--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/CallbackHandler-1.0.lua	Fri Nov 07 23:55:33 2008 +0000
@@ -0,0 +1,239 @@
+--[[ $Id: CallbackHandler-1.0.lua 504 2008-02-07 11:04:06Z nevcairiel $ ]]
+local MAJOR, MINOR = "CallbackHandler-1.0", 3
+local CallbackHandler = LibStub:NewLibrary(MAJOR, MINOR)
+
+if not CallbackHandler then return end -- No upgrade needed
+
+local meta = {__index = function(tbl, key) tbl[key] = {} return tbl[key] end}
+
+local type = type
+local pcall = pcall
+local pairs = pairs
+local assert = assert
+local concat = table.concat
+local loadstring = loadstring
+local next = next
+local select = select
+local type = type
+local xpcall = xpcall
+
+local function errorhandler(err)
+	return geterrorhandler()(err)
+end
+
+local function CreateDispatcher(argCount)
+	local code = [[
+	local next, xpcall, eh = ...
+
+	local method, ARGS
+	local function call() method(ARGS) end
+
+	local function dispatch(handlers, ...)
+		local index
+		index, method = next(handlers)
+		if not method then return end
+		local OLD_ARGS = ARGS
+		ARGS = ...
+		repeat
+			xpcall(call, eh)
+			index, method = next(handlers, index)
+		until not method
+		ARGS = OLD_ARGS
+	end
+
+	return dispatch
+	]]
+
+	local ARGS, OLD_ARGS = {}, {}
+	for i = 1, argCount do ARGS[i], OLD_ARGS[i] = "arg"..i, "old_arg"..i end
+	code = code:gsub("OLD_ARGS", concat(OLD_ARGS, ", ")):gsub("ARGS", concat(ARGS, ", "))
+	return assert(loadstring(code, "safecall Dispatcher["..argCount.."]"))(next, xpcall, errorhandler)
+end
+
+local Dispatchers = setmetatable({}, {__index=function(self, argCount)
+	local dispatcher = CreateDispatcher(argCount)
+	rawset(self, argCount, dispatcher)
+	return dispatcher
+end})
+
+--------------------------------------------------------------------------
+-- CallbackHandler:New
+--
+--   target            - target object to embed public APIs in
+--   RegisterName      - name of the callback registration API, default "RegisterCallback"
+--   UnregisterName    - name of the callback unregistration API, default "UnregisterCallback"
+--   UnregisterAllName - name of the API to unregister all callbacks, default "UnregisterAllCallbacks". false == don't publish this API.
+
+function CallbackHandler:New(target, RegisterName, UnregisterName, UnregisterAllName, OnUsed, OnUnused)
+	-- TODO: Remove this after beta has gone out
+	assert(not OnUsed and not OnUnused, "ACE-80: OnUsed/OnUnused are deprecated. Callbacks are now done to registry.OnUsed and registry.OnUnused")
+
+	RegisterName = RegisterName or "RegisterCallback"
+	UnregisterName = UnregisterName or "UnregisterCallback"
+	if UnregisterAllName==nil then	-- false is used to indicate "don't want this method"
+		UnregisterAllName = "UnregisterAllCallbacks"
+	end
+
+	-- we declare all objects and exported APIs inside this closure to quickly gain access
+	-- to e.g. function names, the "target" parameter, etc
+
+
+	-- Create the registry object
+	local events = setmetatable({}, meta)
+	local registry = { recurse=0, events=events }
+
+	-- registry:Fire() - fires the given event/message into the registry
+	function registry:Fire(eventname, ...)
+		if not rawget(events, eventname) or not next(events[eventname]) then return end
+		local oldrecurse = registry.recurse
+		registry.recurse = oldrecurse + 1
+
+		Dispatchers[select('#', ...) + 1](events[eventname], eventname, ...)
+
+		registry.recurse = oldrecurse
+
+		if registry.insertQueue and oldrecurse==0 then
+			-- Something in one of our callbacks wanted to register more callbacks; they got queued
+			for eventname,callbacks in pairs(registry.insertQueue) do
+				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.
+				for self,func in pairs(callbacks) do
+					events[eventname][self] = func
+					-- fire OnUsed callback?
+					if first and registry.OnUsed then
+						registry.OnUsed(registry, target, eventname)
+						first = nil
+					end
+				end
+			end
+			registry.insertQueue = nil
+		end
+	end
+
+	-- Registration of a callback, handles:
+	--   self["method"], leads to self["method"](self, ...)
+	--   self with function ref, leads to functionref(...)
+	--   "addonId" (instead of self) with function ref, leads to functionref(...)
