pipewire/src/media-session/default-routes.c

/* PipeWire
 *
 * Copyright © 2020 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 <math.h>
#include <time.h>
#include <fcntl.h>
#include <unistd.h>

#include "config.h"

#include <spa/utils/hook.h>
#include <spa/utils/result.h>
#include <spa/utils/json.h>
#include <spa/utils/string.h>
#include <spa/pod/parser.h>
#include <spa/pod/builder.h>
#include <spa/debug/pod.h>

#include "pipewire/pipewire.h"
#include "pipewire/extensions/metadata.h"

#include "media-session.h"

/** \page page_media_session_module_default_routes Media Session Module: Default Routes
 */
#define NAME		"default-routes"
#define SESSION_KEY	"default-routes"
#define PREFIX		"default.route."

#define SAVE_INTERVAL	1

struct impl {
	struct timespec now;

	struct sm_media_session *session;
	struct spa_hook listener;

	struct pw_context *context;
	struct spa_source *idle_timeout;

	struct spa_hook meta_listener;

	struct pw_properties *to_restore;
};

struct device {
	struct sm_device *obj;

	uint32_t id;
	struct impl *impl;
	char *name;

	struct spa_hook listener;

	uint32_t active_profile;

	uint32_t generation;
	struct pw_array route_info;
};

static void remove_idle_timeout(struct impl *impl)
{
	struct pw_loop *main_loop = pw_context_get_main_loop(impl->context);
	int res;

	if (impl->idle_timeout) {
		if ((res = sm_media_session_save_state(impl->session,
						SESSION_KEY, impl->to_restore)) < 0)
			pw_log_error("can't save "SESSION_KEY" state: %s", spa_strerror(res));
		pw_loop_destroy_source(main_loop, impl->idle_timeout);
		impl->idle_timeout = NULL;
	}
}

static void idle_timeout(void *data, uint64_t expirations)
{
	struct impl *impl = data;
	pw_log_debug(NAME " %p: idle timeout", impl);
	remove_idle_timeout(impl);
}

static void add_idle_timeout(struct impl *impl)
{
	struct timespec value;
	struct pw_loop *main_loop = pw_context_get_main_loop(impl->context);

	if (impl->idle_timeout == NULL)
		impl->idle_timeout = pw_loop_add_timer(main_loop, idle_timeout, impl);

	value.tv_sec = SAVE_INTERVAL;
	value.tv_nsec = 0;
	pw_loop_update_timer(main_loop, impl->idle_timeout, &value, NULL, false);
}

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 const char *channel_to_name(uint32_t channel)
{
	int i;
	for (i = 0; spa_type_audio_channel[i].name; i++) {
		if (spa_type_audio_channel[i].type == channel)
			return spa_debug_type_short_name(spa_type_audio_channel[i].name);
	}
	return "UNK";
}

static uint32_t iec958Codec_from_name(const char *name)
{
	int i;
	for (i = 0; spa_type_audio_iec958_codec[i].name; i++) {
		if (spa_streq(name, spa_debug_type_short_name(spa_type_audio_iec958_codec[i].name)))
			return spa_type_audio_iec958_codec[i].type;
	}
	return SPA_AUDIO_IEC958_CODEC_UNKNOWN;
}

static const char *iec958Codec_to_name(uint32_t codec)
{
	int i;
	for (i = 0; spa_type_audio_iec958_codec[i].name; i++) {
		if (spa_type_audio_iec958_codec[i].type == codec)
			return spa_debug_type_short_name(spa_type_audio_iec958_codec[i].name);
	}
	return "UNKNOWN";
}

struct route_info {
	uint32_t index;
	uint32_t generation;
	enum spa_param_availability available;
	enum spa_param_availability prev_available;
	enum spa_direction direction;
	char name[64];
	unsigned int save:1;
	unsigned int prev_active:1;
	unsigned int active:1;
};

struct route {
	struct sm_param *p;
	uint32_t index;
	uint32_t device_id;
	enum spa_direction direction;
	const char *name;
	uint32_t priority;
	enum spa_param_availability available;
	struct spa_pod *props;
	struct spa_pod *profiles;
	bool save;
};

