dwmblocks/pulse-listener.c

#include "pulse-listener.h"

#include <pulse/pulseaudio.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <signal.h>
#include <limits.h>

#define ERROR(...) fprintf(stderr, "error: " __VA_ARGS__)

#ifdef __OpenBSD__
#define SIGMAX     (SIGUSR2 - 1)
#define SIGMIN     (SIGUSR1 - 1)
#else
#define SIGMAX     SIGRTMAX
#define SIGMIN     SIGRTMIN
#endif

static void sink_info_callback(pa_context *ctx, const pa_sink_info *info,
                               int eol, pthread_t *main_thread) {
    pthread_kill(*main_thread, SIGMIN + 1);
}

static void server_info_callback(pa_context *ctx, const pa_server_info *info,
                                 pthread_t *main_thread) {
    pa_operation *op = pa_context_get_sink_info_by_name(
            ctx,
            info->default_sink_name,
            (pa_sink_info_cb_t) sink_info_callback,
            main_thread);
    pa_operation_unref(op);
}

static void subscribe_callback(pa_context *ctx,
                               pa_subscription_event_type_t type, uint32_t idx,
                               pthread_t *main_thread) {
    if ((type & PA_SUBSCRIPTION_EVENT_FACILITY_MASK) == PA_SUBSCRIPTION_EVENT_SINK) {
        pa_operation *op = pa_context_get_sink_info_by_index(ctx,
                           idx,
                           (pa_sink_info_cb_t) sink_info_callback,
                           main_thread);
        pa_operation_unref(op);
    }
}

static void state_callback(pa_context *ctx, pthread_t *main_thread) {
    pa_operation *op;
    switch (pa_context_get_state(ctx)) {
    case PA_CONTEXT_READY:
        op = pa_context_get_server_info(ctx,
                                        (pa_server_info_cb_t) server_info_callback,
                                        main_thread);
        pa_operation_unref(op);
        pa_context_set_subscribe_callback(ctx,
                                          (pa_context_subscribe_cb_t) subscribe_callback,
                                          main_thread);
        op = pa_context_subscribe(ctx, PA_SUBSCRIPTION_MASK_SINK, NULL, NULL);
        pa_operation_unref(op);
        break;
    case PA_CONTEXT_FAILED:
        pthread_kill(*main_thread, SIGMIN + 1);
        break;
    default:
        break;
    }
}

static void cleanup(void *data_to_free[2]) {
    pa_context_unref(data_to_free[1]);
    pa_mainloop_free(data_to_free[0]);
}

void pulse_listener_main(pthread_t *main_thread) {
    pthread_setcanceltype(PTHREAD_CANCEL_DISABLE, NULL);
    pa_mainloop *mainloop = pa_mainloop_new();
    if (!mainloop) {
        ERROR("could not create pulse mainloop\n");
        return;
    }
    pa_mainloop_api *api = pa_mainloop_get_api(mainloop);
    if (!api) {
        ERROR("could not create pulse mainloop api\n");
        return;
    }
    pa_context *context = pa_context_new(api, "dwmblocks-listener");
    if (!context) {
        ERROR("could not create pulse context\n");
        return;
    }
    pa_context_set_state_callback(context,
                                  (pa_context_notify_cb_t)&state_callback,
                                  main_thread);
    if (pa_context_connect(context, NULL, PA_CONTEXT_NOAUTOSPAWN, NULL) < 0) {
        ERROR("could not connect to pulse\n");
        return;
    }
    void *data_to_free[2] = { mainloop, context };
    pthread_cleanup_push((void(*)(void *)) cleanup, data_to_free);
    pthread_setcanceltype(PTHREAD_CANCEL_ENABLE, NULL);
    pa_mainloop_run(mainloop, NULL);
    pthread_cleanup_pop(1);
}