extensions/browser/lazy_background_task_queue.cc

   1 // Copyright 2013 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/lazy_background_task_queue.h"
   6
   7 #include "base/callback.h"
   8 #include "content/public/browser/browser_context.h"
   9 #include "content/public/browser/notification_service.h"
  10 #include "content/public/browser/render_process_host.h"
  11 #include "content/public/browser/render_view_host.h"
  12 #include "content/public/browser/site_instance.h"
  13 #include "content/public/browser/web_contents.h"
  14 #include "extensions/browser/extension_host.h"
  15 #include "extensions/browser/extension_registry.h"
  16 #include "extensions/browser/extensions_browser_client.h"
  17 #include "extensions/browser/notification_types.h"
  18 #include "extensions/browser/process_manager.h"
  19 #include "extensions/browser/process_map.h"
  20 #include "extensions/common/extension.h"
  21 #include "extensions/common/manifest_handlers/background_info.h"
  22 #include "extensions/common/view_type.h"
  23
  24 namespace extensions {
  25
  26 LazyBackgroundTaskQueue::LazyBackgroundTaskQueue(
  27     content::BrowserContext* browser_context)
  28     : browser_context_(browser_context), extension_registry_observer_(this) {
  29   registrar_.Add(this,
  30                  extensions::NOTIFICATION_EXTENSION_HOST_DID_STOP_FIRST_LOAD,
  31                  content::NotificationService::AllBrowserContextsAndSources());
  32   registrar_.Add(this,
  33                  extensions::NOTIFICATION_EXTENSION_HOST_DESTROYED,
  34                  content::NotificationService::AllBrowserContextsAndSources());
  35
  36   extension_registry_observer_.Add(ExtensionRegistry::Get(browser_context));
  37 }
  38
  39 LazyBackgroundTaskQueue::~LazyBackgroundTaskQueue() {
  40 }
  41
  42 bool LazyBackgroundTaskQueue::ShouldEnqueueTask(
  43     content::BrowserContext* browser_context,
  44     const Extension* extension) {
  45   // Note: browser_context may not be the same as browser_context_ for incognito
  46   // extension tasks.
  47   DCHECK(extension);
  48   if (BackgroundInfo::HasBackgroundPage(extension)) {
  49     ProcessManager* pm = ProcessManager::Get(browser_context);
  50     ExtensionHost* background_host =
  51         pm->GetBackgroundHostForExtension(extension->id());
  52     if (!background_host || !background_host->has_loaded_once())
  53       return true;
  54     if (pm->IsBackgroundHostClosing(extension->id()))
  55       pm->CancelSuspend(extension);
  56   }
  57
  58   return false;
  59 }
  60
  61 void LazyBackgroundTaskQueue::AddPendingTask(
  62     content::BrowserContext* browser_context,
  63     const std::string& extension_id,
  64     const PendingTask& task) {
  65   if (ExtensionsBrowserClient::Get()->IsShuttingDown()) {
  66     task.Run(NULL);
  67     return;
  68   }
  69   PendingTasksList* tasks_list = NULL;
  70   PendingTasksKey key(browser_context, extension_id);
  71   PendingTasksMap::iterator it = pending_tasks_.find(key);
  72   if (it == pending_tasks_.end()) {
  73     tasks_list = new PendingTasksList();
  74     pending_tasks_[key] = linked_ptr<PendingTasksList>(tasks_list);
  75
  76     const Extension* extension =
  77         ExtensionRegistry::Get(browser_context)->enabled_extensions().GetByID(
  78             extension_id);
  79     if (extension && BackgroundInfo::HasLazyBackgroundPage(extension)) {
  80       // If this is the first enqueued task, and we're not waiting for the
  81       // background page to unload, ensure the background page is loaded.
  82       ProcessManager* pm = ProcessManager::Get(browser_context);
  83       pm->IncrementLazyKeepaliveCount(extension);
  84       // Creating the background host may fail, e.g. if |profile| is incognito
  85       // but the extension isn't enabled in incognito mode.
