extensions/browser/event_router.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 "extensions/browser/event_router.h"
   6
   7 #include <utility>
   8
   9 #include "base/bind.h"
  10 #include "base/command_line.h"
  11 #include "base/message_loop/message_loop.h"
  12 #include "base/stl_util.h"
  13 #include "base/values.h"
  14 #include "content/public/browser/child_process_security_policy.h"
  15 #include "content/public/browser/notification_service.h"
  16 #include "content/public/browser/render_process_host.h"
  17 #include "extensions/browser/api_activity_monitor.h"
  18 #include "extensions/browser/extension_host.h"
  19 #include "extensions/browser/extension_prefs.h"
  20 #include "extensions/browser/extension_registry.h"
  21 #include "extensions/browser/extension_system.h"
  22 #include "extensions/browser/extensions_browser_client.h"
  23 #include "extensions/browser/lazy_background_task_queue.h"
  24 #include "extensions/browser/notification_types.h"
  25 #include "extensions/browser/process_manager.h"
  26 #include "extensions/browser/process_map.h"
  27 #include "extensions/common/extension.h"
  28 #include "extensions/common/extension_api.h"
  29 #include "extensions/common/extension_messages.h"
  30 #include "extensions/common/extension_urls.h"
  31 #include "extensions/common/manifest_handlers/background_info.h"
  32 #include "extensions/common/manifest_handlers/incognito_info.h"
  33 #include "extensions/common/permissions/permissions_data.h"
  34
  35 using base::DictionaryValue;
  36 using base::ListValue;
  37 using content::BrowserContext;
  38 using content::BrowserThread;
  39
  40 namespace extensions {
  41
  42 namespace {
  43
  44 void DoNothing(ExtensionHost* host) {}
  45
  46 // A dictionary of event names to lists of filters that this extension has
  47 // registered from its lazy background page.
  48 const char kFilteredEvents[] = "filtered_events";
  49
  50 // Sends a notification about an event to the API activity monitor on the
  51 // UI thread. Can be called from any thread.
  52 void NotifyApiEventDispatched(void* browser_context_id,
  53                               const std::string& extension_id,
  54                               const std::string& event_name,
  55                               scoped_ptr<ListValue> args) {
  56   // The ApiActivityMonitor can only be accessed from the UI thread.
  57   if (!BrowserThread::CurrentlyOn(BrowserThread::UI)) {
  58     BrowserThread::PostTask(
  59         BrowserThread::UI,
  60         FROM_HERE,
  61         base::Bind(&NotifyApiEventDispatched,
  62                    browser_context_id,
  63                    extension_id,
  64                    event_name,
  65                    base::Passed(&args)));
  66     return;
  67   }
  68
  69   // Notify the ApiActivityMonitor about the event dispatch.
  70   BrowserContext* context = static_cast<BrowserContext*>(browser_context_id);
  71   if (!ExtensionsBrowserClient::Get()->IsValidContext(context))
  72     return;
  73   ApiActivityMonitor* monitor =
  74       ExtensionsBrowserClient::Get()->GetApiActivityMonitor(context);
  75   if (monitor)
  76     monitor->OnApiEventDispatched(extension_id, event_name, args.Pass());
  77 }
  78
  79 }  // namespace
  80
  81 const char EventRouter::kRegisteredEvents[] = "events";
  82
  83 struct EventRouter::ListenerProcess {
  84   content::RenderProcessHost* process;
  85   std::string extension_id;
  86
  87   ListenerProcess(content::RenderProcessHost* process,
  88                   const std::string& extension_id)
  89       : process(process), extension_id(extension_id) {}
  90
  91   bool operator<(const ListenerProcess& that) const {
  92     if (process < that.process)
  93       return true;
  94     if (process == that.process && extension_id < that.extension_id)
  95       return true;
  96     return false;
  97   }
  98 };
  99
 100 // static
 101 void EventRouter::DispatchExtensionMessage(IPC::Sender* ipc_sender,
 102                                            void* browser_context_id,
 103                                            const std::string& extension_id,
 104                                            const std::string& event_name,
 105                                            ListValue* event_args,
 106                                            UserGestureState user_gesture,
 107                                            const EventFilteringInfo& info) {
 108   NotifyApiEventDispatched(browser_context_id,
 109                            extension_id,
 110                            event_name,
 111                            make_scoped_ptr(event_args->DeepCopy()));
 112
 113   ListValue args;
 114   args.Set(0, new base::StringValue(event_name));
 115   args.Set(1, event_args);
 116   args.Set(2, info.AsValue().release());
 117   ipc_sender->Send(new ExtensionMsg_MessageInvoke(
 118       MSG_ROUTING_CONTROL,
 119       extension_id,
 120       kEventBindings,
 121       "dispatchEvent",
 122       args,
 123       user_gesture == USER_GESTURE_ENABLED));
 124
 125   // DispatchExtensionMessage does _not_ take ownership of event_args, so we
 126   // must ensure that the destruction of args does not attempt to free it.
