Private nodemeta (#5702)

* Private node metadata that isn't sent to the client

doc/lua_api.txt

@@ -2895,6 +2895,10 @@ Can be obtained via `minetest.get_meta(pos)`.
 #### Methods
 * All methods in MetaDataRef
 * `get_inventory()`: returns `InvRef`
+* `mark_as_private(name or {name1, name2, ...})`: Mark specific vars as private
+  This will prevent them from being sent to the client. Note that the "private"
+  status will only be remembered if an associated key-value pair exists, meaning
+  it's best to call this when initializing all other meta (e.g. on_construct).
 
 ### `ItemStackMetaRef`
 ItemStack metadata: reference extra data and functionality stored in a stack.

games/minimal/mods/default/init.lua

@@ -1228,6 +1228,8 @@ minetest.register_node("default:chest_locked", {
 		meta:set_string("owner", "")
 		local inv = meta:get_inventory()
 		inv:set_size("main", 8*4)
+		-- this is not really the intended usage but works for testing purposes:
+		meta:mark_as_private("owner")
 	end,
 	can_dig = function(pos,player)
 		local meta = minetest.get_meta(pos);

games/minimal/mods/experimental/init.lua

@@ -502,10 +502,16 @@ minetest.register_craftitem("experimental:tester_tool_1", {
     on_use = function(itemstack, user, pointed_thing)
 		--print(dump(pointed_thing))
 		if pointed_thing.type == "node" then
-			if minetest.get_node(pointed_thing.under).name == "experimental:tester_node_1" then
+			local node = minetest.get_node(pointed_thing.under)
+			if node.name == "experimental:tester_node_1" or node.name == "default:chest" then
 				local p = pointed_thing.under
 				minetest.log("action", "Tester tool used at "..minetest.pos_to_string(p))
+				if node.name == "experimental:tester_node_1" then
 					minetest.dig_node(p)
+				else
+					minetest.get_meta(p):mark_as_private({"infotext", "formspec"})
+					minetest.chat_send_player(user:get_player_name(), "Verify that chest is unusable now.")
+				end
 			else
 				local p = pointed_thing.above
 				minetest.log("action", "Tester tool used at "..minetest.pos_to_string(p))

src/mapblock.cpp

@@ -611,7 +611,7 @@ void MapBlock::serialize(std::ostream &os, u8 version, bool disk)
 		Node metadata
 	*/
 	std::ostringstream oss(std::ios_base::binary);
-	m_node_metadata.serialize(oss);
+	m_node_metadata.serialize(oss, version, disk);
 	compressZlib(oss.str(), os);
 
 	/*
@@ -669,11 +669,10 @@ void MapBlock::deSerialize(std::istream &is, u8 version, bool disk)
 	u8 flags = readU8(is);
 	is_underground = (flags & 0x01) ? true : false;
 	m_day_night_differs = (flags & 0x02) ? true : false;
-	if (version < 27) {
+	if (version < 27)
 		m_lighting_complete = 0xFFFF;
-	} else {
+	else
 		m_lighting_complete = readU16(is);
-	}
 	m_generated = (flags & 0x08) ? false : true;
 
 	/*

src/nodemetadata.cpp

@@ -23,6 +23,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "inventory.h"
 #include "log.h"
 #include "util/serialize.h"
+#include "util/basic_macros.h"
 #include "constants.h" // MAP_BLOCKSIZE
 #include <sstream>
 
@@ -39,28 +40,38 @@ NodeMetadata::~NodeMetadata()
 	delete m_inventory;
 }
 
-void NodeMetadata::serialize(std::ostream &os) const
+void NodeMetadata::serialize(std::ostream &os, u8 version, bool disk) const
 {
-	int num_vars = m_stringvars.size();
+	int num_vars = disk ? m_stringvars.size() : countNonPrivate();
 	writeU32(os, num_vars);
 	for (StringMap::const_iterator
 			it = m_stringvars.begin();
 			it != m_stringvars.end(); ++it) {
+		bool priv = isPrivate(it->first);
+		if (!disk && priv)
+			continue;
+
 		os << serializeString(it->first);
 		os << serializeLongString(it->second);
+		if (version >= 2)
+			writeU8(os, (priv) ? 1 : 0);
 	}
 
 	m_inventory->serialize(os);
 }
 
-void NodeMetadata::deSerialize(std::istream &is)
+void NodeMetadata::deSerialize(std::istream &is, u8 version)
 {
-	m_stringvars.clear();
+	clear();
 	int num_vars = readU32(is);
 	for(int i=0; i<num_vars; i++){
 		std::string name = deSerializeString(is);
 		std::string var = deSerializeLongString(is);
 		m_stringvars[name] = var;
+		if (version >= 2) {
+			if (readU8(is) == 1)
+				markPrivate(name, true);
+		}
 	}
 
 	m_inventory->deSerialize(is);
@@ -69,6 +80,7 @@ void NodeMetadata::deSerialize(std::istream &is)
 void NodeMetadata::clear()
 {
 	Metadata::clear();
+	m_privatevars.clear();
 	m_inventory->clear();
 }
 
