sync/js/sync_js_controller.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "sync/js/sync_js_controller.h"
   6
   7 #include "base/location.h"
   8 #include "sync/js/js_backend.h"
   9 #include "sync/js/js_event_details.h"
  10
  11 namespace syncer {
  12
  13 SyncJsController::SyncJsController() {}
  14
  15 SyncJsController::~SyncJsController() {
  16   AttachJsBackend(WeakHandle<JsBackend>());
  17 }
  18
  19 void SyncJsController::AddJsEventHandler(JsEventHandler* event_handler) {
  20   js_event_handlers_.AddObserver(event_handler);
  21   UpdateBackendEventHandler();
  22 }
  23
  24 void SyncJsController::RemoveJsEventHandler(JsEventHandler* event_handler) {
  25   js_event_handlers_.RemoveObserver(event_handler);
  26   UpdateBackendEventHandler();
  27 }
  28
  29 void SyncJsController::AttachJsBackend(
  30     const WeakHandle<JsBackend>& js_backend) {
  31   js_backend_ = js_backend;
  32   UpdateBackendEventHandler();
  33 }
  34
  35 void SyncJsController::HandleJsEvent(const std::string& name,
  36                                      const JsEventDetails& details) {
  37   FOR_EACH_OBSERVER(JsEventHandler, js_event_handlers_,
  38                     HandleJsEvent(name, details));
  39 }
  40
  41 void SyncJsController::UpdateBackendEventHandler() {
  42   if (js_backend_.IsInitialized()) {
  43     // To avoid making the backend send useless events, we clear the
  44     // event handler we pass to it if we don't have any event
  45     // handlers.
  46     WeakHandle<JsEventHandler> backend_event_handler =
  47         js_event_handlers_.might_have_observers() ?
  48         MakeWeakHandle(AsWeakPtr()) : WeakHandle<SyncJsController>();
  49     js_backend_.Call(FROM_HERE, &JsBackend::SetJsEventHandler,
  50                      backend_event_handler);
  51   }
  52 }
  53
  54 }  // namespace syncer