Make smallest area concept optional (#80)

This restores the behaviour to before #79.

api.lua

@@ -114,37 +114,44 @@ function areas:getSmallestAreaAtPos(pos)
 end
 
 -- Checks if the area is unprotected, open, owned by player
--- or player is part of faction of smallest area at position.
+-- or player is part of faction of [smallest] area at position.
 function areas:canInteract(pos, name)
 	if minetest.check_player_privs(name, self.adminPrivs) then
 		return true
 	end
-	local area = self:getSmallestAreaAtPos(pos)
-	-- No area, player owns it or area is open
-	if not area
-		or area.owner == name
-		or area.open
-	then
+	local areas_list
+	if areas.config.use_smallest_area_precedence then
+		local smallest_area, _ = self:getSmallestAreaAtPos(pos)
+		areas_list = { smallest_area }
+	else
+		areas_list = self:getAreasAtPos(pos)
+	end
+	local owned = false
+	for _, area in pairs(areas_list) do
+		-- Player owns the area or area is open
+		if area.owner == name or area.open then
 			return true
 		elseif areas.factions_available and area.faction_open then
 			if (factions.version or 0) < 2 then
 				local faction_name = factions.get_player_faction(name)
 				if faction_name then
-				for _, fname in ipairs(area.faction_open or {}) do
+					for _, fname in ipairs(area.faction_open) do
 						if faction_name == fname then
 							return true
 						end
 					end
 				end
 			else
-			for _, fname in ipairs(area.faction_open or {}) do
+				for _, fname in ipairs(area.faction_open) do
 					if factions.player_is_in_faction(fname, name) then
 						return true
 					end
 				end
 			end
 		end
-	return false
+		owned = true
+	end
+	return not owned
 end
 
 -- Returns a table (list) of all players that own an area

settingtypes.txt

@@ -3,6 +3,20 @@
 # Static paths do not work well with settings
 #areas.filename (Configuration file path) string (world_path)/areas.dat
 
+# Use smallest area volume precedence concept. (experimental; may change)
+#
+# If set to `true`:
+#    The interaction permission is defined by the smallest area volume that
+#    contains the interaction position. Granting access to areas is achieved
+#    by factions instead of using `/add_owner`.
+#    This allows players to have private areas within a greater open/shared
+#    area and also define open/shared areas within those private areas.
+# If set to `false`: (default)
+#    Interacting is permitted if the interaction position resides in any of the
+#    player's own areas, shared or open areas.
+#    This permission is not impacted by more restrictive, intersecting areas.
+areas.use_smallest_area_precedence (Smallest area rules) bool false
+
 # Allow players with a privilege create their own areas using /protect
 # within the specified size and amount limits.
 areas.self_protection (Self protection) bool false