util/watchdog.lua

   1 local timer = require "util.timer";
   2 local setmetatable = setmetatable;
   3 local os_time = os.time;
   4
   5 local _ENV = nil;
   6
   7 local watchdog_methods = {};
   8 local watchdog_mt = { __index = watchdog_methods };
   9
  10 local function new(timeout, callback)
  11         local watchdog = setmetatable({ timeout = timeout, last_reset = os_time(), callback = callback }, watchdog_mt);
  12         timer.add_task(timeout+1, function (current_time)
  13                 local last_reset = watchdog.last_reset;
  14                 if not last_reset then
  15                         return;
  16                 end
  17                 local time_left = (last_reset + timeout) - current_time;
  18                 if time_left < 0 then
  19                         return watchdog:callback();
  20                 end
  21                 return time_left + 1;
  22         end);
  23         return watchdog;
  24 end
  25
  26 function watchdog_methods:reset()
  27         self.last_reset = os_time();
  28 end
  29
  30 function watchdog_methods:cancel()
  31         self.last_reset = nil;
  32 end
  33
  34 return {
  35         new = new;
  36 };