 127   scoped_ptr<base::Value> removed_event_args;
 128   args.Remove(1, &removed_event_args);
 129   ignore_result(removed_event_args.release());
 130 }
 131
 132 // static
 133 EventRouter* EventRouter::Get(content::BrowserContext* browser_context) {
 134   return ExtensionSystem::Get(browser_context)->event_router();
 135 }
 136
 137 // static
 138 std::string EventRouter::GetBaseEventName(const std::string& full_event_name) {
 139   size_t slash_sep = full_event_name.find('/');
 140   return full_event_name.substr(0, slash_sep);
 141 }
 142
 143 // static
 144 void EventRouter::DispatchEvent(IPC::Sender* ipc_sender,
 145                                 void* browser_context_id,
 146                                 const std::string& extension_id,
 147                                 const std::string& event_name,
 148                                 scoped_ptr<ListValue> event_args,
 149                                 UserGestureState user_gesture,
 150                                 const EventFilteringInfo& info) {
 151   DispatchExtensionMessage(ipc_sender,
 152                            browser_context_id,
 153                            extension_id,
 154                            event_name,
 155                            event_args.get(),
 156                            user_gesture,
 157                            info);
 158
 159   BrowserThread::PostTask(
 160       BrowserThread::UI,
 161       FROM_HERE,
 162       base::Bind(&EventRouter::IncrementInFlightEventsOnUI,
 163                   browser_context_id,
 164                   extension_id));
 165 }
 166
 167 EventRouter::EventRouter(BrowserContext* browser_context,
 168                          ExtensionPrefs* extension_prefs)
 169     : browser_context_(browser_context),
 170       extension_prefs_(extension_prefs),
 171       extension_registry_observer_(this),
 172       listeners_(this) {
 173   registrar_.Add(this, content::NOTIFICATION_RENDERER_PROCESS_TERMINATED,
 174                  content::NotificationService::AllSources());
 175   registrar_.Add(this, content::NOTIFICATION_RENDERER_PROCESS_CLOSED,
 176                  content::NotificationService::AllSources());
 177   registrar_.Add(this,
 178                  extensions::NOTIFICATION_EXTENSION_ENABLED,
 179                  content::Source<BrowserContext>(browser_context_));
 180   extension_registry_observer_.Add(ExtensionRegistry::Get(browser_context_));
 181 }
 182
 183 EventRouter::~EventRouter() {}
 184
 185 void EventRouter::AddEventListener(const std::string& event_name,
 186                                    content::RenderProcessHost* process,
 187                                    const std::string& extension_id) {
 188   listeners_.AddListener(EventListener::ForExtension(
 189       event_name, extension_id, process, scoped_ptr<DictionaryValue>()));
 190 }
 191
 192 void EventRouter::RemoveEventListener(const std::string& event_name,
 193                                       content::RenderProcessHost* process,
 194                                       const std::string& extension_id) {
 195   scoped_ptr<EventListener> listener = EventListener::ForExtension(
 196       event_name, extension_id, process, scoped_ptr<DictionaryValue>());
 197   listeners_.RemoveListener(listener.get());
 198 }
 199
 200 void EventRouter::AddEventListenerForURL(const std::string& event_name,
 201                                          content::RenderProcessHost* process,
 202                                          const GURL& listener_url) {
 203   listeners_.AddListener(EventListener::ForURL(
 204       event_name, listener_url, process, scoped_ptr<DictionaryValue>()));
 205 }
 206
 207 void EventRouter::RemoveEventListenerForURL(const std::string& event_name,
 208                                             content::RenderProcessHost* process,
 209                                             const GURL& listener_url) {
 210   scoped_ptr<EventListener> listener = EventListener::ForURL(
 211       event_name, listener_url, process, scoped_ptr<DictionaryValue>());
 212   listeners_.RemoveListener(listener.get());
 213 }
 214
 215 void EventRouter::RegisterObserver(Observer* observer,
 216                                    const std::string& event_name) {
 217   // Observing sub-event names like "foo.onBar/123" is not allowed.
