initial commit

LibTSM/Util/Event.lua

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+-- ------------------------------------------------------------------------------ --
+--                                TradeSkillMaster                                --
+--                          https://tradeskillmaster.com                          --
+--    All Rights Reserved - Detailed license information included with addon.     --
+-- ------------------------------------------------------------------------------ --
+
+--- Event Functions
+-- @module Event
+
+local _, TSM = ...
+local Event = TSM.Init("Util.Event")
+local TempTable = TSM.Include("Util.TempTable")
+local Log = TSM.Include("Util.Log")
+local private = {
+	registry = {
+		event = {},
+		callback = {},
+	},
+	eventFrame = nil,
+	temp = {},
+	eventQueue = {},
+	processingEvent = false,
+}
+local CALLBACK_TIME_WARNING_THRESHOLD_MS = 20
+
+
+
+-- ============================================================================
+-- Module Functions
+-- ============================================================================
+
+--- Registers an event callback.
+-- @tparam string event The WoW event to register for (i.e. BAG_UPDATE)
+-- @tparam function callback The function to be called from the event handler
+function Event.Register(event, callback)
+	assert(type(event) == "string" and event == strupper(event) and type(callback) == "function")
+	-- make sure this event/callback isn't already registered
+	for i = 1, #private.registry.event do
+		assert(private.registry.event[i] ~= event or private.registry.callback[i] ~= callback)
+	end
+	private.eventFrame:RegisterEvent(event)
+	tinsert(private.registry.event, event)
+	tinsert(private.registry.callback, callback)
+end
+
+--- Unregisters an event callback.
+-- @tparam string event The WoW event which the callback was registered for
+-- @tparam function callback The function which was passed to @{Event.Register} for this event
+function Event.Unregister(event, callback)
+	assert(type(event) == "string" and event == strupper(event) and type(callback) == "function")
+	local index = nil
+	local shouldUnregister = true
+	for i = 1, #private.registry.event do
+		if private.registry.event[i] == event and private.registry.callback[i] == callback then
+			assert(not index)
+			index = i
+		elseif private.registry.event[i] == event then
+			shouldUnregister = false
+		end
+	end
+	assert(index)
+	tremove(private.registry.event, index)
+	tremove(private.registry.callback, index)
+	if shouldUnregister then
+		private.eventFrame:UnregisterEvent(event)
+	end
+end
+
+
+
+-- ============================================================================
+-- Event Frame
+-- ============================================================================
+
+function private.ProcessEvent(event, ...)
+	-- NOTE: the registered events may change within the callback, so copy them to a temp table
+	wipe(private.temp)
+	for i = 1, #private.registry.event do
+		if private.registry.event[i] == event then
+			tinsert(private.temp, private.registry.callback[i])
+		end
+	end
+	for _, callback in ipairs(private.temp) do
+		local startTime = debugprofilestop()
+		callback(event, ...)
+		local timeTaken = debugprofilestop() - startTime
+		if timeTaken > CALLBACK_TIME_WARNING_THRESHOLD_MS then
+			Log.Warn("Event (%s) callback took %.2fms", event, timeTaken)
+		end
+	end
+end
+
+function private.EventHandler(_, event, ...)
+	if private.processingEvent then
+		-- we are already in the middle of processing another event, so queue this one up
+		tinsert(private.eventQueue, TempTable.Acquire(event, ...))
+		assert(#private.eventQueue < 50)
+		return
+	end
+	private.processingEvent = true
+	private.ProcessEvent(event, ...)
+	-- process queued events
+	while #private.eventQueue > 0 do
+		local tbl = tremove(private.eventQueue, 1)
+		private.ProcessEvent(TempTable.UnpackAndRelease(tbl))
+	end
+	private.processingEvent = false
+end
+
+private.eventFrame = CreateFrame("Frame")
+private.eventFrame:SetScript("OnEvent", private.EventHandler)
+private.eventFrame:Show()