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::PendingJsMessage::PendingJsMessage(
  14     const std::string& name, const JsArgList& args,
  15     const WeakHandle<JsReplyHandler>& reply_handler)
  16     : name(name), args(args), reply_handler(reply_handler) {}
  17
  18 SyncJsController::PendingJsMessage::~PendingJsMessage() {}
  19
  20 SyncJsController::SyncJsController() {}
  21
  22 SyncJsController::~SyncJsController() {
  23   AttachJsBackend(WeakHandle<JsBackend>());
  24 }
  25
  26 void SyncJsController::AddJsEventHandler(JsEventHandler* event_handler) {
  27   js_event_handlers_.AddObserver(event_handler);
  28   UpdateBackendEventHandler();
  29 }
  30
  31 void SyncJsController::RemoveJsEventHandler(JsEventHandler* event_handler) {
  32   js_event_handlers_.RemoveObserver(event_handler);
  33   UpdateBackendEventHandler();
  34 }
  35
  36 void SyncJsController::AttachJsBackend(
  37     const WeakHandle<JsBackend>& js_backend) {
  38   js_backend_ = js_backend;
  39   UpdateBackendEventHandler();
  40
  41   if (js_backend_.IsInitialized()) {
  42     // Process any queued messages.
  43     for (PendingJsMessageList::const_iterator it =
  44              pending_js_messages_.begin();
  45          it != pending_js_messages_.end(); ++it) {
  46       js_backend_.Call(FROM_HERE, &JsBackend::ProcessJsMessage,
  47                        it->name, it->args, it->reply_handler);
  48     }
  49   }
  50 }
  51
  52 void SyncJsController::ProcessJsMessage(
  53     const std::string& name, const JsArgList& args,
  54     const WeakHandle<JsReplyHandler>& reply_handler) {
  55   if (js_backend_.IsInitialized()) {
  56     js_backend_.Call(FROM_HERE, &JsBackend::ProcessJsMessage,
  57                      name, args, reply_handler);
  58   } else {
  59     pending_js_messages_.push_back(
  60         PendingJsMessage(name, args, reply_handler));
  61   }
  62 }
  63
  64 void SyncJsController::HandleJsEvent(const std::string& name,
  65                                      const JsEventDetails& details) {
  66   FOR_EACH_OBSERVER(JsEventHandler, js_event_handlers_,
  67                     HandleJsEvent(name, details));
  68 }
  69
  70 void SyncJsController::UpdateBackendEventHandler() {
  71   if (js_backend_.IsInitialized()) {
  72     // To avoid making the backend send useless events, we clear the
  73     // event handler we pass to it if we don't have any event
  74     // handlers.
  75     WeakHandle<JsEventHandler> backend_event_handler =
  76         (js_event_handlers_.size() > 0) ?
  77         MakeWeakHandle(AsWeakPtr()) : WeakHandle<SyncJsController>();
  78     js_backend_.Call(FROM_HERE, &JsBackend::SetJsEventHandler,
  79                      backend_event_handler);
  80   }
  81 }
  82
  83 }  // namespace syncer