nodobjc-x/examples/EventLoop.js

The Node.js ⇆ Objective-C bridge

var $, EventEmitter = require('events').EventEmitter;

// export EventLoop at module and as 'EventLoop'
module.exports = EventLoop.EventLoop = EventLoop
EventLoop.initObjC = function(NodObjC) {
  $ = NodObjC || $ || require('NodObjC')
  $.import('Cocoa')

  EventLoop.prototype._runLoopMode = $.NSDefaultRunLoopMode
  if (EventLoop.prototype._runLoopMode === null) {
    EventLoop.prototype._runLoopMode = $('kCFRunLoopDefaultMode')
    console.warn('WARNING: Falling back to hard-coded string for NSDefaultRunLoopMode constant. See https://github.com/TooTallNate/NodObjC/pull/56 for details.')
  }
}

function EventLoop(start, options) {
  EventEmitter.call(this)
  if (options) {
    if (options.runLoopMode) this._runLoopMode = options.runLoopMode
  }
  this.runInfo = {recurring:null, schedule_id:null, loop:{}}

  if (start) this.start()
  return this
}
require('util').inherits(EventLoop, EventEmitter)

EventLoop.prototype.start = function() {
  this.emit('start')
  return this.schedule(true)
}
EventLoop.prototype.stop = function() {
  this.runInfo.recurring = false
  this.emit('stop')
  return this
}
EventLoop.prototype._schedule = setTimeout
EventLoop.prototype._clearSchedule = clearTimeout
EventLoop.prototype.schedule = function(runRecurring) {
  var runInfo = this.runInfo
  if (runRecurring !== undefined)
    runInfo.recurring = !!runRecurring

  if (runInfo.schedule_id != null)
    return this; // exit if already scheduled

  var id = this._schedule(this.eventLoop.bind(this))
  runInfo.schedule_id = (id !== undefined) ? id : true
  this.emit('scheduled', runInfo)
  return this
}
EventLoop.prototype.clearSchedule = function() {
  var runInfo = this.runInfo
  var id = runInfo.schedule_id
  runInfo.recurring = false

  if (id != null) {
    runInfo.schedule_id = null
    this._clearSchedule(id)
    this.emit('unscheduled', runInfo)
  }
  return this
}

EventLoop.prototype.isScheduled = function(runInfo) {
  if (!runInfo) runInfo = this.runInfo
  return runInfo.schedule_id!=null }
EventLoop.prototype.isActive = function(runInfo) {
  if (!runInfo) runInfo = this.runInfo
  return this.isScheduled(runInfo) || runInfo.recurring }

EventLoop.prototype.eventLoop = function(runRecurring) {
  var runInfo = this.runInfo
  runInfo.schedule_id = null
  this.eventLoopCore()
  if (runInfo.recurring || runRecurring)
    this.schedule(runRecurring)
  else if (runInfo.schedule_id==null)
    this.emit('deactivate', this.runInfo)
  return this
}
EventLoop.prototype.eventLoopCore = function(block) {
  if ($==null) EventLoop.initObjC();

  var runInfo = this.runInfo,
      loopInfo = {running:true, count:0, t0:Date.now()},
      event, app = $.NSApplication('sharedApplication'),
      untilDate = block ? $.NSDate('distantFuture') : null, // or $.NSDate('distantPast') to not block
      inMode = this._runLoopMode

  var runLoopPool = $.NSAutoreleasePool('alloc')('init')
  try {
    runInfo.loop = loopInfo
    this.emit('eventLoop-enter', runInfo)
    do {
      this.emit('event-next', event, app, runInfo)
      event = app('nextEventMatchingMask',
              $.NSAnyEventMask.toString(), // …grumble… uint64 as string …grumble…
              'untilDate', untilDate,
              'inMode', inMode,
              'dequeue', 1)
      this.emit('event-match', event, app, runInfo)
      if (event) {
        app('sendEvent', event)
        this.emit('event-sent', event, app, runInfo)
      }
      ++loopInfo.count
    } while (event)
    loopInfo.t1 = Date.now()
    loopInfo.running = false
    this.emit('eventLoop-exit', runInfo)
  } catch (err) {
    loopInfo.t1 = Date.now()
    loopInfo.running = false
    loopInfo.error = err
    this.emit('error', err, runInfo)
    throw err
  } finally {
    runLoopPool('drain')
  }
  delete loopInfo.running
  this.emit('eventLoop', runInfo)
  return this
}