fix(config): Apply config change from Atom, process locking

Summary:
d1c44dcb54

Also lock config across processes to prevent the user from being logged out when the main process reads config before it's finished writing. This is what is causing the login window to appear.

Test Plan: Rapidly tap between the two display modes. Note that it no longer reverts to the wrong one intermittently.

Reviewers: evan

Reviewed By: evan

Differential Revision: https://phab.nylas.com/D1931

spec/config-spec.coffee

@@ -486,6 +486,7 @@ describe "Config", ->
 
       atom.config.set('foo.bar.baz', "value 1")
       expect(observeHandler).toHaveBeenCalledWith("value 1")
+      advanceClock(100) # complete pending save that was requested in ::set
 
       observeHandler.reset()
       atom.config.loadUserConfig()
@@ -772,6 +773,22 @@ describe "Config", ->
           expect(warnSpy).toHaveBeenCalled()
           expect(warnSpy.mostRecentCall.args[0]).toContain "foo.int"
 
+      describe "when there is a pending save", ->
+        it "does not change the config settings", ->
+          fs.writeFileSync atom.config.configFilePath, "'*': foo: bar: 'baz'"
+
+          atom.config.set("foo.bar", "quux")
+          atom.config.loadUserConfig()
+          expect(atom.config.get("foo.bar")).toBe "quux"
+
+          advanceClock(100)
+          expect(atom.config.save.callCount).toBe 1
+
+          expect(atom.config.get("foo.bar")).toBe "quux"
+          atom.config.loadUserConfig()
+          expect(atom.config.get("foo.bar")).toBe "baz"
+
+
     describe ".observeUserConfig()", ->
       updatedHandler = null
 

src/browser/application.coffee

@@ -1,10 +1,10 @@
-Config = require '../config'
 AtomWindow = require './atom-window'
 BrowserWindow = require 'browser-window'
 WindowManager = require './window-manager'
 ApplicationMenu = require './application-menu'
 AutoUpdateManager = require './auto-update-manager'
 NylasProtocolHandler = require './nylas-protocol-handler'
+SharedFileManager = require './shared-file-manager'
 
 _ = require 'underscore'
 fs = require 'fs-plus'
@@ -73,13 +73,16 @@ class Application
 
     global.application = this
 
+    @sharedFileManager = new SharedFileManager()
+    @nylasProtocolHandler = new NylasProtocolHandler(@resourcePath, @safeMode)
+
+    Config = require '../config'
     @config = new Config({configDirPath, @resourcePath})
     @config.load()
 
     @windowManager = new WindowManager({@resourcePath, @config, @devMode, @safeMode})
     @autoUpdateManager = new AutoUpdateManager(@version, @config, @specMode)
     @applicationMenu = new ApplicationMenu(@version)
-    @nylasProtocolHandler = new NylasProtocolHandler(@resourcePath, @safeMode)
     @_databasePhase = 'setup'
 
     @listenForArgumentsFromNewProcess()

src/browser/shared-file-manager.coffee

@@ -0,0 +1,15 @@
+class SharedFileManager
+
+  constructor: ->
+    @_inflight = {}
+
+  processWillWriteFile: (filePath) ->
+    @_inflight[filePath] += 1
+
+  processDidWriteFile: (filePath) ->
+    @_inflight[filePath] -= 1
+
+  processCanReadFile: (filePath) ->
+    !@_inflight[filePath] or @_inflight[filePath] is 0
+
+module.exports = SharedFileManager

src/config.coffee

@@ -13,6 +13,11 @@ Color = require './color'
 ScopedPropertyStore = require 'scoped-property-store'
 ScopeDescriptor = require './scope-descriptor'
 
+if global.application
+  app = global.application
+else
+  app = require('remote').getGlobal('application')
+
 # Essential: Used to access all of Atom's configuration details.
 #
 # An instance of this class is always available as the `atom.config` global.
@@ -334,9 +339,17 @@ class Config
     @configFilePath = fs.resolve(@configDirPath, 'config', ['json', 'cson'])
     @configFilePath ?= path.join(@configDirPath, 'config.cson')
     @transactDepth = 0
+    @savePending = false
 
-    @debouncedSave = _.debounce(@save, 100)
+    @requestLoad = _.debounce(@loadUserConfig, 100)
     @debouncedLoad = _.debounce(@loadUserConfig, 100)
+    @requestSave = =>
+      @savePending = true
+      debouncedSave.call(this)
+    save = =>
+      @savePending = false
+      @save()
+    debouncedSave = _.debounce(save, 100)
 
   ###
   Section: Config Subscription
@@ -607,7 +620,7 @@ class Config
     else
       @setRawValue(keyPath, value)
 
-    @debouncedSave() if source is @getUserConfigPath() and shouldSave and not @configFileHasErrors
+    @requestSave() if source is @getUserConfigPath() and shouldSave and not @configFileHasErrors
     true
 
   # Essential: Restore the setting at `keyPath` to its default value.
@@ -637,7 +650,7 @@ class Config
           _.setValueForKeyPath(settings, keyPath, undefined)
           settings = withoutEmptyObjects(settings)
           @set(null, settings, {scopeSelector, source, priority: @priorityForSource(source)}) if settings?
-          @debouncedSave()
+          @requestSave()
       else
         @scopedSettingsStore.removePropertiesForSourceAndSelector(source, scopeSelector)
         @emitChangeEvent()
@@ -816,11 +829,17 @@ class Config
     fs.copySync(templateConfigDirPath, @configDirPath)
 
   loadUserConfig: ->
+    manager = app.sharedFileManager
+    if not manager.processCanReadFile(@configFilePath)
+      @requestLoad()
+      return
+
     unless fs.existsSync(@configFilePath)
       fs.makeTreeSync(path.dirname(@configFilePath))
       CSON.writeFileSync(@configFilePath, {})
 
     try
+      unless @savePending
         userConfig = CSON.readFileSync(@configFilePath)
         @resetUserSettings(userConfig)
         @configFileHasErrors = false
@@ -840,7 +859,7 @@ class Config
   observeUserConfig: ->
     try
       @watchSubscription ?= pathWatcher.watch @configFilePath, (eventType) =>
-        @debouncedLoad() if eventType is 'change' and @watchSubscription?
+        @requestLoad() if eventType is 'change' and @watchSubscription?
     catch error
       @notifyFailure """
         Unable to watch path: `#{path.basename(@configFilePath)}`. Make sure you have permissions to
@@ -857,9 +876,12 @@ class Config
     console.log(errorMessage, detail)
 
   save: ->
+    manager = app.sharedFileManager
+    manager.processWillWriteFile(@configFilePath)
     allSettings = {'*': @settings}
     allSettings = _.extend allSettings, @scopedSettingsStore.propertiesForSource(@getUserConfigPath())
     CSON.writeFileSync(@configFilePath, allSettings)
+    manager.processDidWriteFile(@configFilePath)
 
   ###
   Section: Private methods managing global settings