[MP] Make replication mode an enum + optimizations

REPLICATION_MODE_ALWAYS (sync) and REPLICATION_MODE_ON_CHANGE (watch)
are now mutually exclusive.

Prevent invalid NodePath from being added to the config.

Optimize the replication config loading by composing the lists on
demand.

3 files changed, 149 insertions, 81 deletions

diff --git a/modules/multiplayer/doc_classes/SceneReplicationConfig.xml b/modules/multiplayer/doc_classes/SceneReplicationConfig.xml
index b976eea30b..1a51e4b6e9 100644
--- a/modules/multiplayer/doc_classes/SceneReplicationConfig.xml
+++ b/modules/multiplayer/doc_classes/SceneReplicationConfig.xml
@@ -37,6 +37,13 @@
 				Finds the index of the given [param path].
 			</description>
 		</method>
+		<method name="property_get_replication_mode">
+			<return type="int" enum="SceneReplicationConfig.ReplicationMode" />
+			<param index="0" name="path" type="NodePath" />
+			<description>
+				Returns the replication mode for the property identified by the given [param path]. See [enum ReplicationMode].
+			</description>
+		</method>
 		<method name="property_get_spawn">
 			<return type="bool" />
 			<param index="0" name="path" type="NodePath" />
@@ -44,18 +51,28 @@
 				Returns whether the property identified by the given [param path] is configured to be synchronized on spawn.
 			</description>
 		</method>
-		<method name="property_get_sync">
+		<method name="property_get_sync" is_deprecated="true">
 			<return type="bool" />
 			<param index="0" name="path" type="NodePath" />
 			<description>
 				Returns whether the property identified by the given [param path] is configured to be synchronized on process.
+				[i]Deprecated.[/i] Use [method property_get_replication_mode] instead.
 			</description>
 		</method>
-		<method name="property_get_watch">
+		<method name="property_get_watch" is_deprecated="true">
 			<return type="bool" />
 			<param index="0" name="path" type="NodePath" />
 			<description>
 				Returns whether the property identified by the given [param path] is configured to be reliably synchronized when changes are detected on process.
+				[i]Deprecated.[/i] Use [method property_get_replication_mode] instead.
+			</description>
+		</method>
+		<method name="property_set_replication_mode">
+			<return type="void" />
+			<param index="0" name="path" type="NodePath" />
+			<param index="1" name="mode" type="int" enum="SceneReplicationConfig.ReplicationMode" />
+			<description>
+				Sets the synchronization mode for the property identified by the given [param path]. See [enum ReplicationMode].
 			</description>
 		</method>
 		<method name="property_set_spawn">
@@ -66,20 +83,22 @@
 				Sets whether the property identified by the given [param path] is configured to be synchronized on spawn.
 			</description>
 		</method>
-		<method name="property_set_sync">
+		<method name="property_set_sync" is_deprecated="true">
 			<return type="void" />
 			<param index="0" name="path" type="NodePath" />
 			<param index="1" name="enabled" type="bool" />
 			<description>
 				Sets whether the property identified by the given [param path] is configured to be synchronized on process.
+				[i]Deprecated.[/i] Use [method property_set_replication_mode] with [constant REPLICATION_MODE_ALWAYS] instead.
 			</description>
 		</method>
-		<method name="property_set_watch">
+		<method name="property_set_watch" is_deprecated="true">
 			<return type="void" />
 			<param index="0" name="path" type="NodePath" />
 			<param index="1" name="enabled" type="bool" />
 			<description>
 				Sets whether the property identified by the given [param path] is configured to be reliably synchronized when changes are detected on process.
+				[i]Deprecated.[/i] Use [method property_set_replication_mode] with [constant REPLICATION_MODE_ON_CHANGE] instead.
 			</description>
 		</method>
 		<method name="remove_property">
@@ -90,4 +109,15 @@
 			</description>
 		</method>
 	</methods>
