crowdstf/lib/units/device/plugins/screen/stream.js - release.projects.luma_third_party - Git at Google

 var util = require('util')

 var Promise = require('bluebird')
 var syrup = require('stf-syrup')
 var WebSocket = require('ws')
 var uuid = require('node-uuid')
 var EventEmitter = require('eventemitter3').EventEmitter
 var split = require('split')
 var adbkit = require('adbkit')

 var logger = require('../../../../util/logger')
 var lifecycle = require('../../../../util/lifecycle')
 var bannerutil = require('./util/banner')
 var FrameParser = require('./util/frameparser')
 var FrameConfig = require('./util/frameconfig')
 var FrameStore = require('./util/framestore')
 var BroadcastSet = require('./util/broadcastset')
 var StateQueue = require('../../../../util/statequeue')
 var RiskyStream = require('../../../../util/riskystream')
 var FailCounter = require('../../../../util/failcounter')

 const FINAL_DEVICE_CAPTURE_WIDTH = 1080;
 const FINAL_DEVICE_CAPTURE_HEIGHT = 1920;

 module.exports = syrup.serial()
   .dependency(require('../../support/adb'))
   .dependency(require('../../resources/minicap'))
   .dependency(require('../util/display'))
   .dependency(require('./options'))
   .define(function(options, adb, minicap, display, screenOptions) {
     var log = logger.createLogger('device:plugins:screen:stream')
     var frameStore = new FrameStore();

     function FrameProducer(config) {
       EventEmitter.call(this)
       this.actionQueue = []
       this.runningState = FrameProducer.STATE_STOPPED
       this.desiredState = new StateQueue()
       this.output = null
       this.socket = null
       this.pid = -1
       this.banner = null
       this.parser = null
       this.frameConfig = config
       this.readable = false
       this.needsReadable = false
       this.failCounter = new FailCounter(3, 10000)
       this.failCounter.on('exceedLimit', this._failLimitExceeded.bind(this))
       this.failed = false
       this.readableListener = this._readableListener.bind(this)
     }

     util.inherits(FrameProducer, EventEmitter)

     FrameProducer.STATE_STOPPED = 1
     FrameProducer.STATE_STARTING = 2
     FrameProducer.STATE_STARTED = 3
     FrameProducer.STATE_STOPPING = 4

     FrameProducer.prototype._ensureState = function() {
       if (this.desiredState.empty()) {
         return
       }

       if (this.failed) {
         log.warn('Will not apply desired state due to too many failures')
         return
       }

       switch (this.runningState) {
       case FrameProducer.STATE_STARTING:
       case FrameProducer.STATE_STOPPING:
         // Just wait.
         break
       case FrameProducer.STATE_STOPPED:
         if (this.desiredState.next() === FrameProducer.STATE_STARTED) {
           this.runningState = FrameProducer.STATE_STARTING
           this._startService().bind(this)
             .then(function(out) {
               this.output = new RiskyStream(out)
                 .on('unexpectedEnd', this._outputEnded.bind(this))
               return this._readOutput(this.output.stream)
             })
             .then(function() {
               return this._waitForPid()
             })
             .then(function() {
               return this._connectService()
             })
             .then(function(socket) {
               this.parser = new FrameParser()
               this.socket = new RiskyStream(socket)
                 .on('unexpectedEnd', this._socketEnded.bind(this))
               return this._readBanner(this.socket.stream)
             })
             .then(function(banner) {
               this.banner = banner
               return this._readFrames(this.socket.stream)
             })
             .then(function() {
               this.runningState = FrameProducer.STATE_STARTED
               this.emit('start')
             })
             .catch(Promise.CancellationError, function() {
               return this._stop()
             })
             .catch(function(err) {
               return this._stop().finally(function() {
                 this.failCounter.inc()
                 this.emit('error', err)
               })
             })
             .finally(function() {
               this._ensureState()
             })
         }
         else {
           setImmediate(this._ensureState.bind(this))
         }
         break
       case FrameProducer.STATE_STARTED:
         if (this.desiredState.next() === FrameProducer.STATE_STOPPED) {
           this.runningState = FrameProducer.STATE_STOPPING
           this._stop().finally(function() {
             this._ensureState()
           })
         }
         else {
           setImmediate(this._ensureState.bind(this))
         }
         break
       }
     }

