1 // Copyright (c) 2009 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 APP_SQL_TRANSACTION_H_ 6 #define APP_SQL_TRANSACTION_H_ 7 #pragma once 8 9 #include "base/basictypes.h" 10 11 namespace sql { 12 13 class Connection; 14 15 class 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 explicit Transaction(Connection* connection); 22 ~Transaction(); 23 24 // Returns true when there is a transaction that has been successfully begun. 25 bool is_open() const { return is_open_; } 26 27 // Begins the transaction. This uses the default sqlite "deferred" transaction 28 // type, which means that the DB lock is lazily acquired the next time the 29 // database is accessed, not in the begin transaction command. 30 // 31 // Returns false on failure. Note that if this fails, you shouldn't do 32 // anything you expect to be actually transactional, because it won't be! 33 bool Begin(); 34 35 // Rolls back the transaction. This will happen automatically if you do 36 // nothing when the transaction goes out of scope. 37 void Rollback(); 38 39 // Commits the transaction, returning true on success. This will return 40 // false if sqlite could not commit it, or if another transaction in the 41 // same outermost transaction has been rolled back (which necessitates a 42 // rollback of all transactions in that outermost one). 43 bool Commit(); 44 45 private: 46 Connection* connection_; 47 48 // True when the transaction is open, false when it's already been committed 49 // or rolled back. 50 bool is_open_; 51 52 DISALLOW_COPY_AND_ASSIGN(Transaction); 53 }; 54 55 } // namespace sql 56 57 #endif // APP_SQL_TRANSACTION_H_ 58
