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+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef SQL_TRANSACTION_H_
+#define SQL_TRANSACTION_H_
+#pragma once
+
+#include "base/basictypes.h"
+
+namespace sql {
+
+class Connection;
+
+class Transaction {
+ public:
+  // Creates the scoped transaction object. You MUST call Begin() to begin the
+  // transaction. If you have begun a transaction and not committed it, the
+  // constructor will roll back the transaction. If you want to commit, you
+  // need to manually call Commit before this goes out of scope.
+  explicit Transaction(Connection* connection);
+  ~Transaction();
+
+  // Returns true when there is a transaction that has been successfully begun.
+  bool is_open() const { return is_open_; }
+
+  // Begins the transaction. This uses the default sqlite "deferred" transaction
+  // type, which means that the DB lock is lazily acquired the next time the
+  // database is accessed, not in the begin transaction command.
+  //
+  // Returns false on failure. Note that if this fails, you shouldn't do
+  // anything you expect to be actually transactional, because it won't be!
+  bool Begin();
+
+  // Rolls back the transaction. This will happen automatically if you do
+  // nothing when the transaction goes out of scope.
+  void Rollback();
+
+  // Commits the transaction, returning true on success. This will return
+  // false if sqlite could not commit it, or if another transaction in the
+  // same outermost transaction has been rolled back (which necessitates a
+  // rollback of all transactions in that outermost one).
+  bool Commit();
+
+ private:
+  Connection* connection_;
+
+  // True when the transaction is open, false when it's already been committed
+  // or rolled back.
+  bool is_open_;
+
+  DISALLOW_COPY_AND_ASSIGN(Transaction);
+};
+
+}  // namespace sql
+
+#endif  // SQL_TRANSACTION_H_