[CSM] Add local node meta reference. (#5508)

doc/client_lua_api.md

@@ -690,6 +690,8 @@ Call these functions only at load time!
       for unloaded areas.
 * `minetest.get_node_or_nil(pos)`
     * Same as `get_node` but returns `nil` for unloaded areas.
+* `minetest.get_meta(pos)`
+    * Get a `NodeMetaRef` at that position
 
 ### Player
 * `minetest.get_wielded_item()`
@@ -794,7 +796,18 @@ It can be created via `Settings(filename)`.
     * write changes to file
 * `to_table()`: returns `{[key1]=value1,...}`
 
-Definition tables
+### NodeMetaRef
+Node metadata: reference extra data and functionality stored in a node.
+Can be obtained via `minetest.get_meta(pos)`.
+
+#### Methods
+* `get_string(name)`
+* `get_int(name)`
+* `get_float(name)`
+* `to_table()`: returns `nil` or a table with keys:
+    * `fields`: key-value storage
+    * `inventory`: `{list1 = {}, ...}}`
+
 -----------------
 
 ### Chat command definition (`register_chatcommand`)

src/script/clientscripting.cpp

@@ -28,6 +28,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "lua_api/l_sound.h"
 #include "lua_api/l_util.h"
 #include "lua_api/l_item.h"
+#include "lua_api/l_nodemeta.h"
 
 ClientScripting::ClientScripting(Client *client):
 	ScriptApiBase()
@@ -68,4 +69,5 @@ void ClientScripting::InitializeModApi(lua_State *L, int top)
 	LuaItemStack::Register(L);
 	StorageRef::Register(L);
 	LuaMinimap::Register(L);
+	NodeMetaRef::RegisterClient(L);
 }

src/script/lua_api/l_client.cpp

@@ -25,8 +25,11 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "gettext.h"
 #include "l_internal.h"
 #include "lua_api/l_item.h"
+#include "lua_api/l_nodemeta.h"
 #include "mainmenumanager.h"
 #include "util/string.h"
+#include "clientenvironment.h"
+#include "map.h"
 
 extern MainGameCallback *g_gamecallback;
 
@@ -182,6 +185,15 @@ int ModApiClient::l_get_wielded_item(lua_State *L)
 	return 1;
 }
 
+// get_meta(pos)
+int ModApiClient::l_get_meta(lua_State *L)
+{
+	v3s16 p = read_v3s16(L, 1);
+	NodeMetadata *meta = getClient(L)->getEnv().getMap().getNodeMetadata(p);
+	NodeMetaRef::createClient(L, meta);
+	return 1;
+}
+
 void ModApiClient::Initialize(lua_State *L, int top)
 {
 	API_FCT(get_current_modname);
@@ -196,4 +208,5 @@ void ModApiClient::Initialize(lua_State *L, int top)
 	API_FCT(get_node_or_nil);
 	API_FCT(get_wielded_item);
 	API_FCT(disconnect);
+	API_FCT(get_meta);
 }

src/script/lua_api/l_client.h

@@ -62,6 +62,9 @@ class ModApiClient : public ModApiBase
 	// get_wielded_item()
 	static int l_get_wielded_item(lua_State *L);
 
+	// get_meta(pos)
+	static int l_get_meta(lua_State *L);
+
 public:
 	static void Initialize(lua_State *L, int top);
 };

src/script/lua_api/l_nodemeta.cpp

@@ -38,6 +38,9 @@ NodeMetaRef* NodeMetaRef::checkobject(lua_State *L, int narg)
 
 Metadata* NodeMetaRef::getmeta(bool auto_create)
 {
+	if (m_is_local)
+		return m_meta;
+
 	NodeMetadata *meta = m_env->getMap().getNodeMetadata(m_p);
 	if (meta == NULL && auto_create) {
 		meta = new NodeMetadata(m_env->getGameDef()->idef());
@@ -142,7 +145,14 @@ bool NodeMetaRef::handleFromTable(lua_State *L, int table, Metadata *_meta)
 
 NodeMetaRef::NodeMetaRef(v3s16 p, ServerEnvironment *env):
 	m_p(p),
-	m_env(env)
+	m_env(env),
+	m_is_local(false)
+{
+}
+
+NodeMetaRef::NodeMetaRef(Metadata *meta):
+	m_meta(meta),
+	m_is_local(true)
 {
 }
 