#define ROUTE_INIT(__p) (struct route) {				\
			.p = (__p),					\
			.available = SPA_PARAM_AVAILABILITY_unknown,	\
		}

static struct route_info *find_route_info(struct device *dev, const struct route *r)
{
	struct route_info *i;

	pw_array_for_each(i, &dev->route_info) {
		if (i->index == r->index)
			return i;
	}
	i = pw_array_add(&dev->route_info, sizeof(*i));
	if (i == NULL)
		return NULL;

	pw_log_info("device %d: new route %d '%s' found", dev->id, r->index, r->name);
	spa_zero(*i);
	i->index = r->index;
	snprintf(i->name, sizeof(i->name), "%s", r->name);
	i->direction = r->direction;
	i->generation = dev->generation;
	i->available = r->available;
	i->prev_available = r->available;

	return i;
}

static int parse_route(struct sm_param *p, struct route *r)
{
	*r = ROUTE_INIT(p);
	return spa_pod_parse_object(p->param,
			SPA_TYPE_OBJECT_ParamRoute, NULL,
			SPA_PARAM_ROUTE_index, SPA_POD_Int(&r->index),
			SPA_PARAM_ROUTE_direction, SPA_POD_Id(&r->direction),
			SPA_PARAM_ROUTE_device, SPA_POD_Int(&r->device_id),
			SPA_PARAM_ROUTE_name, SPA_POD_String(&r->name),
			SPA_PARAM_ROUTE_priority,  SPA_POD_OPT_Int(&r->priority),
			SPA_PARAM_ROUTE_available,  SPA_POD_OPT_Id(&r->available),
			SPA_PARAM_ROUTE_props, SPA_POD_OPT_Pod(&r->props),
			SPA_PARAM_ROUTE_save, SPA_POD_OPT_Bool(&r->save));
}

static bool array_contains(const struct spa_pod *pod, uint32_t val)
{
	uint32_t *vals, n_vals;
	uint32_t n;

	if (pod == NULL)
		return false;
	vals = spa_pod_get_array(pod, &n_vals);
	if (vals == NULL || n_vals == 0)
		return false;
	for (n = 0; n < n_vals; n++)
		if (vals[n] == val)
			return true;
	return false;
}

static int parse_enum_route(struct sm_param *p, uint32_t device_id, struct route *r)
{
	struct spa_pod *devices = NULL;
	int res;

	*r = ROUTE_INIT(p);
	if ((res = spa_pod_parse_object(p->param,
			SPA_TYPE_OBJECT_ParamRoute, NULL,
			SPA_PARAM_ROUTE_index, SPA_POD_Int(&r->index),
			SPA_PARAM_ROUTE_direction, SPA_POD_Id(&r->direction),
			SPA_PARAM_ROUTE_name, SPA_POD_String(&r->name),
			SPA_PARAM_ROUTE_priority,  SPA_POD_OPT_Int(&r->priority),
			SPA_PARAM_ROUTE_available,  SPA_POD_OPT_Id(&r->available),
			SPA_PARAM_ROUTE_devices, SPA_POD_OPT_Pod(&devices),
			SPA_PARAM_ROUTE_profiles, SPA_POD_OPT_Pod(&r->profiles))) < 0)
		return res;

	if (device_id != SPA_ID_INVALID && !array_contains(devices, device_id))
		return -ENOENT;

	r->device_id = device_id;
	return 0;
}

static char *serialize_props(const struct device *dev, const struct spa_pod *param)
{
	struct spa_pod_prop *prop;
	struct spa_pod_object *obj = (struct spa_pod_object *) param;
	bool comma = false;
	char *ptr;
	size_t size;
	FILE *f;

        f = open_memstream(&ptr, &size);
	fprintf(f, "{");

	SPA_POD_OBJECT_FOREACH(obj, prop) {
		switch (prop->key) {
		case SPA_PROP_volume:
		{
			float val;
			if (spa_pod_get_float(&prop->value, &val) < 0)
				continue;
			fprintf(f, "%s \"volume\": %f", (comma ? "," : ""), val);
			break;
		}
		case SPA_PROP_mute:
		{
			bool b;
			if (spa_pod_get_bool(&prop->value, &b) < 0)
				continue;
			fprintf(f, "%s \"mute\": %s", (comma ? "," : ""), b ? "true" : "false");
			break;
		}
		case SPA_PROP_channelVolumes:
		{
			uint32_t i, n_vals;
			float vals[SPA_AUDIO_MAX_CHANNELS];

			n_vals = spa_pod_copy_array(&prop->value, SPA_TYPE_Float,
					vals, SPA_AUDIO_MAX_CHANNELS);
			if (n_vals == 0)
				continue;

