components/webdata/common/web_data_service_base.h

   1 // Copyright (c) 2012 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_BASE_H_
   6 #define COMPONENTS_WEBDATA_COMMON_WEB_DATA_SERVICE_BASE_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/ref_counted_delete_on_message_loop.h"
  12 #include "base/memory/scoped_ptr.h"
  13 #include "components/webdata/common/webdata_export.h"
  14 #include "sql/init_status.h"
  15
  16 class WebDatabase;
  17 class WebDatabaseService;
  18 class WebDatabaseTable;
  19
  20 namespace base {
  21 class Thread;
  22 }
  23
  24 // Base for WebDataService class hierarchy.
  25 // WebDataServiceBase is destroyed on the UI thread.
  26 class WEBDATA_EXPORT WebDataServiceBase
  27     : public base::RefCountedDeleteOnMessageLoop<WebDataServiceBase> {
  28  public:
  29   // All requests return an opaque handle of the following type.
  30   typedef int Handle;
  31
  32   // Users of this class may provide a callback to handle errors
  33   // (e.g. by showing a UI). The callback is called only on error, and
  34   // takes a single parameter, the sql::InitStatus value from trying
  35   // to open the database.
  36   // TODO(joi): Should we combine this with WebDatabaseService::InitCallback?
  37   typedef base::Callback<void(sql::InitStatus)> ProfileErrorCallback;
  38
  39   typedef base::Closure DBLoadedCallback;
  40
  41   // |callback| will only be invoked on error, and only if
  42   // |callback.is_null()| evaluates to false.
  43   //
  44   // The ownership of |wdbs| is shared, with the primary owner being the
  45   // WebDataServiceWrapper, and secondary owners being subclasses of
  46   // WebDataServiceBase, which receive |wdbs| upon construction. The
  47   // WebDataServiceWrapper handles the initializing and shutting down and of
  48   // the |wdbs| object.
  49   // WebDataServiceBase is destroyed on |ui_thread|.
  50   WebDataServiceBase(scoped_refptr<WebDatabaseService> wdbs,
  51                      const ProfileErrorCallback& callback,
  52                      const scoped_refptr<base::MessageLoopProxy>& ui_thread);
  53
  54   // Cancel any pending request. You need to call this method if your
  55   // WebDataServiceConsumer is about to be deleted.
  56   virtual void CancelRequest(Handle h);
  57
  58   // Shutdown the web data service. The service can no longer be used after this
  59   // call.
  60   virtual void ShutdownOnUIThread();
  61
  62   // Initializes the web data service.
  63   virtual void Init();
  64
  65   // Unloads the database and shuts down service.
  66   void ShutdownDatabase();
  67
  68   // Register a callback to be notified that the database has loaded. Multiple
  69   // callbacks may be registered, and each will be called at most once
  70   // (following a successful database load), then cleared.
  71   // Note: if the database load is already complete, then the callback will NOT
  72   // be stored or called.
  73   virtual void RegisterDBLoadedCallback(const DBLoadedCallback& callback);
  74
  75   // Returns true if the database load has completetd successfully, and
  76   // ShutdownOnUIThread has not yet been called.
  77   virtual bool IsDatabaseLoaded();
  78
  79   // Returns a pointer to the DB (used by SyncableServices). May return NULL if
  80   // the database is not loaded or otherwise unavailable. Must be called on
  81   // DBThread.
  82   virtual WebDatabase* GetDatabase();
  83
  84  protected:
  85   friend class base::RefCountedDeleteOnMessageLoop<WebDataServiceBase>;
  86   friend class base::DeleteHelper<WebDataServiceBase>;
  87
  88   virtual ~WebDataServiceBase();
  89
  90   // Our database service.
  91   scoped_refptr<WebDatabaseService> wdbs_;
  92
  93  private:
  94   ProfileErrorCallback profile_error_callback_;
  95
  96   DISALLOW_COPY_AND_ASSIGN(WebDataServiceBase);
  97 };
  98
  99 #endif  // COMPONENTS_WEBDATA_COMMON_WEB_DATA_SERVICE_BASE_H_