Spike out an update wrapper

We can expose just a few event subscription methods on atom.update to
take care of what most packages (e.g. About) would be interested in. Of
course the updater runs on the main thread so we’re proxying them
through IPC. It’s fine.

src/application-delegate.coffee

@@ -182,6 +182,34 @@ class ApplicationDelegate
     new Disposable ->
       ipcRenderer.removeListener('message', outerCallback)
 
+  onDidBeginCheckingForUpdate: (callback) ->
+    outerCallback = (message, detail) ->
+      if message is 'checking-for-update'
+        callback(detail)
+
+    ipc.on('message', outerCallback)
+    new Disposable ->
+      ipc.removeListener('message', outerCallback)
+
+  onDidCompleteDownloadingUpdate: (callback) ->
+    outerCallback = (message, detail) ->
+      if message is 'update-downloaded'
+        callback(detail)
+
+    ipc.on('message', outerCallback)
+    new Disposable ->
+      ipc.removeListener('message', outerCallback)
+
+  onUpdateNotAvailable: (callback) ->
+    outerCallback = (message, detail) ->
+      if message is 'update-not-available'
+        callback(detail)
+
+    ipc.on('message', outerCallback)
+    new Disposable ->
+      ipc.removeListener('message', outerCallback)
+
+
   onApplicationMenuCommand: (callback) ->
     outerCallback = (event, args...) ->
       callback(args...)

src/atom-environment.coffee

@@ -115,6 +115,9 @@ class AtomEnvironment extends Model
   # Public: A {TextEditorRegistry} instance
   textEditors: null
 
+  # Public: An {Update} instance
+  update: null
+
   saveStateDebounceInterval: 1000
 
   ###

src/browser/auto-update-manager.coffee

@@ -39,12 +39,19 @@ class AutoUpdateManager
 
     autoUpdater.on 'checking-for-update', =>
       @setState(CheckingState)
+      @emitWindowEvent('checking-for-update')
 
     autoUpdater.on 'update-not-available', =>
       @setState(NoUpdateAvailableState)
 
     autoUpdater.on 'update-available', =>
       @setState(DownladingState)
+      # We use sendMessage to send an event called 'update-available' below
+      # once the update download is complete. This mismatch between the electron
+      # autoUpdater events is unfortunate but in the interest of not changing the
+      # one existing event handled by applicationDelegate
+      @emitWindowEvent('did-begin-downloading-update')
+      @emit('did-begin-download')
 
     autoUpdater.on 'update-downloaded', (event, releaseNotes, @releaseVersion) =>
       @setState(UpdateAvailableState)
@@ -66,10 +73,16 @@ class AutoUpdateManager
 
   emitUpdateAvailableEvent: (windows...) ->
     return unless @releaseVersion?
+    @emitWindowEvent('update-available', {@releaseVersion})
     for atomWindow in windows
       atomWindow.sendMessage('update-available', {@releaseVersion})
     return
 
+  emitWindowEvent: (eventName, windows, payload) ->
+    for atomWindow in windows
+      atomWindow.sendMessage(eventName, payload)
+    return
+
   setState: (state) ->
     return if @state is state
     @state = state
@@ -93,6 +106,7 @@ class AutoUpdateManager
       @checkForUpdatesIntervalID = null
 
   check: ({hidePopups}={}) ->
+    console.log 'checking for update'
     unless hidePopups
       autoUpdater.once 'update-not-available', @onUpdateNotAvailable
       autoUpdater.once 'error', @onUpdateError

src/update.js

@@ -0,0 +1,56 @@
+'use babel'
+
+import {Emitter} from 'event-kit'
+
+export default class Update {
+  constructor () {
+    this.subscriptions = new CompositeDisposable()
+    this.emitter = new Emitter()
+  }
+
+  initialize () {
+    atom.applicationDelegate.onDidBeginDownloadingUpdate(() => {
+      this.emitter.emit('did-begin-downloading-update')
+    })
+    atom.applicationDelegate.onDidBeginCheckingForUpdate(() => {
+      this.emitter.emit('did-begin-checking-for-update')
+    })
+    atom.applicationDelegate.onUpdateAvailable(() => {
+      this.emitter.emit('did-complete-downloading-update')
+    })
+  }
+
+  dispose () {
+    this.subscriptions.dispose()
+  }
+
+  onDidBeginCheckingForUpdate (callback) {
+    this.subscriptions.add(
+      this.emitter.on('did-begin-checking-for-update', callback)
+    )
+  }
+
+  onDidBeginDownload (callback) {
+    this.subscriptions.add(
+      this.emitter.on('did-begin-downloading-update', callback)
+    )
+  }
+
+  onDidCompleteDownload (callback) {
+    this.subscriptions.add(
+      this.emitter.on('did-complete-downloading-update', callback)
+    )
+  }
+
+  onUpdateNotAvailable (callback) {
+    this.subscriptions.add()
+  }
+
+  check () {
+    // TODO
+  }
+
+  getState () {
+    // TODO
+  }
+}