Asa@0: --[[ $Id: CallbackHandler-1.0.lua 895 2009-12-06 16:28:55Z nevcairiel $ ]]
Asa@0: local MAJOR, MINOR = "CallbackHandler-1.0", 5
Asa@0: local CallbackHandler = LibStub:NewLibrary(MAJOR, MINOR)
Asa@0: 
Asa@0: if not CallbackHandler then return end -- No upgrade needed
Asa@0: 
Asa@0: local meta = {__index = function(tbl, key) tbl[key] = {} return tbl[key] end}
Asa@0: 
Asa@0: -- Lua APIs
Asa@0: local tconcat = table.concat
Asa@0: local assert, error, loadstring = assert, error, loadstring
Asa@0: local setmetatable, rawset, rawget = setmetatable, rawset, rawget
Asa@0: local next, select, pairs, type, tostring = next, select, pairs, type, tostring
Asa@0: 
Asa@0: -- Global vars/functions that we don't upvalue since they might get hooked, or upgraded
Asa@0: -- List them here for Mikk's FindGlobals script
Asa@0: -- GLOBALS: geterrorhandler
Asa@0: 
Asa@0: local xpcall = xpcall
Asa@0: 
Asa@0: local function errorhandler(err)
Asa@0: 	return geterrorhandler()(err)
Asa@0: end
Asa@0: 
Asa@0: local function CreateDispatcher(argCount)
Asa@0: 	local code = [[
Asa@0: 	local next, xpcall, eh = ...
Asa@0: 
Asa@0: 	local method, ARGS
Asa@0: 	local function call() method(ARGS) end
Asa@0: 
Asa@0: 	local function dispatch(handlers, ...)
Asa@0: 		local index
Asa@0: 		index, method = next(handlers)
Asa@0: 		if not method then return end
Asa@0: 		local OLD_ARGS = ARGS
Asa@0: 		ARGS = ...
Asa@0: 		repeat
Asa@0: 			xpcall(call, eh)
Asa@0: 			index, method = next(handlers, index)
Asa@0: 		until not method
Asa@0: 		ARGS = OLD_ARGS
Asa@0: 	end
Asa@0: 
Asa@0: 	return dispatch
Asa@0: 	]]
Asa@0: 
Asa@0: 	local ARGS, OLD_ARGS = {}, {}
Asa@0: 	for i = 1, argCount do ARGS[i], OLD_ARGS[i] = "arg"..i, "old_arg"..i end
Asa@0: 	code = code:gsub("OLD_ARGS", tconcat(OLD_ARGS, ", ")):gsub("ARGS", tconcat(ARGS, ", "))
Asa@0: 	return assert(loadstring(code, "safecall Dispatcher["..argCount.."]"))(next, xpcall, errorhandler)
Asa@0: end
Asa@0: 
Asa@0: local Dispatchers = setmetatable({}, {__index=function(self, argCount)
Asa@0: 	local dispatcher = CreateDispatcher(argCount)
Asa@0: 	rawset(self, argCount, dispatcher)
Asa@0: 	return dispatcher
Asa@0: end})
Asa@0: 
Asa@0: --------------------------------------------------------------------------
Asa@0: -- CallbackHandler:New
Asa@0: --
Asa@0: --   target            - target object to embed public APIs in
Asa@0: --   RegisterName      - name of the callback registration API, default "RegisterCallback"
Asa@0: --   UnregisterName    - name of the callback unregistration API, default "UnregisterCallback"
Asa@0: --   UnregisterAllName - name of the API to unregister all callbacks, default "UnregisterAllCallbacks". false == don't publish this API.
Asa@0: 
Asa@0: function CallbackHandler:New(target, RegisterName, UnregisterName, UnregisterAllName, OnUsed, OnUnused)
Asa@0: 	-- TODO: Remove this after beta has gone out
Asa@0: 	assert(not OnUsed and not OnUnused, "ACE-80: OnUsed/OnUnused are deprecated. Callbacks are now done to registry.OnUsed and registry.OnUnused")
Asa@0: 
Asa@0: 	RegisterName = RegisterName or "RegisterCallback"
Asa@0: 	UnregisterName = UnregisterName or "UnregisterCallback"
Asa@0: 	if UnregisterAllName==nil then	-- false is used to indicate "don't want this method"
Asa@0: 		UnregisterAllName = "UnregisterAllCallbacks"
Asa@0: 	end
Asa@0: 
Asa@0: 	-- we declare all objects and exported APIs inside this closure to quickly gain access
Asa@0: 	-- to e.g. function names, the "target" parameter, etc
Asa@0: 
Asa@0: 
Asa@0: 	-- Create the registry object
Asa@0: 	local events = setmetatable({}, meta)
Asa@0: 	local registry = { recurse=0, events=events }
Asa@0: 
Asa@0: 	-- registry:Fire() - fires the given event/message into the registry
Asa@0: 	function registry:Fire(eventname, ...)
