pipewire/src/modules/module-protocol-pulse/module-loopback.c

/* PipeWire
 *
 * Copyright © 2021 Wim Taymans <wim.taymans@gmail.com>
 * Copyright © 2021 Arun Raghavan <arun@asymptotic.io>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */

#define ERROR_RETURN(str) 		\
	{ 				\
		pw_log_error(str); 	\
		res = -EINVAL; 		\
		goto out; 		\
	}

struct module_loopback_data {
	struct module *module;
	struct pw_core *core;

	struct pw_stream *capture;
	struct pw_stream *playback;

	struct spa_hook core_listener;
	struct spa_hook capture_listener;
	struct spa_hook playback_listener;

	struct pw_properties *capture_props;
	struct pw_properties *playback_props;

	struct spa_audio_info_raw info;
};

static void capture_process(void *d)
{
	struct module_loopback_data *data = d;
	struct pw_buffer *in, *out;

	if ((in = pw_stream_dequeue_buffer(data->capture)) == NULL)
		pw_log_warn("out of capture buffers: %m");

	if ((out = pw_stream_dequeue_buffer(data->playback)) == NULL)
		pw_log_warn("out of playback buffers: %m");

	if (in != NULL && out != NULL)
		*out->buffer = *in->buffer;

	if (in != NULL)
		pw_stream_queue_buffer(data->capture, in);
	if (out != NULL)
		pw_stream_queue_buffer(data->playback, out);
}

static void on_core_error(void *data, uint32_t id, int seq, int res, const char *message)
{
	struct module_loopback_data *d = data;
	struct module *module = d->module;

	pw_log_error("error id:%u seq:%d res:%d (%s): %s",
			id, seq, res, spa_strerror(res), message);

	if (id == PW_ID_CORE && res == -EPIPE)
		pw_loop_signal_event(module->impl->loop, module->unload);
}

static const struct pw_core_events core_events = {
	PW_VERSION_CORE_EVENTS,
	.error = on_core_error,
};

static void on_stream_state_changed(void *data, enum pw_stream_state old,
		enum pw_stream_state state, const char *error)
{
	struct module_loopback_data *d = data;
	struct module *module = d->module;

	if (state == PW_STREAM_STATE_UNCONNECTED) {
		pw_log_info("stream disconnected, unloading");
		pw_loop_signal_event(module->impl->loop, module->unload);
	}
}

static const struct pw_stream_events in_stream_events = {
	PW_VERSION_STREAM_EVENTS,
	.state_changed = on_stream_state_changed,
	.process = capture_process
};

static const struct pw_stream_events out_stream_events = {
	PW_VERSION_STREAM_EVENTS,
	.state_changed = on_stream_state_changed,
};

static int module_loopback_load(struct client *client, struct module *module)
{
	struct module_loopback_data *data = module->user_data;
	int res;
	uint32_t n_params;
	const struct spa_pod *params[1];
	uint8_t buffer[1024];
	struct spa_pod_builder b = SPA_POD_BUILDER_INIT(buffer, sizeof(buffer));

	data->core = pw_context_connect(module->impl->context,
			pw_properties_copy(client->props),
			0);
	if (data->core == NULL)
		return -errno;

	pw_core_add_listener(data->core,
			&data->core_listener,
			&core_events, data);

	pw_properties_setf(data->capture_props, PW_KEY_NODE_GROUP, "loopback-%u", module->idx);
	pw_properties_setf(data->playback_props, PW_KEY_NODE_GROUP, "loopback-%u", module->idx);

	data->capture = pw_stream_new(data->core,
			"loopback capture", data->capture_props);
	data->capture_props = NULL;
	if (data->capture == NULL)
		return -errno;

	pw_stream_add_listener(data->capture,
			&data->capture_listener,
			&in_stream_events, data);

	data->playback = pw_stream_new(data->core,
			"loopback playback", data->playback_props);
	data->playback_props = NULL;
	if (data->playback == NULL)
		return -errno;

	pw_stream_add_listener(data->playback,
			&data->playback_listener,
			&out_stream_events, data);

	n_params = 0;
	params[n_params++] = spa_pod_builder_add_object(&b,
                        SPA_TYPE_OBJECT_Format, SPA_PARAM_EnumFormat,
                        SPA_FORMAT_mediaType,           SPA_POD_Id(SPA_MEDIA_TYPE_audio),
                        SPA_FORMAT_mediaSubtype,        SPA_POD_Id(SPA_MEDIA_SUBTYPE_raw),
                        SPA_FORMAT_AUDIO_format,        SPA_POD_Id(data->info.format),
                        SPA_FORMAT_AUDIO_channels,      SPA_POD_Int(data->info.channels),
                        SPA_FORMAT_AUDIO_position,      SPA_POD_Array(sizeof(uint32_t),
				SPA_TYPE_Id, data->info.channels, data->info.position));

	if ((res = pw_stream_connect(data->capture,
			PW_DIRECTION_INPUT,
			PW_ID_ANY,
			PW_STREAM_FLAG_AUTOCONNECT |
			PW_STREAM_FLAG_MAP_BUFFERS |
			PW_STREAM_FLAG_RT_PROCESS,
			params, n_params)) < 0)
		return res;

	if ((res = pw_stream_connect(data->playback,
			PW_DIRECTION_OUTPUT,
			PW_ID_ANY,
			PW_STREAM_FLAG_AUTOCONNECT |
			PW_STREAM_FLAG_MAP_BUFFERS |
			PW_STREAM_FLAG_RT_PROCESS,
			params, n_params)) < 0)
		return res;

