pulse-server: implement subscribe in device-restore

Add a client that subscribes to the list of subscribers and make the
client watch for EnumFormat changes.

When a subscribed client sees an EnumFormat change for a sink, emit EVENT
to the client.

This will send the EVENT to pavucontrol when the supported IEC958
formats change so that it can update the gui.

src/modules/module-protocol-pulse/modules/module-device-restore.c

@@ -19,6 +19,15 @@
 
 #define EXT_DEVICE_RESTORE_VERSION	1
 
+enum {
+    SUBCOMMAND_TEST,
+    SUBCOMMAND_SUBSCRIBE,
+    SUBCOMMAND_EVENT,
+    SUBCOMMAND_READ_FORMATS_ALL,
+    SUBCOMMAND_READ_FORMATS,
+    SUBCOMMAND_SAVE_FORMATS
+};
+
 #include <stdbool.h>
 #include <stdint.h>
 #include <stdio.h>
@@ -38,11 +47,13 @@
 
 #include "../client.h"
 #include "../collect.h"
+#include "../commands.h"
 #include "../defs.h"
 #include "../extension.h"
 #include "../format.h"
 #include "../manager.h"
 #include "../message.h"
+#include "../operation.h"
 #include "../reply.h"
 #include "../volume.h"
 
@@ -59,6 +70,8 @@ PW_LOG_TOPIC_STATIC(mod_topic, "mod." NAME);
 
 struct module_device_restore_data {
 	struct module *module;
+
+	struct spa_list subscribed;
 };
 
 static const struct spa_dict_item module_device_restore_info[] = {
@@ -83,11 +96,127 @@ static int do_extension_device_restore_test(struct module *module, struct client
 	return client_queue_message(client, reply);
 }
 
-static int do_extension_device_restore_subscribe(struct module *module, struct client *client, uint32_t command, uint32_t tag, struct message *m)
+struct subscribe {
+	struct spa_list link;
+	struct module_device_restore_data *data;
+
+	struct client *client;
+	struct spa_hook listener;
+
+	struct spa_hook manager_listener;
+};
+
+static void remove_subscribe(struct subscribe *s)
 {
-	return reply_simple_ack(client, tag);
+	spa_list_remove(&s->link);
+	spa_hook_remove(&s->listener);
+	spa_hook_remove(&s->manager_listener);
+	free(s);
 }
 
+static void emit_event(struct subscribe *s, uint32_t type, uint32_t idx)
+{
+	struct client *client = s->client;
+	struct message *msg = message_alloc(client->impl, -1, 0);
+
+	pw_log_info("[%s] EVENT index:%u name:%s %d/%d", client->name,
+			s->data->module->index, s->data->module->info->name, type, idx);
+
+	message_put(msg,
+		TAG_U32, COMMAND_EXTENSION,
+		TAG_U32, 0,
+		TAG_U32, s->data->module->index,
+		TAG_STRING, s->data->module->info->name,
+		TAG_U32, SUBCOMMAND_EVENT,
+		TAG_U32, type,
+		TAG_U32, idx,
+		TAG_INVALID);
+
+	client_queue_message(client, msg);
+}
+
+static void module_client_disconnect(void *data)
+{
+	struct subscribe *s = data;
+	remove_subscribe(s);
+}
+
+static const struct client_events module_client_events = {
+	VERSION_CLIENT_EVENTS,
+	.disconnect = module_client_disconnect,
+};
+
+static void manager_updated(void *data, struct pw_manager_object *object)
+{
+	struct subscribe *s = data;
+	uint32_t i;
+
+	if (!pw_manager_object_is_sink(object))
+		return;
+
+	for (i = 0; i < object->n_params; i++) {
+		if (object->params[i].id == SPA_PARAM_EnumFormat &&
+		    object->params[i].user != 0)
+			emit_event(s, DEVICE_TYPE_SINK, object->index);
+	}
+}
+
+struct pw_manager_events manager_events = {
+	PW_VERSION_MANAGER_EVENTS,
+	.added = manager_updated,
+	.updated = manager_updated,
+};
+
+static struct subscribe *add_subscribe(struct module_device_restore_data *data, struct client *c)
+{
+	struct subscribe *s;
+	s = calloc(1, sizeof(*s));
+	if (s == NULL)
+		return NULL;
+	s->data = data;
+	s->client = c;
+	client_add_listener(c, &s->listener, &module_client_events, s);
+	spa_list_append(&data->subscribed, &s->link);
+
+	pw_manager_add_listener(c->manager, &s->manager_listener,
+			&manager_events, s);
+	return s;
+}
+
+static struct subscribe *find_subscribe(struct module_device_restore_data *data, struct client *c)
+{
+	struct subscribe *s;
+	spa_list_for_each(s, &data->subscribed, link) {
+		if (s->client == c)
+			return s;
+	}
+	return NULL;
+}
+
+static int do_extension_device_restore_subscribe(struct module *module, struct client *client, uint32_t command, uint32_t tag, struct message *m)
+{
+	struct module_device_restore_data * const d = module->user_data;
+	int res;
+	bool enabled;
+	struct subscribe *s;
+
+	if ((res = message_get(m,
+			TAG_BOOLEAN, &enabled,
+			TAG_INVALID)) < 0)
+		return -EPROTO;
+
+	s = find_subscribe(d, client);
+	if (enabled) {
+		if (s == NULL)
+			s = add_subscribe(d, client);
+		if (s == NULL)
+			return -errno;
+	} else {
+		if (s != NULL)
+			remove_subscribe(s);
+	}
+	return reply_simple_ack(client, tag);
+}
 
