web_data_service_backend.h revision c2e0dbddbe15c98d52c4786dac06cb8952a8ae6d 
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/scoped_ptr.h"
14#include "base/memory/scoped_vector.h"
15#include "components/webdata/common/web_database_service.h"
16#include "content/public/browser/browser_thread.h"
17
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
32class WebDataServiceBackend
33    : public base::RefCountedThreadSafe<
34          WebDataServiceBackend,
35          content::BrowserThread::DeleteOnDBThread> {
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  explicit WebDataServiceBackend(const base::FilePath& path,
46                                 Delegate* delegate);
47
48  // Must call only before InitDatabaseWithCallback.
49  void AddTable(scoped_ptr<WebDatabaseTable> table);
50
51  // Initializes the database and notifies caller via callback when complete.
52  // Callback is called synchronously.
53  void InitDatabase();
54
55  // Opens the database file from the profile path if an init has not yet been
56  // attempted. Separated from the constructor to ease construction/destruction
57  // of this object on one thread but database access on the DB thread. Returns
58  // the status of the database.
59  sql::InitStatus LoadDatabaseIfNecessary();
60
61  // Shuts down database. |should_reinit| tells us whether or not it should be
62  // possible to re-initialize the DB after the shutdown.
63  void ShutdownDatabase(bool should_reinit);
64
65  // Task wrappers to run database tasks.
66  void DBWriteTaskWrapper(
67      const WebDatabaseService::WriteTask& task,
68      scoped_ptr<WebDataRequest> request);
69  void DBReadTaskWrapper(
70      const WebDatabaseService::ReadTask& task,
71      scoped_ptr<WebDataRequest> request);
72
73  const scoped_refptr<WebDataRequestManager>& request_manager() {
74    return request_manager_;
75  }
76
77  WebDatabase* database() { return db_.get(); }
78
79 private:
80  friend struct content::BrowserThread::DeleteOnThread<
81      content::BrowserThread::DB>;
82  friend class base::DeleteHelper<WebDataServiceBackend>;
83
84  virtual ~WebDataServiceBackend();
85
86  // Commit the current transaction.
87  void Commit();
88
89  // Path to database file.
90  base::FilePath db_path_;
91
92  // The tables that participate in managing the database. These are
93  // owned here but other than that this class does nothing with
94  // them. Their initialization is in whatever factory creates
95  // WebDatabaseService, and lookup by type is provided by the
96  // WebDatabase class. The tables need to be owned by this refcounted
97  // object, or they themselves would need to be refcounted. Owning
98  // them here rather than having WebDatabase own them makes for
99  // easier unit testing of WebDatabase.
100  ScopedVector<WebDatabaseTable> tables_;
101
102  scoped_ptr<WebDatabase> db_;
103
104  // Keeps track of all pending requests made to the db.
105  scoped_refptr<WebDataRequestManager> request_manager_;
106
107  // State of database initialization. Used to prevent the executing of tasks
108  // before the db is ready.
109  sql::InitStatus init_status_;
110
111  // True if an attempt has been made to load the database (even if the attempt
112  // fails), used to avoid continually trying to reinit if the db init fails.
113  bool init_complete_;
114
115  // Delegate. See the class definition above for more information.
116  scoped_ptr<Delegate> delegate_;
117
118  DISALLOW_COPY_AND_ASSIGN(WebDataServiceBackend);
119};
120
121#endif  // COMPONENTS_WEBDATA_COMMON_WEB_DATA_SERVICE_BACKEND_H_
122