[Net] Move RPC, Node cache out of MultiplayerAPI.

Now uses two interfaces so it can be overridden in the future, and
core no longer depends on Node.

The interfaces are implements in scene/multiplayer.
Replaces root_node with root_path.
Remove all Node references from MultiplayerAPI.

1 files changed, 82 insertions, 0 deletions

diff --git a/scene/multiplayer/scene_cache_interface.h b/scene/multiplayer/scene_cache_interface.h
new file mode 100644
index 0000000000..91a53cb948
--- /dev/null
+++ b/scene/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 "core/multiplayer/multiplayer_api.h"
+
+class SceneCacheInterface : public MultiplayerCacheInterface {
+	GDCLASS(SceneCacheInterface, MultiplayerCacheInterface);
+
+private:
+	MultiplayerAPI *multiplayer;
+
+	//path sent caches
+	struct PathSentCache {
+		Map<int, bool> confirmed_peers;
+		int id;
+	};
+
+	//path get caches
+	struct PathGetCache {
+		struct NodeInfo {
+			NodePath path;
+			ObjectID instance;
+		};
+
+		Map<int, NodeInfo> nodes;
+	};
+
+	HashMap<NodePath, PathSentCache> path_send_cache;
+	Map<int, PathGetCache> path_get_cache;
+	int last_send_cache_id = 1;
+
+protected:
+	bool _send_confirm_path(Node *p_node, NodePath p_path, PathSentCache *psc, int p_target);
+	static MultiplayerCacheInterface *_create(MultiplayerAPI *p_multiplayer);
+
+public:
+	static void make_default();
+
+	virtual void clear() override;
+	virtual void on_peer_change(int p_id, bool p_connected) override;
+	virtual void process_simplify_path(int p_from, const uint8_t *p_packet, int p_packet_len) override;
+	virtual void process_confirm_path(int p_from, const uint8_t *p_packet, int p_packet_len) override;
+
+	// Returns true if all peers have cached path.
+	virtual bool send_object_cache(Object *p_obj, NodePath p_path, int p_target, int &p_id) override;
+	virtual Object *get_cached_object(int p_from, uint32_t p_cache_id) override;
+	virtual bool is_cache_confirmed(NodePath p_path, int p_peer) override;
+
+	SceneCacheInterface(MultiplayerAPI *p_multiplayer) { multiplayer = p_multiplayer; }
+};
+
+#endif // SCENE_CACHE_INTERFACE_H