[RandomStorage] Adds random storage in jio

Gruntfile.js

@@ -182,7 +182,8 @@ module.exports = function (grunt) {
           'src/jio.storage/indexeddbstorage.js',
           'src/jio.storage/cryptstorage.js',
           'src/jio.storage/websqlstorage.js',
-          'src/jio.storage/fbstorage.js'
+          'src/jio.storage/fbstorage.js',
+          'src/jio.storage/randomstorage.js'
         ],
         dest: 'dist/<%= pkg.name %>-<%= pkg.version %>.js'
 //         dest: 'jio.js'

src/jio.storage/randomstorage.js

+/*jslint nomen: true*/
+(function (jIO) {
+  "use strict";
+
+  /**
+   * The jIO RandomStorage extension
+   *
+   * @class RandomStorage
+   * @constructor
+   */
+  function RandomStorage(spec) {
+    this._sub_storage = jIO.createJIO(spec.sub_storage);
+  }
+
+  RandomStorage.prototype.get = function () {
+    return this._sub_storage.get.apply(this._sub_storage, arguments);
+  };
+  RandomStorage.prototype.allAttachments = function () {
+    return this._sub_storage.allAttachments.apply(this._sub_storage, arguments);
+  };
+  RandomStorage.prototype.post = function () {
+    return this._sub_storage.post.apply(this._sub_storage, arguments);
+  };
+  RandomStorage.prototype.put = function () {
+    return this._sub_storage.put.apply(this._sub_storage, arguments);
+  };
+  RandomStorage.prototype.remove = function () {
+    return this._sub_storage.remove.apply(this._sub_storage, arguments);
+  };
+  RandomStorage.prototype.getAttachment = function () {
+    return this._sub_storage.getAttachment.apply(this._sub_storage, arguments);
+  };
+  RandomStorage.prototype.putAttachment = function () {
+    return this._sub_storage.putAttachment.apply(this._sub_storage, arguments);
+  };
+  RandomStorage.prototype.removeAttachment = function () {
+    return this._sub_storage.removeAttachment.apply(this._sub_storage,
+                                                    arguments);
+  };
+  RandomStorage.prototype.hasCapacity = function (name) {
+    return this._sub_storage.hasCapacity(name);
+  };
+  RandomStorage.prototype.buildQuery = function (options) {
+    var limit;
+    if (options.sort_on[0][0] === 'random') {
+      limit = options.limit;
+      delete options.limit;
+    }
+    return this._sub_storage.buildQuery.apply(this._sub_storage,
+                                              arguments)
+      .push(function (result) {
+        // Random shuffle the result when random is present in the options.
+        if (options.sort_on[0][0] === 'random') {
+          var final_result = [],
+            random_number;
+
+          while (limit[1] && result.length - limit[0]) {
+            random_number = Math.floor(Math.random() * result.length);
+            random_number = random_number === result.length ?
+                result.length - 1 : random_number;
+            final_result.push(result.splice(random_number, 1)[0]);
+            limit[1] -= 1;
+          }
+
+          return final_result;
+        }
+        return result;
+      });
+  };
+
+  jIO.addStorage('random', RandomStorage);
+
+}(jIO));

test/tests.html

@@ -56,6 +56,7 @@
   <script src="jio.storage/websqlstorage.tests.js"></script>
   <script src="jio.storage/fbstorage.tests.js"></script>
   <script src="jio.storage/httpstorage.tests.js"></script>
+  <script src="jio.storage/randomstorage.tests.js"></script>
   <!--script src="../lib/jquery/jquery.min.js"></script>
   <script src="../src/jio.storage/xwikistorage.js"></script>
   <script src="jio.storage/xwikistorage.tests.js"></script-->