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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 #pragma once
      8 
      9 #include "base/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 #include "content/browser/cancelable_request.h"
     14 
     15 class FilePath;
     16 
     17 namespace history {
     18 
     19 class TopSitesDatabase;
     20 
     21 // Service used by TopSites to have db interaction happen on the DB thread.  All
     22 // public methods are invoked on the ui thread and get funneled to the DB
     23 // thread.
     24 class TopSitesBackend
     25     : public base::RefCountedThreadSafe<TopSitesBackend>,
     26       public CancelableRequestProvider {
     27  public:
     28   TopSitesBackend();
     29 
     30   void Init(const FilePath& path);
     31 
     32   // Schedules the db to be shutdown.
     33   void Shutdown();
     34 
     35   // The boolean parameter indicates if the DB existed on disk or needs to be
     36   // migrated.
     37   typedef Callback3<Handle, scoped_refptr<MostVisitedThumbnails>, bool >::Type
     38       GetMostVisitedThumbnailsCallback;
     39   typedef CancelableRequest1<TopSitesBackend::GetMostVisitedThumbnailsCallback,
     40                              scoped_refptr<MostVisitedThumbnails> >
     41       GetMostVisitedThumbnailsRequest;
     42 
     43   // Fetches MostVisitedThumbnails.
     44   Handle GetMostVisitedThumbnails(CancelableRequestConsumerBase* consumer,
     45                                   GetMostVisitedThumbnailsCallback* callback);
     46 
     47   // Updates top sites database from the specified delta.
     48   void UpdateTopSites(const TopSitesDelta& delta);
     49 
     50   // Sets the thumbnail.
     51   void SetPageThumbnail(const MostVisitedURL& url,
     52                         int url_rank,
     53                         const Images& thumbnail);
     54 
     55   // Deletes the database and recreates it.
     56   void ResetDatabase();
     57 
     58   typedef Callback1<Handle>::Type EmptyRequestCallback;
     59   typedef CancelableRequest<TopSitesBackend::EmptyRequestCallback>
     60       EmptyRequestRequest;
     61 
     62   // Schedules a request that does nothing on the DB thread, but then notifies
     63   // the callback on the calling thread. This is used to make sure the db has
     64   // finished processing a request.
     65   Handle DoEmptyRequest(CancelableRequestConsumerBase* consumer,
     66                         EmptyRequestCallback* callback);
     67 
     68  private:
     69   friend class base::RefCountedThreadSafe<TopSitesBackend>;
     70 
     71   ~TopSitesBackend();
     72 
     73   // Invokes Init on the db_.
     74   void InitDBOnDBThread(const FilePath& path);
     75 
     76   // Shuts down the db.
     77   void ShutdownDBOnDBThread();
     78 
     79   // Does the work of getting the most visted thumbnails.
     80   void GetMostVisitedThumbnailsOnDBThread(
     81       scoped_refptr<GetMostVisitedThumbnailsRequest> request);
     82 
     83   // Updates top sites.
     84   void UpdateTopSitesOnDBThread(const TopSitesDelta& delta);
     85 
     86   // Sets the thumbnail.
     87   void SetPageThumbnailOnDBThread(const MostVisitedURL& url,
     88                                   int url_rank,
     89                                   const Images& thumbnail);
     90 
     91   // Resets the database.
     92   void ResetDatabaseOnDBThread(const FilePath& file_path);
     93 
     94   // Notifies the request.
     95   void DoEmptyRequestOnDBThread(scoped_refptr<EmptyRequestRequest> request);
     96 
     97   FilePath db_path_;
     98 
     99   scoped_ptr<TopSitesDatabase> db_;
    100 
    101   DISALLOW_COPY_AND_ASSIGN(TopSitesBackend);
    102 };
    103 
    104 }  // namespace history
    105 
    106 #endif  // CHROME_BROWSER_HISTORY_TOP_SITES_BACKEND_H_
    107