Move burn state to ImageWriterService

Previously, the burn state lived in the controller, however if the user
moved to another page (the settings page for example) and then returned,
the progress state would be lost, leading to a broken progress bar.

Fixes: https://github.com/resin-io/etcher/issues/190

lib/browser/app.js

@@ -35,6 +35,7 @@ require('./browser/modules/settings');
 require('./browser/modules/drive-scanner');
 require('./browser/modules/image-writer');
 require('./browser/modules/path');
+require('./browser/modules/notifier');
 require('./browser/modules/analytics');
 
 const app = angular.module('Etcher', [
@@ -47,6 +48,7 @@ const app = angular.module('Etcher', [
   'Etcher.settings',
   'Etcher.drive-scanner',
   'Etcher.image-writer',
+  'Etcher.notifier',
   'Etcher.analytics'
 ]);
 
@@ -74,6 +76,8 @@ app.config(function($stateProvider, $urlRouterProvider) {
 app.controller('AppController', function(
   $q,
   $state,
+  $scope,
+  NotifierService,
   DriveScannerService,
   SelectionStateService,
   ImageWriterService,
@@ -87,12 +91,16 @@ app.controller('AppController', function(
   AnalyticsService.logEvent('Restart');
 
   if (!this.writer.isBurning()) {
-    this.state = {
-      progress: 0,
-      percentage: 0
-    };
+    this.writer.resetState();
   }
 
+  NotifierService.subscribe($scope, 'image-writer:state', function(state) {
+    AnalyticsService.log(`Progress: ${state.progress}% at ${state.speed} MB/s`);
+
+    // Show progress inline in operating system task bar
+    currentWindow.setProgressBar(state.progress / 100);
+  });
+
   this.scanner.start(2000).on('scan', function(drives) {
 
     // Notice we only autoselect the drive if there is an image,
@@ -183,14 +191,7 @@ app.controller('AppController', function(
       device: drive.device
     });
 
-    return self.writer.burn(image, drive, function(state) {
-      self.state = state;
-      AnalyticsService.log(`Progress: ${self.state.progress}% at ${self.state.speed} MB/s`);
-
-      // Show progress inline in operating system task bar
-      currentWindow.setProgressBar(self.state.progress / 100);
-
-    }).then(function() {
+    return self.writer.burn(image, drive).then(function() {
       AnalyticsService.logEvent('Done');
       $state.go('success');
     }).catch(dialog.showError).finally(function() {

lib/browser/modules/image-writer.js

@@ -30,14 +30,39 @@ if (window.mocha) {
 }
 
 require('./settings');
+require('./notifier');
 const imageWriter = angular.module('Etcher.image-writer', [
-  'Etcher.settings'
+  'Etcher.settings',
+  'Etcher.notifier'
 ]);
 
-imageWriter.service('ImageWriterService', function($q, $timeout, SettingsService) {
+imageWriter.service('ImageWriterService', function($q, $timeout, SettingsService, NotifierService) {
   let self = this;
   let burning = false;
 
+  /**
+   * @summary Reset burn state
+   * @function
+   * @public
+   *
+   * @example
+   * ImageWriterService.resetState();
+   */
+  this.resetState = function() {
+    self.state = {
+      progress: 0,
+      speed: 0
+    };
+  };
+
+  /**
+   * @summary Burn progress state
+   * @type Object
+   * @public
+   */
+  this.state = {};
+  this.resetState();
+
   /**
    * @summary Check if currently burning
    * @function
@@ -102,11 +127,10 @@ imageWriter.service('ImageWriterService', function($q, $timeout, SettingsService
    * @public
    *
    * @description
-   * This function will update `state.progress` with the current writing percentage.
+   * This function will update `ImageWriterService.state` with the current writing state.
    *
    * @param {String} image - image path
    * @param {Object} drive - drive
-   * @param {Function} onProgress - in progress callback (state)
    *
    * @returns {Promise}
    *
@@ -117,7 +141,7 @@ imageWriter.service('ImageWriterService', function($q, $timeout, SettingsService
    *   console.log('Write completed!');
    * });
    */
-  this.burn = function(image, drive, onProgress) {
+  this.burn = function(image, drive) {
     if (self.isBurning()) {
       return $q.reject(new Error('There is already a burn in progress'));
     }
@@ -129,13 +153,14 @@ imageWriter.service('ImageWriterService', function($q, $timeout, SettingsService
       // Safely bring the state to the world of Angular
       $timeout(function() {
 