     FrameProducer.prototype.start = function() {
       log.info('Requesting frame producer to start')
       this.desiredState.push(FrameProducer.STATE_STARTED)
       this._ensureState()
     }

     FrameProducer.prototype.stop = function() {
       log.info('Requesting frame producer to stop')
       this.desiredState.push(FrameProducer.STATE_STOPPED)
       this._ensureState()
     }

     FrameProducer.prototype.restart = function() {
       switch (this.runningState) {
       case FrameProducer.STATE_STARTED:
       case FrameProducer.STATE_STARTING:
         this.desiredState.push(FrameProducer.STATE_STOPPED)
         this.desiredState.push(FrameProducer.STATE_STARTED)
         this._ensureState()
         break
       }
     }

     FrameProducer.prototype.updateRotation = function(rotation) {
       if (this.frameConfig.rotation === rotation) {
         log.info('Keeping %d as current frame producer rotation', rotation)
         return
       }

       log.info('Setting frame producer rotation to %d', rotation)
       this.frameConfig.rotation = rotation
       this._configChanged()
     }

     FrameProducer.prototype.updateProjection = function(width, height) {
       if (this.frameConfig.virtualWidth === width &&
           this.frameConfig.virtualHeight === height) {
         log.info(
           'Keeping %dx%d as current frame producer projection', width, height)
         return
       }

       log.info('Setting frame producer projection to %dx%d', width, height)
       this.frameConfig.virtualWidth = width
       this.frameConfig.virtualHeight = height
       this._configChanged()
     }

     FrameProducer.prototype.setStaticProjection = function() {
       if (this.frameConfig.virtualWidth === FINAL_DEVICE_CAPTURE_WIDTH &&
           this.frameConfig.virtualHeight === FINAL_DEVICE_CAPTURE_HEIGHT) {
         log.info('Keeping %dx%d as current frame producer projection',
           FINAL_DEVICE_CAPTURE_WIDTH, FINAL_DEVICE_CAPTURE_HEIGHT)
         return
       }

       log.info('Setting frame producer projection to %dx%d',
         FINAL_DEVICE_CAPTURE_WIDTH,
         FINAL_DEVICE_CAPTURE_HEIGHT)
       this.frameConfig.virtualWidth = FINAL_DEVICE_CAPTURE_WIDTH
       this.frameConfig.virtualHeight = FINAL_DEVICE_CAPTURE_HEIGHT
       this._configChanged()
     }

     FrameProducer.prototype.nextFrame = function() {
       var frame = null
       var chunk

       if (this.parser) {
         while ((frame = this.parser.nextFrame()) === null) {
           chunk = this.socket.stream.read()
           if (chunk) {
             this.parser.push(chunk)
           }
           else {
             this.readable = false
             break
           }
         }
       }

       return frame
     }

     FrameProducer.prototype.needFrame = function() {
       this.needsReadable = true
       this._maybeEmitReadable()
     }

     FrameProducer.prototype._configChanged = function() {
       this.restart()
     }

     FrameProducer.prototype._socketEnded = function() {
       log.warn('Connection to minicap ended unexpectedly')
       this.failCounter.inc()
       this.restart()
     }

     FrameProducer.prototype._outputEnded = function() {
       log.warn('Shell keeping minicap running ended unexpectedly')
       this.failCounter.inc()
       this.restart()
     }

     FrameProducer.prototype._failLimitExceeded = function(limit, time) {
       this._stop()
       this.failed = true
       this.emit('error', new Error(util.format(
         'Failed more than %d times in %dms'
       , limit
       , time
       )))
     }

     FrameProducer.prototype._startService = function() {
       log.info('Launching screen service')
       return minicap.run(util.format('-S -P %s', this.frameConfig.toString()))
         .timeout(10000)
     }

     FrameProducer.prototype._readOutput = function(out) {
       out.pipe(split()).on('data', function(line) {
         var trimmed = line.toString().trim()

         if (trimmed === '') {
           return
         }

         if (/ERROR/.test(line)) {
           log.fatal('minicap error: "%s"', line)
           return lifecycle.fatal()
         }

         var match = /^PID: (\d+)$/.exec(line)
         if (match) {
           this.pid = Number(match[1])
           this.emit('pid', this.pid)
         }

         log.info('minicap says: "%s"', line)
       }.bind(this))
     }

     FrameProducer.prototype._waitForPid = function() {
       if (this.pid > 0) {
         return Promise.resolve(this.pid)
       }

       var pidListener
       return new Promise(function(resolve) {
           this.on('pid', pidListener = resolve)
         }.bind(this)).bind(this)
         .timeout(2000)
         .finally(function() {
           this.removeListener('pid', pidListener)
         })
     }

