Initial commit

Change-Id: I2bb38bffdd92602659670901b8442201b7c56214
Signed-off-by: Romain Forlot <romain.forlot@iot.bzh>

1 files changed, 86 insertions, 0 deletions

diff --git a/conf.d/project/lua.d/onload-daemon-00-utils.lua b/conf.d/project/lua.d/onload-daemon-00-utils.lua
new file mode 100644
index 0000000..29d2c70
--- /dev/null
+++ b/conf.d/project/lua.d/onload-daemon-00-utils.lua
@@ -0,0 +1,86 @@
+--[[
+  Copyright (C) 2016 "IoT.bzh"
+  Author Fulup Ar Foll <fulup@iot.bzh>
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+  Note: this file should be called before any other to assert declare function
+  is loaded before anything else.
+
+  References:
+    http://lua-users.org/wiki/DetectingUndefinedVariables
+
+--]]
+
+
+--===================================================
+--=  Niklas Frykholm
+-- basically if user tries to create global variable
+-- the system will not let them!!
+-- call GLOBAL_lock(_G)
+--
+--===================================================
+function GLOBAL_lock(t)
+  local mt = getmetatable(t) or {}
+  mt.__newindex = lock_new_index
+  setmetatable(t, mt)
+end
+
+--===================================================
+-- call GLOBAL_unlock(_G)
+-- to change things back to normal.
+--===================================================
+function GLOBAL_unlock(t)
+  local mt = getmetatable(t) or {}
+  mt.__newindex = unlock_new_index
+  setmetatable(t, mt)
+end
+
+function lock_new_index(t, k, v)
+  if (string.sub(k,1,1) ~= "_") then
+    GLOBAL_unlock(_G)
+    error("GLOBALS are locked -- " .. k ..
+          " must be declared local or prefix with '_' for globals.", 2)
+  else
+    rawset(t, k, v)
+  end
+end
+
+function unlock_new_index(t, k, v)
+  rawset(t, k, v)
+end
+
+-- return serialised version of printable table
+function Dump_Table(o)
+   if type(o) == 'table' then
+      local s = '{ '
+      for k,v in pairs(o) do
+         if type(k) ~= 'number' then k = '"'..k..'"' end
+         s = s .. '['..k..'] = ' .. Dump_Table(v) .. ','
+      end
+      return s .. '} '
+   else
+      return tostring(o)
+   end
+end
+
+
+-- simulate C prinf function
+printf = function(s,...)
+    io.write(s:format(...))
+    io.write("\n")
+    return
+end
+
+-- lock global variable
+GLOBAL_lock(_G)