export-spa.c

Exporting and loading a SPA node, using Core API.

/* PipeWire */
/* SPDX-FileCopyrightText: Copyright © 2018 Wim Taymans */
/* SPDX-License-Identifier: MIT */
 
/*
 [title]
 Exporting and loading a SPA node, using \ref api_pw_core.
 [title]
 */
 
#include <stdio.h>
#include <sys/mman.h>
#include <signal.h>
 
#include <spa/utils/result.h>
#include <spa/param/video/format-utils.h>
#include <spa/param/props.h>
 
#include <pipewire/impl.h>
 
struct data {
        struct pw_main_loop *loop;
 
        struct pw_context *context;
 
        struct pw_core *core;
        struct spa_hook core_listener;
 
        struct spa_node *node;
        const char *library;
        const char *factory;
        const char *path;
 
        struct pw_proxy *proxy;
        struct spa_hook proxy_listener;
        uint32_t id;
};
 
static void proxy_event_bound(void *_data, uint32_t global_id)
{
        struct data *data = _data;
        if (data->id != global_id) {
                printf("node id: %u\n", global_id);
                data->id = global_id;
        }
}
 
static const struct pw_proxy_events proxy_events = {
        PW_VERSION_PROXY_EVENTS,
        .bound = proxy_event_bound,
};
 
static int make_node(struct data *data)
{
        struct pw_properties *props;
        struct spa_handle *hndl;
        void *iface;
        int res;
 
        props = pw_properties_new(SPA_KEY_LIBRARY_NAME, data->library,
                                  SPA_KEY_FACTORY_NAME, data->factory,
                                  NULL);
 
 
        hndl = pw_context_load_spa_handle(data->context, data->factory, &props->dict);
        if (hndl == NULL)
                return -errno;
 
        if ((res = spa_handle_get_interface(hndl, SPA_TYPE_INTERFACE_Node, &iface)) < 0)
                return res;
 
        data->node = iface;
 
        if (data->path) {
                pw_properties_set(props, PW_KEY_NODE_AUTOCONNECT, "true");
                pw_properties_set(props, PW_KEY_TARGET_OBJECT, data->path);
        }
 
        data->proxy = pw_core_export(data->core,
                        SPA_TYPE_INTERFACE_Node, &props->dict,
                        data->node, 0);
        pw_properties_free(props);
 
        if (data->proxy == NULL)
                return -errno;
 
        pw_proxy_add_listener(data->proxy,
                        &data->proxy_listener, &proxy_events, data);
 
        return 0;
}
 
static void on_core_error(void *data, uint32_t id, int seq, int res, const char *message)
{
        struct data *d = data;
 
        pw_log_error("error id:%u seq:%d res:%d (%s): %s",
                        id, seq, res, spa_strerror(res), message);
 
        if (id == PW_ID_CORE)
                pw_main_loop_quit(d->loop);
}
 
static const struct pw_core_events core_events = {
        PW_VERSION_CORE_EVENTS,
        .error = on_core_error,
};
 
static void do_quit(void *data, int signal_number)
{
        struct data *d = data;
        pw_main_loop_quit(d->loop);
}
 
int main(int argc, char *argv[])
{
        struct data data = { 0, };
        struct pw_loop *l;
 
        pw_init(&argc, &argv);
 
        if (argc < 3) {
                fprintf(stderr, "usage: %s <library> <factory> [path]\n\n"
                                "\texample: %s v4l2/libspa-v4l2 api.v4l2.source\n\n",
                                argv[0], argv[0]);
                return -1;
        }
 
        data.loop = pw_main_loop_new(NULL);
        l = pw_main_loop_get_loop(data.loop);
        pw_loop_add_signal(l, SIGINT, do_quit, &data);
        pw_loop_add_signal(l, SIGTERM, do_quit, &data);
        data.context = pw_context_new(l, NULL, 0);
        data.library = argv[1];
        data.factory = argv[2];
        if (argc > 3)
                data.path = argv[3];
 
        pw_context_load_module(data.context, "libpipewire-module-spa-node-factory", NULL, NULL);
 
        data.core = pw_context_connect(data.context, NULL, 0);
        if (data.core == NULL) {
                printf("can't connect: %m\n");
                return -1;
        }
        pw_core_add_listener(data.core,
                                   &data.core_listener,
                                   &core_events, &data);
 
        if (make_node(&data) < 0) {
                pw_log_error("can't make node");
                return -1;
        }
 
        pw_main_loop_run(data.loop);
 
        pw_proxy_destroy(data.proxy);
        pw_core_disconnect(data.core);
        pw_context_destroy(data.context);
        pw_main_loop_destroy(data.loop);
 
        return 0;
}