si);
}

static void shutdown_callback(void *arg) {
    struct SoundIoPrivate *si = (struct SoundIoPrivate *)arg;
    struct SoundIo *soundio = &si->pub;
    struct SoundIoJack *sij = &si->backend_data.jack;
    soundio_os_mutex_lock(sij->mutex);
    sij->is_shutdown = true;
    soundio_os_cond_signal(sij->cond, sij->mutex);
    soundio->on_events_signal(soundio);
    soundio_os_mutex_unlock(sij->mutex);
}

static void destroy_jack(struct SoundIoPrivate *si) {
    struct SoundIoJack *sij = &si->backend_data.jack;

    if (sij->client)
        jack_client_close(sij->client);

    if (sij->cond)
        soundio_os_cond_destroy(sij->cond);

    if (sij->mutex)
        soundio_os_mutex_destroy(sij->mutex);
}

int soundio_jack_init(struct SoundIoPrivate *si) {
    struct SoundIoJack *sij = &si->backend_data.jack;
    struct SoundIo *soundio = &si->pub;

    if (!SOUNDIO_ATOMIC_FLAG_TEST_AND_SET(global_msg_callback_flag)) {
        if (soundio->jack_error_callback)
            jack_set_error_function(soundio->jack_error_callback);
        if (soundio->jack_info_callback)
            jack_set_info_function(soundio->jack_info_callback);
        SOUNDIO_ATOMIC_FLAG_CLEAR(global_msg_callback_flag);
    }

    sij->mutex = soundio_os_mutex_create();
    if (!sij->mutex) {
        destroy_jack(si);
        return SoundIoErrorNoMem;
    }

    sij->cond = soundio_os_cond_create();
    if (!sij->cond) {
        destroy_jack(si);
        return SoundIoErrorNoMem;
    }

    // We pass JackNoStartServer due to
    // https://github.com/jackaudio/jack2/issues/138
    jack_status_t status;
    sij->client = jack_client_open(soundio->app_name, JackNoStartServer, &status);
    if (!sij->client) {
        destroy_jack(si);
        assert(!(status & JackInvalidOption));
        if (status & JackShmFailure)
            return SoundIoErrorSystemResources;
        if (status & JackNoSuchClient)
            return SoundIoErrorNoSuchClient;

        return SoundIoErrorInitAudioBackend;
    }

    int err;
    if ((err = jack_set_buffer_size_callback(sij->client, buffer_size_callback, si))) {
        destroy_jack(si);
        return SoundIoErrorInitAudioBackend;
    }
    if ((err = jack_set_sample_rate_callback(sij->client, sample_rate_callback, si))) {
        destroy_jack(si);
        return SoundIoErrorInitAudioBackend;
    }
    if ((err = jack_set_port_registration_callback(sij->client, port_registration_callback, si))) {
        destroy_jack(si);
        return SoundIoErrorInitAudioBackend;
    }
    if ((err = jack_set_port_rename_callback(sij->client, port_rename_calllback, si))) {
        destroy_jack(si);
        return SoundIoErrorInitAudioBackend;
    }
    jack_on_shutdown(sij->client, shutdown_callback, si);

    SOUNDIO_ATOMIC_FLAG_CLEAR(sij->refresh_devices_flag);
    sij->period_size = jack_get_buffer_size(sij->client);
    sij->sample_rate = jack_get_sample_rate(sij->client);

    if ((err = jack_activate(sij->client))) {
        destroy_jack(si);
        return SoundIoErrorInitAudioBackend;
    }

    if ((err = refresh_devices(si))) {
        destroy_jack(si);
        return err;
    }

    si->destroy = destroy_jack;
    si->flush_events = flush_events_jack;
    si->wait_events = wait_events_jack;
    si->wakeup = wakeup_jack;
    si->force_device_scan = force_device_scan_jack;

    si->outstream_open = outstream_open_jack;
    si->outstream_destroy = outstream_destroy_jack;
    si->outstream_start = outstream_start_jack;
    si->outstream_begin_write = outstream_begin_write_jack;
    si->outstream_end_write = outstream_end_write_jack;
    si->outstream_clear_buffer = outstream_clear_buffer_jack;
    si->outstream_pause = outstream_pause_jack;
    si->outstream_get_latency = outstream_get_latency_jack;

    si->instream_open = instream_open_jack;
    si->instream_destroy = instream_destroy_jack;
    si->instream_start = instream_start_jack;
    si->instream_begin_read = instream_begin_read_jack;
    si->instream_end_read = instream_end_read_jack;
    si->instream_pause = instream_pause_jack;
    si->instream_get_latency = instream_get_latency_jack;

    return 0;
}