--[[ $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.