			fprintf(f, "%s \"volumes\": [", (comma ? "," : ""));
			for (i = 0; i < n_vals; i++)
				fprintf(f, "%s %f", (i == 0 ? "" : ","), vals[i]);
			fprintf(f, " ]");
			break;
		}
		case SPA_PROP_channelMap:
		{
			uint32_t i, n_vals;
			uint32_t map[SPA_AUDIO_MAX_CHANNELS];

			n_vals = spa_pod_copy_array(&prop->value, SPA_TYPE_Id,
					map, SPA_AUDIO_MAX_CHANNELS);
			if (n_vals == 0)
				continue;

			fprintf(f, "%s \"channels\": [", (comma ? "," : ""));
			for (i = 0; i < n_vals; i++)
				fprintf(f, "%s \"%s\"", (i == 0 ? "" : ","), channel_to_name(map[i]));
			fprintf(f, " ]");
			break;
		}
		case SPA_PROP_latencyOffsetNsec:
		{
			int64_t delay;
			if (spa_pod_get_long(&prop->value, &delay) < 0)
				continue;
			fprintf(f, "%s \"latencyOffsetNsec\": %"PRIi64, (comma ? "," : ""), delay);
			break;
		}
		case SPA_PROP_iec958Codecs:
		{
			uint32_t i, codecs[64], n_codecs;

			n_codecs = spa_pod_copy_array(&prop->value, SPA_TYPE_Id,
					codecs, sizeof(codecs));
			if (n_codecs == 0)
				continue;

			fprintf(f, "%s \"iec958Codecs\": [", (comma ? "," : ""));
			for (i = 0; i < n_codecs; i++)
				fprintf(f, "%s \"%s\"", (i == 0 ? "" : ","), iec958Codec_to_name(codecs[i]));
			fprintf(f, " ]");
			break;
		}
		default:
			continue;
		}
		comma = true;
	}
	fprintf(f, " }");
        fclose(f);
	return ptr;
}

static int restore_route_params(struct device *dev, const char *val, const struct route *r)
{
	struct spa_json it[3];
	char buf[1024], key[128];
	const char *value;
	struct spa_pod_builder b = SPA_POD_BUILDER_INIT(buf, sizeof(buf));
	struct spa_pod_frame f[2];
	struct spa_pod *param;

	spa_json_init(&it[0], val, strlen(val));

	if (spa_json_enter_object(&it[0], &it[1]) <= 0)
                return -EINVAL;

	spa_pod_builder_push_object(&b, &f[0],
			SPA_TYPE_OBJECT_ParamRoute, SPA_PARAM_Route);
	spa_pod_builder_add(&b,
			SPA_PARAM_ROUTE_index, SPA_POD_Int(r->index),
			SPA_PARAM_ROUTE_device, SPA_POD_Int(r->device_id),
			0);
	spa_pod_builder_prop(&b, SPA_PARAM_ROUTE_props, 0);
	spa_pod_builder_push_object(&b, &f[1],
			SPA_TYPE_OBJECT_Props, SPA_PARAM_Route);

	while (spa_json_get_string(&it[1], key, sizeof(key)-1) > 0) {
		if (spa_streq(key, "volume")) {
			float vol;
			if (spa_json_get_float(&it[1], &vol) <= 0)
                                continue;
			spa_pod_builder_prop(&b, SPA_PROP_volume, 0);
			spa_pod_builder_float(&b, vol);
		}
		else if (spa_streq(key, "mute")) {
			bool mute;
			if (spa_json_get_bool(&it[1], &mute) <= 0)
                                continue;
			spa_pod_builder_prop(&b, SPA_PROP_mute, 0);
			spa_pod_builder_bool(&b, mute);
		}
		else if (spa_streq(key, "volumes")) {
			uint32_t n_vols;
			float vols[SPA_AUDIO_MAX_CHANNELS];

			if (spa_json_enter_array(&it[1], &it[2]) <= 0)
				continue;

			for (n_vols = 0; n_vols < SPA_AUDIO_MAX_CHANNELS; n_vols++) {
                                if (spa_json_get_float(&it[2], &vols[n_vols]) <= 0)
                                        break;
                        }
			if (n_vols == 0)
				continue;

			spa_pod_builder_prop(&b, SPA_PROP_channelVolumes, 0);
			spa_pod_builder_array(&b, sizeof(float), SPA_TYPE_Float,
					n_vols, vols);
		}
		else if (spa_streq(key, "channels")) {
			uint32_t n_ch;
			uint32_t map[SPA_AUDIO_MAX_CHANNELS];