 218   DCHECK(event_name.find('/') == std::string::npos);
 219   observers_[event_name] = observer;
 220 }
 221
 222 void EventRouter::UnregisterObserver(Observer* observer) {
 223   std::vector<ObserverMap::iterator> iters_to_remove;
 224   for (ObserverMap::iterator iter = observers_.begin();
 225        iter != observers_.end(); ++iter) {
 226     if (iter->second == observer)
 227       iters_to_remove.push_back(iter);
 228   }
 229   for (size_t i = 0; i < iters_to_remove.size(); ++i)
 230     observers_.erase(iters_to_remove[i]);
 231 }
 232
 233 void EventRouter::OnListenerAdded(const EventListener* listener) {
 234   const EventListenerInfo details(listener->event_name(),
 235                                   listener->extension_id(),
 236                                   listener->listener_url(),
 237                                   listener->GetBrowserContext());
 238   std::string base_event_name = GetBaseEventName(listener->event_name());
 239   ObserverMap::iterator observer = observers_.find(base_event_name);
 240   if (observer != observers_.end())
 241     observer->second->OnListenerAdded(details);
 242 }
 243
 244 void EventRouter::OnListenerRemoved(const EventListener* listener) {
 245   const EventListenerInfo details(listener->event_name(),
 246                                   listener->extension_id(),
 247                                   listener->listener_url(),
 248                                   listener->GetBrowserContext());
 249   std::string base_event_name = GetBaseEventName(listener->event_name());
 250   ObserverMap::iterator observer = observers_.find(base_event_name);
 251   if (observer != observers_.end())
 252     observer->second->OnListenerRemoved(details);
 253 }
 254
 255 void EventRouter::AddLazyEventListener(const std::string& event_name,
 256                                        const std::string& extension_id) {
 257   bool is_new = listeners_.AddListener(EventListener::ForExtension(
 258       event_name, extension_id, NULL, scoped_ptr<DictionaryValue>()));
 259
 260   if (is_new) {
 261     std::set<std::string> events = GetRegisteredEvents(extension_id);
 262     bool prefs_is_new = events.insert(event_name).second;
 263     if (prefs_is_new)
 264       SetRegisteredEvents(extension_id, events);
 265   }
 266 }
 267
 268 void EventRouter::RemoveLazyEventListener(const std::string& event_name,
 269                                           const std::string& extension_id) {
 270   scoped_ptr<EventListener> listener = EventListener::ForExtension(
 271       event_name, extension_id, NULL, scoped_ptr<DictionaryValue>());
 272   bool did_exist = listeners_.RemoveListener(listener.get());
 273
 274   if (did_exist) {
 275     std::set<std::string> events = GetRegisteredEvents(extension_id);
 276     bool prefs_did_exist = events.erase(event_name) > 0;
 277     DCHECK(prefs_did_exist);
 278     SetRegisteredEvents(extension_id, events);
 279   }
 280 }
 281
 282 void EventRouter::AddFilteredEventListener(const std::string& event_name,
 283                                            content::RenderProcessHost* process,
 284                                            const std::string& extension_id,
 285                                            const base::DictionaryValue& filter,
 286                                            bool add_lazy_listener) {
 287   listeners_.AddListener(EventListener::ForExtension(
 288       event_name,
 289       extension_id,
 290       process,
 291       scoped_ptr<DictionaryValue>(filter.DeepCopy())));
 292
 293   if (add_lazy_listener) {
 294     bool added = listeners_.AddListener(EventListener::ForExtension(
 295         event_name,
 296         extension_id,
 297         NULL,
 298         scoped_ptr<DictionaryValue>(filter.DeepCopy())));
 299
 300     if (added)
 301       AddFilterToEvent(event_name, extension_id, &filter);
 302   }
 303 }
 304
 305 void EventRouter::RemoveFilteredEventListener(
 306     const std::string& event_name,
 307     content::RenderProcessHost* process,
 308     const std::string& extension_id,
 309     const base::DictionaryValue& filter,
 310     bool remove_lazy_listener) {
