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// file : brep/database-lock -*- C++ -*-
// copyright : Copyright (c) 2014-2016 Code Synthesis Ltd
// license : MIT; see accompanying LICENSE file
#ifndef BREP_DATABASE_LOCK
#define BREP_DATABASE_LOCK
#include <memory> // unique_ptr
#include <exception>
#include <odb/pgsql/forward.hxx> // database, transaction
#include <odb/pgsql/connection.hxx>
namespace brep
{
struct database_locked: std::exception
{
virtual char const*
what () const throw () {return "database locked";}
};
// Try to "lock" the PostgreSQL database in the constructor and release the
// lock in the destructor. Throw database_locked if the database is already
// locked by someone else. May also throw odb::pgsql::database_exception.
//
// This mechanism is used by the brep loader and schema migration tool to
// make sure they don't step on each others toes.
//
// Note: movable but not copyable.
//
class database_lock
{
public:
explicit
database_lock (odb::pgsql::database&);
private:
odb::pgsql::connection_ptr connection_;
std::unique_ptr<odb::pgsql::transaction> transaction_;
};
}
#endif // BREP_DATABASE_LOCK
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