gcc/libstdc++-v3/testsuite/20_util/function_ref/conv.cc

294 lines
8.3 KiB
C++

// { dg-do run { target c++26 } }
// { dg-require-effective-target hosted }
#include <functional>
#include <string_view>
#include <testsuite_hooks.h>
using std::function_ref;
static_assert( std::is_constructible_v<std::function_ref<void() const>,
std::function_ref<void()>> );
// Non-trivial args, guarantess that type is not passed by copy
struct CountedArg
{
CountedArg() = default;
CountedArg(const CountedArg& f) noexcept : counter(f.counter) { ++counter; }
CountedArg& operator=(CountedArg&&) = delete;
int counter = 0;
};
CountedArg const c;
using FuncType = int(int);
// Top level const qualifiers are ignored in function types, and decay
// is performed.
static_assert( std::is_same_v<std::function_ref<void(int const)>,
std::function_ref<void(int)>> );
static_assert( std::is_same_v<std::function_ref<void(int[2])>,
std::function_ref<void(int*)>>);
static_assert( std::is_same_v<std::function_ref<void(int[])>,
std::function_ref<void(int*)>>);
static_assert( std::is_same_v<std::function_ref<void(int const[5])>,
std::function_ref<void(int const*)>>);
static_assert( std::is_same_v<std::function_ref<void(FuncType)>,
std::function_ref<void(FuncType*)>>);
// The C++26 [func.wrap.general] p2 does not currently cover funciton_ref,
// so we make extra copies of arguments.
void
test01()
{
auto f = [](CountedArg const& arg) noexcept { return arg.counter; };
std::function_ref<int(CountedArg) const noexcept> r1(f);
std::move_only_function<int(CountedArg) const noexcept> m1(f);
std::copyable_function<int(CountedArg) const noexcept> c1(f);
// Complatible signatures
std::function_ref<int(CountedArg) const noexcept> r2m(m1);
VERIFY( r2m(c) == 2 );
std::function_ref<int(CountedArg) const noexcept> r2c(c1);
VERIFY( r2c(c) == 2 );
std::function_ref<int(CountedArg) const> r3r(r1);
VERIFY( r3r(c) == 2 );
std::function_ref<int(CountedArg) const> r3m(m1);
VERIFY( r3m(c) == 2 );
std::function_ref<int(CountedArg) const> r3c(c1);
VERIFY( r3c(c) == 2 );
std::function_ref<int(CountedArg)> r4r(r1);
VERIFY( r4r(c) == 2 );
std::function_ref<int(CountedArg)> r4m(m1);
VERIFY( r4m(c) == 2 );
std::function_ref<int(CountedArg)> r4c(c1);
VERIFY( r4c(c) == 2 );
// Incompatible signatures
std::function_ref<long(CountedArg) const noexcept> r5r(r1);
VERIFY( r5r(c) == 2 );
std::function_ref<long(CountedArg) const noexcept> r5m(m1);
VERIFY( r5r(c) == 2 );
std::function_ref<long(CountedArg) const noexcept> r5c(c1);
VERIFY( r5r(c) == 2 );
}
void
test02()
{
// Constructing move_only_function and copyable_function from function_ref,
// have not chance to restore manager, so we store function_ref inside.
auto f = [](CountedArg const& arg) noexcept { return arg.counter; };
std::function_ref<int(CountedArg) const noexcept> r1(f);
std::move_only_function<int(CountedArg) const noexcept> m1(r1);
VERIFY( m1(c) == 2 );
std::copyable_function<int(CountedArg) const noexcept> c1(r1);
VERIFY( c1(c) == 2 );
}
void
test03()
{
struct F
{
int operator()(CountedArg const& arg) noexcept
{ return arg.counter; }
int operator()(CountedArg const& arg) const noexcept
{ return arg.counter + 1000; }
};
F f;
std::function_ref<int(CountedArg) const> r1(f);
VERIFY( r1(c) == 1001 );
// Call const overload as std::function_ref<int(CountedArg) const>
// inside std::function_ref<int(CountedArg)> would do.
std::function_ref<int(CountedArg)> r2(r1);
VERIFY( r2(c) == 1002 );
std::move_only_function<int(CountedArg)> m2(r1);
VERIFY( m2(c) == 1002 );
// Call non-const overload as const-qualifed operator() for
// std::function_ref<int(CountedArg)> do.