+	<constants>
+		<constant name="REPLICATION_MODE_NEVER" value="0" enum="ReplicationMode">
+			Do not keep the given property synchronized.
+		</constant>
+		<constant name="REPLICATION_MODE_ALWAYS" value="1" enum="ReplicationMode">
+			Replicate the given property on process by constantly sending updates using unreliable transfer mode.
+		</constant>
+		<constant name="REPLICATION_MODE_ON_CHANGE" value="2" enum="ReplicationMode">
+			Replicate the given property on process by sending updates using reliable transfer mode when its value changes.
+		</constant>
+	</constants>
 </class>
diff --git a/modules/multiplayer/scene_replication_config.cpp b/modules/multiplayer/scene_replication_config.cpp
index db615f8c20..836fa1014d 100644
--- a/modules/multiplayer/scene_replication_config.cpp
+++ b/modules/multiplayer/scene_replication_config.cpp
@@ -47,38 +47,26 @@ bool SceneReplicationConfig::_set(const StringName &p_name, const Variant &p_val
 			add_property(path);
 			return true;
 		}
-		ERR_FAIL_COND_V(p_value.get_type() != Variant::BOOL, false);
 		ERR_FAIL_INDEX_V(idx, properties.size(), false);
 		ReplicationProperty &prop = properties[idx];
-		if (what == "sync") {
-			if ((bool)p_value == prop.sync) {
-				return true;
-			}
-			prop.sync = p_value;
-			if (prop.sync) {
-				sync_props.push_back(prop.name);
-			} else {
-				sync_props.erase(prop.name);
-			}
+		if (what == "replication_mode") {
+			ERR_FAIL_COND_V(p_value.get_type() != Variant::INT, false);
+			ReplicationMode mode = (ReplicationMode)p_value.operator int();
+			ERR_FAIL_COND_V(mode < REPLICATION_MODE_NEVER || mode > REPLICATION_MODE_ON_CHANGE, false);
+			property_set_replication_mode(prop.name, mode);
 			return true;
-		} else if (what == "spawn") {
-			if ((bool)p_value == prop.spawn) {
-				return true;
-			}
-			prop.spawn = p_value;
-			if (prop.spawn) {
-				spawn_props.push_back(prop.name);
-			} else {
-				spawn_props.erase(prop.name);
-			}
+		}
+		ERR_FAIL_COND_V(p_value.get_type() != Variant::BOOL, false);
+		if (what == "spawn") {
+			property_set_spawn(prop.name, p_value);
+			return true;
+		} else if (what == "sync") {
+			// Deprecated.
+			property_set_sync(prop.name, p_value);
 			return true;
 		} else if (what == "watch") {
-			prop.watch = p_value;
-			if (prop.watch) {
-				watch_props.push_back(prop.name);
-			} else {
-				watch_props.erase(prop.name);
-			}
+			// Deprecated.
+			property_set_watch(prop.name, p_value);
 			return true;
 		}
 	}
@@ -96,14 +84,11 @@ bool SceneReplicationConfig::_get(const StringName &p_name, Variant &r_ret) cons
 		if (what == "path") {
 			r_ret = prop.name;
 			return true;
-		} else if (what == "sync") {
-			r_ret = prop.sync;
-			return true;
 		} else if (what == "spawn") {
 			r_ret = prop.spawn;
 			return true;
-		} else if (what == "watch") {
-			r_ret = prop.watch;
+		} else if (what == "replication_mode") {
+			r_ret = prop.mode;
 			return true;
 		}
 	}
@@ -114,8 +99,7 @@ void SceneReplicationConfig::_get_property_list(List<PropertyInfo> *p_list) cons
 	for (int i = 0; i < properties.size(); i++) {
 		p_list->push_back(PropertyInfo(Variant::STRING, "properties/" + itos(i) + "/path", PROPERTY_HINT_NONE, "", PROPERTY_USAGE_NO_EDITOR | PROPERTY_USAGE_INTERNAL));
 		p_list->push_back(PropertyInfo(Variant::STRING, "properties/" + itos(i) + "/spawn", PROPERTY_HINT_NONE, "", PROPERTY_USAGE_NO_EDITOR | PROPERTY_USAGE_INTERNAL));
-		p_list->push_back(PropertyInfo(Variant::STRING, "properties/" + itos(i) + "/sync", PROPERTY_HINT_NONE, "", PROPERTY_USAGE_NO_EDITOR | PROPERTY_USAGE_INTERNAL));
-		p_list->push_back(PropertyInfo(Variant::STRING, "properties/" + itos(i) + "/watch", PROPERTY_HINT_NONE, "", PROPERTY_USAGE_NO_EDITOR | PROPERTY_USAGE_INTERNAL));
+		p_list->push_back(PropertyInfo(Variant::INT, "properties/" + itos(i) + "/replication_mode", PROPERTY_HINT_ENUM, "Never,Always,On Change", PROPERTY_USAGE_NO_EDITOR | PROPERTY_USAGE_INTERNAL));
 	}
 }
 
