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/*
* Copyright 2003 - 2016, The libsigc++ Development Team
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef SIGC_ADAPTORS_EXCEPTION_CATCH_H
#define SIGC_ADAPTORS_EXCEPTION_CATCH_H
#include <sigc++/adaptors/adapts.h>
namespace sigc
{
/*
functor adaptor: exception_catch(functor, catcher)
usage:
Future directions:
The catcher should be told what type of return it needs to
return for multiple type functors, to do this the user
will need to derive from catcher_base.
*/
/** @defgroup exception_catch exception_catch()
* sigc::exception_catch() catches an exception thrown from within
* the wrapped functor and directs it to a catcher functor.
* This catcher can then rethrow the exception and catch it with the proper type.
*
* Note that the catcher is expected to return the same type
* as the wrapped functor so that normal flow can continue.
*
* Catchers can be cascaded to catch multiple types, because uncaught
* rethrown exceptions proceed to the next catcher adaptor.
*
* @par Examples:
* @code
* struct my_catch
* {
* int operator()()
* {
* try { throw; }
* catch (std::range_error e) // catch what types we know
* { std::cerr << "caught " << e.what() << std::endl; }
* return 1;
* }
* }
* int foo(); // throws std::range_error
* sigc::exception_catch(&foo, my_catch())();
* @endcode
*
* The functor sigc::exception_catch() returns can be directly passed into
* sigc::signal::connect().
*
* @par Example:
* @code
* sigc::signal<int()> some_signal;
* some_signal.connect(sigc::exception_catch(&foo, my_catch));
* @endcode
*
* @ingroup adaptors
*/
template<typename T_functor, typename T_catcher>
struct exception_catch_functor : public adapts<T_functor>
{
decltype(auto) operator()()
{
try
{
return std::invoke(this->functor_);
}
catch (...)
{
return catcher_();
}
}
template<typename... T_arg>
decltype(auto) operator()(T_arg... a)
{
try
{
return std::invoke(this->functor_, a...);
}
catch (...)
{
return catcher_();
}
}
exception_catch_functor(const T_functor& func, const T_catcher& catcher)
: adapts<T_functor>(func), catcher_(catcher)
{
}
T_catcher catcher_;
};
#ifndef DOXYGEN_SHOULD_SKIP_THIS
// template specialization of visitor<>::do_visit_each<>(action, functor):
template<typename T_functor, typename T_catcher>
struct visitor<exception_catch_functor<T_functor, T_catcher>>
{
template<typename T_action>
static void do_visit_each(const T_action& action,
const exception_catch_functor<T_functor, T_catcher>& target)
{
sigc::visit_each(action, target.functor_);
sigc::visit_each(action, target.catcher_);
}
};
#endif // DOXYGEN_SHOULD_SKIP_THIS
template<typename T_functor, typename T_catcher>
inline decltype(auto)
exception_catch(const T_functor& func, const T_catcher& catcher)
{
return exception_catch_functor<T_functor, T_catcher>(func, catcher);
}
} /* namespace sigc */
#endif /* SIGC_ADAPTORS_EXCEPTION_CATCH_H */
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