+	-- all with an optional arg, which, if present, gets passed as first argument (after self if present)
+	target[RegisterName] = function(self, eventname, method, ... --[[actually just a single arg]])
+		if type(eventname) ~= "string" then
+			error("Usage: "..RegisterName.."(eventname, method[, arg]): 'eventname' - string expected.", 2)
+		end
+
+		method = method or eventname
+
+		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.
+
+		if type(method) ~= "string" and type(method) ~= "function" then
+			error("Usage: "..RegisterName.."(\"eventname\", \"methodname\"): 'methodname' - string or function expected.", 2)
+		end
+
+		local regfunc
+
+		if type(method) == "string" then
+			-- self["method"] calling style
+			if type(self) ~= "table" then
+				error("Usage: "..RegisterName.."(\"eventname\", \"methodname\"): self was not a table?", 2)
+			elseif self==target then
+				error("Usage: "..RegisterName.."(\"eventname\", \"methodname\"): do not use Library:"..RegisterName.."(), use your own 'self'", 2)
+			elseif type(self[method]) ~= "function" then
+				error("Usage: "..RegisterName.."(\"eventname\", \"methodname\"): 'methodname' - method '"..tostring(method).."' not found on self.", 2)
+			end
+
+			if select("#",...)>=1 then	-- this is not the same as testing for arg==nil!
+				local arg=select(1,...)
+				regfunc = function(...) self[method](self,arg,...) end
+			else
+				regfunc = function(...) self[method](self,...) end
+			end
+		else
+			-- function ref with self=object or self="addonId"
+			if type(self)~="table" and type(self)~="string" then
+				error("Usage: "..RegisterName.."(self or \"addonId\", eventname, method): 'self or addonId': table or string expected.", 2)
+			end
+
+			if select("#",...)>=1 then	-- this is not the same as testing for arg==nil!
+				local arg=select(1,...)
+				regfunc = function(...) method(arg,...) end
+			else
+				regfunc = method
+			end
+		end
+
+
+		if events[eventname][self] or registry.recurse<1 then
+		-- if registry.recurse<1 then
+			-- we're overwriting an existing entry, or not currently recursing. just set it.
+			events[eventname][self] = regfunc
+			-- fire OnUsed callback?
+			if registry.OnUsed and first then
+				registry.OnUsed(registry, target, eventname)
+			end
+		else
+			-- we're currently processing a callback in this registry, so delay the registration of this new entry!
+			-- yes, we're a bit wasteful on garbage, but this is a fringe case, so we're picking low implementation overhead over garbage efficiency
+			registry.insertQueue = registry.insertQueue or setmetatable({},meta)
+			registry.insertQueue[eventname][self] = regfunc
+		end
+	end
+
+	-- Unregister a callback
+	target[UnregisterName] = function(self, eventname)
+		if not self or self==target then
+			error("Usage: "..UnregisterName.."(eventname): bad 'self'", 2)
+		end
+		if type(eventname) ~= "string" then
+			error("Usage: "..UnregisterName.."(eventname): 'eventname' - string expected.", 2)
+		end
+		if rawget(events, eventname) and events[eventname][self] then
+			events[eventname][self] = nil
+			-- Fire OnUnused callback?
+			if registry.OnUnused and not next(events[eventname]) then
+				registry.OnUnused(registry, target, eventname)
+			end
+		end
+		if registry.insertQueue and rawget(registry.insertQueue, eventname) and registry.insertQueue[eventname][self] then
+			registry.insertQueue[eventname][self] = nil
+		end
+	end
+
+	-- OPTIONAL: Unregister all callbacks for given selfs/addonIds
+	if UnregisterAllName then
+		target[UnregisterAllName] = function(...)
+			if select("#",...)<1 then
+				error("Usage: "..UnregisterAllName.."([whatFor]): missing 'self' or \"addonId\" to unregister events for.", 2)
+			end
+			if select("#",...)==1 and ...==target then
+				error("Usage: "..UnregisterAllName.."([whatFor]): supply a meaningful 'self' or \"addonId\"", 2)
+			end
+
+
+			for i=1,select("#",...) do
+				local self = select(i,...)
+				if registry.insertQueue then
+					for eventname, callbacks in pairs(registry.insertQueue) do
+						if callbacks[self] then
+							callbacks[self] = nil
+						end
+					end
+				end
+				for eventname, callbacks in pairs(events) do
+					if callbacks[self] then
+						callbacks[self] = nil
+						-- Fire OnUnused callback?
+						if registry.OnUnused and not next(callbacks) then
+							registry.OnUnused(registry, target, eventname)
+						end
+					end
+				end
+			end
+		end
+	end
+
+	return registry
+end
+
+
+-- CallbackHandler purposefully does NOT do explicit embedding. Nor does it
+-- try to upgrade old implicit embeds since the system is selfcontained and
+-- relies on closures to work.
+