[CSM] Implement minetest.get_csm_restrictions()

fixes #8068

clientmods/preview/init.lua

@@ -14,6 +14,9 @@ print("Server version: " .. server_info.protocol_version)
 print("Server ip: " .. server_info.ip)
 print("Server address: " .. server_info.address)
 print("Server port: " .. server_info.port)
+
+print("CSM restrictions: " .. dump(core.get_csm_restrictions()))
+
 mod_channel = core.mod_channel_join("experimental_preview")
 
 core.after(4, function()

doc/client_lua_api.txt

@@ -649,6 +649,11 @@ Minetest namespace reference
 * `minetest.sha1(data, [raw])`: returns the sha1 hash of data
     * `data`: string of data to hash
     * `raw`: return raw bytes instead of hex digits, default: false
+* `minetest.get_csm_restrictions()`: returns a table of `Flags` indicating the
+   restrictions applied to the current mod.
+   * If a flag in this table is set to true, the feature is RESTRICTED.
+   * Possible flags: `load_client_mods`, `chat_messages`, `read_itemdefs`,
+                   `read_nodedefs`, `lookup_nodes`, `read_playerinfo`
 
 ### Logging
 * `minetest.debug(...)`

src/client/client.h

@@ -410,6 +410,11 @@ class Client : public con::PeerHandler, public InventoryManager, public IGameDef
 		return m_address_name;
 	}
 
+	inline u64 getCSMRestrictionFlags() const
+	{
+		return m_csm_restriction_flags;
+	}
+
 	inline bool checkCSMRestrictionFlag(CSMRestrictionFlags flag) const
 	{
 		return m_csm_restriction_flags & flag;

src/script/lua_api/l_client.cpp

@@ -39,6 +39,27 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #define checkCSMRestrictionFlag(flag) \
 	( getClient(L)->checkCSMRestrictionFlag(CSMRestrictionFlags::flag) )
 
+// Not the same as FlagDesc, which contains an `u32 flag`
+struct CSMFlagDesc {
+	const char *name;
+	u64 flag;
+};
+
+/*
+	FIXME: This should eventually be moved somewhere else
+	It also needs to be kept in sync with the definition of CSMRestrictionFlags
+	in network/networkprotocol.h
+*/
+const static CSMFlagDesc flagdesc_csm_restriction[] = {
+	{"load_client_mods",  CSM_RF_LOAD_CLIENT_MODS},
+	{"chat_messages",     CSM_RF_CHAT_MESSAGES},
+	{"read_itemdefs",     CSM_RF_READ_ITEMDEFS},
+	{"read_nodedefs",     CSM_RF_READ_NODEDEFS},
+	{"lookup_nodes",      CSM_RF_LOOKUP_NODES},
+	{"read_playerinfo",   CSM_RF_READ_PLAYERINFO},
+	{NULL,      0}
+};
+
 // get_current_modname()
 int ModApiClient::l_get_current_modname(lua_State *L)
 {
@@ -363,6 +384,19 @@ int ModApiClient::l_get_builtin_path(lua_State *L)
 	return 1;
 }
 
+// get_csm_restrictions()
+int ModApiClient::l_get_csm_restrictions(lua_State *L)
+{
+	u64 flags = getClient(L)->getCSMRestrictionFlags();
+	const CSMFlagDesc *flagdesc = flagdesc_csm_restriction;
+
+	lua_newtable(L);
+	for (int i = 0; flagdesc[i].name; i++) {
+		setboolfield(L, -1, flagdesc[i].name, !!(flags & flagdesc[i].flag));
+	}
+	return 1;
+}
+
 void ModApiClient::Initialize(lua_State *L, int top)
 {
 	API_FCT(get_current_modname);
@@ -389,4 +423,5 @@ void ModApiClient::Initialize(lua_State *L, int top)
 	API_FCT(get_privilege_list);
 	API_FCT(get_builtin_path);
 	API_FCT(get_language);
+	API_FCT(get_csm_restrictions);
 }

src/script/lua_api/l_client.h

@@ -96,6 +96,9 @@ class ModApiClient : public ModApiBase
 	// get_builtin_path()
 	static int l_get_builtin_path(lua_State *L);
 
+	// get_csm_restrictions()
+	static int l_get_csm_restrictions(lua_State *L);
+
 public:
 	static void Initialize(lua_State *L, int top);
 };