i3status/src/pulse.c

// vim:ts=4:sw=4:expandtab
#include <string.h>
#include <stdio.h>
#include <pulse/pulseaudio.h>
#include "i3status.h"
#include "queue.h"

#define APP_NAME "i3status"
#define APP_ID "org.i3wm"

typedef struct indexed_volume_s {
    uint32_t idx;
    int volume;
    TAILQ_ENTRY(indexed_volume_s) entries;
} indexed_volume_t;

static pa_threaded_mainloop *main_loop = NULL;
static pa_context *context = NULL;
static pa_mainloop_api *api = NULL;
static bool context_ready = false;
static uint32_t default_sink_idx = DEFAULT_SINK_INDEX;
TAILQ_HEAD(tailhead, indexed_volume_s) cached_volume =
    TAILQ_HEAD_INITIALIZER(cached_volume);
static pthread_mutex_t pulse_mutex = PTHREAD_MUTEX_INITIALIZER;

static void pulseaudio_error_log(pa_context *c) {
    fprintf(stderr,
            "i3status: PulseAudio: %s\n",
            pa_strerror(pa_context_errno(c)));
}

static bool pulseaudio_free_operation(pa_context *c, pa_operation *o) {
    if (o)
        pa_operation_unref(o);
    else
        pulseaudio_error_log(c);
    /* return false if the operation failed */
    return o;
}

/*
 * save the volume for the specified sink index
 * returning true if the value was changed
 */
static bool save_volume(uint32_t sink_idx, int new_volume) {
    pthread_mutex_lock(&pulse_mutex);
    indexed_volume_t *entry;
    TAILQ_FOREACH(entry, &cached_volume, entries) {
        if (entry->idx == sink_idx) {
            const bool changed = (new_volume != entry->volume);
            entry->volume = new_volume;
            pthread_mutex_unlock(&pulse_mutex);
            return changed;
        }
    }
    /* index not found, store it */
    entry = malloc(sizeof(*entry));
    TAILQ_INSERT_HEAD(&cached_volume, entry, entries);
    entry->idx = sink_idx;
    entry->volume = new_volume;
    pthread_mutex_unlock(&pulse_mutex);
    return true;
}

static void store_volume_from_sink_cb(pa_context *c,
                                      const pa_sink_info *info,
                                      int eol,
                                      void *userdata) {
    if (eol < 0) {
        if (pa_context_errno(c) == PA_ERR_NOENTITY)
            return;

        pulseaudio_error_log(c);
        return;
    }

    if (eol > 0)
        return;

    int avg_vol = pa_cvolume_avg(&info->volume);
    int vol_perc = (int)((long long)avg_vol * 100 / PA_VOLUME_NORM);

    /* if this is the default sink we must try to save it twice: once with
     * DEFAULT_SINK_INDEX as the index, and another with its proper value
     * (using bitwise OR to avoid early-out logic) */
    if ((info->index == default_sink_idx &&
         save_volume(DEFAULT_SINK_INDEX, vol_perc)) |
        save_volume(info->index, vol_perc)) {
        /* if the volume changed, wake the main thread */
        pthread_mutex_lock(&i3status_sleep_mutex);
        pthread_cond_broadcast(&i3status_sleep_cond);
        pthread_mutex_unlock(&i3status_sleep_mutex);
    }
}

static void get_sink_info(pa_context *c, uint32_t idx) {
    pa_operation *o =
        idx == DEFAULT_SINK_INDEX ? pa_context_get_sink_info_by_name(
                                        c, "@DEFAULT_SINK@", store_volume_from_sink_cb, NULL)
                                  : pa_context_get_sink_info_by_index(
                                        c, idx, store_volume_from_sink_cb, NULL);
    pulseaudio_free_operation(c, o);
}

static void store_default_sink_cb(pa_context *c,
                                  const pa_sink_info *i,
                                  int eol,
                                  void *userdata) {
    if (i) {
        if (default_sink_idx != i->index) {
            /* default sink changed? */
            default_sink_idx = i->index;
            store_volume_from_sink_cb(c, i, eol, userdata);
        }
    }
}

static void update_default_sink(pa_context *c) {
    pa_operation *o = pa_context_get_sink_info_by_name(
        c,
        "@DEFAULT_SINK@",
        store_default_sink_cb,
        NULL);
    pulseaudio_free_operation(c, o);
}

