variant/test/rvalue_test.cpp

//-----------------------------------------------------------------------------
// boost-libs variant/test/rvalue_test.cpp source file
// See http://www.boost.org for updates, documentation, and revision history.
//-----------------------------------------------------------------------------
//
// Copyright (c) 2012-2013 Antony Polukhin
//
// 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/config.hpp"

#include "boost/test/minimal.hpp"
#include "boost/variant.hpp"
#include "boost/type_traits/is_nothrow_move_assignable.hpp"

// This test requires rvalue references support

#ifdef BOOST_NO_CXX11_RVALUE_REFERENCES

void run()
{
    BOOST_CHECK(true);
}

void run1()
{
    BOOST_CHECK(true);
}

void run_move_only()
{
    BOOST_CHECK(true);
}

void run_moves_are_noexcept()
{
    BOOST_CHECK(true);
}

#else 

class move_copy_conting_class {
public:
    static unsigned int moves_count;
    static unsigned int copy_count;

    move_copy_conting_class(){}
    move_copy_conting_class(move_copy_conting_class&&) {
        ++ moves_count;
    }

    move_copy_conting_class& operator=(move_copy_conting_class&&) {
        ++ moves_count;
        return *this;
    }

    move_copy_conting_class(const move_copy_conting_class&) {
        ++ copy_count;
    }
    move_copy_conting_class& operator=(const move_copy_conting_class&) {
        ++ copy_count;
        return *this;
    }
};

unsigned int move_copy_conting_class::moves_count = 0;
unsigned int move_copy_conting_class::copy_count = 0;

void run()
{
    typedef boost::variant<int, move_copy_conting_class> variant_I_type;
    variant_I_type v1, v2;
    
    // Assuring that `move_copy_conting_class` was not created
    BOOST_CHECK(move_copy_conting_class::copy_count == 0);
    BOOST_CHECK(move_copy_conting_class::moves_count == 0);
    
    v1 = move_copy_conting_class();
    // Assuring that `move_copy_conting_class` was moved at least once
    BOOST_CHECK(move_copy_conting_class::moves_count != 0);
    
    unsigned int total_count = move_copy_conting_class::moves_count + move_copy_conting_class::copy_count;
    move_copy_conting_class var;
    v1 = 0;
    move_copy_conting_class::moves_count = 0;
    move_copy_conting_class::copy_count = 0;
    v1 = var;
    // Assuring that move assignment operator moves/copyes value not more times than copy assignment operator
    BOOST_CHECK(total_count <= move_copy_conting_class::moves_count + move_copy_conting_class::copy_count);

    move_copy_conting_class::moves_count = 0;
    move_copy_conting_class::copy_count = 0;
    v2 = static_cast<variant_I_type&&>(v1);
    // Assuring that `move_copy_conting_class` in v1 was moved at least once and was not copied
    BOOST_CHECK(move_copy_conting_class::moves_count != 0);
    BOOST_CHECK(move_copy_conting_class::copy_count == 0);

    v1 = move_copy_conting_class();
    move_copy_conting_class::moves_count = 0;
    move_copy_conting_class::copy_count = 0;
    v2 = static_cast<variant_I_type&&>(v1);
    // Assuring that `move_copy_conting_class` in v1 was moved at least once and was not copied
    BOOST_CHECK(move_copy_conting_class::moves_count != 0);
    BOOST_CHECK(move_copy_conting_class::copy_count == 0);
    total_count = move_copy_conting_class::moves_count + move_copy_conting_class::copy_count;
    move_copy_conting_class::moves_count = 0;
    move_copy_conting_class::copy_count = 0;
    v1 = v2;
    // Assuring that move assignment operator moves/copyes value not more times than copy assignment operator
    BOOST_CHECK(total_count <= move_copy_conting_class::moves_count + move_copy_conting_class::copy_count);


    typedef boost::variant<move_copy_conting_class, int> variant_II_type;
    variant_II_type v3;
    move_copy_conting_class::moves_count = 0;
    move_copy_conting_class::copy_count = 0;
    v1 = static_cast<variant_II_type&&>(v3);
    // Assuring that `move_copy_conting_class` in v3 was moved at least once (v1 and v3 have different types)
    BOOST_CHECK(move_copy_conting_class::moves_count != 0);

