Add ActionQueue priority system

This makes effectors nearer to the source of the action (the receptor) update first.

This defines behaviour for this piston circuit: http://i.imgur.com/9Pp2Mzb.png
And defines, that this memory circuit does not work from this direction: http://i.imgur.com/jJn0aFh.png
But it will work when using the switch from the other side: http://i.imgur.com/nvw0oZB.png

Only if two effectors have the same distance, there is nothing we can do about it, behaviour is not defined.
"Distance" is determined by the stack size of recursions in turnon / turnoff.
Priorities are between 0 (lowest) and 1 (highest).

5 files changed, 63 insertions, 44 deletions

diff --git a/mesecons/actionqueue.lua b/mesecons/actionqueue.lua
index 9d31426..a00054a 100644
--- a/mesecons/actionqueue.lua
+++ b/mesecons/actionqueue.lua
@@ -6,15 +6,19 @@ end
 
 -- If add_action with twice the same overwritecheck and same position are called, the first one is overwritten
 -- use overwritecheck nil to never overwrite, but just add the event to the queue
-function mesecon.queue:add_action(pos, func, params, time, overwritecheck)
+-- priority specifies the order actions are executed within one globalstep, highest by default
+-- should be between 0 and 1
+function mesecon.queue:add_action(pos, func, params, time, overwritecheck, priority)
 	-- Create Action Table:
 	time = time or 0 -- time <= 0 --> execute, time > 0 --> wait time until execution
+	priority = priority or 1
 	overwritecheck = overwritecheck or {}
 	action = {	pos=mesecon:tablecopy(pos),
 			func=func,
 			params=mesecon:tablecopy(params),
 			time=time,
-			owcheck=mesecon:tablecopy(overwritecheck)}
+			owcheck=(overwritecheck and mesecon:tablecopy(overwritecheck)) or nil,
+			priority=priority}
 
 	--print(dump(action))
 	-- if not using the queue, (MESECONS_GLOBALSTEP off), just execute the function an we're done
@@ -42,6 +46,18 @@ end
 -- this makes sure that resuming mesecons circuits when restarting minetest works fine
 -- However, even that does not work in some cases, that's why we delay the time the globalsteps
 -- start to be execute by 5 seconds
+local get_highest_priority = function (actions)
+	local highestp = 0, highesti
+	for i, ac in ipairs(actions) do
+		if ac.priority > highestp then
+			highestp = ac.priority
+			highesti = i
+		end
+	end
+
+	return highesti
+end
+
 local m_time = 0
 minetest.register_globalstep(function (dtime)
 	m_time = m_time + dtime
@@ -53,10 +69,14 @@ minetest.register_globalstep(function (dtime)
 		if action.time > 0 then
 			action.time = action.time - dtime
 			table.insert(mesecon.queue.actions, action) -- will be handled another time
-		else -- execute and remove
-			mesecon.queue:execute(action)
 		end
 	end
+
+	while(#actions > 0) do -- execute highest priorities first, until all are executed
+		local hp = get_highest_priority(actions)
+		mesecon.queue:execute(actions[hp])
+		table.remove(actions, hp)
+	end
 end)
 
 function mesecon.queue:execute(action)
diff --git a/mesecons/init.lua b/mesecons/init.lua
index 8facf73..4d4819c 100644
--- a/mesecons/init.lua
+++ b/mesecons/init.lua
@@ -79,12 +79,18 @@ dofile(minetest.get_modpath("mesecons").."/legacy.lua");
 mesecon.queue:add_function("receptor_on", function (pos, rules)
 	rules = rules or mesecon.rules.default
 
