99 lines
3.3 KiB
C
99 lines
3.3 KiB
C
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/**
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* @file Savepoint.h
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* @ingroup SQLiteCpp
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* @brief A Savepoint is a way to group multiple SQL statements into an atomic
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* secured operation. Similar to a transaction while allowing child savepoints.
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*
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* Copyright (c) 2020 Kelvin Hammond (hammond.kelvin@gmail.com)
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* Copyright (c) 2020-2023 Sebastien Rombauts (sebastien.rombauts@gmail.com)
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*
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* Distributed under the MIT License (MIT) (See accompanying file LICENSE.txt or
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* copy at http://opensource.org/licenses/MIT)
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*/
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#pragma once
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#include <SQLiteCpp/SQLiteCppExport.h>
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#include <SQLiteCpp/Exception.h>
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namespace SQLite
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{
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// Forward declaration
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class Database;
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/**
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* @brief RAII encapsulation of a SQLite Savepoint.
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*
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* SAVEPOINTs are a method of creating Transactions, similar to BEGIN and COMMIT,
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* except that the SAVEPOINT and RELEASE commands are named and may be nested..
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*
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* Resource Acquisition Is Initialization (RAII) means that the Savepoint
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* begins in the constructor and is rolled back in the destructor (unless committed before), so that there is
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* no need to worry about memory management or the validity of the underlying SQLite Connection.
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*
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* This method also offers big performances improvements compared to
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* individually executed statements.
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*
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* Caveats:
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*
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* 1) Calling COMMIT or committing a parent transaction or RELEASE on a parent
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* savepoint will cause this savepoint to be released.
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*
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* 2) Calling ROLLBACK TO or rolling back a parent savepoint will cause this
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* savepoint to be rolled back.
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*
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* 3) This savepoint is not saved to the database until this and all savepoints
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* or transaction in the savepoint stack have been released or committed.
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*
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* See also: https://sqlite.org/lang_savepoint.html
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*
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* Thread-safety: a Savepoint object shall not be shared by multiple threads, because:
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* 1) in the SQLite "Thread Safe" mode, "SQLite can be safely used by multiple threads
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* provided that no single database connection is used simultaneously in two or more threads."
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* 2) the SQLite "Serialized" mode is not supported by SQLiteC++,
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* because of the way it shares the underling SQLite precompiled statement
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* in a custom shared pointer (See the inner class "Statement::Ptr").
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*/
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class SQLITECPP_API Savepoint
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{
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public:
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/**
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* @brief Begins the SQLite savepoint
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*
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* @param[in] aDatabase the SQLite Database Connection
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* @param[in] aName the name of the Savepoint
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*
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* Exception is thrown in case of error, then the Savepoint is NOT
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* initiated.
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*/
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Savepoint(Database& aDatabase, const std::string& aName);
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// Savepoint is non-copyable
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Savepoint(const Savepoint&) = delete;
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Savepoint& operator=(const Savepoint&) = delete;
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/**
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* @brief Safely rollback the savepoint if it has not been committed.
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*/
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~Savepoint();
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/**
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* @brief Commit and release the savepoint.
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*/
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void release();
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/**
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* @brief Rollback to the savepoint, but don't release it.
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*/
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void rollbackTo();
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// @deprecated same as rollbackTo();
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void rollback() { rollbackTo(); }
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private:
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Database& mDatabase; ///< Reference to the SQLite Database Connection
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std::string msName; ///< Name of the Savepoint
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bool mbReleased = false; ///< True when release has been called
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};
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} // namespace SQLite
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