generic config: implement a function to perform generic checks on tables

Signed-off-by: Gordon Hecker <gh@emlix.com>

diff --git a/local/e2tool.lua b/local/e2tool.lua
index b2c299844be42819b2c5bba530021c8b9760cdd2..02bcd20842ddc5098c88109b896e17e72a677979 100644 (file)
--- a/local/e2tool.lua
+++ b/local/e2tool.lua
@@ -196,6 +196,52 @@ local function listofstrings(l, unique, unify)
   return true, nil
 end
 
+--- check a table according to a description table
+-- @param tab table: the table to check
+-- @param keys table: the description table
+-- @param inherit table: table with keys to inherit
+-- @return bool
+-- @return an error object on failure
+local function check_tab(tab, keys, inherit)
+       local e = new_error("checking file configuration")
+
+       if type(tab) ~= "table" then
+               return false, e:append("not a table")
+       end
+
+       -- keys = {
+       --   location = {
+       --     mandatory = true,
+       --     type = "string",
+       --     inherit = false,
+       --   },
+       -- }
+       -- inherit = {
+       --   location = "foo",
+       -- }
+
+       -- inherit keys
+       for k,v in pairs(inherit) do
+               if not tab[k] and keys[k].inherit ~= false then
+                       tab[k] = v
+               end
+       end
+
+       -- check types and mandatory
+       for k,v in pairs(keys) do
+               if keys[k].mandatory and not tab[k] then
+                       e:append("missing mandatory key: %s", k)
+               elseif tab[k] and keys[k].type ~= type(tab[k]) then
+                       e:append("wrong type: %s", k)
+               end
+       end
+
+       if e:getcount() > 1 then
+               return false, e
+       end
+       return true, nil
+end
+
 function e2tool.opendebuglogfile(info)
   local rc, re = e2lib.mkdir(info.root .. "/log", "-p")
   if not rc then