GSL/tests/notnull_tests.cpp

///////////////////////////////////////////////////////////////////////////////
//
// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
//
// This code is licensed under the MIT License (MIT).
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//
///////////////////////////////////////////////////////////////////////////////

#include <gtest/gtest.h>

#include <gsl/pointers> // for not_null, operator<, operator<=, operator>

#include <algorithm> // for addressof
#include <memory>    // for shared_ptr, make_shared, operator<, opera...
#include <sstream>   // for operator<<, ostringstream, basic_ostream:...
#include <stdint.h>  // for uint16_t
#include <string>    // for basic_string, operator==, string, operator<<
#include <typeinfo>  // for type_info

using namespace gsl;

namespace
{
static constexpr char deathstring[] = "Expected Death";
} //namespace

struct MyBase
{
};
struct MyDerived : public MyBase
{
};
struct Unrelated
{
};

// stand-in for a user-defined ref-counted class
template <typename T>
struct RefCounted
{
    RefCounted(T* p) : p_(p) {}
    operator T*() { return p_; }
    T* p_;
};

// user defined smart pointer with comparison operators returning non bool value
template <typename T>
struct CustomPtr
{
    CustomPtr(T* p) : p_(p) {}
    operator T*() { return p_; }
    bool operator!=(std::nullptr_t) const { return p_ != nullptr; }
    T* p_ = nullptr;
};

template <typename T, typename U>
std::string operator==(CustomPtr<T> const& lhs, CustomPtr<U> const& rhs)
{
    GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
    return reinterpret_cast<const void*>(lhs.p_) == reinterpret_cast<const void*>(rhs.p_) ? "true"
                                                                                          : "false";
}

template <typename T, typename U>
std::string operator!=(CustomPtr<T> const& lhs, CustomPtr<U> const& rhs)
{
    GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
    return reinterpret_cast<const void*>(lhs.p_) != reinterpret_cast<const void*>(rhs.p_) ? "true"
                                                                                          : "false";
}

template <typename T, typename U>
std::string operator<(CustomPtr<T> const& lhs, CustomPtr<U> const& rhs)
{
    GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
    return reinterpret_cast<const void*>(lhs.p_) < reinterpret_cast<const void*>(rhs.p_) ? "true"
                                                                                         : "false";
}

template <typename T, typename U>
std::string operator>(CustomPtr<T> const& lhs, CustomPtr<U> const& rhs)
{
    GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
    return reinterpret_cast<const void*>(lhs.p_) > reinterpret_cast<const void*>(rhs.p_) ? "true"
                                                                                         : "false";
}

template <typename T, typename U>
std::string operator<=(CustomPtr<T> const& lhs, CustomPtr<U> const& rhs)
{
    GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
    return reinterpret_cast<const void*>(lhs.p_) <= reinterpret_cast<const void*>(rhs.p_) ? "true"
                                                                                          : "false";
}

template <typename T, typename U>
std::string operator>=(CustomPtr<T> const& lhs, CustomPtr<U> const& rhs)
{
    GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
    return reinterpret_cast<const void*>(lhs.p_) >= reinterpret_cast<const void*>(rhs.p_) ? "true"
                                                                                          : "false";
}

struct NonCopyableNonMovable
{
    NonCopyableNonMovable() = default;
    NonCopyableNonMovable(const NonCopyableNonMovable&) = delete;
    NonCopyableNonMovable& operator=(const NonCopyableNonMovable&) = delete;
    NonCopyableNonMovable(NonCopyableNonMovable&&) = delete;
    NonCopyableNonMovable& operator=(NonCopyableNonMovable&&) = delete;
};

GSL_SUPPRESS(f.4) // NO-FORMAT: attribute
bool helper(not_null<int*> p) { return *p == 12; }
GSL_SUPPRESS(f.4) // NO-FORMAT: attribute
bool helper_const(not_null<const int*> p) { return *p == 12; }

int* return_pointer() { return nullptr; }

TEST(notnull_tests, TestNotNullConstructors)
{
    {
#ifdef CONFIRM_COMPILATION_ERRORS
        not_null<int*> p = nullptr;          // yay...does not compile!
        not_null<std::vector<char>*> p1 = 0; // yay...does not compile!
        not_null<int*> p2;                   // yay...does not compile!
        std::unique_ptr<int> up = std::make_unique<int>(120);
        not_null<int*> p3 = up;