			if (spa_json_enter_array(&it[1], &it[2]) <= 0)
				continue;

			for (n_ch = 0; n_ch < SPA_AUDIO_MAX_CHANNELS; n_ch++) {
				char chname[16];
                                if (spa_json_get_string(&it[2], chname, sizeof(chname)) <= 0)
                                        break;
				map[n_ch] = channel_from_name(chname);
                        }
			if (n_ch == 0)
				continue;

			spa_pod_builder_prop(&b, SPA_PROP_channelMap, 0);
			spa_pod_builder_array(&b, sizeof(uint32_t), SPA_TYPE_Id,
					n_ch, map);
		}
		else if (spa_streq(key, "latencyOffsetNsec")) {
			float delay;
			if (spa_json_get_float(&it[1], &delay) <= 0)
                                continue;
			spa_pod_builder_prop(&b, SPA_PROP_latencyOffsetNsec, 0);
			spa_pod_builder_long(&b, (int64_t)SPA_CLAMP(delay, INT64_MIN, INT64_MAX));
		}
		else if (spa_streq(key, "iec958Codecs")) {
			uint32_t n_codecs;
			uint32_t codecs[64];

			if (spa_json_enter_array(&it[1], &it[2]) <= 0)
				continue;

			for (n_codecs = 0; n_codecs < 64; n_codecs++) {
				char name[16];
                                if (spa_json_get_string(&it[2], name, sizeof(name)) <= 0)
                                        break;
				codecs[n_codecs] = iec958Codec_from_name(name);
                        }
			if (n_codecs == 0)
				continue;

			spa_pod_builder_prop(&b, SPA_PROP_iec958Codecs, 0);
			spa_pod_builder_array(&b, sizeof(uint32_t), SPA_TYPE_Id,
					n_codecs, codecs);
		} else {
			if (spa_json_next(&it[1], &value) <= 0)
                                break;
		}
	}
	spa_pod_builder_pop(&b, &f[1]);
	spa_pod_builder_prop(&b, SPA_PARAM_ROUTE_save, 0);
	spa_pod_builder_bool(&b, r->save);
	param = spa_pod_builder_pop(&b, &f[0]);

	if (pw_log_level_enabled(SPA_LOG_LEVEL_DEBUG))
		spa_debug_pod(2, NULL, param);

	pw_device_set_param((struct pw_node*)dev->obj->obj.proxy,
			SPA_PARAM_Route, 0, param);

	sm_media_session_schedule_rescan(dev->impl->session);

	return 0;
}

struct profile {
	uint32_t index;
	const char *name;
	struct spa_pod *classes;
};

static int parse_profile(const struct sm_param *p, struct profile *pr)
{
	int res;
	spa_zero(*pr);
	if ((res = spa_pod_parse_object(p->param,
			SPA_TYPE_OBJECT_ParamProfile, NULL,
			SPA_PARAM_PROFILE_index,   SPA_POD_Int(&pr->index),
			SPA_PARAM_PROFILE_name,    SPA_POD_String(&pr->name),
			SPA_PARAM_PROFILE_classes, SPA_POD_OPT_Pod(&pr->classes))) < 0)
		return res;
	return 0;
}

static int find_current_profile(const struct device *dev, struct profile *pr)
{
	struct sm_param *p;
	spa_list_for_each(p, &dev->obj->param_list, link) {
		if (p->id == SPA_PARAM_Profile &&
		    parse_profile(p, pr) >= 0)
			return 0;
	}
	return -ENOENT;
}

static int restore_route(struct device *dev, const struct route *r)
{
	struct impl *impl = dev->impl;
	char key[1024];
	const char *val;
	struct route_info *ri;

	if ((ri = find_route_info(dev, r)) == NULL)
		return -errno;

	snprintf(key, sizeof(key), PREFIX"%s:%s:%s", dev->name,
		r->direction == SPA_DIRECTION_INPUT ? "input" : "output", r->name);

	val = pw_properties_get(impl->to_restore, key);
	if (val == NULL)
		val = "{ \"volumes\": [ 0.4 ], \"mute\": false }";

	pw_log_info("device %d: restore route %d '%s' to %s", dev->id, r->index, key, val);

