[Net] Modularize multiplayer, expose MultiplayerAPI to extensions.

- RPC configurations are now dictionaries.
- Script.get_rpc_methods renamed to Script.get_rpc_config.
- Node.rpc[_id] and Callable.rpc now return an Error.
- Refactor MultiplayerAPI to allow extension.
- New MultiplayerAPI.rpc method with Array argument (for scripts).
- Move the default MultiplayerAPI implementation to a module.

1 files changed, 82 insertions, 0 deletions

diff --git a/modules/multiplayer/scene_cache_interface.h b/modules/multiplayer/scene_cache_interface.h
new file mode 100644
index 0000000000..1e80792fe7
--- /dev/null
+++ b/modules/multiplayer/scene_cache_interface.h
@@ -0,0 +1,82 @@
+/*************************************************************************/
+/*  scene_cache_interface.h                                              */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2022 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#ifndef SCENE_CACHE_INTERFACE_H
+#define SCENE_CACHE_INTERFACE_H
+
+#include "scene/main/multiplayer_api.h"
+
+class SceneMultiplayer;
+
+class SceneCacheInterface : public RefCounted {
+	GDCLASS(SceneCacheInterface, RefCounted);
+
+private:
+	SceneMultiplayer *multiplayer = nullptr;
+
+	//path sent caches
+	struct PathSentCache {
+		HashMap<int, bool> confirmed_peers;
+		int id;
+	};
+
+	//path get caches
+	struct PathGetCache {
+		struct NodeInfo {
+			NodePath path;
+			ObjectID instance;
+		};
+
+		HashMap<int, NodeInfo> nodes;
+	};
+
+	HashMap<NodePath, PathSentCache> path_send_cache;
+	HashMap<int, PathGetCache> path_get_cache;
+	int last_send_cache_id = 1;
+
+protected:
+	Error _send_confirm_path(Node *p_node, NodePath p_path, PathSentCache *psc, const List<int> &p_peers);
+
+public:
+	void clear();
+	void on_peer_change(int p_id, bool p_connected);
+	void process_simplify_path(int p_from, const uint8_t *p_packet, int p_packet_len);
+	void process_confirm_path(int p_from, const uint8_t *p_packet, int p_packet_len);
+
+	// Returns true if all peers have cached path.
+	bool send_object_cache(Object *p_obj, int p_target, int &p_id);
+	int make_object_cache(Object *p_obj);
+	Object *get_cached_object(int p_from, uint32_t p_cache_id);
+	bool is_cache_confirmed(NodePath p_path, int p_peer);
+
+	SceneCacheInterface(SceneMultiplayer *p_multiplayer) { multiplayer = p_multiplayer; }
+};
+
+#endif // SCENE_CACHE_INTERFACE_H