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 CHROME_BROWSER_HISTORY_ARCHIVED_DATABASE_H_
6#define CHROME_BROWSER_HISTORY_ARCHIVED_DATABASE_H_
7
8#include "base/basictypes.h"
9#include "chrome/browser/history/url_database.h"
10#include "chrome/browser/history/visit_database.h"
11#include "sql/connection.h"
12#include "sql/init_status.h"
13#include "sql/meta_table.h"
14
15namespace base {
16class FilePath;
17}
18
19namespace history {
20
21// Encapsulates the database operations for archived history.
22//
23// IMPORTANT NOTE: The IDs in this system for URLs and visits will be
24// different than those in the main database. This is to eliminate the
25// dependency between them so we can deal with each one on its own.
26class ArchivedDatabase : public URLDatabase,
27                         public VisitDatabase {
28 public:
29  // Must call Init() before using other members.
30  ArchivedDatabase();
31  virtual ~ArchivedDatabase();
32
33  // Initializes the database connection. This must return true before any other
34  // functions on this class are called.
35  bool Init(const base::FilePath& file_name);
36
37  // Try to trim the cache memory used by the database.  If |aggressively| is
38  // true try to trim all unused cache, otherwise trim by half.
39  void TrimMemory(bool aggressively);
40
41  // Transactions on the database. We support nested transactions and only
42  // commit when the outermost one is committed (sqlite doesn't support true
43  // nested transactions).
44  void BeginTransaction();
45  void CommitTransaction();
46
47  // Returns the current version that we will generate archived databases with.
48  static int GetCurrentVersion();
49
50 private:
51  bool InitTables();
52
53  // Implemented for the specialized databases.
54  virtual sql::Connection& GetDB() OVERRIDE;
55
56  // Makes sure the version is up-to-date, updating if necessary. If the
57  // database is too old to migrate, the user will be notified. In this case, or
58  // for other errors, false will be returned. True means it is up-to-date and
59  // ready for use.
60  //
61  // This assumes it is called from the init function inside a transaction. It
62  // may commit the transaction and start a new one if migration requires it.
63  sql::InitStatus EnsureCurrentVersion();
64
65  // The database.
66  sql::Connection db_;
67  sql::MetaTable meta_table_;
68
69  DISALLOW_COPY_AND_ASSIGN(ArchivedDatabase);
70};
71
72}  // namespace history
73
74#endif  // CHROME_BROWSER_HISTORY_ARCHIVED_DATABASE_H_
75