Added _ parameter to metadata of bryanstorage documents, which increments each...

Added _ parameter to metadata of bryanstorage documents, which increments each time put, putAttachment, or removeAttachment is called on the document.  Created tests to test these features.

src/jio.storage/bryanstorage.js

@@ -16,28 +16,87 @@
   BryanStorage.prototype.get = function () {
     return this._sub_storage.get.apply(this._sub_storage, arguments);
   };
+
   BryanStorage.prototype.allAttachments = function () {
     return this._sub_storage.allAttachments.apply(this._sub_storage, arguments);
   };
+
+  // Not implemented for IndexedDB
   BryanStorage.prototype.post = function () {
     return this._sub_storage.post.apply(this._sub_storage, arguments);
   };
-  BryanStorage.prototype.put = function () {
-    return this._sub_storage.put.apply(this._sub_storage, arguments);
+
+  BryanStorage.prototype.put = function (id, new_metadata) {
+    var substorage = this._sub_storage;
+
+    return this.get(id)
+      .push(
+        function (metadata) {
+          // Increments existing "_revision" attribute
+          new_metadata._revision = metadata._revision + 1;
+          return substorage.put(id, new_metadata);
+        },
+        function () {
+          // Creates new attribute "_revision" = 0
+          new_metadata._revision = 0;
+          return substorage.put(id, new_metadata);
+        }
+      );
   };
+
   BryanStorage.prototype.remove = function () {
     return this._sub_storage.remove.apply(this._sub_storage, arguments);
   };
   BryanStorage.prototype.getAttachment = function () {
     return this._sub_storage.getAttachment.apply(this._sub_storage, arguments);
   };
-  BryanStorage.prototype.putAttachment = function () {
-    return this._sub_storage.putAttachment.apply(this._sub_storage, arguments);
+  BryanStorage.prototype.putAttachment = function (id, name, data) {
+
+    // Save pointer to substorage for use in nested function
+    var substorage = this._sub_storage;
+
+    // First, get document metadata to update "_revision"
+    return this.get(id, name)
+
+      // Increment "_revision" parameter in document
+      .push(function (metadata) {
+        var new_metadata = metadata;
+
+        // "_revision" is guaranteed to exist since the document already exists
+        new_metadata._revision = metadata._revision + 1;
+        return substorage.put(id, new_metadata);
+      })
+
+      // After metadata updates successfully, perform putAttachment
+      .push(function () {
+        return substorage.putAttachment(id, name, data);
+      });
   };
-  BryanStorage.prototype.removeAttachment = function () {
-    return this._sub_storage.removeAttachment.apply(this._sub_storage,
-                                                    arguments);
+
+  BryanStorage.prototype.removeAttachment = function (id, name) {
+
+    // Save pointer to substorage for use in nested function
+    var substorage = this._sub_storage;
+
+    // First, get document metadata to update "_revision"
+    return this.get(id, name)
+
+      // Increment "_revision" parameter in document
+      .push(function (metadata) {
+        var new_metadata = metadata;
+
+        // "_revision" is guaranteed to exist since the document already exists
+        new_metadata._revision = metadata._revision + 1;
+        return substorage.put(id, new_metadata);
+      })
+
+      // After metadata updates successfully, perform removeAttachment
+      .push(function () {
+        return substorage.removeAttachment(id, name);
+      });
   };
+
+  // Not implemented for IndexedDB
   BryanStorage.prototype.repair = function () {
     return this._sub_storage.repair.apply(this._sub_storage, arguments);
   };