Added direct message handling capability to broadcast

Author: Björn Ritzl

ludobits/m/broadcast.lua

@@ -1,5 +1,43 @@
 --- Module to simplify sending a message to multiple receivers
-local listener = require "ludobits.m.listener"
+--
+-- @usage
+--
+--	-- script_a.script
+--	
+--	local broadcast = require "ludobits.m.listener"
+--	
+--	function init(self)
+--		broadcast.register("foo")
+--		broadcast.register("bar", function(message, sender)
+--			-- handle message
+--		end)
+--	end
+--	
+--	function final(self)
+--		broadcast.unregister("foo")
+--		broadcast.unregister("bar")
+--	end
+--	
+--	function on_message(self, message_id, message, sender)
+--		if broadcast.on_message(message_id, message, sender) then
+--			-- message was handled
+--			return
+--		end
+--		if message_id == hash("foo") then
+--			-- handle message "foo"
+--		end
+--	end
+--
+--
+--	-- script_b.script
+--	
+--	local broadcast = require "ludobits.m.listener"
+--
+--	function update(self, dt)
+--		if some condition then
+--			broadcast.send("foo")
+--		end
+--	end
 
 local M = {}
 
@@ -17,34 +55,56 @@ function M.send(message_id, message)
 	local key = ensure_hash(message_id)
 	if receivers[key] then
 		message = message or {}
-		receivers[key].trigger(message_id, message)
+		for url,_ in pairs(receivers[key]) do
+			msg.post(url, message_id, message)
+		end
 	end
 end
 
 --- Register the current script as a receiver for a specific message
 -- @param message_id
--- @param url_or_fn Optional URL or function to register. Defaults to the
--- current script url
-function M.register(message_id, url_or_fn)
+-- @param on_message_handler Optional message handler function to call
+-- when a message is received. The function will receive the message
+-- and sender as it's arguments. You must call @{on_message} for this
+-- to work
+function M.register(message_id, on_message_handler)
 	assert(message_id)
-	url_or_fn = url_or_fn or msg.url()
 	local key = ensure_hash(message_id)
-	receivers[key] = receivers[key] or listener.create()
-	receivers[key].add(url_or_fn)
+	receivers[key] = receivers[key] or {}
+	receivers[key][msg.url()] = on_message_handler or true
 end
 
 --- Unregister the current script from receiving a previously registered message
 -- @param message_id
--- @param url_or_fn Optional URL or function to unregister. Defaults to the current
--- script url
-function M.unregister(message_id, url_or_fn)
+function M.unregister(message_id)
 	assert(message_id)
-	url_or_fn = url_or_fn or msg.url()
 	local key = ensure_hash(message_id)
 	if receivers[key] then
-		receivers[key].remove(url_or_fn)
+		receivers[key][msg.url()] = nil
 	end
 end
 
+--- Forward received messages in scripts where the broadcast module is used and where
+-- registered messages have also provide a message handler function. If no message
+-- handler functions are used then there is no need to call this function.
+-- @param message_id
+-- @param message
+-- @param sender
+function M.on_message(message_id, message, sender)
+	local message_receivers = receivers[message_id]
+	if not message_receivers then
+		return false
+	end
+	local message_receiver = message_receivers[msg.url()]
+	if not message_receiver then
+		return false
+	end
+	if message_receiver == true then
+		return false
+	end
+	message_receiver(message, sender)
+	return true
+end
+
 
 return M