EventEmitter: document

This commit is contained in:
Starbeamrainbowlabs 2022-09-18 16:19:52 +01:00
parent 17d92870b3
commit cf0be6c1fb
No known key found for this signature in database
GPG Key ID: 1BE5172E637709C2

@ -1,11 +1,13 @@
--- A 3-dimensional vector. --- Event manager object.
-- @class -- @class
local EventEmitter = {} local EventEmitter = {}
EventEmitter.__index = EventEmitter EventEmitter.__index = EventEmitter
EventEmitter.__name = "EventEmitter" -- A hack to allow identification in wea.inspect EventEmitter.__name = "EventEmitter" -- A hack to allow identification in wea.inspect
--- Create a new event emitter.
-- @param tbl table|nil Optional. A table to base the new EventEmitter object on. EventEmitter will attach ann instance of itself to this object. The 'events' property on the object MUST NOT be set. IT WILL BE OVERWRITTEN!
-- @returns table The new EventEmitter object. If a table is passed in, a new table is NOT created.
function EventEmitter.new(tbl) function EventEmitter.new(tbl)
if not tbl then tbl = {} end if not tbl then tbl = {} end
tbl.events = {} tbl.events = {}
@ -13,14 +15,29 @@ function EventEmitter.new(tbl)
return tbl return tbl
end end
--- Add a new listener to the given named event.
-- @param this EventEmitter The EventEmitter instance to add the listener to.
-- @param event_name string The name of the event to listen on.
-- @param func function The callback function to call when the event is emitted.
-- @returns number The number of listeners attached to that event.
function EventEmitter.addEventListener(this, event_name, func) function EventEmitter.addEventListener(this, event_name, func)
if this.events[event_name] == nil then this.events[event_name] = {} end if this.events[event_name] == nil then this.events[event_name] = {} end
table.insert(this.events[event_name], func) table.insert(this.events[event_name], func)
local count = #this.events[event_name]
if count > 10 then
minetest.log("warning", count.." listeners registered for event "..event_name..", possible leak? You MUST remove listeners when you're done with them!")
end
return count
end end
function EventEmitter.on(this, event_name, func) function EventEmitter.on(this, event_name, func)
return EventEmitter.addEventListener(this, event_name, func) return EventEmitter.addEventListener(this, event_name, func)
end end
--- Remove an existing listener from the given named event.
-- @param this EventEmitter The EventEmitter instance to remove the listener from.
-- @param event_name string The name of the event to remove from.
-- @param func function The callback function to remove from the list of listeners for the given named event.
-- @return bool Whether it was actually removed or not. False means it failed to find the given listener function.
function EventEmitter.removeEventListener(this, event_name, func) function EventEmitter.removeEventListener(this, event_name, func)
if this.events[event_name] == nil then return false end if this.events[event_name] == nil then return false end
for index, next_func in ipairs(this.events[event_name]) do for index, next_func in ipairs(this.events[event_name]) do
@ -29,21 +46,35 @@ function EventEmitter.removeEventListener(this, event_name, func)
break break
end end
end end
return true
end end
function EventEmitter.off(this, event_name, func) function EventEmitter.off(this, event_name, func)
return EventEmitter.removeEventListener(this, event_name, func) return EventEmitter.removeEventListener(this, event_name, func)
end end
--- Emit an event.
-- @param this EventEmitter The EventEmitter instance to emit the event from.
-- @param event_name string The name of the event to emit.
-- @param args table|any The argument(s) to pass to listener functions. It is strongly advised you pass a table here.
function EventEmitter.emit(this, event_name, args) function EventEmitter.emit(this, event_name, args)
if this.events[event_name] == nil then return end if this.events[event_name] == nil then return end
for index,next_func in ipairs(this.events[event_name]) do for index,next_func in ipairs(this.events[event_name]) do
next_func(args) -- TODO: Move unpack compat to wea_c next_func(args)
end end
-- TODO: Monitor execution time, log if it's slow? We'll need to move WEA utils over to wea_c first though... -- TODO: Monitor execution time, log if it's slow? We'll need to move WEA utils over to wea_c first though...
end end
--- Clear all listeners from a given event name.
-- @param this EventEmitter The EventEmitter instance to clear listeners from.
-- @param event_name string The name of the event to clear the listeners from.
function EventEmitter.clear(this, event_name) function EventEmitter.clear(this, event_name)
this.events[event_name] = nil this.events[event_name] = nil
end end
--- Clear all listeners.
-- @param this EventEmitter The EventEmitter instance to clear listeners from.
function EventEmitter.clear_all(this, event_name)
this.events = {}
end
return EventEmitter return EventEmitter