1 files changed, 65 insertions, 0 deletions
diff --git a/services/cloudsync/CloudSyncEventSource.jsm b/services/cloudsync/CloudSyncEventSource.jsm
new file mode 100644
index 000000000..edb9c426b
--- /dev/null
+++ b/services/cloudsync/CloudSyncEventSource.jsm
@@ -0,0 +1,65 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+this.EXPORTED_SYMBOLS = ["EventSource"];
+
+Components.utils.import("resource://services-common/utils.js");
+
+var EventSource = function (types, suspendFunc, resumeFunc) {
+  this.listeners = new Map();
+  for (let type of types) {
+    this.listeners.set(type, new Set());
+  }
+
+  this.suspend = suspendFunc || function () {};
+  this.resume = resumeFunc || function () {};
+
+  this.addEventListener = this.addEventListener.bind(this);
+  this.removeEventListener = this.removeEventListener.bind(this);
+};
+
+EventSource.prototype = {
+  addEventListener: function (type, listener) {
+    if (!this.listeners.has(type)) {
+      return;
+    }
+    this.listeners.get(type).add(listener);
+    this.resume();
+  },
+
+  removeEventListener: function (type, listener) {
+    if (!this.listeners.has(type)) {
+      return;
+    }
+    this.listeners.get(type).delete(listener);
+    if (!this.hasListeners()) {
+      this.suspend();
+    }
+  },
+
+  hasListeners: function () {
+    for (let l of this.listeners.values()) {
+      if (l.size > 0) {
+        return true;
+      }
+    }
+    return false;
+  },
+
+  emit: function (type, arg) {
+    if (!this.listeners.has(type)) {
+      return;
+    }
+    CommonUtils.nextTick(
+      function () {
+        for (let listener of this.listeners.get(type)) {
+          listener.call(undefined, arg);
+        }
+      },
+      this
+    );
+  },
+};
+
+this.EventSource = EventSource;