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      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
     84