bal-util

# Import {EventEmitter} = require('events') typeChecker = require('typechecker') # ===================================== # Event & EventSystem # Extends the EventEmitterEnhanced with support for: # - blocking events # - start and finish events # Event class Event # The name of the event name: null # Is the event currently locked? locked: false # Has the event finished running? finished: false # Apply our name on construction constructor: ({@name}) -> # EventSystem class EventSystem extends EventEmitter # Event store # initialised in our event function to prevent javascript reference problems _eventSystemEvents: null # Fetch the event object for the event event: (eventName) -> # Prepare @_eventSystemEvents or= {} # Return the fetched event, create it if it doesn't exist already @_eventSystemEvents[eventName] or= new Event(eventName) # Lock the event # next(err) lock: (eventName, next) -> # Grab the event event = @event eventName # Grab a lock on the event if event.locked is false # Place the lock event.locked = true # Trigger our event # then fire our callback try @emit eventName+':locked' catch err next(err) return @ finally next() else # Wait until the current task has finished @onceUnlocked eventName, (err) => return next(err) if err # Then try again @lock eventName, next # Chain @ # Unlock the event # next(err) unlock: (eventName, next) -> # Grab the event event = @event eventName # Release the lock event.locked = false # Trigger our event # then fire our callback try @emit eventName+':unlocked' catch err next(err) return @ finally next() # Chain @ # Start our event # 1. Performs a lock # 2. Sets event's finished flag to false # 3. Fires callback # next(err) start: (eventName, next) -> # Grab a locak @lock eventName, (err) => # Error? return next(err) if err # Grab the event event = @event eventName # Set as started event.finished = false # Trigger our event # then fire our callback try @emit eventName+':started' catch err next(err) return @ finally next() # Chain @ # Finish, alias for finished finish: (args...) -> @finished.apply(@,args) # Finished our event # 1. Sets event's finished flag to true # 2. Unlocks the event # 3. Fires callback # next(err) finished: (eventName, next) -> # Grab the event event = @event eventName # Set as finished event.finished = true # Unlock @unlock eventName, (err) => # Error? return next(err) if err # Trigger our event # then fire our callback try @emit eventName+':finished' catch err next(err) return @ finally next() # Chain @ # Run one time once an event has unlocked # next(err) onceUnlocked: (eventName, next) -> # Grab the event event = @event eventName # Check lock status if event.locked # Wait until our event has unlocked to fire the callback @once eventName+':unlocked', next else # Fire our callback now next() # Chain @ # Run one time once an event has finished # next(err) onceFinished: (eventName, next) -> # Grab the event event = @event eventName # Check finish status if event.finished # Fire our callback now next() else # Wait until our event has finished to fire the callback @once eventName+':finished', next # Chain @ # Run every time an event has finished # next(err) whenFinished: (eventName, next) -> # Grab the event event = @event eventName # Check finish status if event.finished # Fire our callback now next() # Everytime our even has finished, fire the callback @on eventName+':finished', next # Chain @ # When, alias for on when: (args...) -> @on.apply(@,args) # Block an event from running # next(err) block: (eventNames, next) -> # Ensure array unless typeChecker.isArray(eventNames) if typeChecker.isString(eventNames) eventNames = eventNames.split(/[,\s]+/g) else err = new Error('Unknown eventNames type') return next(err) total = eventNames.length done = 0 # Block these events for eventName in eventNames @lock eventName, (err) -> # Error? if err done = total return next(err) # Increment done++ if done is total next() # Chain @ # Unblock an event from running # next(err) unblock: (eventNames, next) -> # Ensure array unless typeChecker.isArray(eventNames) if typeChecker.isString(eventNames) eventNames = eventNames.split /[,\s]+/g else err = new Error('Unknown eventNames type') return next(err) total = eventNames.length done = 0 # Block these events for eventName in eventNames @unlock eventName, (err) -> # Error? if err done = total return next(err) # Increment done++ if done is total next() # Chain @ # ===================================== # Export module.exports = {Event,EventSystem}