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 SQL_TRANSACTION_H_
6#define SQL_TRANSACTION_H_
7
8#include "base/basictypes.h"
9#include "sql/sql_export.h"
10
11namespace sql {
12
13class Connection;
14
15class SQL_EXPORT Transaction {
16 public:
17  // Creates the scoped transaction object. You MUST call Begin() to begin the
18  // transaction. If you have begun a transaction and not committed it, the
19  // constructor will roll back the transaction. If you want to commit, you
20  // need to manually call Commit before this goes out of scope.
21  //
22  // Nested transactions are supported. See sql::Connection::BeginTransaction
23  // for details.
24  explicit Transaction(Connection* connection);
25  ~Transaction();
26
27  // Returns true when there is a transaction that has been successfully begun.
28  bool is_open() const { return is_open_; }
29
30  // Begins the transaction. This uses the default sqlite "deferred" transaction
31  // type, which means that the DB lock is lazily acquired the next time the
32  // database is accessed, not in the begin transaction command.
33  //
34  // Returns false on failure. Note that if this fails, you shouldn't do
35  // anything you expect to be actually transactional, because it won't be!
36  bool Begin();
37
38  // Rolls back the transaction. This will happen automatically if you do
39  // nothing when the transaction goes out of scope.
40  void Rollback();
41
42  // Commits the transaction, returning true on success. This will return
43  // false if sqlite could not commit it, or if another transaction in the
44  // same outermost transaction has been rolled back (which necessitates a
45  // rollback of all transactions in that outermost one).
46  bool Commit();
47
48 private:
49  Connection* connection_;
50
51  // True when the transaction is open, false when it's already been committed
52  // or rolled back.
53  bool is_open_;
54
55  DISALLOW_COPY_AND_ASSIGN(Transaction);
56};
57
58}  // namespace sql
59
60#endif  // SQL_TRANSACTION_H_
61