components/webdata/common/web_data_service_backend.h

   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 COMPONENTS_WEBDATA_COMMON_WEB_DATA_SERVICE_BACKEND_H_
   6 #define COMPONENTS_WEBDATA_COMMON_WEB_DATA_SERVICE_BACKEND_H_
   7
   8 #include "base/basictypes.h"
   9 #include "base/callback_forward.h"
  10 #include "base/compiler_specific.h"
  11 #include "base/files/file_path.h"
  12 #include "base/memory/ref_counted.h"
  13 #include "base/memory/ref_counted_delete_on_message_loop.h"
  14 #include "base/memory/scoped_ptr.h"
  15 #include "base/memory/scoped_vector.h"
  16 #include "components/webdata/common/web_database_service.h"
  17 #include "components/webdata/common/webdata_export.h"
  18
  19 class WebDatabase;
  20 class WebDatabaseTable;
  21 class WebDataRequest;
  22 class WebDataRequestManager;
  23
  24 namespace tracked_objects {
  25 class Location;
  26 }
  27
  28 // WebDataServiceBackend handles all database tasks posted by
  29 // WebDatabaseService. It is refcounted to allow asynchronous destruction on the
  30 // DB thread.
  31
  32 // TODO(caitkp): Rename this class to WebDatabaseBackend.
  33
  34 class WEBDATA_EXPORT WebDataServiceBackend
  35     : public base::RefCountedDeleteOnMessageLoop<WebDataServiceBackend> {
  36  public:
  37   class Delegate {
  38    public:
  39     virtual ~Delegate() {}
  40
  41     // Invoked when the backend has finished loading the db.
  42     virtual void DBLoaded(sql::InitStatus status) = 0;
  43   };
  44
  45   WebDataServiceBackend(const base::FilePath& path,
  46                         Delegate* delegate,
  47                         const scoped_refptr<base::MessageLoopProxy>& db_thread);
  48
  49   // Must call only before InitDatabaseWithCallback.
  50   void AddTable(scoped_ptr<WebDatabaseTable> table);
  51
  52   // Initializes the database and notifies caller via callback when complete.
  53   // Callback is called synchronously.
  54   void InitDatabase();
  55
  56   // Opens the database file from the profile path if an init has not yet been
  57   // attempted. Separated from the constructor to ease construction/destruction
  58   // of this object on one thread but database access on the DB thread. Returns
  59   // the status of the database.
  60   sql::InitStatus LoadDatabaseIfNecessary();
  61
  62   // Shuts down the database.
  63   void ShutdownDatabase();
  64
  65   // Task wrappers to update requests and and notify |request_manager_|. These
  66   // are used in cases where the request is being made from the UI thread and an
  67   // asyncronous callback is required to notify the client of |request|'s
  68   // completion.
  69   void DBWriteTaskWrapper(
  70       const WebDatabaseService::WriteTask& task,
  71       scoped_ptr<WebDataRequest> request);
  72   void DBReadTaskWrapper(
  73       const WebDatabaseService::ReadTask& task,
  74       scoped_ptr<WebDataRequest> request);
  75
  76   // Task runners to run database tasks.
  77   void ExecuteWriteTask(const WebDatabaseService::WriteTask& task);
  78   scoped_ptr<WDTypedResult> ExecuteReadTask(
  79       const WebDatabaseService::ReadTask& task);
  80
  81   const scoped_refptr<WebDataRequestManager>& request_manager() {
  82     return request_manager_;
  83   }
  84
  85   WebDatabase* database() { return db_.get(); }
  86
  87  protected:
  88   friend class base::RefCountedDeleteOnMessageLoop<WebDataServiceBackend>;
  89   friend class base::DeleteHelper<WebDataServiceBackend>;
  90
  91   virtual ~WebDataServiceBackend();
  92
  93  private:
  94   // Commit the current transaction.
  95   void Commit();
  96
  97   // Path to database file.
  98   base::FilePath db_path_;
  99
 100   // The tables that participate in managing the database. These are
 101   // owned here but other than that this class does nothing with
 102   // them. Their initialization is in whatever factory creates
 103   // WebDatabaseService, and lookup by type is provided by the
 104   // WebDatabase class. The tables need to be owned by this refcounted
 105   // object, or they themselves would need to be refcounted. Owning
 106   // them here rather than having WebDatabase own them makes for
 107   // easier unit testing of WebDatabase.
 108   ScopedVector<WebDatabaseTable> tables_;
 109
 110   scoped_ptr<WebDatabase> db_;
 111
 112   // Keeps track of all pending requests made to the db.
 113   scoped_refptr<WebDataRequestManager> request_manager_;
 114
 115   // State of database initialization. Used to prevent the executing of tasks
 116   // before the db is ready.
 117   sql::InitStatus init_status_;
 118
 119   // True if an attempt has been made to load the database (even if the attempt
 120   // fails), used to avoid continually trying to reinit if the db init fails.
 121   bool init_complete_;
 122
 123   // Delegate. See the class definition above for more information.
 124   scoped_ptr<Delegate> delegate_;
 125
 126   DISALLOW_COPY_AND_ASSIGN(WebDataServiceBackend);
 127 };
 128
 129 #endif  // COMPONENTS_WEBDATA_COMMON_WEB_DATA_SERVICE_BACKEND_H_