@@ -161,7 +171,17 @@ void NodeMetaRef::create(lua_State *L, v3s16 p, ServerEnvironment *env)
 	lua_setmetatable(L, -2);
 }
 
-void NodeMetaRef::Register(lua_State *L)
+// Client-sided version of the above
+void NodeMetaRef::createClient(lua_State *L, Metadata *meta)
+{
+	NodeMetaRef *o = new NodeMetaRef(meta);
+	*(void **)(lua_newuserdata(L, sizeof(void *))) = o;
+	luaL_getmetatable(L, className);
+	lua_setmetatable(L, -2);
+}
+
+const char NodeMetaRef::className[] = "NodeMetaRef";
+void NodeMetaRef::RegisterCommon(lua_State *L)
 {
 	lua_newtable(L);
 	int methodtable = lua_gettop(L);
@@ -185,16 +205,17 @@ void NodeMetaRef::Register(lua_State *L)
 	lua_settable(L, metatable);
 
 	lua_pop(L, 1);  // drop metatable
+}
 
-	luaL_openlib(L, 0, methods, 0);  // fill methodtable
+void NodeMetaRef::Register(lua_State *L)
+{
+	RegisterCommon(L);
+	luaL_openlib(L, 0, methodsServer, 0);  // fill methodtable
 	lua_pop(L, 1);  // drop methodtable
-
-	// Cannot be created from Lua
-	//lua_register(L, className, create_object);
 }
 
-const char NodeMetaRef::className[] = "NodeMetaRef";
-const luaL_reg NodeMetaRef::methods[] = {
+
+const luaL_reg NodeMetaRef::methodsServer[] = {
 	luamethod(MetaDataRef, get_string),
 	luamethod(MetaDataRef, set_string),
 	luamethod(MetaDataRef, get_int),
@@ -206,3 +227,20 @@ const luaL_reg NodeMetaRef::methods[] = {
 	luamethod(NodeMetaRef, get_inventory),
 	{0,0}
 };
+
+
+void NodeMetaRef::RegisterClient(lua_State *L)
+{
+	RegisterCommon(L);
+	luaL_openlib(L, 0, methodsClient, 0);  // fill methodtable
+	lua_pop(L, 1);  // drop methodtable
+}
+
+
+const luaL_reg NodeMetaRef::methodsClient[] = {
+	luamethod(MetaDataRef, get_string),
+	luamethod(MetaDataRef, get_int),
+	luamethod(MetaDataRef, get_float),
+	luamethod(MetaDataRef, to_table),
+	{0,0}
+};

src/script/lua_api/l_nodemeta.h

@@ -22,6 +22,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "lua_api/l_base.h"
 #include "lua_api/l_metadata.h"
 #include "irrlichttypes_bloated.h"
+#include "nodemetadata.h"
 
 class ServerEnvironment;
 class NodeMetadata;
@@ -34,9 +35,12 @@ class NodeMetaRef : public MetaDataRef {
 private:
 	v3s16 m_p;
 	ServerEnvironment *m_env;
+	Metadata *m_meta;
+	bool m_is_local;
 
 	static const char className[];
-	static const luaL_reg methods[];
+	static const luaL_reg methodsServer[];
+	static const luaL_reg methodsClient[];
 
 	static NodeMetaRef *checkobject(lua_State *L, int narg);
 
@@ -71,14 +75,20 @@ class NodeMetaRef : public MetaDataRef {
 
 public:
 	NodeMetaRef(v3s16 p, ServerEnvironment *env);
+	NodeMetaRef(Metadata *meta);
 
 	~NodeMetaRef();
 
 	// Creates an NodeMetaRef and leaves it on top of stack
 	// Not callable from Lua; all references are created on the C side.
 	static void create(lua_State *L, v3s16 p, ServerEnvironment *env);
 
+	// Client-sided version of the above
+	static void createClient(lua_State *L, Metadata *meta);
+
+	static void RegisterCommon(lua_State *L);
 	static void Register(lua_State *L);
+	static void RegisterClient(lua_State *L);
 };
 
 #endif /* L_NODEMETA_H_ */