 311   scoped_ptr<EventListener> listener = EventListener::ForExtension(
 312       event_name,
 313       extension_id,
 314       process,
 315       scoped_ptr<DictionaryValue>(filter.DeepCopy()));
 316
 317   listeners_.RemoveListener(listener.get());
 318
 319   if (remove_lazy_listener) {
 320     listener->MakeLazy();
 321     bool removed = listeners_.RemoveListener(listener.get());
 322
 323     if (removed)
 324       RemoveFilterFromEvent(event_name, extension_id, &filter);
 325   }
 326 }
 327
 328 bool EventRouter::HasEventListener(const std::string& event_name) {
 329   return listeners_.HasListenerForEvent(event_name);
 330 }
 331
 332 bool EventRouter::ExtensionHasEventListener(const std::string& extension_id,
 333                                             const std::string& event_name) {
 334   return listeners_.HasListenerForExtension(extension_id, event_name);
 335 }
 336
 337 bool EventRouter::HasEventListenerImpl(const ListenerMap& listener_map,
 338                                        const std::string& extension_id,
 339                                        const std::string& event_name) {
 340   ListenerMap::const_iterator it = listener_map.find(event_name);
 341   if (it == listener_map.end())
 342     return false;
 343
 344   const std::set<ListenerProcess>& listeners = it->second;
 345   if (extension_id.empty())
 346     return !listeners.empty();
 347
 348   for (std::set<ListenerProcess>::const_iterator listener = listeners.begin();
 349        listener != listeners.end(); ++listener) {
 350     if (listener->extension_id == extension_id)
 351       return true;
 352   }
 353   return false;
 354 }
 355
 356 std::set<std::string> EventRouter::GetRegisteredEvents(
 357     const std::string& extension_id) {
 358   std::set<std::string> events;
 359   const ListValue* events_value = NULL;
 360
 361   if (!extension_prefs_ ||
 362       !extension_prefs_->ReadPrefAsList(
 363            extension_id, kRegisteredEvents, &events_value)) {
 364     return events;
 365   }
 366
 367   for (size_t i = 0; i < events_value->GetSize(); ++i) {
 368     std::string event;
 369     if (events_value->GetString(i, &event))
 370       events.insert(event);
 371   }
 372   return events;
 373 }
 374
 375 void EventRouter::SetRegisteredEvents(const std::string& extension_id,
 376                                       const std::set<std::string>& events) {
 377   ListValue* events_value = new ListValue;
 378   for (std::set<std::string>::const_iterator iter = events.begin();
 379        iter != events.end(); ++iter) {
 380     events_value->Append(new base::StringValue(*iter));
 381   }
 382   extension_prefs_->UpdateExtensionPref(
 383       extension_id, kRegisteredEvents, events_value);
 384 }
 385
 386 void EventRouter::AddFilterToEvent(const std::string& event_name,
 387                                    const std::string& extension_id,
 388                                    const DictionaryValue* filter) {
 389   ExtensionPrefs::ScopedDictionaryUpdate update(
 390       extension_prefs_, extension_id, kFilteredEvents);
 391   DictionaryValue* filtered_events = update.Get();
 392   if (!filtered_events)
 393     filtered_events = update.Create();
 394
 395   ListValue* filter_list = NULL;
 396   if (!filtered_events->GetList(event_name, &filter_list)) {
 397     filter_list = new ListValue;
 398     filtered_events->SetWithoutPathExpansion(event_name, filter_list);
 399   }
 400
 401   filter_list->Append(filter->DeepCopy());
 402 }
 403
 404 void EventRouter::RemoveFilterFromEvent(const std::string& event_name,
 405                                         const std::string& extension_id,
 406                                         const DictionaryValue* filter) {
 407   ExtensionPrefs::ScopedDictionaryUpdate update(
 408       extension_prefs_, extension_id, kFilteredEvents);
 409   DictionaryValue* filtered_events = update.Get();
 410   ListValue* filter_list = NULL;
 411   if (!filtered_events ||
 412       !filtered_events->GetListWithoutPathExpansion(event_name, &filter_list)) {
 413     return;
 414   }
 415
 416   for (size_t i = 0; i < filter_list->GetSize(); i++) {
 417     DictionaryValue* filter = NULL;
