Refactor CSM restriction code a bit

This also fixes find_node_near restrictions being ineffective.

src/client/client.cpp

@@ -1313,7 +1313,7 @@ void Client::removeNode(v3s16 p)
  * @param is_valid_position
  * @return
  */
-MapNode Client::getNode(v3s16 p, bool *is_valid_position)
+MapNode Client::CSMGetNode(v3s16 p, bool *is_valid_position)
 {
 	if (checkCSMRestrictionFlag(CSMRestrictionFlags::CSM_RF_LOOKUP_NODES)) {
 		v3s16 ppos = floatToInt(m_env.getLocalPlayer()->getPosition(), BS);
@@ -1325,6 +1325,18 @@ MapNode Client::getNode(v3s16 p, bool *is_valid_position)
 	return m_env.getMap().getNode(p, is_valid_position);
 }
 
+int Client::CSMClampRadius(v3s16 pos, int radius)
+{
+	if (!checkCSMRestrictionFlag(CSMRestrictionFlags::CSM_RF_LOOKUP_NODES))
+		return radius;
+	// This is approximate and will cause some allowed nodes to be excluded
+	v3s16 ppos = floatToInt(m_env.getLocalPlayer()->getPosition(), BS);
+	u32 distance = ppos.getDistanceFrom(pos);
+	if (distance >= m_csm_restriction_noderange)
+		return 0;
+	return std::min<int>(radius, m_csm_restriction_noderange - distance);
+}
+
 void Client::addNode(v3s16 p, MapNode n, bool remove_metadata)
 {
 	//TimeTaker timer1("Client::addNode()");

src/client/client.h

@@ -261,14 +261,10 @@ public:
 	// Causes urgent mesh updates (unlike Map::add/removeNodeWithEvent)
 	void removeNode(v3s16 p);
 
-	/**
-	 * Helper function for Client Side Modding
-	 * CSM restrictions are applied there, this should not be used for core engine
-	 * @param p
-	 * @param is_valid_position
-	 * @return
-	 */
-	MapNode getNode(v3s16 p, bool *is_valid_position);
+	// helpers to enforce CSM restrictions
+	MapNode CSMGetNode(v3s16 p, bool *is_valid_position);
+	int CSMClampRadius(v3s16 pos, int radius);
+
 	void addNode(v3s16 p, MapNode n, bool remove_metadata = true);
 
 	void setPlayerControl(PlayerControl &control);

src/script/lua_api/l_client.cpp

@@ -36,6 +36,9 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "util/string.h"
 #include "nodedef.h"
 
+#define checkCSMRestrictionFlag(flag) \
+	( getClient(L)->checkCSMRestrictionFlag(CSMRestrictionFlags::flag) )
+
 // get_current_modname()
 int ModApiClient::l_get_current_modname(lua_State *L)
 {
@@ -106,11 +109,8 @@ int ModApiClient::l_send_chat_message(lua_State *L)
 
 	// If server disabled this API, discard
 
-	// clang-format off
-	if (getClient(L)->checkCSMRestrictionFlag(
-			CSMRestrictionFlags::CSM_RF_CHAT_MESSAGES))
+	if (checkCSMRestrictionFlag(CSM_RF_CHAT_MESSAGES))
 		return 0;
-	// clang-format on
 
 	std::string message = luaL_checkstring(L, 1);
 	getClient(L)->sendChatMessage(utf8_to_wide(message));
@@ -127,12 +127,8 @@ int ModApiClient::l_clear_out_chat_queue(lua_State *L)
 // get_player_names()
 int ModApiClient::l_get_player_names(lua_State *L)
 {
-	// clang-format off
-	if (getClient(L)->checkCSMRestrictionFlag(
-			CSMRestrictionFlags::CSM_RF_READ_PLAYERINFO)) {
+	if (checkCSMRestrictionFlag(CSM_RF_READ_PLAYERINFO))
 		return 0;
-	}
-	// clang-format on
 
 	const std::list<std::string> &plist = getClient(L)->getConnectedPlayerNames();
 	lua_createtable(L, plist.size(), 0);
@@ -201,7 +197,7 @@ int ModApiClient::l_get_node_or_nil(lua_State *L)
 
 	// Do it
 	bool pos_ok;
-	MapNode n = getClient(L)->getNode(pos, &pos_ok);
+	MapNode n = getClient(L)->CSMGetNode(pos, &pos_ok);
 	if (pos_ok) {
 		// Return node
 		pushnode(L, n, getClient(L)->ndef());
@@ -308,11 +304,8 @@ int ModApiClient::l_get_item_def(lua_State *L)
 	IItemDefManager *idef = gdef->idef();
 	assert(idef);
 
-	// clang-format off
-	if (getClient(L)->checkCSMRestrictionFlag(
-			CSMRestrictionFlags::CSM_RF_READ_ITEMDEFS))
+	if (checkCSMRestrictionFlag(CSM_RF_READ_ITEMDEFS))
 		return 0;
-	// clang-format on
 
 	if (!lua_isstring(L, 1))
 		return 0;
@@ -339,11 +332,8 @@ int ModApiClient::l_get_node_def(lua_State *L)
 	if (!lua_isstring(L, 1))
 		return 0;
 
-	// clang-format off
-	if (getClient(L)->checkCSMRestrictionFlag(
-			CSMRestrictionFlags::CSM_RF_READ_NODEDEFS))
+	if (checkCSMRestrictionFlag(CSM_RF_READ_NODEDEFS))
 		return 0;
-	// clang-format on
 
 	std::string name = readParam<std::string>(L, 1);
 	const ContentFeatures &cf = ndef->get(ndef->getId(name));

src/script/lua_api/l_env.cpp

@@ -769,11 +769,8 @@ int ModApiEnvMod::l_find_node_near(lua_State *L)
 
 #ifndef SERVER
 	// Client API limitations
-	if (getClient(L) &&
-			getClient(L)->checkCSMRestrictionFlag(
-			CSMRestrictionFlags::CSM_RF_LOOKUP_NODES)) {
-		radius = std::max<int>(radius, getClient(L)->getCSMNodeRangeLimit());
-	}
+	if (getClient(L))
+		radius = getClient(L)->CSMClampRadius(pos, radius);
 #endif
 
 	for (int d = start_radius; d <= radius; d++) {