        // Forbid non-nullptr assignable types
        not_null<std::vector<int>> f(std::vector<int>{1});
        not_null<int> z(10);
        not_null<std::vector<int>> y({1, 2});
#endif
    }

    std::set_terminate([] {
        std::cerr << "Expected Death. TestNotNullConstructors";
        std::abort();
    });
    {
        // from shared pointer
        int i = 12;
        auto rp = RefCounted<int>(&i);
        not_null<int*> p(rp);
        EXPECT_TRUE(p.get() == &i);

        not_null<std::shared_ptr<int>> x(
            std::make_shared<int>(10)); // shared_ptr<int> is nullptr assignable

        int* pi = nullptr;
        EXPECT_DEATH((not_null<decltype(pi)>(pi)), deathstring);
    }

    {
        // from pointer to local
        int t = 42;

        not_null<int*> x = &t;
        helper(&t);
        helper_const(&t);

        EXPECT_TRUE(*x == 42);
    }

    {
        // from raw pointer
        // from not_null pointer

        int t = 42;
        int* p = &t;

        not_null<int*> x = p;
        helper(p);
        helper_const(p);
        helper(x);
        helper_const(x);

        EXPECT_TRUE(*x == 42);
    }

    {
        // from raw const pointer
        // from not_null const pointer

        int t = 42;
        const int* cp = &t;

        not_null<const int*> x = cp;
        helper_const(cp);
        helper_const(x);

        EXPECT_TRUE(*x == 42);
    }

    {
        // from not_null const pointer, using auto
        int t = 42;
        const int* cp = &t;

        auto x = not_null<const int*>{cp};

        EXPECT_TRUE(*x == 42);
    }

    {
        // from returned pointer

        EXPECT_DEATH(helper(return_pointer()), deathstring);
        EXPECT_DEATH(helper_const(return_pointer()), deathstring);
    }
}

template <typename T>
void ostream_helper(T v)
{
    not_null<T*> p(&v);
    {
        std::ostringstream os;
        std::ostringstream ref;
        os << static_cast<void*>(p);
        ref << static_cast<void*>(&v);
        EXPECT_TRUE(os.str() == ref.str());
    }
    {
        std::ostringstream os;
        std::ostringstream ref;
        os << *p;
        ref << v;
        EXPECT_TRUE(os.str() == ref.str());
    }
}

TEST(notnull_tests, TestNotNullostream)
{
    ostream_helper<int>(17);
    ostream_helper<float>(21.5f);
    ostream_helper<double>(3.4566e-7);
    ostream_helper<char>('c');
    ostream_helper<uint16_t>(0x0123u);
    ostream_helper<const char*>("cstring");
    ostream_helper<std::string>("string");
}

TEST(notnull_tests, TestNotNullCasting)
{
    MyBase base;
    MyDerived derived;
    Unrelated unrelated;
    not_null<Unrelated*> u{&unrelated};
    (void) u;
    not_null<MyDerived*> p{&derived};
    not_null<MyBase*> q(&base);
    q = p; // allowed with heterogeneous copy ctor
    EXPECT_TRUE(q == p);

#ifdef CONFIRM_COMPILATION_ERRORS
    q = u; // no viable conversion possible between MyBase* and Unrelated*
    p = q; // not possible to implicitly convert MyBase* to MyDerived*

    not_null<Unrelated*> r = p;
    not_null<Unrelated*> s = reinterpret_cast<Unrelated*>(p);
#endif
    not_null<Unrelated*> t(reinterpret_cast<Unrelated*>(p.get()));
    EXPECT_TRUE(reinterpret_cast<void*>(p.get()) == reinterpret_cast<void*>(t.get()));
}