 418     CHECK(filter_list->GetDictionary(i, &filter));
 419     if (filter->Equals(filter)) {
 420       filter_list->Remove(i, NULL);
 421       break;
 422     }
 423   }
 424 }
 425
 426 const DictionaryValue* EventRouter::GetFilteredEvents(
 427     const std::string& extension_id) {
 428   const DictionaryValue* events = NULL;
 429   extension_prefs_->ReadPrefAsDictionary(
 430       extension_id, kFilteredEvents, &events);
 431   return events;
 432 }
 433
 434 void EventRouter::BroadcastEvent(scoped_ptr<Event> event) {
 435   DispatchEventImpl(std::string(), linked_ptr<Event>(event.release()));
 436 }
 437
 438 void EventRouter::DispatchEventToExtension(const std::string& extension_id,
 439                                            scoped_ptr<Event> event) {
 440   DCHECK(!extension_id.empty());
 441   DispatchEventImpl(extension_id, linked_ptr<Event>(event.release()));
 442 }
 443
 444 void EventRouter::DispatchEventWithLazyListener(const std::string& extension_id,
 445                                                 scoped_ptr<Event> event) {
 446   DCHECK(!extension_id.empty());
 447   std::string event_name = event->event_name;
 448   bool has_listener = ExtensionHasEventListener(extension_id, event_name);
 449   if (!has_listener)
 450     AddLazyEventListener(event_name, extension_id);
 451   DispatchEventToExtension(extension_id, event.Pass());
 452   if (!has_listener)
 453     RemoveLazyEventListener(event_name, extension_id);
 454 }
 455
 456 void EventRouter::DispatchEventImpl(const std::string& restrict_to_extension_id,
 457                                     const linked_ptr<Event>& event) {
 458   // We don't expect to get events from a completely different browser context.
 459   DCHECK(!event->restrict_to_browser_context ||
 460          ExtensionsBrowserClient::Get()->IsSameContext(
 461              browser_context_, event->restrict_to_browser_context));
 462
 463   std::set<const EventListener*> listeners(
 464       listeners_.GetEventListeners(*event));
 465
 466   std::set<EventDispatchIdentifier> already_dispatched;
 467
 468   // We dispatch events for lazy background pages first because attempting to do
 469   // so will cause those that are being suspended to cancel that suspension.
 470   // As canceling a suspension entails sending an event to the affected
 471   // background page, and as that event needs to be delivered before we dispatch
 472   // the event we are dispatching here, we dispatch to the lazy listeners here
 473   // first.
 474   for (std::set<const EventListener*>::iterator it = listeners.begin();
 475        it != listeners.end(); it++) {
 476     const EventListener* listener = *it;
 477     if (restrict_to_extension_id.empty() ||
 478         restrict_to_extension_id == listener->extension_id()) {
 479       if (listener->IsLazy()) {
 480         DispatchLazyEvent(listener->extension_id(), event, &already_dispatched);
 481       }
 482     }
 483   }
 484
 485   for (std::set<const EventListener*>::iterator it = listeners.begin();
 486        it != listeners.end(); it++) {
 487     const EventListener* listener = *it;
 488     if (restrict_to_extension_id.empty() ||
 489         restrict_to_extension_id == listener->extension_id()) {
 490       if (listener->process()) {
 491         EventDispatchIdentifier dispatch_id(listener->GetBrowserContext(),
 492                                             listener->extension_id());
 493         if (!ContainsKey(already_dispatched, dispatch_id)) {
 494           DispatchEventToProcess(listener->extension_id(),
 495                                  listener->listener_url(),
 496                                  listener->process(),
 497                                  event);
 498         }
 499       }
 500     }
 501   }
 502 }
 503
 504 void EventRouter::DispatchLazyEvent(
 505     const std::string& extension_id,
 506     const linked_ptr<Event>& event,
 507     std::set<EventDispatchIdentifier>* already_dispatched) {
 508   // Check both the original and the incognito browser context to see if we
 509   // should load a lazy bg page to handle the event. The latter case
 510   // occurs in the case of split-mode extensions.