     FrameProducer.prototype._connectService = function() {
       function tryConnect(times, delay) {
         return adb.openLocal(options.serial, 'localabstract:minicap')
           .timeout(10000)
           .then(function(out) {
             return out
           })
           .catch(function(err) {
             if (/closed/.test(err.message) && times > 1) {
               return Promise.delay(delay)
                 .then(function() {
                   return tryConnect(times - 1, delay * 2)
                 })
             }
             return Promise.reject(err)
           })
       }
       log.info('Connecting to minicap service')
       return tryConnect(5, 100)
     }

     FrameProducer.prototype._stop = function() {
       return this._disconnectService(this.socket).bind(this)
         .timeout(2000)
         .then(function() {
           return this._stopService(this.output).timeout(10000)
         })
         .then(function() {
           this.runningState = FrameProducer.STATE_STOPPED
           this.emit('stop')
         })
         .catch(function(err) {
           // In practice we _should_ never get here due to _stopService()
           // being quite aggressive. But if we do, well... assume it
           // stopped anyway for now.
           this.runningState = FrameProducer.STATE_STOPPED
           this.emit('error', err)
           this.emit('stop')
         })
         .finally(function() {
           this.output = null
           this.socket = null
           this.pid = -1
           this.banner = null
           this.parser = null
         })
     }

     FrameProducer.prototype._disconnectService = function(socket) {
       log.info('Disconnecting from minicap service')

       if (!socket || socket.ended) {
         return Promise.resolve(true)
       }

       socket.stream.removeListener('readable', this.readableListener)

       var endListener
       return new Promise(function(resolve) {
           socket.on('end', endListener = function() {
             resolve(true)
           })

           socket.stream.resume()
           socket.end()
         })
         .finally(function() {
           socket.removeListener('end', endListener)
         })
     }

     FrameProducer.prototype._stopService = function(output) {
       log.info('Stopping minicap service')

       if (!output || output.ended) {
         return Promise.resolve(true)
       }

       var pid = this.pid

       function kill(signal) {
         if (pid <= 0) {
           return Promise.reject(new Error('Minicap service pid is unknown'))
         }

         var signum = {
           SIGTERM: -15
         , SIGKILL: -9
         }[signal]

         log.info('Sending %s to minicap', signal)
         return Promise.all([
             output.waitForEnd()
           , adb.shell(options.serial, ['kill', signum, pid])
               .then(adbkit.util.readAll)
               .return(true)
           ])
           .timeout(2000)
       }

       function kindKill() {
         return kill('SIGTERM')
       }

       function forceKill() {
         return kill('SIGKILL')
       }

       function forceEnd() {
         log.info('Ending minicap I/O as a last resort')
         output.end()
         return Promise.resolve(true)
       }

       return kindKill()
         .catch(Promise.TimeoutError, forceKill)
         .catch(forceEnd)
     }

     FrameProducer.prototype._readBanner = function(socket) {
       log.info('Reading minicap banner')
       return bannerutil.read(socket).timeout(2000)
     }

     FrameProducer.prototype._readFrames = function(socket) {
       this.needsReadable = true
       socket.on('readable', this.readableListener)

       // We may already have data pending. Let the user know they should
       // at least attempt to read frames now.
       this.readableListener()
     }

     FrameProducer.prototype._maybeEmitReadable = function() {
       if (this.readable && this.needsReadable) {
         this.needsReadable = false
         this.emit('readable')
       }
     }

