Addressing issues from code review

platform/commonUI/edit/src/capabilities/EditorCapability.js

@@ -124,7 +124,6 @@ define(
          */
         EditorCapability.prototype.cancel = function () {
             this.editableObject.getCapability("status").set("editing", false);
-            //TODO: Reset the cache as well here.
             this.cache.markClean();
             return resolvePromise(undefined);
         };

platform/commonUI/edit/src/controllers/EditObjectController.js

@@ -36,8 +36,9 @@ define(
          * @memberof platform/commonUI/edit
          * @constructor
          */
-        function EditObjectController($scope, $location) {
+        function EditObjectController($scope, $location, policyService) {
             this.scope = $scope;
+            this.policyService = policyService;
 
             var navigatedObject;
             function setViewForDomainObject(domainObject) {
@@ -73,16 +74,14 @@ define(
          */
         EditObjectController.prototype.getUnloadWarning = function () {
             var navigatedObject = this.scope.domainObject,
-                editorCapability = navigatedObject &&
-                    navigatedObject.getCapability("editor"),
-                statusCapability = navigatedObject &&
-                    navigatedObject.getCapability("status"),
-                hasChanges = statusCapability && statusCapability.get('editing')
-                    && editorCapability && editorCapability.dirty();
+                policyMessage;
+
+            this.policyService.allow("navigation", navigatedObject, undefined, function(message) {
+               policyMessage = message;
+            });
+
+            return policyMessage;
 
-            return hasChanges ?
-                "Unsaved changes will be lost if you leave this page." :
-                undefined;
         };
 
         return EditObjectController;

platform/commonUI/edit/src/directives/MCTBeforeUnload.js

@@ -35,7 +35,7 @@ define(
          * @constructor
          * @param $window the window
          */
-        function MCTBeforeUnload($window, navigationService) {
+        function MCTBeforeUnload($window) {
             var unloads = [],
                 oldBeforeUnload = $window.onbeforeunload;
 
@@ -57,7 +57,6 @@ define(
 
                 // Stop using this unload expression
                 function removeUnload() {
-                    navigationService.removeListener(checkNavigationEvent, "before");
                     unloads = unloads.filter(function (callback) {
                         return callback !== unload;
                     });
@@ -66,28 +65,17 @@ define(
                     }
                 }
 
-                function shouldAllowNavigation(){
+                // Show a dialog before allowing a location change
+                function checkLocationChange(event) {
                     // Get an unload message (if any)
                     var warning = unload();
                     // Prompt the user if there's an unload message
-                    return !warning || $window.confirm(warning);
-                }
-
-                // Show a dialog before allowing a location change
-                function checkLocationChange(event) {
-                    if (!shouldAllowNavigation()) {
-                        // Prevent the route change if it was confirmed
+                    if (warning && !$window.confirm(warning)) {
+                        // ...and prevent the route change if it was confirmed
                         event.preventDefault();
                     }
                 }
 
-                // Show a dialog before allowing a location change
-                function checkNavigationEvent(event) {
-                    // Return a false value to the navigationService to
-                    // indicate that the navigation event should be prevented
-                    return shouldAllowNavigation();
-                }
-
                 // If this is the first active instance of this directive,
                 // register as the window's beforeunload handler
                 if (unloads.length === 0) {
@@ -102,8 +90,6 @@ define(
 
                 // Also handle route changes
                 scope.$on("$locationChangeStart", checkLocationChange);
-
-                navigationService.addListener(checkNavigationEvent, "before");
             }
 
             return {

platform/commonUI/edit/src/policies/EditNavigationPolicy.js

@@ -0,0 +1,68 @@
+/*****************************************************************************
+ * Open MCT Web, Copyright (c) 2014-2015, United States Government
+ * as represented by the Administrator of the National Aeronautics and Space
+ * Administration. All rights reserved.
+ *
+ * Open MCT Web is licensed under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ * Open MCT Web includes source code licensed under additional open source
+ * licenses. See the Open Source Licenses file (LICENSES.md) included with
+ * this source code distribution or the Licensing information page available
+ * at runtime from the About dialog for additional information.
+ *****************************************************************************/
+/*global define*/
+
+define(
+    [],
+    function () {
+        "use strict";
+
+        /**
+         * Policy controlling whether navigation events should proceed
+         * when object is being edited.
+         * @memberof platform/commonUI/edit
+         * @constructor
+         * @implements {Policy.<Action, ActionContext>}
+         */
+        function EditNavigationPolicy($window, policyService) {
+            this.window = $window;
+            this.policyService = policyService;
+        }
+
+        /**
+         * @private
+         */
+        EditNavigationPolicy.prototype.isDirty = function(domainObject) {
+            var navigatedObject = domainObject,
+                editorCapability = navigatedObject &&
+                    navigatedObject.getCapability("editor"),
+                statusCapability = navigatedObject &&
+                    navigatedObject.getCapability("status");
+
+            return statusCapability && statusCapability.get('editing')
+                && editorCapability && editorCapability.dirty();
+        };
+
+        /**
+         * Allow navigation if an object is not dirty, or if the user elects
+         * to proceed anyway.
+         * @param currentNavigation
+         * @returns {boolean|*} true if the object model is clean; or if
+         * it's dirty and the user wishes to proceed anyway.
+         */
+        EditNavigationPolicy.prototype.allow = function (currentNavigation) {
+            return !this.isDirty(currentNavigation);
+        };
+
+        return EditNavigationPolicy;
+    }
+);

platform/commonUI/edit/src/representers/EditRepresenter.js

@@ -147,7 +147,6 @@ define(
 
         // Respond to the destruction of the current representation.
         EditRepresenter.prototype.destroy = function destroy() {
-            // Nothing to clean up
             return this.listenHandle && this.listenHandle();
         };