pipewire/src/modules/module-example-source.c

/* PipeWire
 *
 * Copyright © 2021 Wim Taymans
 *
 * 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.
 */

#include <string.h>
#include <stdio.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include <signal.h>
#include <limits.h>
#include <math.h>

#include "config.h"

#include <spa/utils/result.h>
#include <spa/utils/string.h>
#include <spa/utils/json.h>
#include <spa/utils/ringbuffer.h>
#include <spa/debug/pod.h>
#include <spa/pod/builder.h>
#include <spa/param/audio/format-utils.h>
#include <spa/param/audio/raw.h>

#include <pipewire/impl.h>
#include <pipewire/i18n.h>

/** \page page_module_example_source PipeWire Module: Example Source
 *
 * The example source is a good starting point for writing a custom
 * source. We refer to the source code for more information.
 *
 * ## Module Options
 *
 * - `node.name`: a unique name for the stream
 * - `node.description`: a human readable name for the stream
 * - `stream.props = {}`: properties to be passed to the stream
 *
 * ## General options
 *
 * Options with well-known behavior.
 *
 * - \ref PW_KEY_REMOTE_NAME
 * - \ref PW_KEY_AUDIO_RATE
 * - \ref PW_KEY_AUDIO_CHANNELS
 * - \ref SPA_KEY_AUDIO_POSITION
 * - \ref PW_KEY_MEDIA_NAME
 * - \ref PW_KEY_NODE_LATENCY
 * - \ref PW_KEY_NODE_NAME
 * - \ref PW_KEY_NODE_DESCRIPTION
 * - \ref PW_KEY_NODE_GROUP
 * - \ref PW_KEY_NODE_VIRTUAL
 * - \ref PW_KEY_MEDIA_CLASS
 *
 * ## Example configuration
 *
 *\code{.unparsed}
 * context.modules = [
 * {   name = libpipewire-module-example-source
 *     args = {
 *         node.name = "example_source"
 *         node.description = "My Example Source"
 *         stream.props = {
 *             audio.position = [ FL FR ]
 *         }
 *     }
 * }
 * ]
 *\endcode
 */

#define NAME "example-source"

PW_LOG_TOPIC_STATIC(mod_topic, "mod." NAME);
#define PW_LOG_TOPIC_DEFAULT mod_topic

#define DEFAULT_FORMAT "S16"
#define DEFAULT_RATE 48000
#define DEFAULT_CHANNELS 2
#define DEFAULT_POSITION "[ FL FR ]"

#define MODULE_USAGE	"[ node.latency=<latency as fraction> ] "				\
			"[ node.name=<name of the nodes> ] "					\
			"[ node.description=<description of the nodes> ] "			\
			"[ audio.format=<format, default:"DEFAULT_FORMAT"> ] "			\
			"[ audio.rate=<sample rate, default: "SPA_STRINGIFY(DEFAULT_RATE)"> ] "			\
			"[ audio.channels=<number of channels, default:"SPA_STRINGIFY(EFAULT_CHANNELS) "> ] "	\
			"[ audio.position=<channel map, default:"DEFAULT_POSITION"> ] "		\
			"[ stream.props=<properties> ] "


static const struct spa_dict_item module_props[] = {
	{ PW_KEY_MODULE_AUTHOR, "Wim Taymans <wim.taymans@gmail.com>" },
	{ PW_KEY_MODULE_DESCRIPTION, "An example audio source" },
	{ PW_KEY_MODULE_USAGE, MODULE_USAGE },
	{ PW_KEY_MODULE_VERSION, PACKAGE_VERSION },
};

struct impl {
	struct pw_context *context;

	struct pw_properties *props;

	struct pw_impl_module *module;
	struct pw_work_queue *work;

	struct spa_hook module_listener;

	struct pw_core *core;
	struct spa_hook core_proxy_listener;
	struct spa_hook core_listener;

