Track when callbacks are invoked so that we can ensure that all screens are shown/hidden before invoking callbacks

README.md

@@ -352,16 +352,32 @@ Remove a previously added listener.
 Enable verbose logging of the internals of Monarch.
 
 
-### monarch.SCREEN_VISIBLE
-Message sent to listeners when a screen becomes visible.
+### monarch.SCREEN_TRANSITION_IN_STARTED
+Message sent to listeners when a screen has started to transition in.
 
 **PARAMETERS**
 * ```screen``` (hash) - Id of the screen
-* ```previous_screen``` (hash) - Id of theprevious screen (if any)
+* ```previous_screen``` (hash) - Id of the previous screen (if any)
 
 
-### monarch.SCREEN_HIDDEN
-Message sent to listeners when a screen is hidden.
+### monarch.SCREEN_TRANSITION_IN_FINISHED
+Message sent to listeners when a screen has finished to transition in.
+
+**PARAMETERS**
+* ```screen``` (hash) - Id of the screen
+* ```previous_screen``` (hash) - Id of the previous screen (if any)
+
+
+### monarch.SCREEN_TRANSITION_OUT_STARTED
+Message sent to listeners when a screen has started to transition out.
+
+**PARAMETERS**
+* ```screen``` (hash) - Id of the screen
+* ```next_screen``` (hash) - Id of the next screen (if any)
+
+
+### monarch.SCREEN_TRANSITION_OUT_FINISHED
+Message sent to listeners when a screen has finished to transition out.
 
 **PARAMETERS**
 * ```screen``` (hash) - Id of the screen

monarch/monarch.lua

@@ -1,3 +1,5 @@
+local callback_tracker = require "monarch.utils.callback_tracker"
+
 local M = {}
 
 local CONTEXT = hash("monarch_context")
@@ -24,8 +26,10 @@ M.FOCUS.GAINED = hash("monarch_focus_gained")
 M.FOCUS.LOST = hash("monarch_focus_lost")
 
 -- listener messages
-M.SCREEN_VISIBLE = hash("monarch_screen_visible")
-M.SCREEN_HIDDEN = hash("monarch_screen_hidden")
+M.SCREEN_TRANSITION_IN_STARTED = hash("monarch_screen_transition_in_started")
+M.SCREEN_TRANSITION_IN_FINISHED = hash("monarch_screen_transition_in_finished")
+M.SCREEN_TRANSITION_OUT_STARTED = hash("monarch_screen_transition_out_started")
+M.SCREEN_TRANSITION_OUT_FINISHED = hash("monarch_screen_transition_out_finished")
 
 
 -- all registered screens
@@ -248,6 +252,7 @@ local function show_out(screen, next_screen, cb)
 	local co
 	co = coroutine.create(function()
 		active_transition_count = active_transition_count + 1
+		notify_listeners(M.SCREEN_TRANSITION_OUT_STARTED, { screen = screen.id, next_screen = next_screen.id })
 		screen.co = co
 		change_context(screen)
 		release_input(screen)
@@ -263,7 +268,7 @@ local function show_out(screen, next_screen, cb)
 		screen.co = nil
 		active_transition_count = active_transition_count - 1
 		if cb then cb() end
-		notify_listeners(M.SCREEN_HIDDEN, { screen = screen.id, next_screen = next_screen.id })
+		notify_listeners(M.SCREEN_TRANSITION_OUT_FINISHED, { screen = screen.id, next_screen = next_screen.id })
 	end)
 	coroutine.resume(co)
 end
@@ -273,6 +278,7 @@ local function show_in(screen, previous_screen, reload, cb)
 	local co
 	co = coroutine.create(function()
 		active_transition_count = active_transition_count + 1
+		notify_listeners(M.SCREEN_TRANSITION_IN_STARTED, { screen = screen.id, previous_screen = previous_screen and previous_screen.id })
 		screen.co = co
 		change_context(screen)
 		if reload and screen.loaded then
@@ -299,17 +305,17 @@ local function show_in(screen, previous_screen, reload, cb)
 		screen.co = nil
 		active_transition_count = active_transition_count - 1
 		if cb then cb() end
-		notify_listeners(M.SCREEN_VISIBLE, { screen = screen.id, previous_screen = previous_screen and previous_screen.id })
+		notify_listeners(M.SCREEN_TRANSITION_IN_FINISHED, { screen = screen.id, previous_screen = previous_screen and previous_screen.id })
 	end)
 	coroutine.resume(co)
 end
 
