Use vacancy_updated event

nano/core_test/active_elections.cpp

@@ -1308,7 +1308,9 @@ TEST (active_elections, vacancy)
 				.sign (nano::dev::genesis_key.prv, nano::dev::genesis_key.pub)
 				.work (*system.work.generate (nano::dev::genesis->hash ()))
 				.build ();
-	node.active.vacancy_update = [&updated] () { updated = true; };
+	node.active.vacancy_updated.add ([&updated] () {
+		updated = true;
+	});
 	ASSERT_EQ (nano::block_status::progress, node.process (send));
 	ASSERT_EQ (1, node.active.vacancy (nano::election_behavior::priority));
 	ASSERT_EQ (0, node.active.size ());

nano/node/active_elections.cpp

@@ -312,7 +312,7 @@ void nano::active_elections::cleanup_election (nano::unique_lock<nano::mutex> &
 		entry.erased_callback (election);
 	}
 
-	vacancy_update ();
+	vacancy_updated.notify ();
 
 	for (auto const & [hash, block] : blocks_l)
 	{
@@ -435,7 +435,7 @@ nano::election_insertion_result nano::active_elections::insert (std::shared_ptr<
 
 		node.vote_cache_processor.trigger (hash);
 		node.observers.active_started.notify (hash);
-		vacancy_update ();
+		vacancy_updated.notify ();
 	}
 
 	// Votes are generated for inserted or ongoing elections
@@ -541,8 +541,7 @@ void nano::active_elections::clear ()
 		nano::lock_guard<nano::mutex> guard{ mutex };
 		roots.clear ();
 	}
-
-	vacancy_update ();
+	vacancy_updated.notify ();
 }
 
 nano::container_info nano::active_elections::container_info () const

nano/node/active_elections.hpp

@@ -2,6 +2,7 @@
 
 #include <nano/lib/enum_util.hpp>
 #include <nano/lib/numbers.hpp>
+#include <nano/lib/observer_set.hpp>
 #include <nano/node/election_behavior.hpp>
 #include <nano/node/election_insertion_result.hpp>
 #include <nano/node/election_status.hpp>
@@ -121,10 +122,12 @@ public:
 	 * How many election slots are available for specified election type
 	 */
 	int64_t vacancy (nano::election_behavior behavior) const;
-	std::function<void ()> vacancy_update{ [] () {} };
 
 	nano::container_info container_info () const;
 
+public: // Events
+	nano::observer_set<> vacancy_updated;
+
 private:
 	void request_loop ();
 	void request_confirm (nano::unique_lock<nano::mutex> &);

nano/node/node.cpp

@@ -187,13 +187,6 @@ nano::node::node (std::shared_ptr<boost::asio::io_context> io_ctx_a, std::filesy
 
 	if (!init_error ())
 	{
-		// Notify election schedulers when AEC frees election slot
-		active.vacancy_update = [this] () {
-			scheduler.priority.notify ();
-			scheduler.hinted.notify ();
-			scheduler.optimistic.notify ();
-		};
-
 		wallets.observer = [this] (bool active) {
 			observers.wallet.notify (active);
 		};

nano/node/scheduler/component.cpp

@@ -15,6 +15,12 @@ nano::scheduler::component::component (nano::node_config & node_config, nano::no
 	optimistic{ *optimistic_impl },
 	priority{ *priority_impl }
 {
+	// Notify election schedulers when AEC frees election slot
+	active.vacancy_updated.add ([this] () {
+		priority.notify ();
+		hinted.notify ();
+		optimistic.notify ();
+	});
 }
 
 nano::scheduler::component::~component ()