	struct pw_properties *stream_props;
	struct pw_stream *stream;
	struct spa_hook stream_listener;
	struct spa_audio_info_raw info;
	uint32_t frame_size;

	unsigned int do_disconnect:1;
	unsigned int unloading:1;
};

static void do_unload_module(void *obj, void *data, int res, uint32_t id)
{
	struct impl *impl = data;
	pw_impl_module_destroy(impl->module);
}

static void unload_module(struct impl *impl)
{
	if (!impl->unloading) {
		impl->unloading = true;
		pw_work_queue_add(impl->work, impl, 0, do_unload_module, impl);
	}
}

static void stream_destroy(void *d)
{
	struct impl *impl = d;
	spa_hook_remove(&impl->stream_listener);
	impl->stream = NULL;
}

static void stream_state_changed(void *d, enum pw_stream_state old,
		enum pw_stream_state state, const char *error)
{
	struct impl *impl = d;
	switch (state) {
	case PW_STREAM_STATE_ERROR:
	case PW_STREAM_STATE_UNCONNECTED:
		unload_module(impl);
		break;
	case PW_STREAM_STATE_PAUSED:
	case PW_STREAM_STATE_STREAMING:
		break;
	default:
		break;
	}
}

static void capture_stream_process(void *d)
{
	struct impl *impl = d;
	struct pw_buffer *buf;
	struct spa_data *bd;
	void *data;
	uint32_t size;

	if ((buf = pw_stream_dequeue_buffer(impl->stream)) == NULL) {
		pw_log_debug("out of buffers: %m");
		return;
	}

	bd = &buf->buffer->datas[0];

	data = bd->data;
	size = buf->requested ? buf->requested * impl->frame_size : bd->maxsize;

	/* fill buffer contents here */
	pw_log_info("fill buffer data %p with up to %u bytes", data, size);

	bd->chunk->size = size;
	bd->chunk->stride = impl->frame_size;
	bd->chunk->offset = 0;
	buf->size = size / impl->frame_size;

	pw_stream_queue_buffer(impl->stream, buf);
}

static const struct pw_stream_events capture_stream_events = {
	PW_VERSION_STREAM_EVENTS,
	.destroy = stream_destroy,
	.state_changed = stream_state_changed,
	.process = capture_stream_process
};

static int create_stream(struct impl *impl)
{
	int res;
	uint32_t n_params;
	const struct spa_pod *params[1];
	uint8_t buffer[1024];
	struct spa_pod_builder b;

	impl->stream = pw_stream_new(impl->core, "example source", impl->stream_props);
	impl->stream_props = NULL;

	if (impl->stream == NULL)
		return -errno;

	pw_stream_add_listener(impl->stream,
			&impl->stream_listener,
			&capture_stream_events, impl);

	n_params = 0;
	spa_pod_builder_init(&b, buffer, sizeof(buffer));
	params[n_params++] = spa_format_audio_raw_build(&b,
			SPA_PARAM_EnumFormat, &impl->info);

	if ((res = pw_stream_connect(impl->stream,
			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;

	return 0;
}

static void core_error(void *data, uint32_t id, int seq, int res, const char *message)
{
	struct impl *impl = 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 && res == -EPIPE)
		unload_module(impl);
}

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

static void core_destroy(void *d)
{
	struct impl *impl = d;
	spa_hook_remove(&impl->core_listener);
	impl->core = NULL;
	unload_module(impl);
}

static const struct pw_proxy_events core_proxy_events = {
	.destroy = core_destroy,
};

static void impl_destroy(struct impl *impl)
{
	if (impl->stream)
		pw_stream_destroy(impl->stream);
	if (impl->core && impl->do_disconnect)
		pw_core_disconnect(impl->core);

	pw_properties_free(impl->stream_props);
	pw_properties_free(impl->props);

	if (impl->work)
		pw_work_queue_cancel(impl->work, impl, SPA_ID_INVALID);
	free(impl);
}

