--[[ $Id: CallbackHandler-1.0.lua 1186 2018-07-21 14:19:18Z nevcairiel $ ]] local MAJOR, MINOR = "CallbackHandler-1.0", 7 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} -- Lua APIs local tconcat = table.concat local assert, error, loadstring = assert, error, loadstring local setmetatable, rawset, rawget = setmetatable, rawset, rawget local next, select, pairs, type, tostring = next, select, pairs, type, tostring -- Global vars/functions that we don't upvalue since they might get hooked, or upgraded -- List them here for Mikk's FindGlobals script -- GLOBALS: geterrorhandler local xpcall = xpcall local function errorhandler(err) return geterrorhandler()(err) end local function Dispatch(handlers, ...) local index, method = next(handlers) if not method then return end repeat xpcall(method, errorhandler, ...) index, method = next(handlers, index) until not method 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) 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 Dispatch(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" or self=thread if type(self)~="table" and type(self)~="string" and type(self)~="thread" then error("Usage: "..RegisterName.."(self or \"addonId\", eventname, method): 'self or addonId': table or string or thread 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.