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// Copyright (C) 2022 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0
#include <QtCore/qxpfunctional.h>
#include <QTest>
#include <type_traits>
// checking dependency q20::remove_cvref_t:
#define CHECK(in, out) \
static_assert(std::is_same_v<q20::remove_cvref_t< in >, out >)
CHECK(int, int);
CHECK(const int, int);
CHECK(int &, int);
CHECK(const int &, int);
CHECK(int &&, int);
CHECK(const int &&, int);
CHECK(int *, int *);
CHECK(const int *, const int *);
CHECK(int[4], int[4]);
CHECK(const int (&)[4], int[4]);
#undef CHECK
template <typename T> constexpr inline bool
is_noexcept_function_ref_helper_v = false;
template <typename R, typename...Args> constexpr inline bool
is_noexcept_function_ref_helper_v<qxp::function_ref<R(Args...) noexcept(true)>> = true;
template <typename R, typename...Args> constexpr inline bool
is_noexcept_function_ref_helper_v<qxp::function_ref<R(Args...) const noexcept(true)>> = true;
template <typename T> constexpr inline bool
is_noexcept_function_ref_v = is_noexcept_function_ref_helper_v<q20::remove_cvref_t<T>>;
class tst_qxp_function_ref : public QObject
{
Q_OBJECT
public:
using QObject::QObject;
private Q_SLOTS:
void basics();
void constOverloads();
void constExpr();
void voidReturning();
void ctad();
};
void tst_qxp_function_ref::basics()
{
static_assert(std::is_trivially_copyable_v<qxp::function_ref<int(int)>>);
static_assert(std::is_trivially_copyable_v<qxp::function_ref<int()>>);
static_assert(std::is_trivially_copyable_v<qxp::function_ref<void()>>);
{
Q_CONSTINIT static int invoked = 0;
auto lambda = [](int i) noexcept { ++invoked; return i; };
const qxp::function_ref<int(int)> f = lambda;
QCOMPARE(invoked, 0);
QCOMPARE(f(42), 42);
QCOMPARE(invoked, 1);
const int fourtyTwo = 42;
const qxp::function_ref<int(int) noexcept> f2 = std::move(lambda);
QCOMPARE(invoked, 1);
QCOMPARE(f2(fourtyTwo), 42);
QCOMPARE(invoked, 2);
int (*fpr)(int) = lambda;
const qxp::function_ref f3 = fpr;
static_assert(!is_noexcept_function_ref_v<decltype(f3)>);
QCOMPARE(invoked, 2);
QCOMPARE(f3(42), 42);
QCOMPARE(invoked, 3);
int (*fpr2)(int) noexcept = lambda;
const qxp::function_ref f4 = fpr2;
static_assert(is_noexcept_function_ref_v<decltype(f4)>);
QCOMPARE(invoked, 3);
QCOMPARE(f4(42), 42);
QCOMPARE(invoked, 4);
}
{
Q_CONSTINIT static int invoked = 0;
auto lambda = [] { ++invoked; return 42; };
const qxp::function_ref<int()> f = lambda;
QCOMPARE(invoked, 0);
QCOMPARE(f(), 42);
QCOMPARE(invoked, 1);
const qxp::function_ref<int()> f2 = std::move(lambda);
QCOMPARE(invoked, 1);
QCOMPARE(f2(), 42);
QCOMPARE(invoked, 2);
int (*fpr)() = lambda;
const qxp::function_ref f3 = fpr;
static_assert(!is_noexcept_function_ref_v<decltype(f3)>);
QCOMPARE(invoked, 2);
QCOMPARE(f3(), 42);
QCOMPARE(invoked, 3);
}
{
Q_CONSTINIT static int invoked = 0;
auto lambda = [] { ++invoked; };
const qxp::function_ref<void()> f = lambda;
QCOMPARE(invoked, 0);
f();
QCOMPARE(invoked, 1);
const qxp::function_ref<void()> f2 = std::move(lambda);
QCOMPARE(invoked, 1);
f2();
QCOMPARE(invoked, 2);
void (*fpr)() = lambda;
const qxp::function_ref f3 = fpr;
QCOMPARE(invoked, 2);
f3();
QCOMPARE(invoked, 3);
}
}
void tst_qxp_function_ref::constOverloads()
{
auto func_c = [](qxp::function_ref<int() const> callable)
{
return callable();
};
auto func_m = [](qxp::function_ref<int() /*mutable*/> callable)
{
return callable();
};
struct S
{
int operator()() { return 1; }
int operator()() const { return 2; }
};
S s;
QCOMPARE(func_c(s), 2);
QCOMPARE(func_m(s), 1);
const S cs;
QCOMPARE(func_c(cs), 2);
#if 0
// this should not compile (and doesn't, but currently fails with an error in the impl,
// not by failing a constructor constaint → spec issue?).