-        return onProgress({
+        self.state = {
           progress: Math.floor(state.percentage),
 
           // Transform bytes to megabytes preserving only two decimal places
           speed: Math.floor(state.speed / 1e+6 * 100) / 100 || 0
+        };
 
-        });
+        NotifierService.emit('image-writer:state', self.state);
       });
 
     }).finally(function() {

lib/partials/main.html

@@ -56,17 +56,17 @@
       <hero-badge class="block space-vertical-medium" ng-disabled="!app.selection.hasImage() || !app.selection.hasDrive()">3</hero-badge>
 
       <div class="space-vertical-large">
-        <hero-progress-button percentage="{{ app.state.progress }}" ng-attr-active="{{ app.writer.isBurning() }}"
+        <hero-progress-button percentage="{{ app.writer.state.progress }}" ng-attr-active="{{ app.writer.isBurning() }}"
           ng-click="app.burn(app.selection.getImage(), app.selection.getDrive())"
           ng-disabled="!app.selection.hasImage() || !app.selection.hasDrive()">
-            <span ng-show="app.state.progress == 100 && app.writer.isBurning()">Finishing...</span>
-            <span ng-show="app.state.progress == 0 && !app.writer.isBurning()">Burn!</span>
-            <span ng-show="app.state.progress == 0 && app.writer.isBurning() && !app.state.speed">Starting...</span>
-            <span ng-show="app.state.speed && app.state.progress != 100"
-              ng-bind="app.state.progress + '% '"></span>
+            <span ng-show="app.writer.state.progress == 100 && app.writer.isBurning()">Finishing...</span>
+            <span ng-show="app.writer.state.progress == 0 && !app.writer.isBurning()">Burn!</span>
+            <span ng-show="app.writer.state.progress == 0 && app.writer.isBurning() && !app.writer.state.speed">Starting...</span>
+            <span ng-show="app.writer.state.speed && app.writer.state.progress != 100"
+              ng-bind="app.writer.state.progress + '% '"></span>
         </hero-progress-button>
 
-        <p class="step-footer" ng-bind="app.state.speed.toFixed(2) + ' MB/s'" ng-show="app.state.speed && app.state.progress != 100"></p>
+        <p class="step-footer" ng-bind="app.writer.state.speed.toFixed(2) + ' MB/s'" ng-show="app.writer.state.speed && app.writer.state.progress != 100"></p>
       </div>
     </div>
   </div>

tests/browser/modules/image-writer.spec.js

@@ -23,6 +23,35 @@ describe('Browser: ImageWriter', function() {
       ImageWriterService = _ImageWriterService_;
     }));
 
+    describe('.state', function() {
+
+      it('should be reset by default', function() {
+        m.chai.expect(ImageWriterService.state).to.deep.equal({
+          progress: 0,
+          speed: 0
+        });
+      });
+
+    });
+
+    describe('.resetState()', function() {
+
+      it('should be able to reset the state', function() {
+        ImageWriterService.state = {
+          progress: 50,
+          speed: 3
+        };
+
+        ImageWriterService.resetState();
+
+        m.chai.expect(ImageWriterService.state).to.deep.equal({
+          progress: 0,
+          speed: 0
+        });
+      });
+
+    });
+
     describe('.isBurning()', function() {
 
       it('should return false by default', function() {