 511   const Extension* extension =
 512       ExtensionRegistry::Get(browser_context_)->enabled_extensions().GetByID(
 513           extension_id);
 514   if (!extension)
 515     return;
 516
 517   if (MaybeLoadLazyBackgroundPageToDispatchEvent(
 518           browser_context_, extension, event)) {
 519     already_dispatched->insert(std::make_pair(browser_context_, extension_id));
 520   }
 521
 522   ExtensionsBrowserClient* browser_client = ExtensionsBrowserClient::Get();
 523   if (browser_client->HasOffTheRecordContext(browser_context_) &&
 524       IncognitoInfo::IsSplitMode(extension)) {
 525     BrowserContext* incognito_context =
 526         browser_client->GetOffTheRecordContext(browser_context_);
 527     if (MaybeLoadLazyBackgroundPageToDispatchEvent(
 528             incognito_context, extension, event)) {
 529       already_dispatched->insert(
 530           std::make_pair(incognito_context, extension_id));
 531     }
 532   }
 533 }
 534
 535 void EventRouter::DispatchEventToProcess(const std::string& extension_id,
 536                                          const GURL& listener_url,
 537                                          content::RenderProcessHost* process,
 538                                          const linked_ptr<Event>& event) {
 539   BrowserContext* listener_context = process->GetBrowserContext();
 540   ProcessMap* process_map = ProcessMap::Get(listener_context);
 541
 542   // TODO(kalman): Convert this method to use
 543   // ProcessMap::GetMostLikelyContextType.
 544
 545   const Extension* extension =
 546       ExtensionRegistry::Get(browser_context_)->enabled_extensions().GetByID(
 547           extension_id);
 548   // NOTE: |extension| being NULL does not necessarily imply that this event
 549   // shouldn't be dispatched. Events can be dispatched to WebUI as well.
 550
 551   if (!extension && !extension_id.empty()) {
 552     // Trying to dispatch an event to an extension that doesn't exist. The
 553     // extension could have been removed, but we do not unregister it until the
 554     // extension process is unloaded.
 555     return;
 556   }
 557
 558   if (extension) {
 559     // Dispatching event to an extension.
 560     // If the event is privileged, only send to extension processes. Otherwise,
 561     // it's OK to send to normal renderers (e.g., for content scripts).
 562     if (!process_map->Contains(extension->id(), process->GetID()) &&
 563         !ExtensionAPI::GetSharedInstance()->IsAvailableInUntrustedContext(
 564             event->event_name, extension)) {
 565       return;
 566     }
 567
 568     // If the event is restricted to a URL, only dispatch if the extension has
 569     // permission for it (or if the event originated from itself).
 570     if (!event->event_url.is_empty() &&
 571         event->event_url.host() != extension->id() &&
 572         !extension->permissions_data()
 573              ->active_permissions()
 574              ->HasEffectiveAccessToURL(event->event_url)) {
 575       return;
 576     }
 577
 578     if (!CanDispatchEventToBrowserContext(listener_context, extension, event)) {
 579       return;
 580     }
 581   } else if (content::ChildProcessSecurityPolicy::GetInstance()
 582                  ->HasWebUIBindings(process->GetID())) {
 583     // Dispatching event to WebUI.
 584     if (!ExtensionAPI::GetSharedInstance()->IsAvailableToWebUI(
 585             event->event_name, listener_url)) {
 586       return;
 587     }
 588   } else {
 589     // Dispatching event to a webpage - however, all such events (e.g.
 590     // messaging) don't go through EventRouter so this should be impossible.
 591     NOTREACHED();
 592     return;
 593   }
 594
 595   if (!event->will_dispatch_callback.is_null()) {
 596     event->will_dispatch_callback.Run(
 597         listener_context, extension, event->event_args.get());
 598   }
 599
 600   DispatchExtensionMessage(process,
 601                            listener_context,
 602                            extension_id,
 603                            event->event_name,
 604                            event->event_args.get(),
 605                            event->user_gesture,
 606                            event->filter_info);
 607
 608   if (extension)
 609     IncrementInFlightEvents(listener_context, extension);
 610 }
 611
 612 bool EventRouter::CanDispatchEventToBrowserContext(
 613     BrowserContext* context,
 614     const Extension* extension,
 615     const linked_ptr<Event>& event) {
 616   // Is this event from a different browser context than the renderer (ie, an
 617   // incognito tab event sent to a normal process, or vice versa).
