Add ring event types

lib/on_membership_event.js

@@ -21,6 +21,7 @@
 
 var Member = require('./membership/member.js');
 var MembershipEvents = require('./membership/events.js');
+var RingEvents = require('../ring/events.js');
 
 function createChecksumComputedHandler(ringpop) {
     return function onMembershipChecksumComputed() {
@@ -63,7 +64,8 @@ function createSetHandler(ringpop) {
         // checksum once.
         if (serversToAdd.length > 0) {
             ringpop.ring.addRemoveServers(serversToAdd, []);
-            ringpop.emit('ringChanged', serversToAdd, []);
+            ringpop.emit('ringChanged', new RingEvents.RingChanged(
+                serversToAdd, []));
         }
     };
 }
@@ -128,7 +130,8 @@ function createUpdatedHandlerForRing(ringpop) {
                 serversToRemove);
 
             if (ringChanged) {
-                ringpop.emit('ringChanged', serversToAdd, serversToRemove);
+                ringpop.emit('ringChanged', new RingEvents.RingChanged(
+                    serversToAdd, serversToRemove));
             }
         }
     };

lib/ring/events.js

@@ -0,0 +1,30 @@
+// Copyright (c) 2015 Uber Technologies, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+'use strict';
+
+function RingChangedEvent(adding, removing) {
+    this.name = this.constructor.name;
+    this.adding = added;
+    this.removing = removing;
+}
+
+module.exports = {
+    RingChangedEvent: RingChangedEvent
+};