@@ -77,11 +89,34 @@ bool NodeMetadata::empty() const
 	return Metadata::empty() && m_inventory->getLists().size() == 0;
 }
 
+
+void NodeMetadata::markPrivate(const std::string &name, bool set)
+{
+	if (set)
+		m_privatevars.insert(name);
+	else
+		m_privatevars.erase(name);
+}
+
+int NodeMetadata::countNonPrivate() const
+{
+	// m_privatevars can contain names not actually present
+	// DON'T: return m_stringvars.size() - m_privatevars.size();
+	int n = 0;
+	for (StringMap::const_iterator
+			it = m_stringvars.begin();
+			it != m_stringvars.end(); ++it) {
+		if (isPrivate(it->first) == false)
+			n++;
+	}
+	return n;
+}
+
 /*
 	NodeMetadataList
 */
 
-void NodeMetadataList::serialize(std::ostream &os) const
+void NodeMetadataList::serialize(std::ostream &os, u8 blockver, bool disk) const
 {
 	/*
 		Version 0 is a placeholder for "nothing to see here; go away."
@@ -93,7 +128,8 @@ void NodeMetadataList::serialize(std::ostream &os) const
 		return;
 	}
 
-	writeU8(os, 1); // version
+	u8 version = (blockver > 27) ? 2 : 1;
+	writeU8(os, version);
 	writeU16(os, count);
 
 	for(std::map<v3s16, NodeMetadata*>::const_iterator
@@ -108,7 +144,7 @@ void NodeMetadataList::serialize(std::ostream &os) const
 		u16 p16 = p.Z * MAP_BLOCKSIZE * MAP_BLOCKSIZE + p.Y * MAP_BLOCKSIZE + p.X;
 		writeU16(os, p16);
 
-		data->serialize(os);
+		data->serialize(os, version, disk);
 	}
 }
 
@@ -123,7 +159,7 @@ void NodeMetadataList::deSerialize(std::istream &is, IItemDefManager *item_def_m
 		return;
 	}
 
-	if (version != 1) {
+	if (version > 2) {
 		std::string err_str = std::string(FUNCTION_NAME)
 			+ ": version " + itos(version) + " not supported";
 		infostream << err_str << std::endl;
@@ -144,14 +180,13 @@ void NodeMetadataList::deSerialize(std::istream &is, IItemDefManager *item_def_m
 
 		if (m_data.find(p) != m_data.end()) {
 			warningstream << "NodeMetadataList::deSerialize(): "
-					<<"already set data at position"
-					<<"("<<p.X<<","<<p.Y<<","<<p.Z<<"): Ignoring."
-					<<std::endl;
+					<< "already set data at position " << PP(p)
+					<< ": Ignoring." << std::endl;
 			continue;
 		}
 
 		NodeMetadata *data = new NodeMetadata(item_def_mgr);
-		data->deSerialize(is);
+		data->deSerialize(is, version);
 		m_data[p] = data;
 	}
 }

src/nodemetadata.h

@@ -21,6 +21,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #define NODEMETADATA_HEADER
 
 #include "metadata.h"
+#include "util/cpp11_container.h"
 
 /*
 	NodeMetadata stores arbitary amounts of data for special blocks.
@@ -40,8 +41,8 @@ public:
 	NodeMetadata(IItemDefManager *item_def_mgr);
 	~NodeMetadata();
 
-	void serialize(std::ostream &os) const;
-	void deSerialize(std::istream &is);
+	void serialize(std::ostream &os, u8 version, bool disk=true) const;
+	void deSerialize(std::istream &is, u8 version);
 
 	void clear();
 	bool empty() const;
@@ -52,8 +53,17 @@ public:
 		return m_inventory;
 	}
 