 618   bool cross_incognito = event->restrict_to_browser_context &&
 619                          context != event->restrict_to_browser_context;
 620   if (!cross_incognito)
 621     return true;
 622   return ExtensionsBrowserClient::Get()->CanExtensionCrossIncognito(
 623       extension, context);
 624 }
 625
 626 bool EventRouter::MaybeLoadLazyBackgroundPageToDispatchEvent(
 627     BrowserContext* context,
 628     const Extension* extension,
 629     const linked_ptr<Event>& event) {
 630   if (!CanDispatchEventToBrowserContext(context, extension, event))
 631     return false;
 632
 633   LazyBackgroundTaskQueue* queue = ExtensionSystem::Get(
 634       context)->lazy_background_task_queue();
 635   if (queue->ShouldEnqueueTask(context, extension)) {
 636     linked_ptr<Event> dispatched_event(event);
 637
 638     // If there's a dispatch callback, call it now (rather than dispatch time)
 639     // to avoid lifetime issues. Use a separate copy of the event args, so they
 640     // last until the event is dispatched.
 641     if (!event->will_dispatch_callback.is_null()) {
 642       dispatched_event.reset(event->DeepCopy());
 643       dispatched_event->will_dispatch_callback.Run(
 644           context, extension, dispatched_event->event_args.get());
 645       // Ensure we don't call it again at dispatch time.
 646       dispatched_event->will_dispatch_callback.Reset();
 647     }
 648
 649     queue->AddPendingTask(context, extension->id(),
 650                           base::Bind(&EventRouter::DispatchPendingEvent,
 651                                      base::Unretained(this), dispatched_event));
 652     return true;
 653   }
 654
 655   return false;
 656 }
 657
 658 // static
 659 void EventRouter::IncrementInFlightEventsOnUI(
 660     void* browser_context_id,
 661     const std::string& extension_id) {
 662   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 663   BrowserContext* browser_context =
 664       reinterpret_cast<BrowserContext*>(browser_context_id);
 665   if (!ExtensionsBrowserClient::Get()->IsValidContext(browser_context))
 666     return;
 667   EventRouter* event_router = EventRouter::Get(browser_context);
 668   if (!event_router)
 669     return;
 670   const Extension* extension =
 671       ExtensionRegistry::Get(browser_context)->enabled_extensions().GetByID(
 672           extension_id);
 673   if (!extension)
 674     return;
 675   event_router->IncrementInFlightEvents(browser_context, extension);
 676 }
 677
 678 void EventRouter::IncrementInFlightEvents(BrowserContext* context,
 679                                           const Extension* extension) {
 680   // Only increment in-flight events if the lazy background page is active,
 681   // because that's the only time we'll get an ACK.
 682   if (BackgroundInfo::HasLazyBackgroundPage(extension)) {
 683     ProcessManager* pm = ExtensionSystem::Get(context)->process_manager();
 684     ExtensionHost* host = pm->GetBackgroundHostForExtension(extension->id());
 685     if (host)
 686       pm->IncrementLazyKeepaliveCount(extension);
 687   }
 688 }
 689
 690 void EventRouter::OnEventAck(BrowserContext* context,
 691                              const std::string& extension_id) {
 692   ProcessManager* pm = ExtensionSystem::Get(context)->process_manager();
 693   ExtensionHost* host = pm->GetBackgroundHostForExtension(extension_id);
 694   // The event ACK is routed to the background host, so this should never be
 695   // NULL.
 696   CHECK(host);
 697   // TODO(mpcomplete): We should never get this message unless
 698   // HasLazyBackgroundPage is true. Find out why we're getting it anyway.
 699   if (host->extension() &&
 700       BackgroundInfo::HasLazyBackgroundPage(host->extension()))
 701     pm->DecrementLazyKeepaliveCount(host->extension());
 702 }
 703
 704 void EventRouter::DispatchPendingEvent(const linked_ptr<Event>& event,
 705                                        ExtensionHost* host) {
 706   if (!host)
 707     return;
 708
 709   if (listeners_.HasProcessListener(host->render_process_host(),
 710                                     host->extension()->id())) {
 711     // URL events cannot be lazy therefore can't be pending, hence the GURL().
 712     DispatchEventToProcess(
 713         host->extension()->id(), GURL(), host->render_process_host(), event);
 714   }
 715 }
 716
 717 void EventRouter::Observe(int type,
 718                           const content::NotificationSource& source,
 719                           const content::NotificationDetails& details) {
 720   switch (type) {
 721     case content::NOTIFICATION_RENDERER_PROCESS_TERMINATED:
 722     case content::NOTIFICATION_RENDERER_PROCESS_CLOSED: {
 723       content::RenderProcessHost* renderer =
 724           content::Source<content::RenderProcessHost>(source).ptr();
 725       // Remove all event listeners associated with this renderer.
