notification: Add registeration interface

lightningd/notification.c

@@ -13,8 +13,26 @@ const char *notification_topics[] = {
 	"forward_event"
 };
 
+static struct notification *find_notification_by_topic(const char* topic)
+{
+	static struct notification **notilist = NULL;
+	static size_t num_notis;
+	if (!notilist)
+		notilist = autodata_get(notifications, &num_notis);
+
+	for (size_t i=0; i<num_notis; i++)
+		if (streq(notilist[i]->topic, topic))
+			return notilist[i];
+	return NULL;
+}
+
 bool notifications_have_topic(const char *topic)
 {
+	struct notification *noti = find_notification_by_topic(topic);
+	if (noti)
+		return true;
+
+	/* TODO: Remove this block after making all notifications registered. */
 	for (size_t i=0; i<ARRAY_SIZE(notification_topics); i++)
 		if (streq(topic, notification_topics[i]))
 			return true;
@@ -131,3 +149,7 @@ void notify_forward_event(struct lightningd *ld,
 	jsonrpc_notification_end(n);
 	plugins_notify(ld->plugins, take(n));
 }
+
+/* TODO: It's a dummy notification. Will be removed when we have a 'real' one
+ * in this file. */
+REGISTER_JSON_INTERNAL_COMMAND(hello_notification, NULL, void *);

lightningd/notification.h

@@ -3,6 +3,7 @@
 #include "config.h"
 #include <bitcoin/short_channel_id.h>
 #include <bitcoin/tx.h>
+#include <ccan/autodata/autodata.h>
 #include <ccan/json_escape/json_escape.h>
 #include <ccan/time/time.h>
 #include <common/amount.h>
@@ -17,6 +18,22 @@
 
 bool notifications_have_topic(const char *topic);
 
+struct notification {
+	const char *topic;
+	/* the serialization interface */
+	void *serialize;
+};
+
+AUTODATA_TYPE(notifications, struct notification);
+
+/* FIXME: Find a way to avoid back-to-back declaration and definition */
+#define REGISTER_NOTIFICATION(topic, serialize)                                  \
+	struct notification topic##_notification_gen = {                         \
+		stringify(topic),                                                \
+		serialize,                                                       \
+	};                                                                       \
+	AUTODATA(notifications, &topic##_notification_gen);
+
 void notify_connect(struct lightningd *ld, struct node_id *nodeid,
 		    struct wireaddr_internal *addr);
 void notify_disconnect(struct lightningd *ld, struct node_id *nodeid);