[Net] Optimize object cache notification send for single peer.

It used to always cycle all the peers when checking which one needed to
be notified, now it only does that when the target is multiple (i.e.
broadcast or exclusion).

scene/multiplayer/scene_cache_interface.cpp

@@ -139,74 +139,46 @@ void SceneCacheInterface::process_confirm_path(int p_from, const uint8_t *p_pack
 	E->get() = true;
 }
 
-bool SceneCacheInterface::_send_confirm_path(Node *p_node, NodePath p_path, PathSentCache *psc, int p_target) {
-	bool has_all_peers = true;
-	List<int> peers_to_add; // If one is missing, take note to add it.
-
-	for (const Set<int>::Element *E = multiplayer->get_connected_peers().front(); E; E = E->next()) {
-		if (p_target < 0 && E->get() == -p_target) {
-			continue; // Continue, excluded.
-		}
-
-		if (p_target > 0 && E->get() != p_target) {
-			continue; // Continue, not for this peer.
-		}
-
-		Map<int, bool>::Element *F = psc->confirmed_peers.find(E->get());
-
-		if (!F || !F->get()) {
-			// Path was not cached, or was cached but is unconfirmed.
-			if (!F) {
-				// Not cached at all, take note.
-				peers_to_add.push_back(E->get());
-			}
+Error SceneCacheInterface::_send_confirm_path(Node *p_node, NodePath p_path, PathSentCache *psc, const List<int> &p_peers) {
+	// Encode function name.
+	const CharString path = String(p_path).utf8();
+	const int path_len = encode_cstring(path.get_data(), nullptr);
 
-			has_all_peers = false;
-		}
-	}
-
-	if (peers_to_add.size() > 0) {
-		// Those that need to be added, send a message for this.
-
-		// Encode function name.
-		const CharString path = String(p_path).utf8();
-		const int path_len = encode_cstring(path.get_data(), nullptr);
+	// Extract MD5 from rpc methods list.
+	const String methods_md5 = multiplayer->get_rpc_md5(p_node);
+	const int methods_md5_len = 33; // 32 + 1 for the `0` that is added by the encoder.
 
-		// Extract MD5 from rpc methods list.
-		const String methods_md5 = multiplayer->get_rpc_md5(p_node);
-		const int methods_md5_len = 33; // 32 + 1 for the `0` that is added by the encoder.
-
-		Vector<uint8_t> packet;
-		packet.resize(1 + 4 + path_len + methods_md5_len);
-		int ofs = 0;
+	Vector<uint8_t> packet;
+	packet.resize(1 + 4 + path_len + methods_md5_len);
+	int ofs = 0;
 
-		packet.write[ofs] = MultiplayerAPI::NETWORK_COMMAND_SIMPLIFY_PATH;
-		ofs += 1;
+	packet.write[ofs] = MultiplayerAPI::NETWORK_COMMAND_SIMPLIFY_PATH;
+	ofs += 1;
 
-		ofs += encode_cstring(methods_md5.utf8().get_data(), &packet.write[ofs]);
+	ofs += encode_cstring(methods_md5.utf8().get_data(), &packet.write[ofs]);
 
-		ofs += encode_uint32(psc->id, &packet.write[ofs]);
+	ofs += encode_uint32(psc->id, &packet.write[ofs]);
 
-		ofs += encode_cstring(path.get_data(), &packet.write[ofs]);
+	ofs += encode_cstring(path.get_data(), &packet.write[ofs]);
 
-		Ref<MultiplayerPeer> multiplayer_peer = multiplayer->get_multiplayer_peer();
-		ERR_FAIL_COND_V(multiplayer_peer.is_null(), false);
+	Ref<MultiplayerPeer> multiplayer_peer = multiplayer->get_multiplayer_peer();
+	ERR_FAIL_COND_V(multiplayer_peer.is_null(), ERR_BUG);
 
 #ifdef DEBUG_ENABLED
-		multiplayer->profile_bandwidth("out", packet.size() * peers_to_add.size());
+	multiplayer->profile_bandwidth("out", packet.size() * p_peers.size());
 #endif
 
-		for (int &E : peers_to_add) {
-			multiplayer_peer->set_target_peer(E); // To all of you.
-			multiplayer_peer->set_transfer_channel(0);
-			multiplayer_peer->set_transfer_mode(Multiplayer::TRANSFER_MODE_RELIABLE);
-			multiplayer_peer->put_packet(packet.ptr(), packet.size());
-
-			psc->confirmed_peers.insert(E, false); // Insert into confirmed, but as false since it was not confirmed.
-		}
+	Error err = OK;
+	for (int peer_id : p_peers) {
+		multiplayer_peer->set_target_peer(peer_id);
+		multiplayer_peer->set_transfer_channel(0);
+		multiplayer_peer->set_transfer_mode(Multiplayer::TRANSFER_MODE_RELIABLE);
+		err = multiplayer_peer->put_packet(packet.ptr(), packet.size());
+		ERR_FAIL_COND_V(err != OK, err);
+		// Insert into confirmed, but as false since it was not confirmed.
+		psc->confirmed_peers.insert(peer_id, false);
 	}
-
-	return has_all_peers;
+	return err;
 }
 
 bool SceneCacheInterface::is_cache_confirmed(NodePath p_path, int p_peer) {
@@ -230,7 +202,43 @@ bool SceneCacheInterface::send_object_cache(Object *p_obj, NodePath p_path, int
 	}
 	r_id = psc->id;
 
-	return _send_confirm_path(node, p_path, psc, p_peer_id);
+	bool has_all_peers = true;
+	List<int> peers_to_add; // If one is missing, take note to add it.
+
+	if (p_peer_id > 0) {
+		// Fast single peer check.
+		Map<int, bool>::Element *F = psc->confirmed_peers.find(p_peer_id);
+		if (!F) {
+			peers_to_add.push_back(p_peer_id); // Need to also be notified.
+			has_all_peers = false;
+		} else if (!F->get()) {
+			has_all_peers = false;
+		}
+	} else {
+		// Long and painful.
+		for (const Set<int>::Element *E = multiplayer->get_connected_peers().front(); E; E = E->next()) {
+			if (p_peer_id < 0 && E->get() == -p_peer_id) {
+				continue; // Continue, excluded.
+			}
+			if (p_peer_id > 0 && E->get() != p_peer_id) {
+				continue; // Continue, not for this peer.
+			}
+
+			Map<int, bool>::Element *F = psc->confirmed_peers.find(E->get());
+			if (!F) {
+				peers_to_add.push_back(E->get()); // Need to also be notified.
+				has_all_peers = false;
+			} else if (!F->get()) {
+				has_all_peers = false;
+			}
+		}
+	}
+
+	if (peers_to_add.size()) {
+		_send_confirm_path(node, p_path, psc, peers_to_add);
+	}
+
+	return has_all_peers;
 }
 
 Object *SceneCacheInterface::get_cached_object(int p_from, uint32_t p_cache_id) {

scene/multiplayer/scene_cache_interface.h

@@ -60,7 +60,7 @@ private:
 	int last_send_cache_id = 1;
 
 protected:
-	bool _send_confirm_path(Node *p_node, NodePath p_path, PathSentCache *psc, int p_target);
+	Error _send_confirm_path(Node *p_node, NodePath p_path, PathSentCache *psc, const List<int> &p_peers);
 	static MultiplayerCacheInterface *_create(MultiplayerAPI *p_multiplayer);
 
 public: