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