+	-- if area (any of the neighbors) is not loaded, keep trying and call this again later
 	for _, rule in ipairs(mesecon:flattenrules(rules)) do
 		local np = mesecon:addPosRule(pos, rule)
-		-- if area is not loaded, keep trying
-		if minetest.env:get_node_or_nil(np) == nil then
+		if minetest.get_node_or_nil(np) == nil then
 			mesecon.queue:add_action(pos, "receptor_on", {rules})
+			return
 		end
+	end
+
+	-- execute action
+	for _, rule in ipairs(mesecon:flattenrules(rules)) do
+		local np = mesecon:addPosRule(pos, rule)
 		local rulenames = mesecon:rules_link_rule_all(pos, rule)
 		for _, rulename in ipairs(rulenames) do
 			mesecon:turnon(np, rulename)
@@ -100,7 +106,7 @@ mesecon.queue:add_function("receptor_off", function (pos, rules)
 	rules = rules or mesecon.rules.default
 	for _, rule in ipairs(mesecon:flattenrules(rules)) do
 		local np = mesecon:addPosRule(pos, rule)
-		if minetest.env:get_node_or_nil(np) == nil then
+		if minetest.get_node_or_nil(np) == nil then
 			mesecon.queue:add_action(pos, "receptor_off", {rules})
 		end
 		local rulenames = mesecon:rules_link_rule_all(pos, rule)
@@ -108,7 +114,7 @@ mesecon.queue:add_function("receptor_off", function (pos, rules)
 			if not mesecon:connected_to_receptor(np, mesecon:invertRule(rule)) then
 				mesecon:turnoff(np, rulename)
 			else
-				mesecon:changesignal(np, minetest.get_node(np), rulename, mesecon.state.off)
+				mesecon:changesignal(np, minetest.get_node(np), rulename, mesecon.state.off, 1)
 			end
 		end
 	end
diff --git a/mesecons/internal.lua b/mesecons/internal.lua
index f575c83..f713a7c 100644
--- a/mesecons/internal.lua
+++ b/mesecons/internal.lua
@@ -22,9 +22,9 @@
 -- mesecon:effector_get_rules(node)  --> Returns the input rules of the effector (mesecon.rules.default if none specified)
 
 -- SIGNALS
--- mesecon:activate(pos, node)     --> Activates   the effector node at the specific pos (calls nodedef.mesecons.effector.action_on)
--- mesecon:deactivate(pos, node)   --> Deactivates the effector node at the specific pos (calls nodedef.mesecons.effector.action_off)
--- mesecon:changesignal(pos, node, rulename, newstate) --> Changes     the effector node at the specific pos (calls nodedef.mesecons.effector.action_change)
+-- mesecon:activate(pos, node, recdepth)		--> Activates   the effector node at the specific pos (calls nodedef.mesecons.effector.action_on), higher recdepths are executed later
+-- mesecon:deactivate(pos, node, recdepth)		--> Deactivates the effector node at the specific pos (calls nodedef.mesecons.effector.action_off), "
+-- mesecon:changesignal(pos, node, rulename, newstate)	--> Changes     the effector node at the specific pos (calls nodedef.mesecons.effector.action_change), "
 
 -- RULES
 -- mesecon:add_rules(name, rules) | deprecated? --> Saves rules table by name
@@ -41,8 +41,8 @@
 -- HIGH-LEVEL Internals
 -- mesecon:is_power_on(pos)             --> Returns true if pos emits power in any way
 -- mesecon:is_power_off(pos)            --> Returns true if pos does not emit power in any way
--- mesecon:turnon(pos, rulename)        --> Returns true  whatever there is at pos. Calls itself for connected nodes (if pos is a conductor) --> recursive, the rulename is the name of the input rule that caused calling turnon
--- mesecon:turnoff(pos, rulename)       --> Turns off whatever there is at pos. Calls itself for connected nodes (if pos is a conductor) --> recursive, the rulename is the name of the input rule that caused calling turnoff
+-- mesecon:turnon(pos, rulename)        --> Returns true  whatever there is at pos. Calls itself for connected nodes (if pos is a conductor) --> recursive, the rulename is the name of the input rule that caused calling turnon; Uses third parameter recdepth internally to determine how far away the current node is from the initial pos as it uses recursion
+-- mesecon:turnoff(pos, rulename)       --> Turns off whatever there is at pos. Calls itself for connected nodes (if pos is a conductor) --> recursive, the rulename is the name of the input rule that caused calling turnoff; Uses third parameter recdepth internally to determine how far away the current node is from the initial pos as it uses recursion
 -- mesecon:connected_to_receptor(pos)   --> Returns true if pos is connected to a receptor directly or via conductors; calls itself if pos is a conductor --> recursive
 -- mesecon:rules_link(output, input, dug_outputrules) --> Returns true if outputposition + outputrules = inputposition and inputposition + inputrules = outputposition (if the two positions connect)
 -- mesecon:rules_link_anydir(outp., inp., d_outpr.)   --> Same as rules mesecon:rules_link but also returns true if output and input are swapped
@@ -191,14 +191,14 @@ mesecon.queue:add_function("activate", function (pos, rulename)
 	end
 end)
 