 local function back_in(screen, previous_screen, cb)
 	log("back_in()", screen.id)
-	print("back_in()", screen.id)
 	local co
 	co = coroutine.create(function()
 		active_transition_count = active_transition_count + 1
+		notify_listeners(M.SCREEN_TRANSITION_IN_STARTED, { screen = screen.id, previous_screen = previous_screen and previous_screen.id })
 		screen.co = co
 		change_context(screen)
 		if screen.preloaded then
@@ -329,16 +335,16 @@ local function back_in(screen, previous_screen, cb)
 		screen.co = nil
 		active_transition_count = active_transition_count - 1
 		if cb then cb() end
-		notify_listeners(M.SCREEN_VISIBLE, { screen = screen.id, previous_screen = previous_screen.id })
+		notify_listeners(M.SCREEN_TRANSITION_IN_FINISHED, { screen = screen.id, previous_screen = previous_screen and previous_screen.id })
 	end)
 	coroutine.resume(co)
 end
 
 local function back_out(screen, next_screen, cb)
 	log("back_out()", screen.id)
-	print("back_out()", screen.id)
 	local co
 	co = coroutine.create(function()
+		notify_listeners(M.SCREEN_TRANSITION_OUT_STARTED, { screen = screen.id, next_screen = next_screen.id })
 		active_transition_count = active_transition_count + 1
 		screen.co = co
 		change_context(screen)
@@ -349,7 +355,7 @@ local function back_out(screen, next_screen, cb)
 		screen.co = nil
 		active_transition_count = active_transition_count - 1
 		if cb then cb() end
-		notify_listeners(M.SCREEN_HIDDEN, { screen = screen.id, next_screen = next_screen and next_screen.id })
+		notify_listeners(M.SCREEN_TRANSITION_OUT_FINISHED, { screen = screen.id, next_screen = next_screen.id })
 	end)
 	coroutine.resume(co)
 end
@@ -395,8 +401,11 @@ end
 function M.show(id, options, data, cb)
 	assert(id, "You must provide a screen id")
 	if M.is_busy() then
+		log("show() monarch is busy, ignoring request")
 		return false
 	end
+
+	local callbacks = callback_tracker()
 	
 	id = tohash(id)
 	assert(screens[id], ("There is no screen registered with id %s"):format(tostring(id)))
@@ -418,13 +427,13 @@ function M.show(id, options, data, cb)
 			-- close all popups
 			while top.popup do
 				stack[#stack] = nil
-				show_out(top, screen)
+				show_out(top, screen, callbacks.track())
 				top = stack[#stack]
 			end
 			-- unload and transition out from top
 			-- unless we're showing the same screen as is already visible
 			if top and top.id ~= screen.id then
-				show_out(top, screen)
+				show_out(top, screen, callbacks.track())
 			end
 		end
 	end
@@ -441,7 +450,9 @@ function M.show(id, options, data, cb)
 	end
 
 	-- show screen
-	show_in(screen, top, options and options.reload, cb)
+	show_in(screen, top, options and options.reload, callbacks.track())
+
+	if cb then callbacks.when_done(cb) end
 
 	return true
 end
@@ -453,9 +464,12 @@ end
 -- @return true if successfully going back, false if busy performing another operation
 function M.back(data, cb)
 	if M.is_busy() then
+		log("back() monarch is busy, ignoring request")
 		return false
 	end
 