    move_copy_conting_class::moves_count = 0;
    move_copy_conting_class::copy_count = 0;
    v2 = static_cast<variant_I_type&&>(v1);
    // Assuring that `move_copy_conting_class` in v1 was moved at least once (v1 and v3 have different types)
    BOOST_CHECK(move_copy_conting_class::moves_count != 0);

    move_copy_conting_class::moves_count = 0;
    move_copy_conting_class::copy_count = 0;
    variant_I_type v5(static_cast<variant_I_type&&>(v1));
    // Assuring that `move_copy_conting_class` in v1 was moved at least once and was not copied
    BOOST_CHECK(move_copy_conting_class::moves_count != 0);
    BOOST_CHECK(move_copy_conting_class::copy_count == 0);

    total_count = move_copy_conting_class::moves_count + move_copy_conting_class::copy_count;
    move_copy_conting_class::moves_count = 0;
    move_copy_conting_class::copy_count = 0;
    variant_I_type v6(v1);
    // Assuring that move constructor moves/copyes value not more times than copy constructor
    BOOST_CHECK(total_count <= move_copy_conting_class::moves_count + move_copy_conting_class::copy_count);
}

void run1()
{
    move_copy_conting_class::moves_count = 0;
    move_copy_conting_class::copy_count = 0;

    move_copy_conting_class c1;
    typedef boost::variant<int, move_copy_conting_class> variant_I_type;
    variant_I_type v1(static_cast<move_copy_conting_class&&>(c1));
    
    // Assuring that `move_copy_conting_class` was not copyied
    BOOST_CHECK(move_copy_conting_class::copy_count == 0);
    BOOST_CHECK(move_copy_conting_class::moves_count > 0);
}

struct move_only_structure {
    move_only_structure(){}
    move_only_structure(move_only_structure&&){}
    move_only_structure& operator=(move_only_structure&&) { return *this; }

private:
    move_only_structure(const move_only_structure&);
    move_only_structure& operator=(const move_only_structure&);
};

void run_move_only()
{
    move_only_structure mo;
    boost::variant<int, move_only_structure > vi, vi2(static_cast<move_only_structure&&>(mo));
    BOOST_CHECK(vi.which() == 0);
    BOOST_CHECK(vi2.which() == 1);

    vi = 10;
    vi2 = 10;
    BOOST_CHECK(vi.which() == 0);
    BOOST_CHECK(vi2.which() == 0);

    vi = static_cast<move_only_structure&&>(mo);
    vi2 = static_cast<move_only_structure&&>(mo);
    BOOST_CHECK(vi.which() == 1);
}

void run_moves_are_noexcept() {
#ifndef BOOST_NO_CXX11_NOEXCEPT
    typedef boost::variant<int, short, double> variant_noexcept_t;
    //BOOST_CHECK(boost::is_nothrow_move_assignable<variant_noexcept_t>::value);
    BOOST_CHECK(boost::is_nothrow_move_constructible<variant_noexcept_t>::value);

    typedef boost::variant<int, short, double, move_only_structure> variant_except_t;
    //BOOST_CHECK(!boost::is_nothrow_move_assignable<variant_except_t>::value);
    BOOST_CHECK(!boost::is_nothrow_move_constructible<variant_except_t>::value);
#endif
}

#endif

struct nothrow_copyable_throw_movable {
    nothrow_copyable_throw_movable(){}
    nothrow_copyable_throw_movable(const nothrow_copyable_throw_movable&) BOOST_NOEXCEPT {}
    nothrow_copyable_throw_movable& operator=(const nothrow_copyable_throw_movable&) BOOST_NOEXCEPT { return *this; }
#ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
    nothrow_copyable_throw_movable(nothrow_copyable_throw_movable&&) BOOST_NOEXCEPT_IF(false) {}
    nothrow_copyable_throw_movable& operator=(nothrow_copyable_throw_movable&&) BOOST_NOEXCEPT_IF(false) { return *this; }
#endif
};

// This test is created to cover the following situation:
// https://svn.boost.org/trac/boost/ticket/8772
void run_tricky_compilation_test()
{
    boost::variant<int, nothrow_copyable_throw_movable> v;
    v = nothrow_copyable_throw_movable();
}

int test_main(int , char* [])
{
   run();
   run1();
   run_move_only();
   run_moves_are_noexcept();
   run_tricky_compilation_test();
   return 0;
}