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 #ifndef EXTENSIONS_BROWSER_LAZY_BACKGROUND_TASK_QUEUE_H_ 6 #define EXTENSIONS_BROWSER_LAZY_BACKGROUND_TASK_QUEUE_H_ 7 8 #include <map> 9 #include <string> 10 11 #include "base/callback_forward.h" 12 #include "base/compiler_specific.h" 13 #include "base/gtest_prod_util.h" 14 #include "base/memory/linked_ptr.h" 15 #include "content/public/browser/notification_observer.h" 16 #include "content/public/browser/notification_registrar.h" 17 18 namespace content { 19 class BrowserContext; 20 } 21 22 namespace extensions { 23 class Extension; 24 class ExtensionHost; 25 26 // This class maintains a queue of tasks that should execute when an 27 // extension's lazy background page is loaded. It is also in charge of loading 28 // the page when the first task is queued. 29 // 30 // It is the consumer's responsibility to use this class when appropriate, i.e. 31 // only with extensions that have not-yet-loaded lazy background pages. 32 class LazyBackgroundTaskQueue : public content::NotificationObserver { 33 public: 34 typedef base::Callback<void(ExtensionHost*)> PendingTask; 35 36 explicit LazyBackgroundTaskQueue(content::BrowserContext* browser_context); 37 virtual ~LazyBackgroundTaskQueue(); 38 39 // Returns the number of extensions having pending tasks. 40 size_t extensions_with_pending_tasks() { return pending_tasks_.size(); } 41 42 // Returns true if the task should be added to the queue (that is, if the 43 // extension has a lazy background page that isn't ready yet). If the 44 // extension has a lazy background page that is being suspended this method 45 // cancels that suspension. 46 bool ShouldEnqueueTask(content::BrowserContext* context, 47 const Extension* extension); 48 49 // Adds a task to the queue for a given extension. If this is the first 50 // task added for the extension, its lazy background page will be loaded. 51 // The task will be called either when the page is loaded, or when the 52 // page fails to load for some reason (e.g. a crash or browser 53 // shutdown). In the latter case, the ExtensionHost parameter is NULL. 54 void AddPendingTask( 55 content::BrowserContext* context, 56 const std::string& extension_id, 57 const PendingTask& task); 58 59 private: 60 FRIEND_TEST_ALL_PREFIXES(LazyBackgroundTaskQueueTest, ProcessPendingTasks); 61 62 // A map between a BrowserContext/extension_id pair and the queue of tasks 63 // pending the load of its background page. 64 typedef std::string ExtensionID; 65 typedef std::pair<content::BrowserContext*, ExtensionID> PendingTasksKey; 66 typedef std::vector<PendingTask> PendingTasksList; 67 typedef std::map<PendingTasksKey, 68 linked_ptr<PendingTasksList> > PendingTasksMap; 69 70 // content::NotificationObserver interface. 71 virtual void Observe(int type, 72 const content::NotificationSource& source, 73 const content::NotificationDetails& details) OVERRIDE; 74 75 // Called when a lazy background page has finished loading, or has failed to 76 // load (host is NULL in that case). All enqueued tasks are run in order. 77 void ProcessPendingTasks( 78 ExtensionHost* host, 79 content::BrowserContext* context, 80 const Extension* extension); 81 82 content::BrowserContext* browser_context_; 83 content::NotificationRegistrar registrar_; 84 PendingTasksMap pending_tasks_; 85 }; 86 87 } // namespace extensions 88 89 #endif // EXTENSIONS_BROWSER_LAZY_BACKGROUND_TASK_QUEUE_H_ 90
