pipewire/spa/plugins/libcamera/libcamera-device.cpp

/* Spa libcamera device */
/* SPDX-FileCopyrightText: Copyright © 2020 Collabora Ltd. */
/*                         @author Raghavendra Rao Sidlagatta <raghavendra.rao@collabora.com> */
/* SPDX-FileCopyrightText: Copyright © 2021 Wim Taymans <wim.taymans@gmail.com> */
/* SPDX-License-Identifier: MIT */

#include <cstddef>
#include <ios>
#include <locale>
#include <optional>
#include <span>
#include <sstream>
#include <string>
#include <string_view>
#include <utility>
#include <vector>

#include <spa/support/plugin.h>
#include <spa/support/log.h>
#include <spa/support/loop.h>
#include <spa/utils/json.h>
#include <spa/utils/keys.h>
#include <spa/utils/result.h>
#include <spa/utils/names.h>
#include <spa/utils/string.h>
#include <spa/node/node.h>
#include <spa/pod/builder.h>
#include <spa/monitor/device.h>
#include <spa/monitor/utils.h>
#include <spa/param/param.h>

#include "libcamera.hpp"

#include <libcamera/camera.h>
#include <libcamera/property_ids.h>

using namespace libcamera;

namespace {

struct impl {
	struct spa_handle handle;
	struct spa_device device = {};

	struct spa_log *log;

	std::string device_id;

	struct spa_hook_list hooks;

	std::shared_ptr<CameraManager> manager;
	std::shared_ptr<Camera> camera;

	std::vector<std::pair<std::string, std::string>> properties;

	impl(spa_log *log,
	     std::shared_ptr<CameraManager> manager,
	     std::shared_ptr<Camera> camera,
	     std::string device_id);
};

std::span<const int64_t> cameraDevice(const Camera& camera)
{
	if (auto devices = camera.properties().get(properties::SystemDevices))
		return devices.value();

	return {};
}

std::string cameraModel(const Camera& camera)
{
	return std::string(camera.properties().get(properties::Model).value_or(camera.id()));
}

const char *cameraLoc(const Camera& camera)
{
	if (auto location = camera.properties().get(properties::Location)) {
		switch (location.value()) {
		case properties::CameraLocationFront:
			return "front";
		case properties::CameraLocationBack:
			return "back";
		case properties::CameraLocationExternal:
			return "external";
		}
	}

	return nullptr;
}

const char *cameraRot(const Camera& camera)
{
	if (auto rotation = camera.properties().get(properties::Rotation)) {
		switch (rotation.value()) {
		case 90:
			return "90";
		case 180:
			return "180";
		case 270:
			return "270";
		default:
			return "0";
		}
	}

	return nullptr;
}

std::optional<std::string>
string_to_json(std::string_view str)
{
	std::string result(str.size() + 2, '\0');

	auto l = spa_json_encode_stringn(result.data(), result.size(), str.data(), str.size());
	if (l > result.size()) {
		result.resize(l);

		l = spa_json_encode_stringn(result.data(), result.size(), str.data(), str.size());
		if (l > result.size())
			return {};
	}

	result.resize(l);
	return result;
}

constexpr auto default_control_value_print = [](std::ostream& os, const auto& x) { os << x; };

template<typename T, typename Print = decltype(default_control_value_print)>
[[nodiscard]]
bool
control_value_to_string(std::ostream& os, const libcamera::ControlValue& v, Print print = {})
{
	if (v.isArray()) {
		os << "[ ";

		bool first = true;
		for (const auto& x : v.get<libcamera::Span<const T>>()) {
			if (!first)
				os << ", ";

			print(os, x);
			first = false;
		}

		os << " ]";
	}
	else {
		print(os, v.get<T>());
	}

	return true;
}

[[nodiscard]]
bool
control_value_to_string(std::ostream& os, const libcamera::ControlValue& v,
			const libcamera::ControlId *cid)
{
	switch (v.type()) {
	case libcamera::ControlTypeNone:
		os << "null";
		return true;
	case libcamera::ControlTypeBool:
		return control_value_to_string<bool>(os, v);
	case libcamera::ControlTypeByte:
		return control_value_to_string<uint8_t>(os, v);
	case libcamera::ControlTypeUnsigned16:
		return control_value_to_string<uint16_t>(os, v);
	case libcamera::ControlTypeUnsigned32:
		return control_value_to_string<uint32_t>(os, v);
	case libcamera::ControlTypeInteger32:
		return control_value_to_string<int32_t>(os, v, [&](std::ostream& os, int32_t x) {
			if (cid) {
				auto it = cid->enumerators().find(x);
				if (it != cid->enumerators().end()) {
					auto str = string_to_json(it->second);
					if (str) {
						os << *str;
						return;
					}
				}
			}

