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/component_export.h"
9 #include "base/macros.h"
10
11 namespace sql {
12
13 class Database;
14
COMPONENT_EXPORT(SQL)15 class COMPONENT_EXPORT(SQL) 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::Database::BeginTransaction
23 // for details.
24 explicit Transaction(Database* 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 Database* database_;
50
51 // True when the transaction is open, false when it's already been committed
52 // or rolled back.
53 bool is_open_ = false;
54
55 DISALLOW_COPY_AND_ASSIGN(Transaction);
56 };
57
58 } // namespace sql
59
60 #endif // SQL_TRANSACTION_H_
61