	restore_route_params(dev, val, r);
	ri->prev_active = true;
	ri->active = true;
	ri->generation = dev->generation;
	ri->save = r->save;

	return 0;
}

static int save_route(const struct device *dev, const struct route *r)
{
	struct impl *impl = dev->impl;
	char key[1024], *val;

	if (r->props == NULL)
		return -EINVAL;

	snprintf(key, sizeof(key), PREFIX"%s:%s:%s", dev->name,
		r->direction == SPA_DIRECTION_INPUT ? "input" : "output", r->name);

	val = serialize_props(dev, r->props);
	if (pw_properties_set(impl->to_restore, key, val)) {
		pw_log_info("device %d: route properties changed %s %s", dev->id, key, val);
		add_idle_timeout(impl);
	}
	free(val);
	return 0;
}

static char *serialize_routes(const struct device *dev)
{
	char *ptr;
	size_t size;
	FILE *f;
	const struct route_info *ri;
	int count = 0;

	f = open_memstream(&ptr, &size);
	fprintf(f, "[");

	pw_array_for_each(ri, &dev->route_info) {
		if (ri->save) {
			fprintf(f, "%s \"%s\"", count++ == 0 ? "" : ",", ri->name);
		}
	}
	fprintf(f, " ]");
	fclose(f);
	return ptr;
}

static int save_profile(struct device *dev, const char *profile_name)
{
	struct impl *impl = dev->impl;
	char key[1024], *val;

	if (pw_array_get_len(&dev->route_info, struct route_info) == 0)
		return 0;

	snprintf(key, sizeof(key), PREFIX"%s:profile:%s", dev->name, profile_name);

	val = serialize_routes(dev);
	if (pw_properties_set(impl->to_restore, key, val)) {
		pw_log_info("device %d: profile %s routes changed %s %s",
				dev->id, profile_name, key, val);
		add_idle_timeout(impl);
	} else {
		pw_log_info("device %d: profile %s unchanged (%s)",
				dev->id, profile_name, val);
	}
	free(val);
	return 0;
}

static int find_best_route(struct device *dev, uint32_t device_id, struct route *r)
{
	struct sm_param *p;
	struct route best, best_avail, best_unk;

	spa_zero(best_avail);
	spa_zero(best_unk);

	spa_list_for_each(p, &dev->obj->param_list, link) {
		struct route t;

		if (p->id != SPA_PARAM_EnumRoute ||
		    parse_enum_route(p, device_id, &t) < 0)
			continue;

		if (t.available == SPA_PARAM_AVAILABILITY_yes || t.available == SPA_PARAM_AVAILABILITY_unknown) {
			struct route_info *ri;
			if ((ri = find_route_info(dev, &t)) && ri->direction == SPA_DIRECTION_OUTPUT &&
			    ri->available != ri->prev_available) {
				/* If route availability changed, that means a user just
				 * plugged in something like headphones, and they probably
				 * expect to hear sound from it. Switch to it immediately.
				 *
				 * TODO: switch INPUT ports without source and the input
				 * ports their source->active_port is part of a group of
				 * ports (see module-switch-on-port-available.c in PulseAudio).
				 */
				best_avail = t;
				ri->save = true;
				break;
			}
			else if (t.available == SPA_PARAM_AVAILABILITY_yes) {
				if (best_avail.name == NULL || t.priority > best_avail.priority)
					best_avail = t;
			} else { // SPA_PARAM_AVAILABILITY_unknown
				if (best_unk.name == NULL || t.priority > best_unk.priority)
					best_unk = t;
			}
		}
	}
	best = best_avail;
	if (best.name == NULL)
		best = best_unk;
	if (best.name == NULL)
		return -ENOENT;
	*r = best;
	return 0;
}

static int find_route(const struct device *dev, uint32_t device_id, const char *name, struct route *r)
{
	struct sm_param *p;

	spa_list_for_each(p, &dev->obj->param_list, link) {
		if (p->id != SPA_PARAM_EnumRoute ||
		    parse_enum_route(p, device_id, r) < 0)
			continue;
		if (!spa_streq(r->name, name))
			continue;
		return 0;
	}
	return -ENOENT;
}

static int find_saved_route(struct device *dev, const char *val, uint32_t device_id, struct route *r)
{
	struct spa_json it[2];
	char key[128];

	if (val == NULL)
		return -ENOENT;

	spa_json_init(&it[0], val, strlen(val));
	if (spa_json_enter_array(&it[0], &it[1]) <= 0)
                return -EINVAL;

