timer callback dispatcher

scada-common/tcallbackdsp.lua

@@ -0,0 +1,31 @@
+--
+-- Timer Callback Dispatcher
+--
+
+local log  = require("scada-common.log")
+local util = require("scada-common.util")
+
+local tcallbackdsp = {}
+
+local registry = {}
+
+-- request a function to be called after the specified time
+---@param time number seconds
+---@param f function callback function
+function tcallbackdsp.dispatch(time, f)
+    log.debug(util.c("TCD: dispatching ", f, " for call in ", time, " seconds"))
+---@diagnostic disable-next-line: undefined-field
+    registry[os.startTimer(time)] = { callback = f }
+end
+
+-- lookup a timer event and execute the callback if found
+---@param event integer timer event timer ID
+function tcallbackdsp.handle(event)
+    if registry[event] ~= nil then
+        log.debug(util.c("TCD: executing callback ", registry[event].callback, " for timer ", event))
+        registry[event].callback()
+        registry[event] = nil
+    end
+end
+
+return tcallbackdsp