     FrameProducer.prototype._readableListener = function() {
       this.readable = true
       this._maybeEmitReadable()
     }

     function createServer() {
       log.info('Starting WebSocket server on port %d', screenOptions.publicPort)

       var wss = new WebSocket.Server({
         port: screenOptions.publicPort
       , perMessageDeflate: false
       })

       var listeningListener, errorListener
       return new Promise(function(resolve, reject) {
           listeningListener = function() {
             return resolve(wss)
           }

           errorListener = function(err) {
             return reject(err)
           }

           wss.on('listening', listeningListener)
           wss.on('error', errorListener)
         })
         .finally(function() {
           wss.removeListener('listening', listeningListener)
           wss.removeListener('error', errorListener)
         })
     }

     return createServer()
       .then(function(wss) {
         var frameProducer = new FrameProducer(
           new FrameConfig(display.properties, display.properties))
         var broadcastSet = frameProducer.broadcastSet = new BroadcastSet()

         broadcastSet.on('nonempty', function() {
           frameProducer.start()
         })

         broadcastSet.on('empty', function() {
           frameProducer.stop()
         })

         broadcastSet.on('insert', function(id) {
           // If two clients join a session in the middle, one of them
           // may not release the initial size because the projection
           // doesn't necessarily change, and the producer doesn't Getting
           // restarted. Therefore we have to call onStart() manually
           // if the producer is already up and running.
           switch (frameProducer.runningState) {
           case FrameProducer.STATE_STARTED:
             broadcastSet.get(id).onStart(frameProducer)
             break
           }
         })

         display.on('rotationChange', function(newRotation) {
           frameProducer.updateRotation(newRotation)
         })

         frameProducer.on('start', function() {
           broadcastSet.keys().map(function(id) {
             return broadcastSet.get(id).onStart(frameProducer)
           })
         })

         frameProducer.on('readable', function next() {
           var frame = frameProducer.nextFrame()
           if (frame) {
             Promise.settle([broadcastSet.keys().map(function(id) {
               return broadcastSet.get(id).onFrame(frame, id)
             })]).then(next)
           }
           else {
             frameProducer.needFrame()
           }
         })

         frameProducer.on('error', function(err) {
           log.fatal('Frame producer had an error', err.stack)
           lifecycle.fatal()
         })

         wss.on('connection', function(ws) {
           var id = uuid.v4()

           function wsStartNotifier() {
             return new Promise(function(resolve, reject) {
               frameProducer.banner.wsId = id;

               var message = util.format('start %s',
                 JSON.stringify(frameProducer.banner))

               switch (ws.readyState) {
               case WebSocket.OPENING:
                 // This should never happen.
                 log.warn('Unable to send banner to OPENING client "%s"', id)
                 break
               case WebSocket.OPEN:
                 // This is what SHOULD happen.
                 ws.send(message, function(err) {
                   return err ? reject(err) : resolve()
                 })
                 break
               case WebSocket.CLOSING:
                 // Ok, a 'close' event should remove the client from the set
                 // soon.
                 break
               case WebSocket.CLOSED:
                 // This should never happen.
                 log.warn('Unable to send banner to CLOSED client "%s"', id)
                 broadcastSet.remove(id)
                 break
               }
             })
           }

           function wsFrameNotifier(frame, id) {
             return new Promise(function(resolve, reject) {
               switch (ws.readyState) {
               case WebSocket.OPENING:
                 // This should never happen.
                 return reject(new Error(util.format(
                   'Unable to send frame to OPENING client "%s"', id)))
               case WebSocket.OPEN:
                 var fileName = frameStore.storeFrame(frame, id);

                 var message = util.format(
                   'nextImgId %s'
                   , fileName
                 )

                 // Send the next img file id first
                 ws.send(message, function (err) {
                   return err ? reject(err) : resolve()
                 })

                 // This is what SHOULD happen.
                 ws.send(frame, {
                   binary: true
                 }, function(err) {
                   return err ? reject(err) : resolve()
                 })
                 return
               case WebSocket.CLOSING:
                 // Ok, a 'close' event should remove the client from the set
                 // soon.
                 return
               case WebSocket.CLOSED:
                 // This should never happen.
                 broadcastSet.remove(id)
                 return reject(new Error(util.format(
                   'Unable to send frame to CLOSED client "%s"', id)))
               }
             })
           }

           ws.on('message', function(data) {
             var match = /^(on|off|(size) ([0-9]+)x([0-9]+))$/.exec(data)
             if (match) {
               switch (match[2] || match[1]) {
               case 'on':
                 broadcastSet.insert(id, {
                   onStart: wsStartNotifier
                 , onFrame: wsFrameNotifier
                 })
                 break
               case 'off':
                 broadcastSet.remove(id)
                 break
               case 'size':
                 frameProducer.setStaticProjection()
                 break
               }
             }
           })

           ws.on('close', function() {
             broadcastSet.remove(id)
           })
         })

         lifecycle.observe(function() {
           wss.close()
         })

