Replace localStorage with StateStore in HistoryManager

Instead of using `localStorage` to store and retrieve the project
history, with this commit we will use `StateStore` so that we can
retrieve state asynchronously without blocking Atom during startup.

src/atom-environment.coffee

@@ -229,14 +229,12 @@ class AtomEnvironment extends Model
 
     @observeAutoHideMenuBar()
 
-    @history = new HistoryManager({@project, @commands, localStorage})
+    @history = new HistoryManager({@project, @commands, @stateStore})
     # Keep instances of HistoryManager in sync
-    @history.onDidChangeProjects (e) =>
+    @disposables.add @history.onDidChangeProjects (e) =>
       @applicationDelegate.didChangeHistoryManager() unless e.reloaded
     @disposables.add @applicationDelegate.onDidChangeHistoryManager(=> @history.loadState())
 
-    (new ReopenProjectMenuManager({@menu, @commands, @history, @config, open: (paths) => @open(pathsToOpen: paths)})).update()
-
   attachSaveStateListeners: ->
     saveState = _.debounce((=>
       window.requestIdleCallback => @saveState({isUnloading: false}) unless @unloaded
@@ -714,7 +712,14 @@ class AtomEnvironment extends Model
 
         @openInitialEmptyEditorIfNecessary()
 
-    Promise.all([loadStatePromise, updateProcessEnvPromise])
+    loadHistoryPromise = @history.loadState().then =>
+      @reopenProjectMenuManager = new ReopenProjectMenuManager({
+        @menu, @commands, @history, @config,
+        open: (paths) => @open(pathsToOpen: paths)
+      })
+      @reopenProjectMenuManager.update()
+
+    Promise.all([loadStatePromise, loadHistoryPromise, updateProcessEnvPromise])
 
   serialize: (options) ->
     version: @constructor.version

src/history-manager.js

@@ -1,6 +1,6 @@
 /** @babel */
 
-import {Emitter} from 'event-kit'
+import {Emitter, CompositeDisposable} from 'event-kit'
 
 // Extended: History manager for remembering which projects have been opened.
 //
@@ -8,12 +8,17 @@ import {Emitter} from 'event-kit'
 //
 // The project history is used to enable the 'Reopen Project' menu.
 export class HistoryManager {
-  constructor ({project, commands, localStorage}) {
-    this.localStorage = localStorage
-    commands.add('atom-workspace', {'application:clear-project-history': this.clearProjects.bind(this)})
+  constructor ({stateStore, project, commands}) {
+    this.stateStore = stateStore
     this.emitter = new Emitter()
-    this.loadState()
-    project.onDidChangePaths((projectPaths) => this.addProject(projectPaths))
+    this.projects = []
+    this.disposables = new CompositeDisposable()
+    this.disposables.add(commands.add('atom-workspace', {'application:clear-project-history': this.clearProjects.bind(this)}))
+    this.disposables.add(project.onDidChangePaths((projectPaths) => this.addProject(projectPaths)))
+  }
+
+  destroy () {
+    this.disposables.dispose()
   }
 
   // Public: Obtain a list of previously opened projects.
@@ -27,9 +32,12 @@ export class HistoryManager {
   //
   // Note: This is not a privacy function - other traces will still exist,
   // e.g. window state.
-  clearProjects () {
+  //
+  // Return a {Promise} that resolves when the history has been successfully
+  // cleared.
+  async clearProjects () {
     this.projects = []
-    this.saveState()
+    await this.saveState()
     this.didChangeProjects()
   }
 
@@ -46,7 +54,7 @@ export class HistoryManager {
     this.emitter.emit('did-change-projects', args || { reloaded: false })
   }
 
-  addProject (paths, lastOpened) {
+  async addProject (paths, lastOpened) {
     if (paths.length === 0) return
 
     let project = this.getProject(paths)
@@ -57,11 +65,11 @@ export class HistoryManager {
     project.lastOpened = lastOpened || new Date()
     this.projects.sort((a, b) => b.lastOpened - a.lastOpened)
 
-    this.saveState()
+    await this.saveState()
     this.didChangeProjects()
   }
 
-  removeProject (paths) {
+  async removeProject (paths) {
     if (paths.length === 0) return
 
     let project = this.getProject(paths)
@@ -70,7 +78,7 @@ export class HistoryManager {
     let index = this.projects.indexOf(project)
     this.projects.splice(index, 1)
 
-    this.saveState()
+    await this.saveState()
     this.didChangeProjects()
   }
 
@@ -84,31 +92,25 @@ export class HistoryManager {
     return null
   }
 
-  loadState () {
-    const state = JSON.parse(this.localStorage.getItem('history'))
-    if (state && state.projects) {
-      this.projects = state.projects.filter(p => Array.isArray(p.paths) && p.paths.length > 0).map(p => new HistoryProject(p.paths, new Date(p.lastOpened)))
-      this.didChangeProjects({ reloaded: true })
+  async loadState () {
+    const history = await this.stateStore.load('history-manager')
+    if (history && history.projects) {
+      this.projects = history.projects.filter(p => Array.isArray(p.paths) && p.paths.length > 0).map(p => new HistoryProject(p.paths, new Date(p.lastOpened)))
+      this.didChangeProjects({reloaded: true})
     } else {
       this.projects = []
     }
   }
 
-  saveState () {
-    const state = JSON.stringify({
-      projects: this.projects.map(p => ({
-        paths: p.paths, lastOpened: p.lastOpened
-      }))
-    })
-    this.localStorage.setItem('history', state)
+  async saveState () {
+    const projects = this.projects.map(p => ({paths: p.paths, lastOpened: p.lastOpened}))
+    await this.stateStore.save('history-manager', {projects})
   }
 
   async importProjectHistory () {
     for (let project of await HistoryImporter.getAllProjects()) {
-      this.addProject(project.paths, project.lastOpened)
+      await this.addProject(project.paths, project.lastOpened)
     }
-    this.saveState()
-    this.didChangeProjects()
   }
 }
 

src/reopen-project-menu-manager.js

@@ -58,7 +58,7 @@ export default class ReopenProjectMenuManager {
   // Windows users can right-click Atom taskbar and remove project from the jump list.
   // We have to honor that or the group stops working. As we only get a partial list
   // each time we remove them from history entirely.
-  applyWindowsJumpListRemovals () {
+  async applyWindowsJumpListRemovals () {
     if (process.platform !== 'win32') return
     if (this.app === undefined) {
       this.app = require('remote').app
@@ -68,7 +68,7 @@ export default class ReopenProjectMenuManager {
     if (removed.length === 0) return
     for (let project of this.historyManager.getProjects()) {
       if (removed.includes(ReopenProjectMenuManager.taskDescription(project.paths))) {
-        this.historyManager.removeProject(project.paths)
+        await this.historyManager.removeProject(project.paths)
       }
     }
   }