static void module_destroy(void *data)
{
	struct impl *impl = data;
	impl->unloading = true;
	spa_hook_remove(&impl->module_listener);
	impl_destroy(impl);
}

static const struct pw_impl_module_events module_events = {
	PW_VERSION_IMPL_MODULE_EVENTS,
	.destroy = module_destroy,
};

static inline uint32_t format_from_name(const char *name, size_t len)
{
	int i;
	for (i = 0; spa_type_audio_format[i].name; i++) {
		if (strncmp(name, spa_debug_type_short_name(spa_type_audio_format[i].name), len) == 0)
			return spa_type_audio_format[i].type;
	}
	return SPA_AUDIO_FORMAT_UNKNOWN;
}

static uint32_t channel_from_name(const char *name)
{
	int i;
	for (i = 0; spa_type_audio_channel[i].name; i++) {
		if (spa_streq(name, spa_debug_type_short_name(spa_type_audio_channel[i].name)))
			return spa_type_audio_channel[i].type;
	}
	return SPA_AUDIO_CHANNEL_UNKNOWN;
}

static void parse_position(struct spa_audio_info_raw *info, const char *val, size_t len)
{
	struct spa_json it[2];
	char v[256];

	spa_json_init(&it[0], val, len);
        if (spa_json_enter_array(&it[0], &it[1]) <= 0)
                spa_json_init(&it[1], val, len);

	info->channels = 0;
	while (spa_json_get_string(&it[1], v, sizeof(v)) > 0 &&
	    info->channels < SPA_AUDIO_MAX_CHANNELS) {
		info->position[info->channels++] = channel_from_name(v);
	}
}

static int parse_audio_info(struct impl *impl)
{
	struct pw_properties *props = impl->stream_props;
	struct spa_audio_info_raw *info = &impl->info;
	const char *str;

	spa_zero(*info);

	if ((str = pw_properties_get(props, PW_KEY_AUDIO_FORMAT)) == NULL)
		str = DEFAULT_FORMAT;
	info->format = format_from_name(str, strlen(str));
	switch (info->format) {
	case SPA_AUDIO_FORMAT_S8:
	case SPA_AUDIO_FORMAT_U8:
		impl->frame_size = 1;
		break;
	case SPA_AUDIO_FORMAT_S16:
		impl->frame_size = 2;
		break;
	case SPA_AUDIO_FORMAT_S24:
		impl->frame_size = 3;
		break;
	case SPA_AUDIO_FORMAT_S24_32:
	case SPA_AUDIO_FORMAT_S32:
	case SPA_AUDIO_FORMAT_F32:
		impl->frame_size = 4;
		break;
	case SPA_AUDIO_FORMAT_F64:
		impl->frame_size = 8;
		break;
	default:
		pw_log_error("unsupported format '%s'", str);
		return -EINVAL;
	}
	info->rate = pw_properties_get_uint32(props, PW_KEY_AUDIO_RATE, DEFAULT_RATE);
	if (info->rate == 0) {
		pw_log_error("invalid rate '%s'", str);
		return -EINVAL;
	}
	info->channels = pw_properties_get_uint32(props, PW_KEY_AUDIO_CHANNELS, DEFAULT_CHANNELS);
	if ((str = pw_properties_get(props, SPA_KEY_AUDIO_POSITION)) == NULL)
		str = DEFAULT_POSITION;
	parse_position(info, str, strlen(str));
	if (info->channels == 0) {
		pw_log_error("invalid channels '%s'", str);
		return -EINVAL;
	}
	impl->frame_size *= info->channels;

	return 0;
}

static void copy_props(struct impl *impl, struct pw_properties *props, const char *key)
{
	const char *str;
	if ((str = pw_properties_get(props, key)) != NULL) {
		if (pw_properties_get(impl->stream_props, key) == NULL)
			pw_properties_set(impl->stream_props, key, str);
	}
}