Asa@0: 		if not rawget(events, eventname) or not next(events[eventname]) then return end
Asa@0: 		local oldrecurse = registry.recurse
Asa@0: 		registry.recurse = oldrecurse + 1
Asa@0: 
Asa@0: 		Dispatchers[select('#', ...) + 1](events[eventname], eventname, ...)
Asa@0: 
Asa@0: 		registry.recurse = oldrecurse
Asa@0: 
Asa@0: 		if registry.insertQueue and oldrecurse==0 then
Asa@0: 			-- Something in one of our callbacks wanted to register more callbacks; they got queued
Asa@0: 			for eventname,callbacks in pairs(registry.insertQueue) do
Asa@0: 				local first = not rawget(events, eventname) or not next(events[eventname])	-- test for empty before. not test for one member after. that one member may have been overwritten.
Asa@0: 				for self,func in pairs(callbacks) do
Asa@0: 					events[eventname][self] = func
Asa@0: 					-- fire OnUsed callback?
Asa@0: 					if first and registry.OnUsed then
Asa@0: 						registry.OnUsed(registry, target, eventname)
Asa@0: 						first = nil
Asa@0: 					end
Asa@0: 				end
Asa@0: 			end
Asa@0: 			registry.insertQueue = nil
Asa@0: 		end
Asa@0: 	end
Asa@0: 
Asa@0: 	-- Registration of a callback, handles:
Asa@0: 	--   self["method"], leads to self["method"](self, ...)
Asa@0: 	--   self with function ref, leads to functionref(...)
Asa@0: 	--   "addonId" (instead of self) with function ref, leads to functionref(...)
Asa@0: 	-- all with an optional arg, which, if present, gets passed as first argument (after self if present)
Asa@0: 	target[RegisterName] = function(self, eventname, method, ... --[[actually just a single arg]])
Asa@0: 		if type(eventname) ~= "string" then
Asa@0: 			error("Usage: "..RegisterName.."(eventname, method[, arg]): 'eventname' - string expected.", 2)
Asa@0: 		end
Asa@0: 
Asa@0: 		method = method or eventname
Asa@0: 
Asa@0: 		local first = not rawget(events, eventname) or not next(events[eventname])	-- test for empty before. not test for one member after. that one member may have been overwritten.
Asa@0: 
Asa@0: 		if type(method) ~= "string" and type(method) ~= "function" then
Asa@0: 			error("Usage: "..RegisterName.."(\"eventname\", \"methodname\"): 'methodname' - string or function expected.", 2)
Asa@0: 		end
Asa@0: 
Asa@0: 		local regfunc
Asa@0: 
Asa@0: 		if type(method) == "string" then
Asa@0: 			-- self["method"] calling style
Asa@0: 			if type(self) ~= "table" then
Asa@0: 				error("Usage: "..RegisterName.."(\"eventname\", \"methodname\"): self was not a table?", 2)
Asa@0: 			elseif self==target then
Asa@0: 				error("Usage: "..RegisterName.."(\"eventname\", \"methodname\"): do not use Library:"..RegisterName.."(), use your own 'self'", 2)
Asa@0: 			elseif type(self[method]) ~= "function" then
Asa@0: 				error("Usage: "..RegisterName.."(\"eventname\", \"methodname\"): 'methodname' - method '"..tostring(method).."' not found on self.", 2)
Asa@0: 			end
Asa@0: 
Asa@0: 			if select("#",...)>=1 then	-- this is not the same as testing for arg==nil!
Asa@0: 				local arg=select(1,...)
Asa@0: 				regfunc = function(...) self[method](self,arg,...) end
Asa@0: 			else
Asa@0: 				regfunc = function(...) self[method](self,...) end
Asa@0: 			end
Asa@0: 		else
Asa@0: 			-- function ref with self=object or self="addonId"
Asa@0: 			if type(self)~="table" and type(self)~="string" then
Asa@0: 				error("Usage: "..RegisterName.."(self or \"addonId\", eventname, method): 'self or addonId': table or string expected.", 2)
Asa@0: 			end
Asa@0: 
Asa@0: 			if select("#",...)>=1 then	-- this is not the same as testing for arg==nil!