static void subscribe_cb(pa_context *c, pa_subscription_event_type_t t,
                         uint32_t idx, void *userdata) {
    if ((t & PA_SUBSCRIPTION_EVENT_TYPE_MASK) != PA_SUBSCRIPTION_EVENT_CHANGE)
        return;
    pa_subscription_event_type_t facility =
        t & PA_SUBSCRIPTION_EVENT_FACILITY_MASK;
    switch (facility) {
        case PA_SUBSCRIPTION_EVENT_SERVER:
            /* server change event, see if the default sink changed */
            update_default_sink(c);
            break;
        case PA_SUBSCRIPTION_EVENT_SINK:
            get_sink_info(c, idx);
            break;
        default:
            break;
    }
}

static void context_state_callback(pa_context *c, void *userdata) {
    switch (pa_context_get_state(c)) {
        case PA_CONTEXT_UNCONNECTED:
        case PA_CONTEXT_CONNECTING:
        case PA_CONTEXT_AUTHORIZING:
        case PA_CONTEXT_SETTING_NAME:
        case PA_CONTEXT_TERMINATED:
        default:
            break;

        case PA_CONTEXT_READY: {
            pa_context_set_subscribe_callback(c, subscribe_cb, NULL);
            update_default_sink(c);

            pa_operation *o = pa_context_subscribe(
                c,
                PA_SUBSCRIPTION_MASK_SINK | PA_SUBSCRIPTION_MASK_SERVER,
                NULL,
                NULL);
            if (!pulseaudio_free_operation(c, o))
                break;
            context_ready = true;
        } break;

        case PA_CONTEXT_FAILED:
            pulseaudio_error_log(c);
            break;
    }
}

/*
 * returns the current volume in percent, which, as per PulseAudio,
 * may be > 100%
 */
int volume_pulseaudio(uint32_t sink_idx) {
    if (!context_ready || default_sink_idx == DEFAULT_SINK_INDEX)
        return -1;

    pthread_mutex_lock(&pulse_mutex);
    const indexed_volume_t *entry;
    TAILQ_FOREACH(entry, &cached_volume, entries) {
        if (entry->idx == sink_idx) {
            int vol = entry->volume;
            pthread_mutex_unlock(&pulse_mutex);
            return vol;
        }
    }
    pthread_mutex_unlock(&pulse_mutex);
    /* first time requires a prime callback call because we only get
     * updates when the volume actually changes, but we need it to
     * be correct even if it never changes */
    pa_threaded_mainloop_lock(main_loop);
    get_sink_info(context, sink_idx);
    pa_threaded_mainloop_unlock(main_loop);
    /* show 0 while we don't have this information */
    return 0;
}

/*
 *  detect and, if necessary, initialize the PulseAudio API
 */
bool pulse_initialize(void) {
    if (!main_loop) {
        main_loop = pa_threaded_mainloop_new();
        if (!main_loop)
            return false;
    }
    if (!api) {
        api = pa_threaded_mainloop_get_api(main_loop);
        if (!api)
            return false;
    }
    if (!context) {
        pa_proplist *proplist = pa_proplist_new();
        pa_proplist_sets(proplist, PA_PROP_APPLICATION_NAME, APP_NAME);
        pa_proplist_sets(proplist, PA_PROP_APPLICATION_ID, APP_ID);
        pa_proplist_sets(proplist, PA_PROP_APPLICATION_VERSION, VERSION);
        context = pa_context_new_with_proplist(api, APP_NAME, proplist);
        pa_proplist_free(proplist);
        if (!context)
            return false;
        pa_context_set_state_callback(context,
                                      context_state_callback,
                                      NULL);
        if (pa_context_connect(context,
                               NULL,
                               PA_CONTEXT_NOFAIL | PA_CONTEXT_NOAUTOSPAWN,
                               NULL) < 0) {
            pulseaudio_error_log(context);
            return false;
        }
        if (pa_threaded_mainloop_start(main_loop) < 0) {
            pulseaudio_error_log(context);
            pa_threaded_mainloop_free(main_loop);
            main_loop = NULL;
            return false;
        }
    }
    return true;
}