QCOMPARE(func_m(cs), 2);
#endif
}
void tst_qxp_function_ref::constExpr()
{
Q_CONSTINIT static int invoked = 0;
{
Q_CONSTINIT static auto lambda = [] (int i) { ++invoked; return i; };
// the function object constructor is constexpr, so this should be constinit:
Q_CONSTINIT static qxp::function_ref<int(int)> f = lambda;
QCOMPARE(invoked, 0);
QCOMPARE(f(15), 15);
QCOMPARE(invoked, 1);
}
{
constexpr static auto lambda = [] (int i) { ++invoked; return i; };
// the function object constructor is constexpr, so this should be constinit:
Q_CONSTINIT static qxp::function_ref<int(int) const> f = lambda;
QCOMPARE(invoked, 1);
QCOMPARE(f(51), 51);
QCOMPARE(invoked, 2);
#if 0 // ### should this work?:
Q_CONSTINIT static qxp::function_ref<int(int)> f2 = lambda;
QCOMPARE(invoked, 2);
QCOMPARE(f(150), 150);
QCOMPARE(invoked, 3);
#endif
}
}
int i_f_i_nx(int i) noexcept { return i; }
void v_f_i_nx(int) noexcept {}
int i_f_v_nx() noexcept { return 42; }
void v_f_v_nx() noexcept {}
int i_f_i_ex(int i) { return i; }
void v_f_i_ex(int) {}
int i_f_v_ex() { return 42; }
void v_f_v_ex() {}
void tst_qxp_function_ref::voidReturning()
{
// check that "casting" int to void returns works:
using Fi = qxp::function_ref<void(int)>;
using Fv = qxp::function_ref<void()>;
{
Fi fi = i_f_i_nx;
fi(42);
Fv fv = i_f_v_nx;
fv();
}
{
Fi fi = i_f_i_ex;
fi(42);
Fv fv = i_f_v_ex;
fv();
}
// now with lambdas
bool ok = false; // prevent lambdas from decaying to function pointers
{
auto lambda1 = [&](int i) noexcept { return i + int(ok); };
Fi fi = lambda1;
fi(42);
auto lambda2 = [&]() noexcept { return int(ok); };
Fv fv = lambda2;
fv();
}
{
auto lambda1 = [&](int i) { return i + int(ok); };
Fi fi = lambda1;
fi(42);
auto lambda2 = [&]() { return int(ok); };
Fv fv = lambda2;
fv();
}
}
void tst_qxp_function_ref::ctad()
{
#define CHECK(fun, sig) \
do { \
qxp::function_ref f = fun; \
static_assert(std::is_same_v<decltype(f), \
qxp::function_ref<sig>>); \
qxp::function_ref f2 = &fun; \
static_assert(std::is_same_v<decltype(f2), \
qxp::function_ref<sig>>); \
} while (false)
CHECK(i_f_i_nx, int (int) noexcept);
CHECK(v_f_i_nx, void(int) noexcept);
CHECK(i_f_v_nx, int ( ) noexcept);
CHECK(v_f_v_nx, void( ) noexcept);
CHECK(i_f_i_ex, int (int));
CHECK(v_f_i_ex, void(int));
CHECK(i_f_v_ex, int ( ));
CHECK(v_f_v_ex, void( ));
#undef CHECK
#if 0 // no deduction guides for the non-function-pointer case, so no CTAD for lambdas
{
auto lambda = [](int i) -> int { return i; };
qxp::function_ref f = lambda;
static_assert(std::is_same_v<decltype(f),
qxp::function_ref<int(int)>>);
}
#endif
}
QTEST_APPLESS_MAIN(tst_qxp_function_ref);
#include "tst_qxp_function_ref.moc"
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