SPA_EXPORT
int pipewire__module_init(struct pw_impl_module *module, const char *args)
{
	struct pw_context *context = pw_impl_module_get_context(module);
	uint32_t id = pw_global_get_id(pw_impl_module_get_global(module));
	uint32_t pid = getpid();
	struct pw_properties *props = NULL;
	struct impl *impl;
	const char *str;
	int res;

	PW_LOG_TOPIC_INIT(mod_topic);

	impl = calloc(1, sizeof(struct impl));
	if (impl == NULL)
		return -errno;

	pw_log_debug("module %p: new %s", impl, args);

	if (args == NULL)
		args = "";

	props = pw_properties_new_string(args);
	if (props == NULL) {
		res = -errno;
		pw_log_error( "can't create properties: %m");
		goto error;
	}
	impl->props = props;

	impl->stream_props = pw_properties_new(NULL, NULL);
	if (impl->stream_props == NULL) {
		res = -errno;
		pw_log_error( "can't create properties: %m");
		goto error;
	}

	impl->module = module;
	impl->context = context;
	impl->work = pw_context_get_work_queue(context);

	if (pw_properties_get(props, PW_KEY_NODE_VIRTUAL) == NULL)
		pw_properties_set(props, PW_KEY_NODE_VIRTUAL, "true");

	if (pw_properties_get(props, PW_KEY_MEDIA_CLASS) == NULL)
		pw_properties_set(props, PW_KEY_MEDIA_CLASS, "Audio/Source");

	if (pw_properties_get(props, PW_KEY_NODE_NAME) == NULL)
		pw_properties_setf(props, PW_KEY_NODE_NAME, "example-source-%u-%u", pid, id);
	if (pw_properties_get(props, PW_KEY_NODE_DESCRIPTION) == NULL)
		pw_properties_set(props, PW_KEY_NODE_DESCRIPTION,
				pw_properties_get(props, PW_KEY_NODE_NAME));

	if ((str = pw_properties_get(props, "stream.props")) != NULL)
		pw_properties_update_string(impl->stream_props, str, strlen(str));

	copy_props(impl, props, PW_KEY_AUDIO_RATE);
	copy_props(impl, props, PW_KEY_AUDIO_CHANNELS);
	copy_props(impl, props, SPA_KEY_AUDIO_POSITION);
	copy_props(impl, props, PW_KEY_NODE_NAME);
	copy_props(impl, props, PW_KEY_NODE_DESCRIPTION);
	copy_props(impl, props, PW_KEY_NODE_GROUP);
	copy_props(impl, props, PW_KEY_NODE_LATENCY);
	copy_props(impl, props, PW_KEY_NODE_VIRTUAL);
	copy_props(impl, props, PW_KEY_MEDIA_CLASS);

	if ((res = parse_audio_info(impl)) < 0) {
		pw_log_error( "can't parse audio format");
		goto error;
	}

	impl->core = pw_context_get_object(impl->context, PW_TYPE_INTERFACE_Core);
	if (impl->core == NULL) {
		str = pw_properties_get(props, PW_KEY_REMOTE_NAME);
		impl->core = pw_context_connect(impl->context,
				pw_properties_new(
					PW_KEY_REMOTE_NAME, str,
					NULL),
				0);
		impl->do_disconnect = true;
	}
	if (impl->core == NULL) {
		res = -errno;
		pw_log_error("can't connect: %m");
		goto error;
	}

	pw_proxy_add_listener((struct pw_proxy*)impl->core,
			&impl->core_proxy_listener,
			&core_proxy_events, impl);
	pw_core_add_listener(impl->core,
			&impl->core_listener,
			&core_events, impl);

	if ((res = create_stream(impl)) < 0)
		goto error;

	pw_impl_module_add_listener(module, &impl->module_listener, &module_events, impl);

	pw_impl_module_update_properties(module, &SPA_DICT_INIT_ARRAY(module_props));

	return 0;

error:
	impl_destroy(impl);
	return res;
}