@@ -129,11 +113,11 @@ TypedArray<NodePath> SceneReplicationConfig::get_properties() const {
 
 void SceneReplicationConfig::add_property(const NodePath &p_path, int p_index) {
 	ERR_FAIL_COND(properties.find(p_path));
+	ERR_FAIL_COND(p_path == NodePath());
 
 	if (p_index < 0 || p_index == properties.size()) {
 		properties.push_back(ReplicationProperty(p_path));
-		sync_props.push_back(p_path);
-		spawn_props.push_back(p_path);
+		dirty = true;
 		return;
 	}
 
@@ -146,23 +130,12 @@ void SceneReplicationConfig::add_property(const NodePath &p_path, int p_index) {
 		c++;
 	}
 	properties.insert_before(I, ReplicationProperty(p_path));
-	sync_props.clear();
-	spawn_props.clear();
-	for (const ReplicationProperty &prop : properties) {
-		if (prop.sync) {
-			sync_props.push_back(prop.name);
-		}
-		if (prop.spawn) {
-			spawn_props.push_back(prop.name);
-		}
-	}
+	dirty = true;
 }
 
 void SceneReplicationConfig::remove_property(const NodePath &p_path) {
 	properties.erase(p_path);
-	sync_props.erase(p_path);
-	spawn_props.erase(p_path);
-	watch_props.clear();
+	dirty = true;
 }
 
 bool SceneReplicationConfig::has_property(const NodePath &p_path) const {
@@ -196,56 +169,99 @@ void SceneReplicationConfig::property_set_spawn(const NodePath &p_path, bool p_e
 		return;
 	}
 	E->get().spawn = p_enabled;
-	spawn_props.clear();
-	for (const ReplicationProperty &prop : properties) {
-		if (prop.spawn) {
-			spawn_props.push_back(prop.name);
-		}
-	}
+	dirty = true;
 }
 
 bool SceneReplicationConfig::property_get_sync(const NodePath &p_path) {
 	List<ReplicationProperty>::Element *E = properties.find(p_path);
 	ERR_FAIL_COND_V(!E, false);
-	return E->get().sync;
+	return E->get().mode == REPLICATION_MODE_ALWAYS;
 }
 
 void SceneReplicationConfig::property_set_sync(const NodePath &p_path, bool p_enabled) {
-	List<ReplicationProperty>::Element *E = properties.find(p_path);
-	ERR_FAIL_COND(!E);
-	if (E->get().sync == p_enabled) {
-		return;
-	}
-	E->get().sync = p_enabled;
-	sync_props.clear();
-	for (const ReplicationProperty &prop : properties) {
-		if (prop.sync) {
-			sync_props.push_back(prop.name);
-		}
+	if (p_enabled) {
+		property_set_replication_mode(p_path, REPLICATION_MODE_ALWAYS);
+	} else if (property_get_replication_mode(p_path) == REPLICATION_MODE_ALWAYS) {
+		property_set_replication_mode(p_path, REPLICATION_MODE_NEVER);
 	}
 }
 
 bool SceneReplicationConfig::property_get_watch(const NodePath &p_path) {
 	List<ReplicationProperty>::Element *E = properties.find(p_path);
 	ERR_FAIL_COND_V(!E, false);
-	return E->get().watch;
+	return E->get().mode == REPLICATION_MODE_ON_CHANGE;
 }
 
 void SceneReplicationConfig::property_set_watch(const NodePath &p_path, bool p_enabled) {
+	if (p_enabled) {
+		property_set_replication_mode(p_path, REPLICATION_MODE_ON_CHANGE);
+	} else if (property_get_replication_mode(p_path) == REPLICATION_MODE_ON_CHANGE) {
+		property_set_replication_mode(p_path, REPLICATION_MODE_NEVER);
+	}
+}
+
+SceneReplicationConfig::ReplicationMode SceneReplicationConfig::property_get_replication_mode(const NodePath &p_path) {
+	List<ReplicationProperty>::Element *E = properties.find(p_path);
+	ERR_FAIL_COND_V(!E, REPLICATION_MODE_NEVER);
+	return E->get().mode;
+}
+
+void SceneReplicationConfig::property_set_replication_mode(const NodePath &p_path, ReplicationMode p_mode) {
 	List<ReplicationProperty>::Element *E = properties.find(p_path);
 	ERR_FAIL_COND(!E);
-	if (E->get().watch == p_enabled) {
+	if (E->get().mode == p_mode) {
 		return;
 	}
-	E->get().watch = p_enabled;
+	E->get().mode = p_mode;
+	dirty = true;
+}
+
+void SceneReplicationConfig::_update() {
+	if (!dirty) {
+		return;
+	}
+	dirty = false;
+	sync_props.clear();
+	spawn_props.clear();
 	watch_props.clear();
 	for (const ReplicationProperty &prop : properties) {
-		if (prop.watch) {
-			watch_props.push_back(p_path);
+		if (prop.spawn) {
+			spawn_props.push_back(prop.name);
+		}
+		switch (prop.mode) {
+			case REPLICATION_MODE_ALWAYS:
+				sync_props.push_back(prop.name);
+				break;
+			case REPLICATION_MODE_ON_CHANGE:
+				watch_props.push_back(prop.name);
+				break;
+			default:
+				break;
 		}
 	}
 }
 