Asa@0: 				local arg=select(1,...)
Asa@0: 				regfunc = function(...) method(arg,...) end
Asa@0: 			else
Asa@0: 				regfunc = method
Asa@0: 			end
Asa@0: 		end
Asa@0: 
Asa@0: 
Asa@0: 		if events[eventname][self] or registry.recurse<1 then
Asa@0: 		-- if registry.recurse<1 then
Asa@0: 			-- we're overwriting an existing entry, or not currently recursing. just set it.
Asa@0: 			events[eventname][self] = regfunc
Asa@0: 			-- fire OnUsed callback?
Asa@0: 			if registry.OnUsed and first then
Asa@0: 				registry.OnUsed(registry, target, eventname)
Asa@0: 			end
Asa@0: 		else
Asa@0: 			-- we're currently processing a callback in this registry, so delay the registration of this new entry!
Asa@0: 			-- yes, we're a bit wasteful on garbage, but this is a fringe case, so we're picking low implementation overhead over garbage efficiency
Asa@0: 			registry.insertQueue = registry.insertQueue or setmetatable({},meta)
Asa@0: 			registry.insertQueue[eventname][self] = regfunc
Asa@0: 		end
Asa@0: 	end
Asa@0: 
Asa@0: 	-- Unregister a callback
Asa@0: 	target[UnregisterName] = function(self, eventname)
Asa@0: 		if not self or self==target then
Asa@0: 			error("Usage: "..UnregisterName.."(eventname): bad 'self'", 2)
Asa@0: 		end
Asa@0: 		if type(eventname) ~= "string" then
Asa@0: 			error("Usage: "..UnregisterName.."(eventname): 'eventname' - string expected.", 2)
Asa@0: 		end
Asa@0: 		if rawget(events, eventname) and events[eventname][self] then
Asa@0: 			events[eventname][self] = nil
Asa@0: 			-- Fire OnUnused callback?
Asa@0: 			if registry.OnUnused and not next(events[eventname]) then
Asa@0: 				registry.OnUnused(registry, target, eventname)
Asa@0: 			end
Asa@0: 		end
Asa@0: 		if registry.insertQueue and rawget(registry.insertQueue, eventname) and registry.insertQueue[eventname][self] then
Asa@0: 			registry.insertQueue[eventname][self] = nil
Asa@0: 		end
Asa@0: 	end
Asa@0: 
Asa@0: 	-- OPTIONAL: Unregister all callbacks for given selfs/addonIds
Asa@0: 	if UnregisterAllName then
Asa@0: 		target[UnregisterAllName] = function(...)
Asa@0: 			if select("#",...)<1 then
Asa@0: 				error("Usage: "..UnregisterAllName.."([whatFor]): missing 'self' or \"addonId\" to unregister events for.", 2)
Asa@0: 			end
Asa@0: 			if select("#",...)==1 and ...==target then
Asa@0: 				error("Usage: "..UnregisterAllName.."([whatFor]): supply a meaningful 'self' or \"addonId\"", 2)
Asa@0: 			end
Asa@0: 
Asa@0: 
Asa@0: 			for i=1,select("#",...) do
Asa@0: 				local self = select(i,...)
Asa@0: 				if registry.insertQueue then
Asa@0: 					for eventname, callbacks in pairs(registry.insertQueue) do
Asa@0: 						if callbacks[self] then
Asa@0: 							callbacks[self] = nil
Asa@0: 						end
Asa@0: 					end
Asa@0: 				end
Asa@0: 				for eventname, callbacks in pairs(events) do
Asa@0: 					if callbacks[self] then
Asa@0: 						callbacks[self] = nil
Asa@0: 						-- Fire OnUnused callback?
Asa@0: 						if registry.OnUnused and not next(callbacks) then
Asa@0: 							registry.OnUnused(registry, target, eventname)
Asa@0: 						end
Asa@0: 					end
Asa@0: 				end
Asa@0: 			end
Asa@0: 		end
Asa@0: 	end
Asa@0: 
Asa@0: 	return registry
Asa@0: end
Asa@0: 
Asa@0: 
Asa@0: -- CallbackHandler purposefully does NOT do explicit embedding. Nor does it
Asa@0: -- try to upgrade old implicit embeds since the system is selfcontained and
Asa@0: -- relies on closures to work.
Asa@0: