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      1 // Copyright (c) 2011 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 CHROME_BROWSER_HISTORY_TOP_SITES_BACKEND_H_
      6 #define CHROME_BROWSER_HISTORY_TOP_SITES_BACKEND_H_
      7 
      8 #include "base/callback.h"
      9 #include "base/files/file_path.h"
     10 #include "base/memory/ref_counted.h"
     11 #include "base/memory/scoped_ptr.h"
     12 #include "chrome/browser/history/history_types.h"
     13 
     14 namespace base {
     15 class CancelableTaskTracker;
     16 class FilePath;
     17 }
     18 
     19 namespace history {
     20 
     21 class TopSitesDatabase;
     22 
     23 // Service used by TopSites to have db interaction happen on the DB thread.  All
     24 // public methods are invoked on the ui thread and get funneled to the DB
     25 // thread.
     26 class TopSitesBackend : public base::RefCountedThreadSafe<TopSitesBackend> {
     27  public:
     28   // The boolean parameter indicates if the DB existed on disk or needs to be
     29   // migrated.
     30   typedef base::Callback<void(const scoped_refptr<MostVisitedThumbnails>&)>
     31       GetMostVisitedThumbnailsCallback;
     32 
     33   TopSitesBackend();
     34 
     35   void Init(const base::FilePath& path);
     36 
     37   // Schedules the db to be shutdown.
     38   void Shutdown();
     39 
     40   // Fetches MostVisitedThumbnails.
     41   void GetMostVisitedThumbnails(
     42       const GetMostVisitedThumbnailsCallback& callback,
     43       base::CancelableTaskTracker* tracker);
     44 
     45   // Updates top sites database from the specified delta.
     46   void UpdateTopSites(const TopSitesDelta& delta);
     47 
     48   // Sets the thumbnail.
     49   void SetPageThumbnail(const MostVisitedURL& url,
     50                         int url_rank,
     51                         const Images& thumbnail);
     52 
     53   // Deletes the database and recreates it.
     54   void ResetDatabase();
     55 
     56   // Schedules a request that does nothing on the DB thread, but then notifies
     57   // the the calling thread with a reply. This is used to make sure the db has
     58   // finished processing a request.
     59   void DoEmptyRequest(const base::Closure& reply,
     60                       base::CancelableTaskTracker* tracker);
     61 
     62  private:
     63   friend class base::RefCountedThreadSafe<TopSitesBackend>;
     64 
     65   virtual ~TopSitesBackend();
     66 
     67   // Invokes Init on the db_.
     68   void InitDBOnDBThread(const base::FilePath& path);
     69 
     70   // Shuts down the db.
     71   void ShutdownDBOnDBThread();
     72 
     73   // Does the work of getting the most visted thumbnails.
     74   void GetMostVisitedThumbnailsOnDBThread(
     75       scoped_refptr<MostVisitedThumbnails> thumbnails);
     76 
     77   // Updates top sites.
     78   void UpdateTopSitesOnDBThread(const TopSitesDelta& delta);
     79 
     80   // Sets the thumbnail.
     81   void SetPageThumbnailOnDBThread(const MostVisitedURL& url,
     82                                   int url_rank,
     83                                   const Images& thumbnail);
     84 
     85   // Resets the database.
     86   void ResetDatabaseOnDBThread(const base::FilePath& file_path);
     87 
     88   base::FilePath db_path_;
     89 
     90   scoped_ptr<TopSitesDatabase> db_;
     91 
     92   DISALLOW_COPY_AND_ASSIGN(TopSitesBackend);
     93 };
     94 
     95 }  // namespace history
     96 
     97 #endif  // CHROME_BROWSER_HISTORY_TOP_SITES_BACKEND_H_
     98