  86       if (!pm->CreateBackgroundHost(
  87             extension, BackgroundInfo::GetBackgroundURL(extension))) {
  88         task.Run(NULL);
  89         return;
  90       }
  91     }
  92   } else {
  93     tasks_list = it->second.get();
  94   }
  95
  96   tasks_list->push_back(task);
  97 }
  98
  99 void LazyBackgroundTaskQueue::ProcessPendingTasks(
 100     ExtensionHost* host,
 101     content::BrowserContext* browser_context,
 102     const Extension* extension) {
 103   if (!ExtensionsBrowserClient::Get()->IsSameContext(browser_context,
 104                                                      browser_context_))
 105     return;
 106
 107   PendingTasksKey key(browser_context, extension->id());
 108   PendingTasksMap::iterator map_it = pending_tasks_.find(key);
 109   if (map_it == pending_tasks_.end()) {
 110     if (BackgroundInfo::HasLazyBackgroundPage(extension))
 111       CHECK(!host);  // lazy page should not load without any pending tasks
 112     return;
 113   }
 114
 115   // Swap the pending tasks to a temporary, to avoid problems if the task
 116   // list is modified during processing.
 117   PendingTasksList tasks;
 118   tasks.swap(*map_it->second);
 119   for (PendingTasksList::const_iterator it = tasks.begin();
 120        it != tasks.end(); ++it) {
 121     it->Run(host);
 122   }
 123
 124   pending_tasks_.erase(key);
 125
 126   // Balance the keepalive in AddPendingTask. Note we don't do this on a
 127   // failure to load, because the keepalive count is reset in that case.
 128   if (host && BackgroundInfo::HasLazyBackgroundPage(extension)) {
 129     ProcessManager::Get(browser_context)
 130         ->DecrementLazyKeepaliveCount(extension);
 131   }
 132 }
 133
 134 void LazyBackgroundTaskQueue::Observe(
 135     int type,
 136     const content::NotificationSource& source,
 137     const content::NotificationDetails& details) {
 138   switch (type) {
 139     case extensions::NOTIFICATION_EXTENSION_HOST_DID_STOP_FIRST_LOAD: {
 140       // If an on-demand background page finished loading, dispatch queued up
 141       // events for it.
 142       ExtensionHost* host =
 143           content::Details<ExtensionHost>(details).ptr();
 144       if (host->extension_host_type() == VIEW_TYPE_EXTENSION_BACKGROUND_PAGE) {
 145         CHECK(host->has_loaded_once());
 146         ProcessPendingTasks(host, host->browser_context(), host->extension());
 147       }
 148       break;
 149     }
 150     case extensions::NOTIFICATION_EXTENSION_HOST_DESTROYED: {
 151       // Notify consumers about the load failure when the background host dies.
 152       // This can happen if the extension crashes. This is not strictly
 153       // necessary, since we also unload the extension in that case (which
 154       // dispatches the tasks below), but is a good extra precaution.
 155       content::BrowserContext* browser_context =
 156           content::Source<content::BrowserContext>(source).ptr();
 157       ExtensionHost* host =
 158            content::Details<ExtensionHost>(details).ptr();
 159       if (host->extension_host_type() == VIEW_TYPE_EXTENSION_BACKGROUND_PAGE) {
 160         ProcessPendingTasks(NULL, browser_context, host->extension());
 161       }
 162       break;
 163     }
 164     default:
 165       NOTREACHED();
 166       break;
 167   }
 168 }
 169
 170 void LazyBackgroundTaskQueue::OnExtensionUnloaded(
 171     content::BrowserContext* browser_context,
 172     const Extension* extension,
 173     UnloadedExtensionInfo::Reason reason) {
 174   // Notify consumers that the page failed to load.
 175   ProcessPendingTasks(NULL, browser_context, extension);
 176   // If this extension is also running in an off-the-record context, notify that
 177   // task queue as well.
 178   ExtensionsBrowserClient* browser_client = ExtensionsBrowserClient::Get();
 179   if (browser_client->HasOffTheRecordContext(browser_context)) {
 180     ProcessPendingTasks(NULL,
 181                         browser_client->GetOffTheRecordContext(browser_context),
 182                         extension);
 183   }
 184 }
 185
 186 }  // namespace extensions