	while (spa_json_get_string(&it[1], key, sizeof(key)-1) > 0) {
		if (find_route(dev, device_id, key, r) >= 0)
			return 0;
	}
	return -ENOENT;
}

static int restore_device_route(struct device *dev, const char *val, uint32_t device_id, bool restore)
{
	int res = -ENOENT;
	struct route t;

	pw_log_info("device %d: restoring device %u", dev->id, device_id);

	if (restore) {
		res = find_saved_route(dev, val, device_id, &t);
		if (res >= 0) {
			/* we found a saved route */
			if (t.available == SPA_PARAM_AVAILABILITY_no) {
				pw_log_info("device %d: saved route '%s' not available", dev->id,
						t.name);
				/* not available, try to find next best port */
				res = -ENOENT;
			} else {
				pw_log_info("device %d: found saved route '%s'", dev->id,
						t.name);
				/* make sure we save it again */
				t.save = true;
			}
		}
	}
	if (res < 0) {
		/* we could not find a saved route, try to find a new best */
		res = find_best_route(dev, device_id, &t);
		if (res < 0) {
			pw_log_info("device %d: can't find best route", dev->id);
		} else {
			pw_log_info("device %d: found best route '%s'", dev->id,
					t.name);
		}
	}
	if (res >= 0)
		restore_route(dev, &t);

	return res;
}

static int reconfigure_profile(struct device *dev, struct profile *pr, bool restore)
{
	struct impl *impl = dev->impl;
	char key[1024];
	const char *json;

	pw_log_info("device %s: restore routes for profile '%s'",
			dev->name, pr->name);
	dev->active_profile = pr->index;

	snprintf(key, sizeof(key), PREFIX"%s:profile:%s", dev->name, pr->name);
	json = pw_properties_get(impl->to_restore, key);

	if (pr->classes != NULL) {
		struct spa_pod *iter;

		SPA_POD_STRUCT_FOREACH(pr->classes, iter) {
			struct spa_pod_parser prs;
			struct spa_pod_frame f[1];
			struct spa_pod *val;
			char *key;

			spa_pod_parser_pod(&prs, iter);
			if (spa_pod_parser_push_struct(&prs, &f[0]) < 0)
				continue;

			while (spa_pod_parser_get(&prs,
						SPA_POD_String(&key),
						SPA_POD_Pod(&val),
						NULL) >= 0) {
				if (key == NULL || val == NULL)
					break;
				if (spa_streq(key, "card.profile.devices")) {
					uint32_t *devices, n_devices, i;

					devices = spa_pod_get_array(val, &n_devices);
					if (devices == NULL || n_devices == 0)
						continue;

					for (i = 0; i < n_devices; i++)
						restore_device_route(dev, json, devices[i], restore);
				}
			}
                        spa_pod_parser_pop(&prs, &f[0]);
		}
	}
	return 0;
}

static void prune_route_info(struct device *dev)
{
	struct route_info *i;

	for (i = pw_array_first(&dev->route_info);
	     pw_array_check(&dev->route_info, i);) {
		if (i->generation != dev->generation) {
			pw_log_info("device %d: route '%s' unused", dev->id, i->name);
			pw_array_remove(&dev->route_info, i);
		} else
			i++;
	}
}

static int handle_route(struct device *dev, const struct route *r)
{
	struct route_info *ri;

	pw_log_info("device %d: port '%s'", dev->id, r->name);
	if ((ri = find_route_info(dev, r)) == NULL)
		return -errno;

	ri->active = true;
	ri->save = r->save;

	if (!ri->prev_active) {
		/* a new port has been found, restore the volume and make sure we
		 * save this as a preferred port */
		pw_log_info("device %d: new active port found '%s'", dev->id, r->name);
		restore_route(dev, r);
	} else if (r->props && r->save) {
		/* just save port properties */
		save_route(dev, r);
	}
	return 0;
}

static int handle_device(struct device *dev)
{
	struct profile pr;
	struct sm_param *p;
	bool route_changed = false;

	dev->generation++;

	if (find_current_profile(dev, &pr) < 0)
		pr.index = SPA_ID_INVALID;

