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 11 namespace sql { 12 13 class Connection; 14 15 class 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
