[Persistence] Separate out CouchDocument

Separate CouchDocument (used to wrap a domain object model
with metadata suitable for persistence to CouchDB) into
its own script, to simplify testing and maintenance.
Ongoing transition of Couch persistence, WTD-537.

platform/persistence/src/CouchDocument.js

@@ -0,0 +1,41 @@
+/*global define*/
+
+define(
+    [],
+    function () {
+        "use strict";
+
+        /**
+         * A CouchDocument describes domain object model in a format
+         * which is easily read-written to CouchDB. This includes
+         * Couch's _id and _rev fields, as well as a sseparate
+         * metadata field which contains a subset of information found
+         * in the model itself (to support search optimization with
+         * CouchDB views.)
+         * @constructor
+         * @param {string} id the id under which to store this mode
+         * @param {object} model the model to store
+         * @param {string} rev the revision to include (or undefined,
+         *        if no revision should be noted for couch)
+         * @param {boolean} whether or not to mark this documnet as
+         *        deleted (see CouchDB docs for _deleted)
+         */
+        function CouchDocument(id, model, rev, markDeleted) {
+            return {
+                "_id": id,
+                "_rev": rev,
+                "_deleted": markDeleted,
+                "metadata": {
+                    "category": "domain object",
+                    "type": model.type,
+                    "owner": "admin",
+                    "name": model.name,
+                    "created": Date.now()
+                },
+                "model": model
+            };
+        }
+
+        return CouchDocument;
+    }
+);

platform/persistence/src/CouchPersistenceProvider.js

@@ -1,8 +1,8 @@
 /*global define*/
 
 define(
-    [],
-    function () {
+    ["./CouchDocument"],
+    function (CouchDocument) {
         'use strict';
 
         function CouchPersistenceProvider($http, $q, SPACE, PATH) {
@@ -25,9 +25,18 @@ define(
                 });
             }
 
-            function get(subpath) { return request(subpath, "GET"); }
-            function put(subpath, value) { return request(subpath, "PUT", value); }
-            function del(subpath, value) { return request(subpath, "DELETE", value); }
+            // Shorthand methods for various get types
+            function get(subpath) {
+                return request(subpath, "GET");
+            }
+
+            function put(subpath, value) {
+                return request(subpath, "PUT", value);
+            }
+
+            function del(subpath, value) {
+                return request(subpath, "DELETE", value);
+            }
 
             function getIdsFromAllDocs(allDocs) {
                 return allDocs.rows.map(function (r) { return r.id; });
@@ -52,22 +61,6 @@ define(
                 }
             }
 
-            function CouchDocument(key, value, includeRevision, markDeleted) {
-                return {
-                    "_id": key,
-                    "_rev": includeRevision ? revs[key] : undefined,
-                    "_deleted": markDeleted,
-                    "metadata": {
-                        "category": "domain object",
-                        "type": value.type,
-                        "owner": "admin",
-                        "name": value.name,
-                        "created": Date.now()
-                    },
-                    "model": value
-                };
-            }
-
             return {
                 listSpaces: function () {
                     return $q.when(spaces);