         lifecycle.observe(function() {
           frameProducer.stop()
         })

         return frameProducer
       })
   })
	var util = require('util')

	var Promise = require('bluebird')
	var syrup = require('stf-syrup')
	var WebSocket = require('ws')
	var uuid = require('node-uuid')
	var EventEmitter = require('eventemitter3').EventEmitter
	var split = require('split')
	var adbkit = require('adbkit')

	var logger = require('../../../../util/logger')
	var lifecycle = require('../../../../util/lifecycle')
	var bannerutil = require('./util/banner')
	var FrameParser = require('./util/frameparser')
	var FrameConfig = require('./util/frameconfig')
	var FrameStore = require('./util/framestore')
	var BroadcastSet = require('./util/broadcastset')
	var StateQueue = require('../../../../util/statequeue')
	var RiskyStream = require('../../../../util/riskystream')
	var FailCounter = require('../../../../util/failcounter')

	const FINAL_DEVICE_CAPTURE_WIDTH = 1080;
	const FINAL_DEVICE_CAPTURE_HEIGHT = 1920;

	module.exports = syrup.serial()
	.dependency(require('../../support/adb'))
	.dependency(require('../../resources/minicap'))
	.dependency(require('../util/display'))
	.dependency(require('./options'))
	.define(function(options, adb, minicap, display, screenOptions) {
	var log = logger.createLogger('device:plugins:screen:stream')
	var frameStore = new FrameStore();

	function FrameProducer(config) {
	EventEmitter.call(this)
	this.actionQueue = []
	this.runningState = FrameProducer.STATE_STOPPED
	this.desiredState = new StateQueue()
	this.output = null
	this.socket = null
	this.pid = -1
	this.banner = null
	this.parser = null
	this.frameConfig = config
	this.readable = false
	this.needsReadable = false
	this.failCounter = new FailCounter(3, 10000)
	this.failCounter.on('exceedLimit', this._failLimitExceeded.bind(this))
	this.failed = false
	this.readableListener = this._readableListener.bind(this)
	}

	util.inherits(FrameProducer, EventEmitter)

	FrameProducer.STATE_STOPPED = 1
	FrameProducer.STATE_STARTING = 2
	FrameProducer.STATE_STARTED = 3
	FrameProducer.STATE_STOPPING = 4

	FrameProducer.prototype._ensureState = function() {
	if (this.desiredState.empty()) {
	return
	}

	if (this.failed) {
	log.warn('Will not apply desired state due to too many failures')
	return
	}

	switch (this.runningState) {
	case FrameProducer.STATE_STARTING:
	case FrameProducer.STATE_STOPPING:
	// Just wait.
	break
	case FrameProducer.STATE_STOPPED:
	if (this.desiredState.next() === FrameProducer.STATE_STARTED) {
	this.runningState = FrameProducer.STATE_STARTING
	this._startService().bind(this)
	.then(function(out) {
	this.output = new RiskyStream(out)
	.on('unexpectedEnd', this._outputEnded.bind(this))
	return this._readOutput(this.output.stream)
	})
	.then(function() {
	return this._waitForPid()
	})
	.then(function() {
	return this._connectService()
	})
	.then(function(socket) {
	this.parser = new FrameParser()
	this.socket = new RiskyStream(socket)
	.on('unexpectedEnd', this._socketEnded.bind(this))
	return this._readBanner(this.socket.stream)
	})
	.then(function(banner) {
	this.banner = banner
	return this._readFrames(this.socket.stream)
	})
	.then(function() {
	this.runningState = FrameProducer.STATE_STARTED
	this.emit('start')
	})
	.catch(Promise.CancellationError, function() {
	return this._stop()
	})
	.catch(function(err) {
	return this._stop().finally(function() {
	this.failCounter.inc()
	this.emit('error', err)
	})
	})
	.finally(function() {
	this._ensureState()
	})
	}
	else {
	setImmediate(this._ensureState.bind(this))
	}
	break
	case FrameProducer.STATE_STARTED:
	if (this.desiredState.next() === FrameProducer.STATE_STOPPED) {
	this.runningState = FrameProducer.STATE_STOPPING
	this._stop().finally(function() {
	this._ensureState()
	})
	}
	else {
	setImmediate(this._ensureState.bind(this))
	}
	break
	}
	}

