Add vertical version of airtight pipe entry

if automatically rotates to connect to the thing you point at, if a connection
is possible.

init.lua

@@ -114,6 +114,12 @@ pipe_bendsphere = {
 
 --  Functions
 
+if minetest.get_modpath("unified_inventory") or not minetest.setting_getbool("creative_mode") then
+	pipeworks_expect_infinite_stacks = false
+else
+	pipeworks_expect_infinite_stacks = true
+end
+
 dbg = function(s)
 	if DEBUG then
 		print('[PIPEWORKS] ' .. s)
@@ -135,6 +141,39 @@ function pipe_addbox(t, b)
 	end
 end
 
+function pipeworks_node_is_owned(pos, placer)
+	local ownername = false
+	if type(IsPlayerNodeOwner) == "function" then					-- node_ownership mod
+		if HasOwner(pos, placer) then						-- returns true if the node is owned
+			if not IsPlayerNodeOwner(pos, placer:get_player_name()) then
+				if type(getLastOwner) == "function" then		-- ...is an old version
+					ownername = getLastOwner(pos)
+				elseif type(GetNodeOwnerName) == "function" then	-- ...is a recent version
+					ownername = GetNodeOwnerName(pos)
+				else
+					ownername = S("someone")
+				end
+			end
+		end
+
+	elseif type(isprotect)=="function" then 					-- glomie's protection mod
+		if not isprotect(5, pos, placer) then
+			ownername = S("someone")
+		end
+	elseif type(protector)=="table" and type(protector.can_dig)=="function" then 	-- Zeg9's protection mod
+		if not protector.can_dig(5, pos, placer) then
+			ownername = S("someone")
+		end
+	end
+
+	if ownername ~= false then
+		minetest.chat_send_player( placer:get_player_name(), S("Sorry, %s owns that spot."):format(ownername) )
+		return true
+	else
+		return false
+	end
+end
+
 -- now define the nodes!
 
 pipes_empty_nodenames = {}