mirror of
https://github.com/sbrl/Minetest-WorldEditAdditions.git
synced 2024-10-31 21:33:02 +00:00
83 lines
No EOL
3.7 KiB
Lua
83 lines
No EOL
3.7 KiB
Lua
local wea_c = worldeditadditions_core
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--- Event manager object.
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-- @class worldeditadditions_core.EventEmitter
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local EventEmitter = {}
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EventEmitter.__index = EventEmitter
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EventEmitter.__name = "EventEmitter" -- A hack to allow identification in wea.inspect
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--- Create a new event emitter.
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-- @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!
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-- @returns table The new EventEmitter object. If a table is passed in, a new table is NOT created.
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function EventEmitter.new(tbl)
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if not tbl then tbl = {} end
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tbl.events = { }
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tbl.debug = false
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setmetatable(tbl, EventEmitter)
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return tbl
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end
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--- Add a new listener to the given named event.
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-- @param this EventEmitter The EventEmitter instance to add the listener to.
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-- @param event_name string The name of the event to listen on.
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-- @param func function The callback function to call when the event is emitted. Will be passed a single argument - the object passed as the second argument to .emit().
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-- @returns number The number of listeners attached to that event.
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function EventEmitter.addEventListener(this, event_name, func)
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if this.events[event_name] == nil then this.events[event_name] = {} end
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table.insert(this.events[event_name], func)
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local count = #this.events[event_name]
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if count > 10 then
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minetest.log("warning", count.." listeners registered for event "..event_name..", possible leak? You MUST remove listeners when you're done with them!")
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end
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return count
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end
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function EventEmitter.on(this, event_name, func)
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return EventEmitter.addEventListener(this, event_name, func)
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end
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--- Remove an existing listener from the given named event.
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-- @param this EventEmitter The EventEmitter instance to remove the listener from.
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-- @param event_name string The name of the event to remove from.
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-- @param func function The callback function to remove from the list of listeners for the given named event.
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-- @return bool Whether it was actually removed or not. False means it failed to find the given listener function.
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function EventEmitter.removeEventListener(this, event_name, func)
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if this.events[event_name] == nil then return false end
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for index, next_func in ipairs(this.events[event_name]) do
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if next_func == func then
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table.remove(this.events[event_name], index)
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break
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end
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end
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return true
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end
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function EventEmitter.off(this, event_name, func)
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return EventEmitter.removeEventListener(this, event_name, func)
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end
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--- Emit an event.
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-- @param this EventEmitter The EventEmitter instance to emit the event from.
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-- @param event_name string The name of the event to emit.
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-- @param args table|any The argument(s) to pass to listener functions. It is strongly advised you pass a table here.
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function EventEmitter.emit(this, event_name, args)
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if this.events[event_name] == nil then return end
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if this.debug then print("DEBUG:EventEmitter emit", event_name, "args", wea_c.inspect(args)) end
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for index,next_func in ipairs(this.events[event_name]) do
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next_func(args)
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end
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-- TODO: Monitor execution time, log if it's slow? We'll need to move WEA utils over to wea_c first though...
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end
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--- Clear all listeners from a given event name.
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-- @param this EventEmitter The EventEmitter instance to clear listeners from.
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-- @param event_name string The name of the event to clear the listeners from.
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function EventEmitter.clear(this, event_name)
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this.events[event_name] = nil
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end
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--- Clear all listeners.
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-- @param this EventEmitter The EventEmitter instance to clear listeners from.
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function EventEmitter.clear_all(this, event_name)
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this.events = {}
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end
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return EventEmitter |