	FrameProducer.prototype.start = function() {
	log.info('Requesting frame producer to start')
	this.desiredState.push(FrameProducer.STATE_STARTED)
	this._ensureState()
	}

	FrameProducer.prototype.stop = function() {
	log.info('Requesting frame producer to stop')
	this.desiredState.push(FrameProducer.STATE_STOPPED)
	this._ensureState()
	}

	FrameProducer.prototype.restart = function() {
	switch (this.runningState) {
	case FrameProducer.STATE_STARTED:
	case FrameProducer.STATE_STARTING:
	this.desiredState.push(FrameProducer.STATE_STOPPED)
	this.desiredState.push(FrameProducer.STATE_STARTED)
	this._ensureState()
	break
	}
	}

	FrameProducer.prototype.updateRotation = function(rotation) {
	if (this.frameConfig.rotation === rotation) {
	log.info('Keeping %d as current frame producer rotation', rotation)
	return
	}

	log.info('Setting frame producer rotation to %d', rotation)
	this.frameConfig.rotation = rotation
	this._configChanged()
	}

	FrameProducer.prototype.updateProjection = function(width, height) {
	if (this.frameConfig.virtualWidth === width &&
	this.frameConfig.virtualHeight === height) {
	log.info(
	'Keeping %dx%d as current frame producer projection', width, height)
	return
	}

	log.info('Setting frame producer projection to %dx%d', width, height)
	this.frameConfig.virtualWidth = width
	this.frameConfig.virtualHeight = height
	this._configChanged()
	}

	FrameProducer.prototype.setStaticProjection = function() {
	if (this.frameConfig.virtualWidth === FINAL_DEVICE_CAPTURE_WIDTH &&
	this.frameConfig.virtualHeight === FINAL_DEVICE_CAPTURE_HEIGHT) {
	log.info('Keeping %dx%d as current frame producer projection',
	FINAL_DEVICE_CAPTURE_WIDTH, FINAL_DEVICE_CAPTURE_HEIGHT)
	return
	}

	log.info('Setting frame producer projection to %dx%d',
	FINAL_DEVICE_CAPTURE_WIDTH,
	FINAL_DEVICE_CAPTURE_HEIGHT)
	this.frameConfig.virtualWidth = FINAL_DEVICE_CAPTURE_WIDTH
	this.frameConfig.virtualHeight = FINAL_DEVICE_CAPTURE_HEIGHT
	this._configChanged()
	}

	FrameProducer.prototype.nextFrame = function() {
	var frame = null
	var chunk

	if (this.parser) {
	while ((frame = this.parser.nextFrame()) === null) {
	chunk = this.socket.stream.read()
	if (chunk) {
	this.parser.push(chunk)
	}
	else {
	this.readable = false
	break
	}
	}
	}

	return frame
	}

	FrameProducer.prototype.needFrame = function() {
	this.needsReadable = true
	this._maybeEmitReadable()
	}

	FrameProducer.prototype._configChanged = function() {
	this.restart()
	}

	FrameProducer.prototype._socketEnded = function() {
	log.warn('Connection to minicap ended unexpectedly')
	this.failCounter.inc()
	this.restart()
	}

	FrameProducer.prototype._outputEnded = function() {
	log.warn('Shell keeping minicap running ended unexpectedly')
	this.failCounter.inc()
	this.restart()
	}

	FrameProducer.prototype._failLimitExceeded = function(limit, time) {
	this._stop()
	this.failed = true
	this.emit('error', new Error(util.format(
	'Failed more than %d times in %dms'
	, limit
	, time
	)))
	}

	FrameProducer.prototype._startService = function() {
	log.info('Launching screen service')
	return minicap.run(util.format('-S -P %s', this.frameConfig.toString()))
	.timeout(10000)
	}

	FrameProducer.prototype._readOutput = function(out) {
	out.pipe(split()).on('data', function(line) {
	var trimmed = line.toString().trim()

	if (trimmed === '') {
	return
	}

	if (/ERROR/.test(line)) {
	log.fatal('minicap error: "%s"', line)
	return lifecycle.fatal()
	}

	var match = /^PID: (\d+)$/.exec(line)
	if (match) {
	this.pid = Number(match[1])
	this.emit('pid', this.pid)
	}

	log.info('minicap says: "%s"', line)
	}.bind(this))
	}

	FrameProducer.prototype._waitForPid = function() {
	if (this.pid > 0) {
	return Promise.resolve(this.pid)
	}

	var pidListener
	return new Promise(function(resolve) {
	this.on('pid', pidListener = resolve)
	}.bind(this)).bind(this)
	.timeout(2000)
	.finally(function() {
	this.removeListener('pid', pidListener)
	})
	}