 struct format_data {
         struct client *client;
@@ -248,7 +377,6 @@ static int set_node_codecs(struct pw_manager_object *o, uint32_t n_codecs, uint3
 	return 0;
 }
 
-
 static int do_extension_device_restore_save_formats(struct module *module, struct client *client,
 		uint32_t command, uint32_t tag, struct message *m)
 {
@@ -318,12 +446,12 @@ static int do_extension_device_restore_save_formats(struct module *module, struc
 }
 
 static const struct extension module_device_restore_extension[] = {
-	{ "TEST", 0, do_extension_device_restore_test, },
+	{ "TEST", SUBCOMMAND_TEST, do_extension_device_restore_test, },
-	{ "SUBSCRIBE", 1, do_extension_device_restore_subscribe, },
+	{ "SUBSCRIBE", SUBCOMMAND_SUBSCRIBE, do_extension_device_restore_subscribe, },
-	{ "EVENT", 2, },
+	{ "EVENT", SUBCOMMAND_EVENT, },
-	{ "READ_FORMATS_ALL", 3, do_extension_device_restore_read_formats_all, },
+	{ "READ_FORMATS_ALL", SUBCOMMAND_READ_FORMATS_ALL, do_extension_device_restore_read_formats_all, },
-	{ "READ_FORMATS", 4, do_extension_device_restore_read_formats, },
+	{ "READ_FORMATS", SUBCOMMAND_READ_FORMATS, do_extension_device_restore_read_formats, },
-	{ "SAVE_FORMATS", 5, do_extension_device_restore_save_formats, },
+	{ "SAVE_FORMATS", SUBCOMMAND_SAVE_FORMATS, do_extension_device_restore_save_formats, },
 	{ NULL },
 };
 
@@ -339,6 +467,17 @@ static int module_device_restore_prepare(struct module * const module)
 
 static int module_device_restore_load(struct module *module)
 {
+	struct module_device_restore_data * const data = module->user_data;
+	spa_list_init(&data->subscribed);
+	return 0;
+}
+static int module_device_restore_unload(struct module *module)
+{
+	struct module_device_restore_data * const data = module->user_data;
+	struct subscribe *s;
+
+	spa_list_consume(s, &data->subscribed, link)
+		remove_subscribe(s);
 	return 0;
 }
 
@@ -347,6 +486,7 @@ DEFINE_MODULE_INFO(module_device_restore) = {
 	.load_once = true,
 	.prepare = module_device_restore_prepare,
 	.load = module_device_restore_load,
+	.unload = module_device_restore_unload,
 	.extension = module_device_restore_extension,
 	.properties = &SPA_DICT_INIT_ARRAY(module_device_restore_info),
 	.data_size = sizeof(struct module_device_restore_data),