TEST(notnull_tests, TestNotNullAssignment)
{
    std::set_terminate([] {
        std::cerr << "Expected Death. TestNotNullAssignmentd";
        std::abort();
    });

    int i = 12;
    not_null<int*> p(&i);
    EXPECT_TRUE(helper(p));

    int* q = nullptr;
    EXPECT_DEATH(p = not_null<int*>(q), deathstring);
}

TEST(notnull_tests, TestNotNullRawPointerComparison)
{
    int ints[2] = {42, 43};
    int* p1 = &ints[0];
    const int* p2 = &ints[1];

    using NotNull1 = not_null<decltype(p1)>;
    using NotNull2 = not_null<decltype(p2)>;

    EXPECT_TRUE((NotNull1(p1) == NotNull1(p1)) == true);
    EXPECT_TRUE((NotNull1(p1) == NotNull2(p2)) == false);

    EXPECT_TRUE((NotNull1(p1) != NotNull1(p1)) == false);
    EXPECT_TRUE((NotNull1(p1) != NotNull2(p2)) == true);

    EXPECT_TRUE((NotNull1(p1) < NotNull1(p1)) == false);
    EXPECT_TRUE((NotNull1(p1) < NotNull2(p2)) == (p1 < p2));
    EXPECT_TRUE((NotNull2(p2) < NotNull1(p1)) == (p2 < p1));

    EXPECT_TRUE((NotNull1(p1) > NotNull1(p1)) == false);
    EXPECT_TRUE((NotNull1(p1) > NotNull2(p2)) == (p1 > p2));
    EXPECT_TRUE((NotNull2(p2) > NotNull1(p1)) == (p2 > p1));

    EXPECT_TRUE((NotNull1(p1) <= NotNull1(p1)) == true);
    EXPECT_TRUE((NotNull1(p1) <= NotNull2(p2)) == (p1 <= p2));
    EXPECT_TRUE((NotNull2(p2) <= NotNull1(p1)) == (p2 <= p1));
}

TEST(notnull_tests, TestNotNullDereferenceOperator)
{
    {
        auto sp1 = std::make_shared<NonCopyableNonMovable>();

        using NotNullSp1 = not_null<decltype(sp1)>;
        EXPECT_TRUE(typeid(*sp1) == typeid(*NotNullSp1(sp1)));
        EXPECT_TRUE(std::addressof(*NotNullSp1(sp1)) == std::addressof(*sp1));
    }

    {
        int ints[1] = {42};
        CustomPtr<int> p1(&ints[0]);

        using NotNull1 = not_null<decltype(p1)>;
        EXPECT_TRUE(typeid(*NotNull1(p1)) == typeid(*p1));
        EXPECT_TRUE(*NotNull1(p1) == 42);
        *NotNull1(p1) = 43;
        EXPECT_TRUE(ints[0] == 43);
    }

    {
        int v = 42;
        gsl::not_null<int*> p(&v);
        EXPECT_TRUE(typeid(*p) == typeid(*(&v)));
        *p = 43;
        EXPECT_TRUE(v == 43);
    }
}

TEST(notnull_tests, TestNotNullSharedPtrComparison)
{
    auto sp1 = std::make_shared<int>(42);
    auto sp2 = std::make_shared<const int>(43);

    using NotNullSp1 = not_null<decltype(sp1)>;
    using NotNullSp2 = not_null<decltype(sp2)>;

    EXPECT_TRUE((NotNullSp1(sp1) == NotNullSp1(sp1)) == true);
    EXPECT_TRUE((NotNullSp1(sp1) == NotNullSp2(sp2)) == false);

    EXPECT_TRUE((NotNullSp1(sp1) != NotNullSp1(sp1)) == false);
    EXPECT_TRUE((NotNullSp1(sp1) != NotNullSp2(sp2)) == true);

    EXPECT_TRUE((NotNullSp1(sp1) < NotNullSp1(sp1)) == false);
    EXPECT_TRUE((NotNullSp1(sp1) < NotNullSp2(sp2)) == (sp1 < sp2));
    EXPECT_TRUE((NotNullSp2(sp2) < NotNullSp1(sp1)) == (sp2 < sp1));

