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
19class WebDatabase;
20class WebDatabaseTable;
21class WebDataRequest;
22class WebDataRequestManager;
23
24namespace tracked_objects {
25class 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
34class 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_
130