display error message on file load error

src/js/Events.js

@@ -82,6 +82,8 @@ var Events = {
 
   PERFORMANCE_REPORT_CHANGED : 'PERFORMANCE_REPORT_CHANGED',
 
+  PISKEL_FILE_IMPORT_FAILED : 'PISKEL_FILE_IMPORT_FAILED',
+
   // Tests
   MOUSE_EVENT : 'MOUSE_EVENT',
   KEYBOARD_EVENT : 'KEYBOARD_EVENT',

src/js/app.js

@@ -126,6 +126,7 @@
       this.storageService.init();
 
       this.importService = new pskl.service.ImportService(this.piskelController);
+      this.importService.init();
 
       this.imageUploadService = new pskl.service.ImageUploadService();
       this.imageUploadService.init();

src/js/controller/settings/ImportController.js

@@ -79,9 +79,15 @@
 
   ns.ImportController.prototype.openPiskelFile_ = function (file) {
     if (this.isPiskel_(file)) {
-      pskl.utils.PiskelFileUtils.loadFromFile(file, function (piskel) {
+      pskl.utils.PiskelFileUtils.loadFromFile(file,
-        pskl.app.piskelController.setPiskel(piskel);
+        // onSuccess
-      });
+        function (piskel) {
+          pskl.app.piskelController.setPiskel(piskel);
+        },
+        // onError
+        function (reason) {
+          $.publish(Events.PISKEL_FILE_IMPORT_FAILED, [reason]);
+        });
       this.closeDrawer_();
     }
   };

src/js/service/FileDropperService.js

@@ -35,7 +35,7 @@
       if (isImage) {
         this.readImageFile_(file);
       } else if (isPiskel) {
-        pskl.utils.PiskelFileUtils.loadFromFile(file, this.onPiskelFileLoaded_);
+        pskl.utils.PiskelFileUtils.loadFromFile(file, this.onPiskelFileLoaded_, this.onPiskelFileError_);
       } else if (isPalette) {
         pskl.app.paletteImportService.read(file, this.onPaletteLoaded_.bind(this));
       }
@@ -57,6 +57,10 @@
     }
   };
 
+  ns.FileDropperService.prototype.onPiskelFileError_ = function (reason) {
+    $.publish(Events.PISKEL_FILE_IMPORT_FAILED, [reason]);
+  };
+
   ns.FileDropperService.prototype.processImageSource_ = function (imageSource) {
     this.importedImage_ = new Image();
     this.importedImage_.onload = this.onImageLoaded_.bind(this);

src/js/service/ImportService.js

@@ -6,11 +6,25 @@
    * @param {!PiskelController} piskelController
    * @constructor
    */
-  ns.ImportService =
+  ns.ImportService = function (piskelController) {
-      function (piskelController) {
     this.piskelController_ = piskelController;
   };
 
+  ns.ImportService.prototype.init = function () {
+    $.subscribe(Events.PISKEL_FILE_IMPORT_FAILED, this.onPiskelFileImportFailed_);
+  };
+
+  /**
+   * Called when a piskel load failed event is published. Display an appropriate error message.
+   * TODO: for some failure reasons, we might want to display a dialog with more details.
+   */
+  ns.ImportService.prototype.onPiskelFileImportFailed_ = function (evt, reason) {
+    $.publish(Events.SHOW_NOTIFICATION, [{
+      'content': 'Piskel file import failed (' + reason + ')',
+      'hideDelay' : 10000
+    }]);
+  };
+
   /**
    * Given an image object and some options, create a new Piskel and open it
    * for editing.

src/js/utils/PiskelFileUtils.js

@@ -2,6 +2,12 @@
   var ns = $.namespace('pskl.utils');
 
   ns.PiskelFileUtils = {
+    FAILURE : {
+      EMPTY : 'No data found in piskel file',
+      INVALID : 'Invalid piskel file, contact us on twitter @piskelapp',
+      DESERIALIZATION : 'Piskel data deserialization failed'
+    },
+
     /**
      * Load a piskel from a piskel file.
      * After deserialization is successful, the provided success callback will be called.
@@ -29,10 +35,22 @@
     },
 
     decodePiskelFile : function (rawPiskel, onSuccess, onError) {
-      var serializedPiskel = JSON.parse(rawPiskel);
+      var serializedPiskel;
+      if (rawPiskel.length === 0) {
+        onError(ns.PiskelFileUtils.FAILURE.EMPTY);
+        return;
+      }
+
+      try {
+        serializedPiskel = JSON.parse(rawPiskel);
+      } catch (e) {
+        onError(ns.PiskelFileUtils.FAILURE.INVALID);
+        return;
+      }
+
       var piskel = serializedPiskel.piskel;
-      pskl.utils.serialization.Deserializer.deserialize(serializedPiskel, function (piskel) {
+      pskl.utils.serialization.Deserializer.deserialize(serializedPiskel, onSuccess, function () {
-        onSuccess(piskel);
+        onError(ns.PiskelFileUtils.FAILURE.DESERIALIZATION);
       });
     }
   };

src/js/utils/serialization/Deserializer.js

@@ -9,16 +9,20 @@
     this.layers_ = [];
   };
 
-  ns.Deserializer.deserialize = function (data, callback) {
+  ns.Deserializer.deserialize = function (data, onSuccess, onError) {
-    var deserializer;
+    try {
-    if (data.modelVersion == Constants.MODEL_VERSION) {
+      var deserializer;
-      deserializer = new ns.Deserializer(data, callback);
+      if (data.modelVersion == Constants.MODEL_VERSION) {
-    } else if (data.modelVersion == 1) {
+        deserializer = new ns.Deserializer(data, onSuccess);
-      deserializer = new ns.backward.Deserializer_v1(data, callback);
+      } else if (data.modelVersion == 1) {
-    } else {
+        deserializer = new ns.backward.Deserializer_v1(data, onSuccess);
-      deserializer = new ns.backward.Deserializer_v0(data, callback);
+      } else {
+        deserializer = new ns.backward.Deserializer_v0(data, onSuccess);
+      }
+      deserializer.deserialize();
+    } catch (e) {
+      onError(e);
     }
-    deserializer.deserialize();
   };
 
   ns.Deserializer.prototype.deserialize = function () {