+	local callbacks = callback_tracker()
+	
 	local screen = table.remove(stack)
 	if screen then
 		log("back()", screen.id)
@@ -467,7 +481,7 @@ function M.back(data, cb)
 				if data then
 					top.data = data
 				end
-				back_in(top, screen, cb)
+				back_in(top, screen, callbacks.track())
 			end)
 		else
 			back_out(screen, top)
@@ -475,12 +489,13 @@ function M.back(data, cb)
 				if data then
 					top.data = data
 				end
-				back_in(top, screen, cb)
+				back_in(top, screen, callbacks.track())
 			end
 		end
-	elseif cb then
-		cb()
 	end
+
+	if cb then callbacks.when_done(cb) end
+	
 	return true
 end
 

monarch/utils/callback_tracker.lua

@@ -0,0 +1,39 @@
+local M = {}
+
+
+function M.create()
+	local instance = {}
+
+	local callback = nil
+	local callback_count = 0
+
+	--- Create a callback function and track when it is done
+	-- @return Callback function
+	function instance.track()
+		callback_count = callback_count + 1
+		return function()
+			callback_count = callback_count - 1
+			if callback_count == 0 and callback then
+				callback()
+			end
+		end
+	end
+
+	--- Call a function when all callbacks have been triggered
+	-- @param cb Function to call when all 
+	function instance.when_done(cb)
+		callback = cb
+		if callback_count == 0 then
+			callback()
+		end
+	end
+
+	return instance
+end
+
+
+return setmetatable(M, {
+	__call = function(_, ...)
+		return M.create(...)
+	end
+})

test/test_monarch.lua

@@ -241,8 +241,16 @@ return function()
 			monarch.add_listener(URL2)
 
 			monarch.show(SCREEN1)
+			assert(mock_msg.messages(URL1)[1].message_id == monarch.SCREEN_TRANSITION_IN_STARTED)
+			assert(mock_msg.messages(URL1)[1].message.screen == SCREEN1)
+			assert(mock_msg.messages(URL2)[1].message_id == monarch.SCREEN_TRANSITION_IN_STARTED)
+			assert(mock_msg.messages(URL2)[1].message.screen == SCREEN1)
 			assert(wait_until_not_busy())
-			
+			assert(mock_msg.messages(URL1)[2].message_id == monarch.SCREEN_TRANSITION_IN_FINISHED)
+			assert(mock_msg.messages(URL1)[2].message.screen == SCREEN1)
+			assert(mock_msg.messages(URL2)[2].message_id == monarch.SCREEN_TRANSITION_IN_FINISHED)
+			assert(mock_msg.messages(URL2)[2].message.screen == SCREEN1)
+												
 			monarch.remove_listener(URL2)
 			monarch.show(SCREEN2)
 			assert(wait_until_not_busy())
@@ -252,15 +260,16 @@ return function()
 						
 			local messages_1 = mock_msg.messages(URL1)
 			local messages_2 = mock_msg.messages(URL2)
-			assert(#messages_1 == 5)
-			assert(#messages_2 == 1)
-			assert(messages_2[1].message_id == monarch.SCREEN_VISIBLE and messages_1[1].message.screen == SCREEN1)
-			
-			assert(messages_1[1].message_id == monarch.SCREEN_VISIBLE and messages_1[1].message.screen == SCREEN1)
-			assert(messages_1[2].message_id == monarch.SCREEN_HIDDEN and messages_1[2].message.screen == SCREEN1)
-			assert(messages_1[3].message_id == monarch.SCREEN_VISIBLE and messages_1[3].message.screen == SCREEN2)
-			assert(messages_1[4].message_id == monarch.SCREEN_HIDDEN and messages_1[4].message.screen == SCREEN2)
-			assert(messages_1[5].message_id == monarch.SCREEN_VISIBLE and messages_1[5].message.screen == SCREEN1)
+			assert(#mock_msg.messages(URL1) == 10)
+			assert(#mock_msg.messages(URL2) == 2)
+			assert(mock_msg.messages(URL1)[3].message_id == monarch.SCREEN_TRANSITION_OUT_STARTED)
+			assert(mock_msg.messages(URL1)[3].message.screen == SCREEN1)
+			assert(mock_msg.messages(URL1)[4].message_id == monarch.SCREEN_TRANSITION_IN_STARTED)
+			assert(mock_msg.messages(URL1)[4].message.screen == SCREEN2)
+			assert(mock_msg.messages(URL1)[5].message_id == monarch.SCREEN_TRANSITION_OUT_FINISHED)
+			assert(mock_msg.messages(URL1)[5].message.screen == SCREEN1)
+			assert(mock_msg.messages(URL1)[6].message_id == monarch.SCREEN_TRANSITION_IN_FINISHED)
+			assert(mock_msg.messages(URL1)[7].message.screen == SCREEN2)
 		end)
 	end)
 end