Optmized data sent during RPC and RSet calls.

- Now is sent the method ID rather the full function name.
- The passed IDs (Node and Method) are compressed so to use less possible space.
- The variant (INT and BOOL) is now encoded and compressed so to use much less data.
- Optimized RPCMode retrieval for GDScript functions.
- Added checksum to assert the methods are the same across peers.

This work has been kindly sponsored by IMVU.

2 files changed, 139 insertions, 20 deletions

diff --git a/scene/main/node.cpp b/scene/main/node.cpp
index 761fe3f90f..6a7971ddb3 100644
--- a/scene/main/node.cpp
+++ b/scene/main/node.cpp
@@ -30,6 +30,8 @@
 
 #include "node.h"
 
+#include <stdint.h>
+
 #include "core/core_string_names.h"
 #include "core/io/resource_loader.h"
 #include "core/message_queue.h"
@@ -498,22 +500,38 @@ bool Node::is_network_master() const {
 
 /***** RPC CONFIG ********/
 
-void Node::rpc_config(const StringName &p_method, MultiplayerAPI::RPCMode p_mode) {
+uint16_t Node::rpc_config(const StringName &p_method, MultiplayerAPI::RPCMode p_mode) {
 
-	if (p_mode == MultiplayerAPI::RPC_MODE_DISABLED) {
-		data.rpc_methods.erase(p_method);
+	uint16_t mid = get_node_rpc_method_id(p_method);
+	if (mid == UINT16_MAX) {
+		// It's new
+		NetData nd;
+		nd.name = p_method;
+		nd.mode = p_mode;
+		data.rpc_methods.push_back(nd);
+		return ((uint16_t)data.rpc_properties.size() - 1) | (1 << 15);
 	} else {
-		data.rpc_methods[p_method] = p_mode;
-	};
+		int c_mid = (~(1 << 15)) & mid;
+		data.rpc_methods.write[c_mid].mode = p_mode;
+		return mid;
+	}
 }
 
-void Node::rset_config(const StringName &p_property, MultiplayerAPI::RPCMode p_mode) {
+uint16_t Node::rset_config(const StringName &p_property, MultiplayerAPI::RPCMode p_mode) {
 
-	if (p_mode == MultiplayerAPI::RPC_MODE_DISABLED) {
-		data.rpc_properties.erase(p_property);
+	uint16_t pid = get_node_rset_property_id(p_property);
+	if (pid == UINT16_MAX) {
+		// It's new
+		NetData nd;
+		nd.name = p_property;
+		nd.mode = p_mode;
+		data.rpc_properties.push_back(nd);
+		return ((uint16_t)data.rpc_properties.size() - 1) | (1 << 15);
 	} else {
-		data.rpc_properties[p_property] = p_mode;
-	};
+		int c_pid = (~(1 << 15)) & pid;
+		data.rpc_properties.write[c_pid].mode = p_mode;
+		return pid;
+	}
 }
 
 /***** RPC FUNCTIONS ********/
@@ -731,12 +749,94 @@ void Node::set_custom_multiplayer(Ref<MultiplayerAPI> p_multiplayer) {
 	multiplayer = p_multiplayer;
 }
 
-const Map<StringName, MultiplayerAPI::RPCMode>::Element *Node::get_node_rpc_mode(const StringName &p_method) {
-	return data.rpc_methods.find(p_method);
+uint16_t Node::get_node_rpc_method_id(const StringName &p_method) const {
+	for (int i = 0; i < data.rpc_methods.size(); i++) {
+		if (data.rpc_methods[i].name == p_method) {
+			// Returns `i` with the high bit set to 1 so we know that this id comes
+			// from the node and not the script.
+			return i | (1 << 15);
+		}
+	}
+	return UINT16_MAX;
+}
+
+StringName Node::get_node_rpc_method(const uint16_t p_rpc_method_id) const {
+	// Make sure this is a node generated ID.
+	if (((1 << 15) & p_rpc_method_id) > 0) {
+		int mid = (~(1 << 15)) & p_rpc_method_id;
+		if (mid < data.rpc_methods.size())
+			return data.rpc_methods[mid].name;
+	}
+	return StringName();
+}
+
+MultiplayerAPI::RPCMode Node::get_node_rpc_mode_by_id(const uint16_t p_rpc_method_id) const {
+	// Make sure this is a node generated ID.
+	if (((1 << 15) & p_rpc_method_id) > 0) {
+		int mid = (~(1 << 15)) & p_rpc_method_id;
+		if (mid < data.rpc_methods.size())
+			return data.rpc_methods[mid].mode;
+	}
+	return MultiplayerAPI::RPC_MODE_DISABLED;
+}
+
+MultiplayerAPI::RPCMode Node::get_node_rpc_mode(const StringName &p_method) const {
+	return get_node_rpc_mode_by_id(get_node_rpc_method_id(p_method));
 }
 
