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 -- luacheck: std none
   7
   8 local watchdog_methods = {};
   9 local watchdog_mt = { __index = watchdog_methods };
  10
  11 local function new(timeout, callback)
  12         local watchdog = setmetatable({ timeout = timeout, last_reset = os_time(), callback = callback }, watchdog_mt);
  13         timer.add_task(timeout+1, function (current_time)
  14                 local last_reset = watchdog.last_reset;
  15                 if not last_reset then
  16                         return;
  17                 end
  18                 local time_left = (last_reset + timeout) - current_time;
  19                 if time_left < 0 then
  20                         return watchdog:callback();
  21                 end
  22                 return time_left + 1;
  23         end);
  24         return watchdog;
  25 end
  26
  27 function watchdog_methods:reset()
  28         self.last_reset = os_time();
  29 end
  30
  31 function watchdog_methods:cancel()
  32         self.last_reset = nil;
  33 end
  34
  35 return {
  36         new = new;
  37 };