[Entanglement] Contextualize objects by location

Add a context capability to domain objects based
on their location at the time they are loaded.
nasa/openmctweb#84

platform/entanglement/bundle.json

@@ -37,6 +37,12 @@
                 "type": "decorator",
                 "provides": "creationService",
                 "implementation": "services/LocatingCreationDecorator.js"
+            },
+            {
+                "type": "decorator",
+                "provides": "objectService",
+                "implementation": "services/LocatingObjectDecorator.js",
+                "depends": ["contextualize", "$q", "$log"]
             }
         ],
         "controllers": [

platform/entanglement/src/services/LocatingObjectDecorator.js

@@ -0,0 +1,88 @@
+/*****************************************************************************
+ * 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";
+
+        /**
+         * Ensures that domain objects are loaded with a context capability
+         * that reflects their location.
+         * @constructor
+         * @implements {ObjectService}
+         * @memberof platform/entanglement
+         */
+        function LocatingObjectDecorator(contextualize, $q, $log, objectService) {
+            this.contextualize = contextualize;
+            this.$log = $log;
+            this.objectService = objectService;
+            this.$q = $q;
+        }
+
+        LocatingObjectDecorator.prototype.getObjects = function (ids) {
+            var $q = this.$q,
+                $log = this.$log,
+                contextualize = this.contextualize,
+                objectService = this.objectService,
+                result = {};
+
+            function loadObjectInContext(id, exclude) {
+                function attachContextById(domainObject, locationId) {
+                    return loadObjectInContext(locationId, exclude)
+                        .then(function (parent) {
+                            return contextualize(domainObject, parent);
+                        });
+                }
+
+                function attachContextForLocation(domainObject) {
+                    var model = domainObject && domainObject.getModel(),
+                        location = (model || {}).location;
+
+                    // Don't pursue a context if we encounter this
+                    // object again during this sequence of invocations.
+                    exclude[id] = true;
+
+                    return location ?
+                            attachContextById(domainObject, location) :
+                            domainObject;
+                }
+
+                return objectService.getObjects([id]).then(function (objects) {
+                    return exclude[id] ?
+                            objects[id] : // Don't loop indefinitely.
+                            attachContextForLocation(objects[id]);
+                });
+            }
+
+            ids.forEach(function (id) {
+                result[id] = loadObjectInContext(id, {});
+            });
+
+            return $q.all(result);
+        };
+
+        return LocatingObjectDecorator;
+    }
+);
+