			os << x;
		});
	case libcamera::ControlTypeInteger64:
		return control_value_to_string<int64_t>(os, v);
	case libcamera::ControlTypeFloat:
		return control_value_to_string<float>(os, v);
	case libcamera::ControlTypeString: {
		auto str = string_to_json(v.get<std::string_view>());
		if (!str)
			return false;

		os << *str;
		return true;
	}
	}

	return false;
}

[[nodiscard]]
std::vector<std::pair<std::string, std::string>>
control_list_to_dict(const libcamera::ControlList& list, std::string_view prefix)
{
	static const std::locale c_locale("C");

	std::vector<std::pair<std::string, std::string>> res;
	const auto *id_map = list.idMap();
	std::ostringstream value_s;
	std::ostringstream key_s;

	spa_assert(id_map);

	key_s.imbue(c_locale);

	value_s.imbue(c_locale);
	value_s << std::boolalpha;

	res.reserve(list.size());

	for (const auto& [ id, value ] : list) {
		auto it = id_map->find(id);
		const auto *cid = it != id_map->end() ? it->second : nullptr;

		if (!control_value_to_string(value_s, value, cid))
			continue;

		key_s << prefix << '.';

		if (cid)
			key_s << cid->vendor() << '.' << cid->name();
		else
			key_s << id;

		res.emplace_back(std::move(key_s).str(), std::move(value_s).str());
	}

	return res;
}

int emit_info(struct impl *impl, bool full)
{
	struct spa_dict dict;
	struct spa_device_info info;
	Camera& camera = *impl->camera;

	info = SPA_DEVICE_INFO_INIT();

	info.change_mask = SPA_DEVICE_CHANGE_MASK_PROPS;

	std::vector<spa_dict_item> items;
#define ADD_ITEM(key, value) items.push_back({ key, value })

	const auto path = "libcamera:" + impl->device_id;
	ADD_ITEM(SPA_KEY_OBJECT_PATH, path.c_str());

	ADD_ITEM(SPA_KEY_DEVICE_API, "libcamera");
	ADD_ITEM(SPA_KEY_MEDIA_CLASS, "Video/Device");
	ADD_ITEM(SPA_KEY_API_LIBCAMERA_PATH, impl->device_id.c_str());
	ADD_ITEM(KEY_VERSION_LIBRARY, libcamera_library_version());
	ADD_ITEM(KEY_VERSION_HEADER, libcamera_header_version());

	if (auto location = cameraLoc(camera))
		ADD_ITEM(SPA_KEY_API_LIBCAMERA_LOCATION, location);
	if (auto rotation = cameraRot(camera))
		ADD_ITEM(SPA_KEY_API_LIBCAMERA_ROTATION, rotation);

	const auto model = cameraModel(camera);
	ADD_ITEM(SPA_KEY_DEVICE_PRODUCT_NAME, model.c_str());
	ADD_ITEM(SPA_KEY_DEVICE_DESCRIPTION, model.c_str());

	const auto name = "libcamera_device." + impl->device_id;
	ADD_ITEM(SPA_KEY_DEVICE_NAME, name.c_str());

	auto device_numbers = cameraDevice(camera);
	std::string devids;

	if (!device_numbers.empty()) {
		std::ostringstream s;

		/* encode device numbers into a json array */
		s << "[ ";
		for (const auto& devid : device_numbers)
			s << devid << ' ';
		s << ']';

		devids = std::move(s).str();
		ADD_ITEM(SPA_KEY_DEVICE_DEVIDS, devids.c_str());
	}

#undef ADD_ITEM

	for (const auto& [ k, v ] : impl->properties)
		items.push_back({ k.c_str(), v.c_str() });

	dict = SPA_DICT_INIT(items.data(), uint32_t(items.size()));
	info.props = &dict;

	spa_device_emit_info(&impl->hooks, &info);

	if (true) {
		struct spa_device_object_info oinfo;

		oinfo = SPA_DEVICE_OBJECT_INFO_INIT();
		oinfo.type = SPA_TYPE_INTERFACE_Node;
		oinfo.factory_name = SPA_NAME_API_LIBCAMERA_SOURCE;
		oinfo.change_mask = SPA_DEVICE_OBJECT_CHANGE_MASK_PROPS;
		oinfo.props = &dict;

		spa_device_emit_object_info(&impl->hooks, 0, &oinfo);
	}
	return 0;
}

int impl_add_listener(void *object,
		      struct spa_hook *listener,
		      const struct spa_device_events *events,
		      void *data)
{
	struct impl *impl = (struct impl*)object;
	struct spa_hook_list save;
	int res = 0;

