Call on_place_node() callbacks after placing door.

Other mods may depend on knowing whether doors are placed
to setup additional attributes or perform node manipulations.

This is something e.g. mesecons does to connect circuits
to doors. This was tested with mesecons. Placing a door next
to a mesecon wire will make the wire automatically
connect, which was otherwise not happening.

mods/doors/init.lua

@@ -154,6 +154,25 @@ function _doors.door_toggle(pos, clicker)
 	return true
 end
 
+
+local function on_place_node(place_to, newnode, placer, oldnode, itemstack, pointed_thing)
+	-- Run script hook
+	local _, callback
+	for _, callback in ipairs(core.registered_on_placenodes) do
+		-- Deepcopy pos, node and pointed_thing because callback can modify them
+		local place_to_copy = {x = place_to.x, y = place_to.y, z = place_to.z}
+		local newnode_copy = {name = newnode.name, param1 = newnode.param1, param2 = newnode.param2}
+		local oldnode_copy = {name = oldnode.name, param1 = oldnode.param1, param2 = oldnode.param2}
+		local pointed_thing_copy = {
+			type  = pointed_thing.type,
+			above = vector.new(pointed_thing.above),
+			under = vector.new(pointed_thing.under),
+			ref   = pointed_thing.ref,
+		}
+		callback(place_to_copy, newnode_copy, placer, oldnode_copy, itemstack, pointed_thing_copy)
+	end
+end
+
 function doors.register(name, def)
 	-- replace old doors of this type automatically
 	minetest.register_abm({
@@ -249,6 +268,8 @@ function doors.register(name, def)
 				itemstack:take_item()
 			end
 
+			on_place_node(pos, minetest.get_node(pos), placer, node, itemstack, pointed_thing)
+
 			return itemstack
 		end
 	})