	FrameProducer.prototype._connectService = function() {
	function tryConnect(times, delay) {
	return adb.openLocal(options.serial, 'localabstract:minicap')
	.timeout(10000)
	.then(function(out) {
	return out
	})
	.catch(function(err) {
	if (/closed/.test(err.message) && times > 1) {
	return Promise.delay(delay)
	.then(function() {
	return tryConnect(times - 1, delay * 2)
	})
	}
	return Promise.reject(err)
	})
	}
	log.info('Connecting to minicap service')
	return tryConnect(5, 100)
	}

	FrameProducer.prototype._stop = function() {
	return this._disconnectService(this.socket).bind(this)
	.timeout(2000)
	.then(function() {
	return this._stopService(this.output).timeout(10000)
	})
	.then(function() {
	this.runningState = FrameProducer.STATE_STOPPED
	this.emit('stop')
	})
	.catch(function(err) {
	// In practice we _should_ never get here due to _stopService()
	// being quite aggressive. But if we do, well... assume it
	// stopped anyway for now.
	this.runningState = FrameProducer.STATE_STOPPED
	this.emit('error', err)
	this.emit('stop')
	})
	.finally(function() {
	this.output = null
	this.socket = null
	this.pid = -1
	this.banner = null
	this.parser = null
	})
	}

	FrameProducer.prototype._disconnectService = function(socket) {
	log.info('Disconnecting from minicap service')

	if (!socket \|\| socket.ended) {
	return Promise.resolve(true)
	}

	socket.stream.removeListener('readable', this.readableListener)

	var endListener
	return new Promise(function(resolve) {
	socket.on('end', endListener = function() {
	resolve(true)
	})

	socket.stream.resume()
	socket.end()
	})
	.finally(function() {
	socket.removeListener('end', endListener)
	})
	}

	FrameProducer.prototype._stopService = function(output) {
	log.info('Stopping minicap service')

	if (!output \|\| output.ended) {
	return Promise.resolve(true)
	}

	var pid = this.pid

	function kill(signal) {
	if (pid <= 0) {
	return Promise.reject(new Error('Minicap service pid is unknown'))
	}

	var signum = {
	SIGTERM: -15
	, SIGKILL: -9
	}[signal]

	log.info('Sending %s to minicap', signal)
	return Promise.all([
	output.waitForEnd()
	, adb.shell(options.serial, ['kill', signum, pid])
	.then(adbkit.util.readAll)
	.return(true)
	])
	.timeout(2000)
	}

	function kindKill() {
	return kill('SIGTERM')
	}

	function forceKill() {
	return kill('SIGKILL')
	}

	function forceEnd() {
	log.info('Ending minicap I/O as a last resort')
	output.end()
	return Promise.resolve(true)
	}

	return kindKill()
	.catch(Promise.TimeoutError, forceKill)
	.catch(forceEnd)
	}

	FrameProducer.prototype._readBanner = function(socket) {
	log.info('Reading minicap banner')
	return bannerutil.read(socket).timeout(2000)
	}

	FrameProducer.prototype._readFrames = function(socket) {
	this.needsReadable = true
	socket.on('readable', this.readableListener)

	// We may already have data pending. Let the user know they should
	// at least attempt to read frames now.
	this.readableListener()
	}

	FrameProducer.prototype._maybeEmitReadable = function() {
	if (this.readable && this.needsReadable) {
	this.needsReadable = false
	this.emit('readable')
	}
	}

