Prompt user only once when quitting/restarting and canceling save dialog

I think this slipped through during the refactoring performed in
dc32018. With this commit we are fixing the regression and adding a new
main process regression test to exercise this behavior.

spec/main-process/atom-application.test.js

@@ -14,10 +14,11 @@ const ATOM_RESOURCE_PATH = path.resolve(__dirname, '..', '..')
 describe('AtomApplication', function () {
   this.timeout(60 * 1000)
 
-  let originalAppQuit, originalAtomHome, atomApplicationsToDestroy
+  let originalAppQuit, originalShowMessageBox, originalAtomHome, atomApplicationsToDestroy
 
   beforeEach(function () {
     originalAppQuit = electron.app.quit
+    originalShowMessageBox = electron.dialog
     mockElectronAppQuit()
     originalAtomHome = process.env.ATOM_HOME
     process.env.ATOM_HOME = makeTempDir('atom-home')
@@ -39,6 +40,7 @@ describe('AtomApplication', function () {
     }
     await clearElectronSession()
     electron.app.quit = originalAppQuit
+    electron.dialog.showMessageBox = originalShowMessageBox
   })
 
   describe('launch', function () {
@@ -462,20 +464,42 @@ describe('AtomApplication', function () {
     })
   })
 
-  describe('before quitting', function () {
-    it('waits until all the windows have saved their state and then quits', async function () {
-      const dirAPath = makeTempDir("a")
-      const dirBPath = makeTempDir("b")
-      const atomApplication = buildAtomApplication()
-      const window1 = atomApplication.launch(parseCommandLine([path.join(dirAPath, 'file-a')]))
-      await focusWindow(window1)
-      const window2 = atomApplication.launch(parseCommandLine([path.join(dirBPath, 'file-b')]))
-      await focusWindow(window2)
-      electron.app.quit()
-      assert(!electron.app.hasQuitted())
-      await Promise.all([window1.lastPrepareToUnloadPromise, window2.lastPrepareToUnloadPromise])
-      assert(electron.app.hasQuitted())
+  it('waits until all the windows have saved their state before quitting', async function () {
+    const dirAPath = makeTempDir("a")
+    const dirBPath = makeTempDir("b")
+    const atomApplication = buildAtomApplication()
+    const window1 = atomApplication.launch(parseCommandLine([path.join(dirAPath, 'file-a')]))
+    await focusWindow(window1)
+    const window2 = atomApplication.launch(parseCommandLine([path.join(dirBPath, 'file-b')]))
+    await focusWindow(window2)
+    electron.app.quit()
+    assert(!electron.app.hasQuitted())
+    await Promise.all([window1.lastPrepareToUnloadPromise, window2.lastPrepareToUnloadPromise])
+    assert(electron.app.hasQuitted())
+  })
+
+  it.only('prevents quitting if user cancels when prompted to save an item', async () => {
+    const atomApplication = buildAtomApplication()
+    const window1 = atomApplication.launch(parseCommandLine([]))
+    const window2 = atomApplication.launch(parseCommandLine([]))
+    await Promise.all([window1.loadedPromise, window2.loadedPromise])
+    await evalInWebContents(window1.browserWindow.webContents, function (sendBackToMainProcess) {
+      atom.workspace.getActiveTextEditor().insertText('unsaved text')
+      sendBackToMainProcess()
     })
+
+    // Choosing "Cancel"
+    mockElectronShowMessageBox({choice: 1})
+    electron.app.quit()
+    await atomApplication.lastBeforeQuitPromise
+    assert(!electron.app.hasQuitted())
+    assert.equal(electron.app.quit.callCount, 1) // Ensure choosing "Cancel" doesn't try to quit the electron app more than once (regression)
+
+    // Choosing "Don't save"
+    mockElectronShowMessageBox({choice: 2})
+    electron.app.quit()
+    await atomApplication.lastBeforeQuitPromise
+    assert(electron.app.hasQuitted())
   })
 
   function buildAtomApplication () {
@@ -496,6 +520,12 @@ describe('AtomApplication', function () {
   function mockElectronAppQuit () {
     let quitted = false
     electron.app.quit = function () {
+      if (electron.app.quit.callCount) {
+        electron.app.quit.callCount++
+      } else {
+        electron.app.quit.callCount = 1
+      }
+
       let shouldQuit = true
       electron.app.emit('before-quit', {preventDefault: () => { shouldQuit = false }})
       if (shouldQuit) {
@@ -507,6 +537,12 @@ describe('AtomApplication', function () {
     }
   }
 
+  function mockElectronShowMessageBox ({choice}) {
+    electron.dialog.showMessageBox = function () {
+      return choice
+    }
+  }
+
   function makeTempDir (name) {
     const temp = require('temp').track()
     return fs.realpathSync(temp.mkdirSync(name))

src/main-process/atom-application.coffee

@@ -269,10 +269,19 @@ class AtomApplication
     @openPathOnEvent('application:open-license', path.join(process.resourcesPath, 'LICENSE.md'))
 
     @disposable.add ipcHelpers.on app, 'before-quit', (event) =>
-      unless @quitting
+      resolveBeforeQuitPromise = null
+      @lastBeforeQuitPromise = new Promise((resolve) -> resolveBeforeQuitPromise = resolve)
+      if @quitting
+        resolveBeforeQuitPromise()
+      else
         event.preventDefault()
         @quitting = true
-        Promise.all(@windows.map((window) -> window.prepareToUnload())).then(-> app.quit())
+        windowUnloadPromises = @windows.map((window) -> window.prepareToUnload())
+        Promise.all(windowUnloadPromises).then((windowUnloadedResults) ->
+          didUnloadAllWindows = windowUnloadedResults.every((didUnloadWindow) -> didUnloadWindow)
+          app.quit() if didUnloadAllWindows
+          resolveBeforeQuitPromise()
+        )
 
     @disposable.add ipcHelpers.on app, 'will-quit', =>
       @killAllProcesses()