	pw_log_info("loaded module %p id:%u name:%s", module, module->idx, module->name);
	module_emit_loaded(module, 0);

	return 0;
}

static int module_loopback_unload(struct client *client, struct module *module)
{
	struct module_loopback_data *d = module->user_data;

	pw_log_info("unload module %p id:%u name:%s", module, module->idx, module->name);

	if (d->capture_props != NULL)
		pw_properties_free(d->capture_props);
	if (d->playback_props != NULL)
		pw_properties_free(d->playback_props);
	if (d->capture != NULL)
		pw_stream_destroy(d->capture);
	if (d->playback != NULL)
		pw_stream_destroy(d->playback);
	if (d->core != NULL)
		pw_core_disconnect(d->core);

	return 0;
}

static const struct module_methods module_loopback_methods = {
	VERSION_MODULE_METHODS,
	.load = module_loopback_load,
	.unload = module_loopback_unload,
};

static struct module *create_module_loopback(struct impl *impl, const char *argument)
{
	struct module *module;
	struct module_loopback_data *d;
	struct pw_properties *props = NULL, *playback_props = NULL, *capture_props = NULL;
	const char *str;
	struct spa_audio_info_raw info = { 0 };
	int res;

	props = pw_properties_new(NULL, NULL);
	capture_props = pw_properties_new(NULL, NULL);
	playback_props = pw_properties_new(NULL, NULL);
	if (!props || !capture_props || !playback_props) {
		res = -EINVAL;
		goto out;
	}
	if (argument)
		add_props(props, argument);

	/* The following modargs are not implemented:
	 * adjust_time, max_latency_msec, fast_adjust_threshold_msec: these are just not relevant
	 */

	if ((str = pw_properties_get(props, "source")) != NULL) {
		pw_properties_set(capture_props, PW_KEY_NODE_TARGET, str);
		pw_properties_set(props, "source", NULL);
	}

	if ((str = pw_properties_get(props, "sink")) != NULL) {
		pw_properties_set(playback_props, PW_KEY_NODE_TARGET, str);
		pw_properties_set(props, "sink", NULL);
	}

	info.format = SPA_AUDIO_FORMAT_F32P;

	if ((str = pw_properties_get(props, "channels")) != NULL) {
		info.channels = pw_properties_parse_int(str);
		pw_properties_set(props, "channels", NULL);
	} else {
		info.channels = 2;
	}

	if ((str = pw_properties_get(props, "channel_map")) != NULL) {
		struct channel_map map;

		channel_map_parse(str, &map);
		if (info.channels != map.channels)
			ERROR_RETURN("Mismatched channel map");
		channel_map_to_positions(&map, info.position);
		pw_properties_set(props, "channel_map", NULL);
	} else {
		if (info.channels > 2)
			ERROR_RETURN("Mismatched channel map");

		if (info.channels == 1) {
			info.position[0] = SPA_AUDIO_CHANNEL_MONO;
		} else {
			info.position[0] = SPA_AUDIO_CHANNEL_FL;
			info.position[1] = SPA_AUDIO_CHANNEL_FR;
		}

		/* TODO: pull in all of pa_channel_map_init_auto() */
	}

	if ((str = pw_properties_get(props, "source_dont_move")) != NULL) {
		pw_properties_set(capture_props, PW_KEY_NODE_DONT_RECONNECT, str);
		pw_properties_set(props, "source_dont_move", NULL);
	}

	if ((str = pw_properties_get(props, "sink_dont_move")) != NULL) {
		pw_properties_set(playback_props, PW_KEY_NODE_DONT_RECONNECT, str);
		pw_properties_set(props, "sink_dont_move", NULL);
	}

	if ((str = pw_properties_get(props, "remix")) != NULL) {
		/* Note that the boolean is inverted */
		pw_properties_set(playback_props, PW_KEY_STREAM_DONT_REMIX,
				pw_properties_parse_bool(str) ? "false" : "true");
		pw_properties_set(props, "remix", NULL);
	}

	if ((str = pw_properties_get(props, "latency_msec")) != NULL) {
		/* Half the latency on each of the playback and capture streams */
		pw_properties_setf(capture_props, PW_KEY_NODE_LATENCY, "%s/2000", str);
		pw_properties_setf(playback_props, PW_KEY_NODE_LATENCY, "%s/2000", str);
		pw_properties_set(props, "latency_msec", NULL);
	} else {
		pw_properties_set(capture_props, PW_KEY_NODE_LATENCY, "100/1000");
		pw_properties_set(playback_props, PW_KEY_NODE_LATENCY, "100/1000");
	}

	if ((str = pw_properties_get(props, "sink_input_properties")) != NULL) {
		add_props(playback_props, str);
		pw_properties_set(props, "sink_input_properties", NULL);
	}

	if ((str = pw_properties_get(props, "source_output_properties")) != NULL) {
		add_props(capture_props, str);
		pw_properties_set(props, "source_output_properties", NULL);
	}

	module = module_new(impl, &module_loopback_methods, sizeof(*d));
	if (module == NULL) {
		res = -errno;
		goto out;
	}

	module->props = props;
	d = module->user_data;
	d->module = module;
	d->capture_props = capture_props;
	d->playback_props = playback_props;
	d->info = info;

	return module;
out:
	if (props)
		pw_properties_free(props);
	if (playback_props)
		pw_properties_free(playback_props);
	if (capture_props)
		pw_properties_free(capture_props);
	errno = -res;

	return NULL;
}