leaf/test/exception_capture_test.cpp

//Copyright (c) 2018 Emil Dotchevski
//Copyright (c) 2018 Second Spectrum, Inc.

//Distributed under the Boost Software License, Version 1.0. (See accompanying
//file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

#include <boost/leaf/exception_capture.hpp>
#include <boost/leaf/preload.hpp>
#include <boost/leaf/exception.hpp>
#include "boost/core/lightweight_test.hpp"
#include <vector>
#include <future>
#include <iterator>
#include <algorithm>

namespace leaf = boost::leaf;

struct my_error: std::exception { };

template <int> struct info { int value; };

struct fut_info
{
	int a;
	int b;
	int result;
	std::future<int> fut;
};

template <class F>
std::vector<fut_info> launch_tasks( int task_count, F && f )
{
	assert(task_count>0);
	std::vector<fut_info> fut;
	std::generate_n( std::inserter(fut,fut.end()), task_count, [&f]
	{
		int const a = rand();
		int const b = rand();
		int const res = (rand()%10) - 5;
		return fut_info { a, b, res, std::async( std::launch::async, [f,a,b,res]
			{
				auto wrapper = leaf::capture_exception<info<1>,info<2>,info<3>>(std::move(f));
				return wrapper( a, b, res );
			} ) };
	} );
	return fut;
}

template <class F>
void test( int task_count, F && f ) noexcept
{
	std::vector<fut_info> fut = launch_tasks( task_count, std::forward<F>(f) );
	for( auto & f : fut )
	{
		using namespace leaf::leaf_detail;
		f.fut.wait();
		leaf::expect<info<1>,info<2>,info<4>> exp;
		try
		{
			int r = leaf::get(f.fut);
			BOOST_TEST(r>=0);
			BOOST_TEST(r==f.result);
		}
		catch( my_error const & e )
		{
			int c=0;
			handle_exception( exp, e, [&f,&c]( info<1> const & x1, info<2> const & x2 )
				{
					BOOST_TEST(x1.value==f.a);
					BOOST_TEST(x2.value==f.b);
					++c;
				} );
			BOOST_TEST(c==1);
		}
	}
}

int main()
{
	test( 42, [ ]( int a, int b, int res )
	{
		if( res>=0 )
			return res;
		else
			throw leaf::exception( my_error(), info<1>{a}, info<2>{b}, info<3>{} );
	} );

	test( 42, [ ]( int a, int b, int res )
	{
		if( res>=0 )
			return res;
		else
		{
			auto propagate = leaf::preload( info<1>{a}, info<2>{b}, info<3>{} );
			throw my_error();
		}
	} );

	return boost::report_errors();
}