-function mesecon:activate(pos, node, rulename)
+function mesecon:activate(pos, node, rulename, recdepth)
 	if rulename == nil then
 		for _,rule in ipairs(mesecon:effector_get_rules(node)) do
-			mesecon:activate(pos, node, rule)
+			mesecon:activate(pos, node, rule, recdepth + 1)
 		end
 		return
 	end
-	mesecon.queue:add_action(pos, "activate", {rulename}, nil, rulename)
+	mesecon.queue:add_action(pos, "activate", {rulename}, nil, rulename, 1 / recdepth)
 end
 
 
@@ -212,14 +212,14 @@ mesecon.queue:add_function("deactivate", function (pos, rulename)
 	end
 end)
 
-function mesecon:deactivate(pos, node, rulename)
+function mesecon:deactivate(pos, node, rulename, recdepth)
 	if rulename == nil then
 		for _,rule in ipairs(mesecon:effector_get_rules(node)) do
-			mesecon:deactivate(pos, node, rule)
+			mesecon:deactivate(pos, node, rule, recdepth + 1)
 		end
 		return
 	end
-	mesecon.queue:add_action(pos, "deactivate", {rulename}, nil, rulename)
+	mesecon.queue:add_action(pos, "deactivate", {rulename}, nil, rulename, 1 / recdepth)
 end
 
 
@@ -233,15 +233,15 @@ mesecon.queue:add_function("change", function (pos, rulename, changetype)
 	end
 end)
 
-function mesecon:changesignal(pos, node, rulename, newstate)
+function mesecon:changesignal(pos, node, rulename, newstate, recdepth)
 	if rulename == nil then
 		for _,rule in ipairs(mesecon:effector_get_rules(node)) do
-			mesecon:changesignal(pos, node, rule, newstate)
+			mesecon:changesignal(pos, node, rule, newstate, recdepth + 1)
 		end
 		return
 	end
 
-	mesecon.queue:add_action(pos, "change", {rulename, newstate}, nil, rulename)
+	mesecon.queue:add_action(pos, "change", {rulename, newstate}, nil, rulename, 1 / recdepth)
 end
 
 -- #########
@@ -365,7 +365,8 @@ function mesecon:is_power_off(pos, rulename)
 	return false
 end
 
-function mesecon:turnon(pos, rulename)
+function mesecon:turnon(pos, rulename, recdepth)
+	recdepth = recdepth or 2
 	local node = minetest.get_node(pos)
 	
 	if mesecon:is_conductor_off(node, rulename) then
@@ -374,7 +375,7 @@ function mesecon:turnon(pos, rulename)
 		if not rulename then
 			for _, rule in ipairs(mesecon:flattenrules(rules)) do
 				if mesecon:connected_to_receptor(pos, rule) then
-					mesecon:turnon(pos, rule)
+					mesecon:turnon(pos, rule, recdepth + 1)
 				end
 			end
 			return
@@ -387,32 +388,23 @@ function mesecon:turnon(pos, rulename)
 			local rulenames = mesecon:rules_link_rule_all(pos, rule)
 