	FrameProducer.prototype._readableListener = function() {
	this.readable = true
	this._maybeEmitReadable()
	}

	function createServer() {
	log.info('Starting WebSocket server on port %d', screenOptions.publicPort)

	var wss = new WebSocket.Server({
	port: screenOptions.publicPort
	, perMessageDeflate: false
	})

	var listeningListener, errorListener
	return new Promise(function(resolve, reject) {
	listeningListener = function() {
	return resolve(wss)
	}

	errorListener = function(err) {
	return reject(err)
	}

	wss.on('listening', listeningListener)
	wss.on('error', errorListener)
	})
	.finally(function() {
	wss.removeListener('listening', listeningListener)
	wss.removeListener('error', errorListener)
	})
	}

	return createServer()
	.then(function(wss) {
	var frameProducer = new FrameProducer(
	new FrameConfig(display.properties, display.properties))
	var broadcastSet = frameProducer.broadcastSet = new BroadcastSet()

	broadcastSet.on('nonempty', function() {
	frameProducer.start()
	})

	broadcastSet.on('empty', function() {
	frameProducer.stop()
	})

	broadcastSet.on('insert', function(id) {
	// If two clients join a session in the middle, one of them
	// may not release the initial size because the projection
	// doesn't necessarily change, and the producer doesn't Getting
	// restarted. Therefore we have to call onStart() manually
	// if the producer is already up and running.
	switch (frameProducer.runningState) {
	case FrameProducer.STATE_STARTED:
	broadcastSet.get(id).onStart(frameProducer)
	break
	}
	})

	display.on('rotationChange', function(newRotation) {
	frameProducer.updateRotation(newRotation)
	})

	frameProducer.on('start', function() {
	broadcastSet.keys().map(function(id) {
	return broadcastSet.get(id).onStart(frameProducer)
	})
	})

	frameProducer.on('readable', function next() {
	var frame = frameProducer.nextFrame()
	if (frame) {
	Promise.settle([broadcastSet.keys().map(function(id) {
	return broadcastSet.get(id).onFrame(frame, id)
	})]).then(next)
	}
	else {
	frameProducer.needFrame()
	}
	})

	frameProducer.on('error', function(err) {
	log.fatal('Frame producer had an error', err.stack)
	lifecycle.fatal()
	})

	wss.on('connection', function(ws) {
	var id = uuid.v4()

	function wsStartNotifier() {
	return new Promise(function(resolve, reject) {
	frameProducer.banner.wsId = id;

	var message = util.format('start %s',
	JSON.stringify(frameProducer.banner))

	switch (ws.readyState) {
	case WebSocket.OPENING:
	// This should never happen.
	log.warn('Unable to send banner to OPENING client "%s"', id)
	break
	case WebSocket.OPEN:
	// This is what SHOULD happen.
	ws.send(message, function(err) {
	return err ? reject(err) : resolve()
	})
	break
	case WebSocket.CLOSING:
	// Ok, a 'close' event should remove the client from the set
	// soon.
	break
	case WebSocket.CLOSED:
	// This should never happen.
	log.warn('Unable to send banner to CLOSED client "%s"', id)
	broadcastSet.remove(id)
	break
	}
	})
	}

	function wsFrameNotifier(frame, id) {
	return new Promise(function(resolve, reject) {
	switch (ws.readyState) {
	case WebSocket.OPENING:
	// This should never happen.
	return reject(new Error(util.format(
	'Unable to send frame to OPENING client "%s"', id)))
	case WebSocket.OPEN:
	var fileName = frameStore.storeFrame(frame, id);

	var message = util.format(
	'nextImgId %s'
	, fileName
	)

	// Send the next img file id first
	ws.send(message, function (err) {
	return err ? reject(err) : resolve()
	})

	// This is what SHOULD happen.
	ws.send(frame, {
	binary: true
	}, function(err) {
	return err ? reject(err) : resolve()
	})
	return
	case WebSocket.CLOSING:
	// Ok, a 'close' event should remove the client from the set
	// soon.
	return
	case WebSocket.CLOSED:
	// This should never happen.
	broadcastSet.remove(id)
	return reject(new Error(util.format(
	'Unable to send frame to CLOSED client "%s"', id)))
	}
	})
	}

	ws.on('message', function(data) {
	var match = /^(on\|off\|(size) ([0-9]+)x([0-9]+))$/.exec(data)
	if (match) {
	switch (match[2] \|\| match[1]) {
	case 'on':
	broadcastSet.insert(id, {
	onStart: wsStartNotifier
	, onFrame: wsFrameNotifier
	})
	break
	case 'off':
	broadcastSet.remove(id)
	break
	case 'size':
	frameProducer.setStaticProjection()
	break
	}
	}
	})

	ws.on('close', function() {
	broadcastSet.remove(id)
	})
	})

	lifecycle.observe(function() {
	wss.close()
	})

	lifecycle.observe(function() {
	frameProducer.stop()
	})

	return frameProducer
	})
	})