 726       listeners_.RemoveListenersForProcess(renderer);
 727       break;
 728     }
 729     case extensions::NOTIFICATION_EXTENSION_ENABLED: {
 730       // If the extension has a lazy background page, make sure it gets loaded
 731       // to register the events the extension is interested in.
 732       const Extension* extension =
 733           content::Details<const Extension>(details).ptr();
 734       if (BackgroundInfo::HasLazyBackgroundPage(extension)) {
 735         LazyBackgroundTaskQueue* queue = ExtensionSystem::Get(
 736             browser_context_)->lazy_background_task_queue();
 737         queue->AddPendingTask(browser_context_, extension->id(),
 738                               base::Bind(&DoNothing));
 739       }
 740       break;
 741     }
 742     default:
 743       NOTREACHED();
 744   }
 745 }
 746
 747 void EventRouter::OnExtensionLoaded(content::BrowserContext* browser_context,
 748                                     const Extension* extension) {
 749   // Add all registered lazy listeners to our cache.
 750   std::set<std::string> registered_events =
 751       GetRegisteredEvents(extension->id());
 752   listeners_.LoadUnfilteredLazyListeners(extension->id(), registered_events);
 753   const DictionaryValue* filtered_events = GetFilteredEvents(extension->id());
 754   if (filtered_events)
 755     listeners_.LoadFilteredLazyListeners(extension->id(), *filtered_events);
 756 }
 757
 758 void EventRouter::OnExtensionUnloaded(content::BrowserContext* browser_context,
 759                                       const Extension* extension,
 760                                       UnloadedExtensionInfo::Reason reason) {
 761   // Remove all registered lazy listeners from our cache.
 762   listeners_.RemoveLazyListenersForExtension(extension->id());
 763 }
 764
 765 Event::Event(const std::string& event_name,
 766              scoped_ptr<base::ListValue> event_args)
 767     : event_name(event_name),
 768       event_args(event_args.Pass()),
 769       restrict_to_browser_context(NULL),
 770       user_gesture(EventRouter::USER_GESTURE_UNKNOWN) {
 771   DCHECK(this->event_args.get());
 772 }
 773
 774 Event::Event(const std::string& event_name,
 775              scoped_ptr<base::ListValue> event_args,
 776              BrowserContext* restrict_to_browser_context)
 777     : event_name(event_name),
 778       event_args(event_args.Pass()),
 779       restrict_to_browser_context(restrict_to_browser_context),
 780       user_gesture(EventRouter::USER_GESTURE_UNKNOWN) {
 781   DCHECK(this->event_args.get());
 782 }
 783
 784 Event::Event(const std::string& event_name,
 785              scoped_ptr<ListValue> event_args,
 786              BrowserContext* restrict_to_browser_context,
 787              const GURL& event_url,
 788              EventRouter::UserGestureState user_gesture,
 789              const EventFilteringInfo& filter_info)
 790     : event_name(event_name),
 791       event_args(event_args.Pass()),
 792       restrict_to_browser_context(restrict_to_browser_context),
 793       event_url(event_url),
 794       user_gesture(user_gesture),
 795       filter_info(filter_info) {
 796   DCHECK(this->event_args.get());
 797 }
 798
 799 Event::~Event() {}
 800
 801 Event* Event::DeepCopy() {
 802   Event* copy = new Event(event_name,
 803                           scoped_ptr<base::ListValue>(event_args->DeepCopy()),
 804                           restrict_to_browser_context,
 805                           event_url,
 806                           user_gesture,
 807                           filter_info);
 808   copy->will_dispatch_callback = will_dispatch_callback;
 809   return copy;
 810 }
 811
 812 EventListenerInfo::EventListenerInfo(const std::string& event_name,
 813                                      const std::string& extension_id,
 814                                      const GURL& listener_url,
 815                                      content::BrowserContext* browser_context)
 816     : event_name(event_name),
 817       extension_id(extension_id),
 818       listener_url(listener_url),
 819       browser_context(browser_context) {
 820 }
 821
 822 }  // namespace extensions