From fc922d3bd74975bd7012132e9386b7a5d3fe5194 Mon Sep 17 00:00:00 2001
From: mbektimirov <mbektimirov@gmail.com>
Date: Tue, 4 Jun 2013 17:07:39 +0600
Subject: [PATCH] Implemented #172 with promises

App.start now returns a promise which depends on all application
widgets promisses. Just return a promise() in widget 'initialize'
method to handle async loading.
---
 lib/aura.js        | 30 +++++++++++++++++++++++++++---
 lib/ext/widgets.js | 24 +++++++++++++++++-------
 2 files changed, 44 insertions(+), 10 deletions(-)

diff --git a/lib/aura.js b/lib/aura.js
index 118c049..d0656f0 100644
--- a/lib/aura.js
+++ b/lib/aura.js
@@ -106,6 +106,8 @@ define([
    */
   Aura.prototype.start = function(options) {
     var app = this;
+    var extsPromisses = [];
+    var appInitDfd = base.data.deferred();
 
     if (app.started) {
       app.logger.error("Aura already started... !");
@@ -119,10 +121,28 @@ define([
 
       // Then we call all the `afterAppStart` provided by the extensions
       base.util.each(exts, function(i, ext) {
-        if (ext && typeof(ext.afterAppStart) === 'function') {
+        if (ext) {
           try {
-            ext.afterAppStart(app);
+            extsPromisses.push((ext.afterAppStart || noop)(app));
+
+            // application is loaded when all widgets has been loaded
+            if (extsPromisses.length === exts.length) { // all widgets are here
+              base.data.when.apply(undefined, extsPromisses).then(
+                function () {
+                  appInitDfd.resolve();
+                },
+
+                function (e) {
+                  appInitDfd.reject();
+
+                  app.logger.error('Error in widget loading: ' + e);
+                }
+              );
+            }
+
           } catch(e) {
+            appInitDfd.reject();
+
             app.logger.error("Error on ", (ext.name || ext) , ".afterAppStart callback: (", e.message, ")", e);
           }
         }
@@ -133,6 +153,8 @@ define([
     // reject every body an do some cleanup
     // TODO: Provide a better error message to the user.
     app.extensions.onFailure(function() {
+      appInitDfd.reject();
+
       app.logger.error("Error initializing app...", app.config.name, arguments);
       app.stop();
     });
@@ -141,7 +163,9 @@ define([
     // to keep track of the loading process...
     //
 
-    return app.extensions.init();
+    app.extensions.init();
+
+    return appInitDfd.promise();
   };
 
   /**
diff --git a/lib/ext/widgets.js b/lib/ext/widgets.js
index 6dc43b2..dad54d3 100644
--- a/lib/ext/widgets.js
+++ b/lib/ext/widgets.js
@@ -28,7 +28,8 @@ define('aura/ext/widgets', function() {
       this._ref       = options._ref;
       this.$el        = core.dom.find(options.el);
 
-      this.initialize.call(this, this.options);
+      this.options.onLoadPromise = this.initialize.call(this, this.options);
+
       return this;
     }
 
@@ -143,12 +144,20 @@ define('aura/ext/widgets', function() {
 
           var newWidget = new WidgetConstructor(options);
 
-          var initialized = core.data.when(newWidget);
+          core.data.when(newWidget.options.onLoadPromise).then(
+            function(ret) {
+              dfd.resolve(ret);
+
+              app.logger.log("Widget loaded:", name, newWidget);
+            },
+
+            function(ret) {
+              dfd.reject(ret);
+
+              app.logger.error("Widget not loaded:", name, newWidget);
+            }
+          );
 
-          initialized.then(function(ret) { dfd.resolve(ret); });
-          initialized.fail(function(err) { dfd.reject(err); });
-          app.logger.log("Widget loaded:", name, newWidget);
-          return initialized;
         } catch(err) {
           app.logger.error(err.message);
           dfd.reject(err);
@@ -292,7 +301,8 @@ define('aura/ext/widgets', function() {
       afterAppStart: function(app) {
         // Auto start widgets when the app is loaded.
         if (app.startOptions.widgets) {
-          app.core.start(app.startOptions.widgets);
+          // return a widget promise to handle async loading in Aura layer
+          return app.core.start(app.startOptions.widgets);
         }
       }