ZeroTierOne/ext/libpqxx-7.7.3/include/pqxx/errorhandler.hxx
Adam Ierymenko b1faebae4a Re-add...
2022-06-23 13:24:33 -04:00

93 lines
2.7 KiB
C++

/* Definition of the pqxx::errorhandler class.
*
* pqxx::errorhandler handlers errors and warnings in a database session.
*
* DO NOT INCLUDE THIS FILE DIRECTLY; include pqxx/errorhandler instead.
*
* Copyright (c) 2000-2022, Jeroen T. Vermeulen.
*
* See COPYING for copyright license. If you did not receive a file called
* COPYING with this source code, please notify the distributor of this
* mistake, or contact the author.
*/
#ifndef PQXX_H_ERRORHANDLER
#define PQXX_H_ERRORHANDLER
#if !defined(PQXX_HEADER_PRE)
# error "Include libpqxx headers as <pqxx/header>, not <pqxx/header.hxx>."
#endif
#include "pqxx/types.hxx"
namespace pqxx::internal::gate
{
class errorhandler_connection;
}
namespace pqxx
{
/**
* @addtogroup errorhandler
*/
//@{
/// Base class for error-handler callbacks.
/** To receive errors and warnings from a connection, subclass this with your
* own error-handler functor, and instantiate it for the connection. Destroying
* the handler un-registers it.
*
* A connection can have multiple error handlers at the same time. When the
* database connection emits an error or warning message, it passes the message
* to each error handler, starting with the most recently registered one and
* progressing towards the oldest one. However an error handler may also
* instruct the connection not to pass the message to further handlers by
* returning "false."
*
* @warning Strange things happen when a result object outlives its parent
* connection. If you register an error handler on a connection, then you must
* not access the result after destroying the connection. This applies even if
* you destroy the error handler first!
*/
class PQXX_LIBEXPORT errorhandler
{
public:
explicit errorhandler(connection &);
virtual ~errorhandler();
/// Define in subclass: receive an error or warning message from the
/// database.
/**
* @return Whether the same error message should also be passed to the
* remaining, older errorhandlers.
*/
virtual bool operator()(char const msg[]) noexcept = 0;
errorhandler() = delete;
errorhandler(errorhandler const &) = delete;
errorhandler &operator=(errorhandler const &) = delete;
private:
connection *m_home;
friend class internal::gate::errorhandler_connection;
void unregister() noexcept;
};
/// An error handler that suppresses any previously registered error handlers.
class quiet_errorhandler : public errorhandler
{
public:
/// Suppress error notices.
quiet_errorhandler(connection &conn) : errorhandler{conn} {}
/// Revert to previous handling of error notices.
virtual bool operator()(char const[]) noexcept override { return false; }
};
//@}
} // namespace pqxx
#endif