-const Map<StringName, MultiplayerAPI::RPCMode>::Element *Node::get_node_rset_mode(const StringName &p_property) {
-	return data.rpc_properties.find(p_property);
+uint16_t Node::get_node_rset_property_id(const StringName &p_property) const {
+	for (int i = 0; i < data.rpc_properties.size(); i++) {
+		if (data.rpc_properties[i].name == p_property) {
+			// Returns `i` with the high bit set to 1 so we know that this id comes
+			// from the node and not the script.
+			return i | (1 << 15);
+		}
+	}
+	return UINT16_MAX;
+}
+
+StringName Node::get_node_rset_property(const uint16_t p_rset_property_id) const {
+	// Make sure this is a node generated ID.
+	if (((1 << 15) & p_rset_property_id) > 0) {
+		int mid = (~(1 << 15)) & p_rset_property_id;
+		if (mid < data.rpc_properties.size())
+			return data.rpc_properties[mid].name;
+	}
+	return StringName();
+}
+
+MultiplayerAPI::RPCMode Node::get_node_rset_mode_by_id(const uint16_t p_rset_property_id) const {
+	if (((1 << 15) & p_rset_property_id) > 0) {
+		int mid = (~(1 << 15)) & p_rset_property_id;
+		if (mid < data.rpc_properties.size())
+			return data.rpc_properties[mid].mode;
+	}
+	return MultiplayerAPI::RPC_MODE_DISABLED;
+}
+
+MultiplayerAPI::RPCMode Node::get_node_rset_mode(const StringName &p_property) const {
+	return get_node_rset_mode_by_id(get_node_rset_property_id(p_property));
+}
+
+String Node::get_rpc_md5() const {
+	String rpc_list;
+	for (int i = 0; i < data.rpc_methods.size(); i += 1) {
+		rpc_list += String(data.rpc_methods[i].name);
+	}
+	for (int i = 0; i < data.rpc_properties.size(); i += 1) {
+		rpc_list += String(data.rpc_properties[i].name);
+	}
+	if (get_script_instance()) {
+		Vector<ScriptNetData> rpc = get_script_instance()->get_rpc_methods();
+		for (int i = 0; i < rpc.size(); i += 1) {
+			rpc_list += String(rpc[i].name);
+		}
+		rpc = get_script_instance()->get_rset_properties();
+		for (int i = 0; i < rpc.size(); i += 1) {
+			rpc_list += String(rpc[i].name);
+		}
+	}
+	return rpc_list.md5_text();
 }
 
 bool Node::can_process_notification(int p_what) const {
diff --git a/scene/main/node.h b/scene/main/node.h
index 6f5544d654..02c828e8ff 100644
--- a/scene/main/node.h
+++ b/scene/main/node.h
@@ -85,6 +85,11 @@ private:
 		GroupData() { persistent = false; }
 	};
 
+	struct NetData {
+		StringName name;
+		MultiplayerAPI::RPCMode mode;
+	};
+
 	struct Data {
 
 		String filename;
@@ -118,8 +123,8 @@ private:
 		Node *pause_owner;
 
 		int network_master;
-		Map<StringName, MultiplayerAPI::RPCMode> rpc_methods;
-		Map<StringName, MultiplayerAPI::RPCMode> rpc_properties;
+		Vector<NetData> rpc_methods;
+		Vector<NetData> rpc_properties;
 
 		// variables used to properly sort the node when processing, ignored otherwise
 		//should move all the stuff below to bits
@@ -427,8 +432,8 @@ public:
 	int get_network_master() const;
 	bool is_network_master() const;
 
-	void rpc_config(const StringName &p_method, MultiplayerAPI::RPCMode p_mode); // config a local method for RPC
-	void rset_config(const StringName &p_property, MultiplayerAPI::RPCMode p_mode); // config a local property for RPC
+	uint16_t rpc_config(const StringName &p_method, MultiplayerAPI::RPCMode p_mode); // config a local method for RPC
+	uint16_t rset_config(const StringName &p_property, MultiplayerAPI::RPCMode p_mode); // config a local property for RPC
 
 	void rpc(const StringName &p_method, VARIANT_ARG_LIST); //rpc call, honors RPCMode
 	void rpc_unreliable(const StringName &p_method, VARIANT_ARG_LIST); //rpc call, honors RPCMode
@@ -446,8 +451,22 @@ public:
 	Ref<MultiplayerAPI> get_multiplayer() const;
 	Ref<MultiplayerAPI> get_custom_multiplayer() const;
 	void set_custom_multiplayer(Ref<MultiplayerAPI> p_multiplayer);
-	const Map<StringName, MultiplayerAPI::RPCMode>::Element *get_node_rpc_mode(const StringName &p_method);
-	const Map<StringName, MultiplayerAPI::RPCMode>::Element *get_node_rset_mode(const StringName &p_property);
+
+	/// Returns the rpc method ID, otherwise UINT32_MAX
+	uint16_t get_node_rpc_method_id(const StringName &p_method) const;
+	StringName get_node_rpc_method(const uint16_t p_rpc_method_id) const;
+	MultiplayerAPI::RPCMode get_node_rpc_mode_by_id(const uint16_t p_rpc_method_id) const;
+	MultiplayerAPI::RPCMode get_node_rpc_mode(const StringName &p_method) const;
+
+	/// Returns the rpc property ID, otherwise UINT32_MAX
+	uint16_t get_node_rset_property_id(const StringName &p_property) const;
+	StringName get_node_rset_property(const uint16_t p_rset_property_id) const;
+	MultiplayerAPI::RPCMode get_node_rset_mode_by_id(const uint16_t p_rpc_method_id) const;
+	MultiplayerAPI::RPCMode get_node_rset_mode(const StringName &p_property) const;
+
+	/// Can be used to check if the rpc methods and the rset properties are the
+	/// same across the peers.
+	String get_rpc_md5() const;
 
 	Node();
 	~Node();