100 lines
3.3 KiB
C++
100 lines
3.3 KiB
C++
/// \file scopedconnection.h
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/// \brief Declares the ScopedConnection class.
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///
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/// This class lets you grab a connection from a ConnectionPool in a
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/// scoped and therefore RAII way. The Connection object will always be
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/// returned to the pool when the scope block ends, plugging a potential
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/// leak in the pool.
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/***********************************************************************
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Copyright © 2010 by Joel Fielder. Others may also hold copyrights
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on code in this file. See the CREDITS.txt file in the top directory
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of the distribution for details.
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This file is part of MySQL++.
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MySQL++ is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published
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by the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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MySQL++ is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with MySQL++; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
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USA
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***********************************************************************/
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#if !defined(MYSQLPP_SCOPEDCONNECTION_H)
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#define MYSQLPP_SCOPEDCONNECTION_H
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#include "common.h"
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namespace mysqlpp {
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#if !defined(DOXYGEN_IGNORE)
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// Make Doxygen ignore this
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class MYSQLPP_EXPORT Connection;
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class MYSQLPP_EXPORT ConnectionPool;
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#endif
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/// \brief Grabs a Connection from a ConnectionPool on construction
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/// and releases it back to the pool on destruction, and provides access
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/// to the relevant Connection pointer.
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class MYSQLPP_EXPORT ScopedConnection
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{
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public:
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/// \brief Standard constructor
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///
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/// Grabs a Connection from the specified pool.
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///
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/// \internal Note that there is no default ctor on purpose. RAII.
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///
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/// \param pool The ConnectionPool to use.
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/// \param safe By default, we get the connection from the pool with
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/// ConnectionPool::grab(), but we can call safe_grab() instead.
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explicit ScopedConnection(ConnectionPool& pool, bool safe = false);
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#if __cplusplus >= 201103L
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// ScopedConnection objects cannot be copied. We want them to be
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// tightly scoped to their use point, not put in containers or
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// passed around promiscuously.
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ScopedConnection(ScopedConnection&&) = default;
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ScopedConnection(const ScopedConnection& no_copies) = delete;
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const ScopedConnection& operator=(const ScopedConnection& no_copies) = delete;
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#endif
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/// \brief Destructor
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///
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/// Releases the Connection back to the ConnectionPool.
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~ScopedConnection();
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/// \brief Access the Connection pointer
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Connection* operator->() const { return connection_; }
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/// \brief Dereference
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Connection& operator*() const { return *connection_; }
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/// \brief Truthiness operator
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operator void*() const { return connection_; }
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private:
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#if __cplusplus < 201103L
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// Pre C++11 alternative to no-copies ctors above.
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ScopedConnection(const ScopedConnection& no_copies);
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const ScopedConnection& operator=(const ScopedConnection& no_copies);
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#endif
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ConnectionPool& pool_;
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Connection* const connection_;
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};
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} // end namespace mysqlpp
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#endif // !defined(MYSQLPP_SCOPEDCONNECTION_H)
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