	/* first look at all routes and update */
	spa_list_for_each(p, &dev->obj->param_list, link) {
		struct route r;
		struct route_info *ri;

		if (p->id != SPA_PARAM_EnumRoute ||
		    parse_enum_route(p, SPA_ID_INVALID, &r) < 0)
			continue;

		if ((ri = find_route_info(dev, &r)) == NULL)
			continue;

		ri->prev_available = ri->available;
		if (ri->available != r.available) {
			pw_log_info("device %d: route %s available changed %d -> %d",
					dev->id, r.name, ri->available, r.available);
			ri->available = r.available;
			if (array_contains(r.profiles, pr.index))
				route_changed = true;
		}
		ri->generation = dev->generation;
		ri->prev_active = ri->active;
		ri->active = false;
		ri->save = false;
	}
	/* then check for changes in the active ports */
	spa_list_for_each(p, &dev->obj->param_list, link) {
		struct route r;
		if (p->id != SPA_PARAM_Route ||
		    parse_route(p, &r) < 0)
			continue;
		handle_route(dev, &r);
	}

	prune_route_info(dev);

	if (pr.index != SPA_ID_INVALID) {
		bool restore = dev->active_profile != pr.index;
		if (restore || route_changed)
			reconfigure_profile(dev, &pr, restore);

		save_profile(dev, pr.name);
	}
	return 0;
}

static void object_update(void *data)
{
	struct device *dev = data;
	struct impl *impl = dev->impl;

	pw_log_debug(NAME" %p: device %p %08x/%08x", impl, dev,
			dev->obj->obj.changed, dev->obj->obj.avail);

	if (dev->obj->obj.changed & SM_DEVICE_CHANGE_MASK_PARAMS)
		handle_device(dev);
}

static const struct sm_object_events object_events = {
	SM_VERSION_OBJECT_EVENTS,
	.update = object_update
};

static void session_create(void *data, struct sm_object *object)
{
	struct impl *impl = data;
	struct device *dev;
	const char *name;

	if (!spa_streq(object->type, PW_TYPE_INTERFACE_Device) ||
	    object->props == NULL ||
	    (name = pw_properties_get(object->props, PW_KEY_DEVICE_NAME)) == NULL)
		return;

	pw_log_debug(NAME " %p: add device '%d' %s", impl, object->id, name);

	dev = sm_object_add_data(object, SESSION_KEY, sizeof(struct device));
	dev->obj = (struct sm_device*)object;
	dev->id = object->id;
	dev->impl = impl;
	dev->name = strdup(name);
	dev->active_profile = SPA_ID_INVALID;
	dev->generation = 0;
	pw_array_init(&dev->route_info, sizeof(struct route_info) * 16);

	dev->obj->obj.mask |= SM_DEVICE_CHANGE_MASK_PARAMS;
	sm_object_add_listener(&dev->obj->obj, &dev->listener, &object_events, dev);
}

static void destroy_device(struct impl *impl, struct device *dev)
{
	spa_hook_remove(&dev->listener);
	pw_array_clear(&dev->route_info);
	free(dev->name);
	sm_object_remove_data((struct sm_object*)dev->obj, SESSION_KEY);
}

static void session_remove(void *data, struct sm_object *object)
{
	struct impl *impl = data;
	struct device *dev;

	if (!spa_streq(object->type, PW_TYPE_INTERFACE_Device))
		return;

	pw_log_debug(NAME " %p: remove device '%d'", impl, object->id);

	if ((dev = sm_object_get_data(object, SESSION_KEY)) != NULL)
		destroy_device(impl, dev);
}

static void session_destroy(void *data)
{
	struct impl *impl = data;
	remove_idle_timeout(impl);
	spa_hook_remove(&impl->listener);
	pw_properties_free(impl->to_restore);
	free(impl);
}

static const struct sm_media_session_events session_events = {
	SM_VERSION_MEDIA_SESSION_EVENTS,
	.create = session_create,
	.remove = session_remove,
	.destroy = session_destroy,
};

int sm_default_routes_start(struct sm_media_session *session)
{
	struct impl *impl;
	int res;

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

	impl->session = session;
	impl->context = session->context;

	impl->to_restore = pw_properties_new(NULL, NULL);
	if (impl->to_restore == NULL) {
		res = -errno;
		goto exit_free;
	}

	if ((res = sm_media_session_load_state(impl->session,
					SESSION_KEY, impl->to_restore)) < 0)
		pw_log_info("can't load "SESSION_KEY" state: %s", spa_strerror(res));

	sm_media_session_add_listener(impl->session, &impl->listener, &session_events, impl);

	return 0;

exit_free:
	free(impl);
	return res;
}