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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 class CancelableTaskTracker;
     15 
     16 namespace base {
     17 class FilePath;
     18 }
     19 
     20 namespace history {
     21 
     22 class TopSitesDatabase;
     23 
     24 // Service used by TopSites to have db interaction happen on the DB thread.  All
     25 // public methods are invoked on the ui thread and get funneled to the DB
     26 // thread.
     27 class TopSitesBackend : public base::RefCountedThreadSafe<TopSitesBackend> {
     28  public:
     29   // The boolean parameter indicates if the DB existed on disk or needs to be
     30   // migrated.
     31   typedef base::Callback<void(const scoped_refptr<MostVisitedThumbnails>&)>
     32       GetMostVisitedThumbnailsCallback;
     33 
     34   TopSitesBackend();
     35 
     36   void Init(const base::FilePath& path);
     37 
     38   // Schedules the db to be shutdown.
     39   void Shutdown();
     40 
     41   // Fetches MostVisitedThumbnails.
     42   void GetMostVisitedThumbnails(
     43       const GetMostVisitedThumbnailsCallback& callback,
     44       CancelableTaskTracker* tracker);
     45 
     46   // Updates top sites database from the specified delta.
     47   void UpdateTopSites(const TopSitesDelta& delta);
     48 
     49   // Sets the thumbnail.
     50   void SetPageThumbnail(const MostVisitedURL& url,
     51                         int url_rank,
     52                         const Images& thumbnail);
     53 
     54   // Deletes the database and recreates it.
     55   void ResetDatabase();
     56 
     57   // Schedules a request that does nothing on the DB thread, but then notifies
     58   // the the calling thread with a reply. This is used to make sure the db has
     59   // finished processing a request.
     60   void DoEmptyRequest(const base::Closure& reply,
     61                       CancelableTaskTracker* tracker);
     62 
     63  private:
     64   friend class base::RefCountedThreadSafe<TopSitesBackend>;
     65 
     66   virtual ~TopSitesBackend();
     67 
     68   // Invokes Init on the db_.
     69   void InitDBOnDBThread(const base::FilePath& path);
     70 
     71   // Shuts down the db.
     72   void ShutdownDBOnDBThread();
     73 
     74   // Does the work of getting the most visted thumbnails.
     75   void GetMostVisitedThumbnailsOnDBThread(
     76       scoped_refptr<MostVisitedThumbnails> thumbnails);
     77 
     78   // Updates top sites.
     79   void UpdateTopSitesOnDBThread(const TopSitesDelta& delta);
     80 
     81   // Sets the thumbnail.
     82   void SetPageThumbnailOnDBThread(const MostVisitedURL& url,
     83                                   int url_rank,
     84                                   const Images& thumbnail);
     85 
     86   // Resets the database.
     87   void ResetDatabaseOnDBThread(const base::FilePath& file_path);
     88 
     89   base::FilePath db_path_;
     90 
     91   scoped_ptr<TopSitesDatabase> db_;
     92 
     93   DISALLOW_COPY_AND_ASSIGN(TopSitesBackend);
     94 };
     95 
     96 }  // namespace history
     97 
     98 #endif  // CHROME_BROWSER_HISTORY_TOP_SITES_BACKEND_H_
     99