+const List<NodePath> &SceneReplicationConfig::get_spawn_properties() {
+	if (dirty) {
+		_update();
+	}
+	return spawn_props;
+}
+
+const List<NodePath> &SceneReplicationConfig::get_sync_properties() {
+	if (dirty) {
+		_update();
+	}
+	return sync_props;
+}
+
+const List<NodePath> &SceneReplicationConfig::get_watch_properties() {
+	if (dirty) {
+		_update();
+	}
+	return watch_props;
+}
+
 void SceneReplicationConfig::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("get_properties"), &SceneReplicationConfig::get_properties);
 	ClassDB::bind_method(D_METHOD("add_property", "path", "index"), &SceneReplicationConfig::add_property, DEFVAL(-1));
@@ -254,6 +270,14 @@ void SceneReplicationConfig::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("property_get_index", "path"), &SceneReplicationConfig::property_get_index);
 	ClassDB::bind_method(D_METHOD("property_get_spawn", "path"), &SceneReplicationConfig::property_get_spawn);
 	ClassDB::bind_method(D_METHOD("property_set_spawn", "path", "enabled"), &SceneReplicationConfig::property_set_spawn);
+	ClassDB::bind_method(D_METHOD("property_get_replication_mode", "path"), &SceneReplicationConfig::property_get_replication_mode);
+	ClassDB::bind_method(D_METHOD("property_set_replication_mode", "path", "mode"), &SceneReplicationConfig::property_set_replication_mode);
+
+	BIND_ENUM_CONSTANT(REPLICATION_MODE_NEVER);
+	BIND_ENUM_CONSTANT(REPLICATION_MODE_ALWAYS);
+	BIND_ENUM_CONSTANT(REPLICATION_MODE_ON_CHANGE);
+
+	// Deprecated.
 	ClassDB::bind_method(D_METHOD("property_get_sync", "path"), &SceneReplicationConfig::property_get_sync);
 	ClassDB::bind_method(D_METHOD("property_set_sync", "path", "enabled"), &SceneReplicationConfig::property_set_sync);
 	ClassDB::bind_method(D_METHOD("property_get_watch", "path"), &SceneReplicationConfig::property_get_watch);
diff --git a/modules/multiplayer/scene_replication_config.h b/modules/multiplayer/scene_replication_config.h
index 44f8259904..3f870ba2d8 100644
--- a/modules/multiplayer/scene_replication_config.h
+++ b/modules/multiplayer/scene_replication_config.h
@@ -39,12 +39,18 @@ class SceneReplicationConfig : public Resource {
 	OBJ_SAVE_TYPE(SceneReplicationConfig);
 	RES_BASE_EXTENSION("repl");
 
+public:
+	enum ReplicationMode {
+		REPLICATION_MODE_NEVER,
+		REPLICATION_MODE_ALWAYS,
+		REPLICATION_MODE_ON_CHANGE,
+	};
+
 private:
 	struct ReplicationProperty {
 		NodePath name;
 		bool spawn = true;
-		bool sync = true;
-		bool watch = false;
+		ReplicationMode mode = REPLICATION_MODE_ALWAYS;
 
 		bool operator==(const ReplicationProperty &p_to) {
 			return name == p_to.name;
@@ -61,6 +67,9 @@ private:
 	List<NodePath> spawn_props;
 	List<NodePath> sync_props;
 	List<NodePath> watch_props;
+	bool dirty = false;
+
+	void _update();
 
 protected:
 	static void _bind_methods();
@@ -86,11 +95,16 @@ public:
 	bool property_get_watch(const NodePath &p_path);
 	void property_set_watch(const NodePath &p_path, bool p_enabled);
 
-	const List<NodePath> &get_spawn_properties() { return spawn_props; }
-	const List<NodePath> &get_sync_properties() { return sync_props; }
-	const List<NodePath> &get_watch_properties() { return watch_props; }
+	ReplicationMode property_get_replication_mode(const NodePath &p_path);
+	void property_set_replication_mode(const NodePath &p_path, ReplicationMode p_mode);
+
+	const List<NodePath> &get_spawn_properties();
+	const List<NodePath> &get_sync_properties();
+	const List<NodePath> &get_watch_properties();
 
 	SceneReplicationConfig() {}
 };
 
+VARIANT_ENUM_CAST(SceneReplicationConfig::ReplicationMode);
+
 #endif // SCENE_REPLICATION_CONFIG_H