std::function_ref<int(CountedArg)> r3(f);
VERIFY( r3(c) == 1 );
std::function_ref<int(CountedArg) const> r4(r3);
VERIFY( r4(c) == 2 );
std::move_only_function<int(CountedArg) const> m4(r3);
VERIFY( m4(c) == 2 );
}
void
test04()
{
auto f = [](CountedArg const& arg) noexcept { return arg.counter; };
std::function_ref<int(CountedArg)> w1(f);
// function_ref stores function_ref due incompatibile signatures
std::function_ref<int(CountedArg const&)> w2(std::move(w1));
// copy is made when passing to int(CountedArg)
VERIFY( w2(c) == 1 );
// wrapped 3 times
std::function_ref<int(CountedArg)> w3(w2);
VERIFY( w3(c) == 2 );
// wrapped 4 times
std::function_ref<int(CountedArg const&)> w4(w3);
VERIFY( w4(c) == 2 );
// wrapped 5 times
std::function_ref<int(CountedArg)> w5(w4);
VERIFY( w5(c) == 3 );
}
void
test05()
{
// No special interoperability with std::function
auto f = [](CountedArg const& arg) noexcept { return arg.counter; };
std::function<int(CountedArg)> f1(f);
std::function_ref<int(CountedArg) const> c1(std::move(f1));
VERIFY( c1(c) == 2 );
std::function_ref<int(CountedArg) const> c2(f);
std::function<int(CountedArg)> f2(c2);
VERIFY( f2(c) == 2 );
}
void
test06()
{
auto* func = +[]{ static int x; return &x; };
std::move_only_function<const void*() const> m1(func);
std::function_ref<const void*() const> rm1(m1);
VERIFY( m1() == rm1() );
std::copyable_function<const void*() const> c1(func);
std::function_ref<const void*() const> rc1(c1);
VERIFY( c1() == rc1() );
struct Trivial
{
void const* operator()() const
{ return this; }
};
std::move_only_function<const void*() const> m2(Trivial{});
std::function_ref<const void*() const> rm2(m2);
VERIFY( m2() == rm2() );
std::copyable_function<const void*() const> c2(Trivial{});
std::function_ref<const void*() const> rc2(c2);
VERIFY( c2() == rc2() );
struct NonTrivial : Trivial
{
NonTrivial() {}
NonTrivial(NonTrivial&&) noexcept {}
NonTrivial(const NonTrivial&) {}
};
std::move_only_function<const void*() const> m3(NonTrivial{});
std::function_ref<const void*() const> rm3(m3);
VERIFY( m3() == rm3() );
std::copyable_function<const void*() const> c3(NonTrivial{});
std::function_ref<const void*() const> rc3(c3);
VERIFY( c3() == rc3() );
struct Large : Trivial
{
int tab[10];
};
std::move_only_function<const void*() const> m4(Large{});
std::function_ref<const void*() const> rm4(m4);
VERIFY( m4() == rm4() );
std::copyable_function<const void*() const> c4(Large{});
std::function_ref<const void*() const> rc4(c4);
VERIFY( c4() == rc4() );
}
void
test07()
{
int (*f1)() = [] { return 1; };
int (*f2)() = [] { return 2; };
std::function_ref<int() const> r1(f1);
std::move_only_function<int() const> m1(f1);
std::copyable_function<int() const> c1(f1);
std::function_ref<int() const> r2r(r1);
VERIFY( r2r() == 1 );
r1 = f2;
VERIFY( r2r() == 1 ); // same-siganture, copy constructor is used
std::function_ref<int() const> r2m(m1);
VERIFY( r2m() == 1 );
m1 = f2;
VERIFY( r2m() == 2 );
std::function_ref<int() const> r2c(c1);
VERIFY( r2c() == 1 );
c1 = f2;
VERIFY( r2c() == 2 );
std::function_ref<int()> r3r(r1);
VERIFY( r3r() == 2 );
r1 = f1;
VERIFY( r3r() == 1 ); // converting-constructor
std::function_ref<int()> r3m(m1);
VERIFY( r3m() == 2 );
m1 = f1;
VERIFY( r3m() == 1 );
std::function_ref<int()> r3c(c1);
VERIFY( r3c() == 2 );
c1 = f1;
VERIFY( r3c() == 1 );
}
constexpr bool
test08()
{
auto f = [](int x) noexcept { return x; };
std::function_ref<int(int) const noexcept> rf(f);
std::function_ref<int(int) const noexcept> rr1(rf);
std::function_ref<int(int)> rr2(rf);
std::function_ref<int(long)> rr3(rf);
return true;
};
void
test09()
{
// Scalar types and small trivially move constructible types are passed
// by value to invoker. So int&& signature is not compatible for such types.
auto fi = [](CountedArg const& arg, int) noexcept { return arg.counter; };
std::function_ref<int(CountedArg, int) const noexcept> ri1(fi);
VERIFY( ri1(c, 0) == 1 );
std::function_ref<int(CountedArg, int&&) const noexcept> ri2(ri1);
VERIFY( ri2(c, 0) == 2 );
auto fs = [](CountedArg const& arg, std::string_view) noexcept { return arg.counter; };
std::function_ref<int(CountedArg, std::string_view) const noexcept> rs1(fs);
VERIFY( rs1(c, "") == 1 );
std::function_ref<int(CountedArg, std::string_view&&) const noexcept> rs2(rs1);
VERIFY( rs2(c, "") == 2 );
}
int main()
{
test01();
test02();
test03();
test04();
test05();
test06();
test07();
test09();
static_assert( test08() );
}