 			for _, rulename in ipairs(rulenames) do
-				mesecon:turnon(np, rulename)
+				mesecon:turnon(np, rulename, recdepth + 1)
 			end
 		end
 	elseif mesecon:is_effector(node.name) then
-		mesecon:changesignal(pos, node, rulename, mesecon.state.on)
+		mesecon:changesignal(pos, node, rulename, mesecon.state.on, recdepth)
 		if mesecon:is_effector_off(node.name) then
-			mesecon:activate(pos, node, rulename)
+			mesecon:activate(pos, node, rulename, recdepth)
 		end
 	end
 end
 
-function mesecon:turnoff(pos, rulename)
+function mesecon:turnoff(pos, rulename, recdepth)
+	recdepth = recdepth or 0
 	local node = minetest.get_node(pos)
 
 	if mesecon:is_conductor_on(node, rulename) then
 		local rules = mesecon:conductor_get_rules(node)
-		--[[
-		if not rulename then
-			for _, rule in ipairs(mesecon:flattenrules(rules)) do
-				if mesecon:is_powered(pos, rule) then
-					mesecon:turnoff(pos, rule)
-				end
-			end
-			return
-		end
-		--]]
 		minetest.swap_node(pos, {name = mesecon:get_conductor_off(node, rulename), param2 = node.param2})
 
 		for _, rule in ipairs(mesecon:rule2meta(rulename, rules)) do
@@ -420,14 +412,14 @@ function mesecon:turnoff(pos, rulename)
 			local rulenames = mesecon:rules_link_rule_all(pos, rule)
 
 			for _, rulename in ipairs(rulenames) do
-				mesecon:turnoff(np, rulename)
+				mesecon:turnoff(np, rulename, recdepth + 1)
 			end
 		end
 	elseif mesecon:is_effector(node.name) then
-		mesecon:changesignal(pos, node, rulename, mesecon.state.off)
+		mesecon:changesignal(pos, node, rulename, mesecon.state.off, recdepth)
 		if mesecon:is_effector_on(node.name)
 		and not mesecon:is_powered(pos) then
-			mesecon:deactivate(pos, node, rulename)
+			mesecon:deactivate(pos, node, rulename, recdepth + 1)
 		end
 	end
 end
diff --git a/mesecons/services.lua b/mesecons/services.lua
index 29b5183..de0c8b6 100644
--- a/mesecons/services.lua
+++ b/mesecons/services.lua
@@ -6,13 +6,13 @@ mesecon.on_placenode = function (pos, node)
 			mesecon:turnon (pos)
 			--mesecon:receptor_on (pos, mesecon:conductor_get_rules(node))
 		else
-			mesecon:changesignal(pos, node, mesecon:effector_get_rules(node), "on")
-			mesecon:activate(pos, node)
+			mesecon:changesignal(pos, node, mesecon:effector_get_rules(node), "on", 1)
+			mesecon:activate(pos, node, nil, 1)
 		end
 	elseif mesecon:is_conductor_on(node) then
 		minetest.swap_node(pos, {name = mesecon:get_conductor_off(node)})
 	elseif mesecon:is_effector_on (node.name) then
-		mesecon:deactivate(pos, node)
+		mesecon:deactivate(pos, node, nil, 1)
 	end
 end
 
diff --git a/mesecons/util.lua b/mesecons/util.lua
index ad2a4ae..91d435a 100644
--- a/mesecons/util.lua
+++ b/mesecons/util.lua
@@ -169,6 +169,7 @@ function mesecon:cmpSpecial(r1, r2)
 end
 
 function mesecon:tablecopy(table) -- deep table copy
+	if type(table) ~= "table" then return table end -- no need to copy
 	local newtable = {}
 
 	for idx, item in pairs(table) do