+	inline bool isPrivate(const std::string &name) const
+	{
+		return m_privatevars.count(name) != 0;
+	}
+	void markPrivate(const std::string &name, bool set);
+
 private:
+	int countNonPrivate() const;
+
 	Inventory *m_inventory;
+	UNORDERED_SET<std::string> m_privatevars;
 };
 
 
@@ -66,7 +76,7 @@ class NodeMetadataList
 public:
 	~NodeMetadataList();
 
-	void serialize(std::ostream &os) const;
+	void serialize(std::ostream &os, u8 blockver, bool disk=true) const;
 	void deSerialize(std::istream &is, IItemDefManager *item_def_mgr);
 
 	// Add all keys in this list to the vector keys

src/rollback_interface.cpp

@@ -44,7 +44,7 @@ RollbackNode::RollbackNode(Map *map, v3s16 p, IGameDef *gamedef)
 	NodeMetadata *metap = map->getNodeMetadata(p);
 	if (metap) {
 		std::ostringstream os(std::ios::binary);
-		metap->serialize(os);
+		metap->serialize(os, 1); // FIXME: version bump??
 		meta = os.str();
 	}
 }
@@ -165,7 +165,7 @@ bool RollbackAction::applyRevert(Map *map, InventoryManager *imgr, IGameDef *gam
 						}
 					}
 					std::istringstream is(n_old.meta, std::ios::binary);
-					meta->deSerialize(is);
+					meta->deSerialize(is, 1); // FIXME: version bump??
 				}
 				// Inform other things that the meta data has changed
 				v3s16 blockpos = getContainerPos(p, MAP_BLOCKSIZE);

src/script/lua_api/l_nodemeta.cpp

@@ -94,6 +94,32 @@ int NodeMetaRef::l_get_inventory(lua_State *L)
 	return 1;
 }
 
+// mark_as_private(self, <string> or {<string>, <string>, ...})
+int NodeMetaRef::l_mark_as_private(lua_State *L)
+{
+	MAP_LOCK_REQUIRED;
+
+	NodeMetaRef *ref = checkobject(L, 1);
+	NodeMetadata *meta = dynamic_cast<NodeMetadata*>(ref->getmeta(true));
+	assert(meta);
+
+	if (lua_istable(L, 2)) {
+		lua_pushnil(L);
+		while (lua_next(L, 2) != 0) {
+			// key at index -2 and value at index -1
+			luaL_checktype(L, -1, LUA_TSTRING);
+			meta->markPrivate(lua_tostring(L, -1), true);
+			// removes value, keeps key for next iteration
+			lua_pop(L, 1);
+		}
+	} else if (lua_isstring(L, 2)) {
+		meta->markPrivate(lua_tostring(L, 2), true);
+	}
+	ref->reportMetadataChange();
+
+	return 0;
+}
+
 void NodeMetaRef::handleToTable(lua_State *L, Metadata *_meta)
 {
 	// fields
@@ -229,6 +255,7 @@ const luaL_Reg NodeMetaRef::methodsServer[] = {
 	luamethod(MetaDataRef, to_table),
 	luamethod(MetaDataRef, from_table),
 	luamethod(NodeMetaRef, get_inventory),
+	luamethod(NodeMetaRef, mark_as_private),
 	luamethod(MetaDataRef, equals),
 	{0,0}
 };

src/script/lua_api/l_nodemeta.h

@@ -73,6 +73,9 @@ private:
 	// get_inventory(self)
 	static int l_get_inventory(lua_State *L);
 
+	// mark_as_private(self, <string> or {<string>, <string>, ...})
+	static int l_mark_as_private(lua_State *L);
+
 public:
 	NodeMetaRef(v3s16 p, ServerEnvironment *env);
 	NodeMetaRef(Metadata *meta);

src/serialization.h

@@ -63,13 +63,14 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 	25: Improved node timer format
 	26: Never written; read the same as 25
 	27: Added light spreading flags to blocks
+	28: Added "private" flag to NodeMetadata
 */
 // This represents an uninitialized or invalid format
 #define SER_FMT_VER_INVALID 255
 // Highest supported serialization version
-#define SER_FMT_VER_HIGHEST_READ 27
+#define SER_FMT_VER_HIGHEST_READ 28
 // Saved on disk version
-#define SER_FMT_VER_HIGHEST_WRITE 27
+#define SER_FMT_VER_HIGHEST_WRITE 28
 // Lowest supported serialization version
 #define SER_FMT_VER_LOWEST_READ 0
 // Lowest serialization version for writing