	spa_return_val_if_fail(impl != nullptr, -EINVAL);
	spa_return_val_if_fail(events != nullptr, -EINVAL);

	spa_hook_list_isolate(&impl->hooks, &save, listener, events, data);

	if (events->info || events->object_info)
		res = emit_info(impl, true);

	spa_hook_list_join(&impl->hooks, &save);

	return res;
}

int impl_sync(void *object, int seq)
{
	struct impl *impl = (struct impl*) object;

	spa_return_val_if_fail(impl != nullptr, -EINVAL);

	spa_device_emit_result(&impl->hooks, seq, 0, 0, nullptr);

	return 0;
}

int impl_enum_params(void *object, int seq,
		     uint32_t id, uint32_t start, uint32_t num,
		     const struct spa_pod *filter)
{
	return -ENOTSUP;
}

int impl_set_param(void *object,
		   uint32_t id, uint32_t flags,
		   const struct spa_pod *param)
{
	return -ENOTSUP;
}

const struct spa_device_methods impl_device = {
	.version = SPA_VERSION_DEVICE_METHODS,
	.add_listener = impl_add_listener,
	.sync = impl_sync,
	.enum_params = impl_enum_params,
	.set_param = impl_set_param,
};

int impl_get_interface(struct spa_handle *handle, const char *type, void **interface)
{
	auto *impl = reinterpret_cast<struct impl *>(handle);

	spa_return_val_if_fail(handle != nullptr, -EINVAL);
	spa_return_val_if_fail(interface != nullptr, -EINVAL);

	if (spa_streq(type, SPA_TYPE_INTERFACE_Device))
		*interface = &impl->device;
	else
		return -ENOENT;

	return 0;
}

int impl_clear(struct spa_handle *handle)
{
	std::destroy_at(reinterpret_cast<impl *>(handle));
	return 0;
}

impl::impl(spa_log *log,
	   std::shared_ptr<CameraManager> manager,
	   std::shared_ptr<Camera> camera,
	   std::string device_id)
	: handle({ SPA_VERSION_HANDLE, impl_get_interface, impl_clear }),
	  log(log),
	  device_id(std::move(device_id)),
	  manager(std::move(manager)),
	  camera(std::move(camera)),
	  properties(control_list_to_dict(this->camera->properties(), KEY_PROPERTY_PREFIX))
{
	libcamera_log_topic_init(log);

	spa_hook_list_init(&hooks);

	device.iface = SPA_INTERFACE_INIT(
			SPA_TYPE_INTERFACE_Device,
			SPA_VERSION_DEVICE,
			&impl_device, this);
}

size_t
impl_get_size(const struct spa_handle_factory *factory,
	      const struct spa_dict *params)
{
	return sizeof(struct impl);
}

int
impl_init(const struct spa_handle_factory *factory,
	  struct spa_handle *handle,
	  const struct spa_dict *info,
	  const struct spa_support *support,
	  uint32_t n_support)
{
	const char *str;
	int res;

	spa_return_val_if_fail(factory != nullptr, -EINVAL);
	spa_return_val_if_fail(handle != nullptr, -EINVAL);

	auto log = static_cast<spa_log *>(spa_support_find(support, n_support, SPA_TYPE_INTERFACE_Log));

	auto manager = libcamera_manager_acquire(res);
	if (!manager) {
		spa_log_error(log, "can't start camera manager: %s", spa_strerror(res));
		return res;
	}

	std::string device_id;
	if (info && (str = spa_dict_lookup(info, SPA_KEY_API_LIBCAMERA_PATH)))
		device_id = str;

	auto camera = manager->get(device_id);
	if (!camera) {
		spa_log_error(log, "unknown camera id %s", device_id.c_str());
		return -ENOENT;
	}

	new (handle) impl(log, std::move(manager), std::move(camera), std::move(device_id));

	return 0;
}

const struct spa_interface_info impl_interfaces[] = {
	{SPA_TYPE_INTERFACE_Device,},
};

int impl_enum_interface_info(const struct spa_handle_factory *factory,
			     const struct spa_interface_info **info,
			     uint32_t *index)
{
	spa_return_val_if_fail(factory != nullptr, -EINVAL);
	spa_return_val_if_fail(info != nullptr, -EINVAL);
	spa_return_val_if_fail(index != nullptr, -EINVAL);

	if (*index >= SPA_N_ELEMENTS(impl_interfaces))
		return 0;

	*info = &impl_interfaces[(*index)++];
	return 1;
}

}

extern "C" {
const struct spa_handle_factory spa_libcamera_device_factory = {
	SPA_VERSION_HANDLE_FACTORY,
	SPA_NAME_API_LIBCAMERA_DEVICE,
	nullptr,
	impl_get_size,
	impl_init,
	impl_enum_interface_info,
};
}