    EXPECT_TRUE((NotNullSp1(sp1) > NotNullSp1(sp1)) == false);
    EXPECT_TRUE((NotNullSp1(sp1) > NotNullSp2(sp2)) == (sp1 > sp2));
    EXPECT_TRUE((NotNullSp2(sp2) > NotNullSp1(sp1)) == (sp2 > sp1));

    EXPECT_TRUE((NotNullSp1(sp1) <= NotNullSp1(sp1)) == true);
    EXPECT_TRUE((NotNullSp1(sp1) <= NotNullSp2(sp2)) == (sp1 <= sp2));
    EXPECT_TRUE((NotNullSp2(sp2) <= NotNullSp1(sp1)) == (sp2 <= sp1));

    EXPECT_TRUE((NotNullSp1(sp1) >= NotNullSp1(sp1)) == true);
    EXPECT_TRUE((NotNullSp1(sp1) >= NotNullSp2(sp2)) == (sp1 >= sp2));
    EXPECT_TRUE((NotNullSp2(sp2) >= NotNullSp1(sp1)) == (sp2 >= sp1));
}

TEST(notnull_tests, TestNotNullCustomPtrComparison)
{
    int ints[2] = {42, 43};
    CustomPtr<int> p1(&ints[0]);
    CustomPtr<const int> p2(&ints[1]);

    using NotNull1 = not_null<decltype(p1)>;
    using NotNull2 = not_null<decltype(p2)>;

    EXPECT_TRUE((NotNull1(p1) == NotNull1(p1)) == "true");
    EXPECT_TRUE((NotNull1(p1) == NotNull2(p2)) == "false");

    EXPECT_TRUE((NotNull1(p1) != NotNull1(p1)) == "false");
    EXPECT_TRUE((NotNull1(p1) != NotNull2(p2)) == "true");

    EXPECT_TRUE((NotNull1(p1) < NotNull1(p1)) == "false");
    EXPECT_TRUE((NotNull1(p1) < NotNull2(p2)) == (p1 < p2));
    EXPECT_TRUE((NotNull2(p2) < NotNull1(p1)) == (p2 < p1));

    EXPECT_TRUE((NotNull1(p1) > NotNull1(p1)) == "false");
    EXPECT_TRUE((NotNull1(p1) > NotNull2(p2)) == (p1 > p2));
    EXPECT_TRUE((NotNull2(p2) > NotNull1(p1)) == (p2 > p1));

    EXPECT_TRUE((NotNull1(p1) <= NotNull1(p1)) == "true");
    EXPECT_TRUE((NotNull1(p1) <= NotNull2(p2)) == (p1 <= p2));
    EXPECT_TRUE((NotNull2(p2) <= NotNull1(p1)) == (p2 <= p1));

    EXPECT_TRUE((NotNull1(p1) >= NotNull1(p1)) == "true");
    EXPECT_TRUE((NotNull1(p1) >= NotNull2(p2)) == (p1 >= p2));
    EXPECT_TRUE((NotNull2(p2) >= NotNull1(p1)) == (p2 >= p1));
}

#if defined(__cplusplus) && (__cplusplus >= 201703L)

TEST(notnull_tests, TestNotNullConstructorTypeDeduction)
{
    {
        int i = 42;

        not_null x{&i};
        helper(not_null{&i});
        helper_const(not_null{&i});

        EXPECT_TRUE(*x == 42);
    }

    {
        int i = 42;
        int* p = &i;

        not_null x{p};
        helper(not_null{p});
        helper_const(not_null{p});

        EXPECT_TRUE(*x == 42);
    }

    std::set_terminate([] {
        std::cerr << "Expected Death. TestNotNullConstructorTypeDeduction";
        std::abort();
    });

    {
        auto workaround_macro = []() {
            int* p1 = nullptr;
            const not_null x{p1};
        };
        EXPECT_DEATH(workaround_macro(), deathstring);
    }

    {
        auto workaround_macro = []() {
            const int* p1 = nullptr;
            const not_null x{p1};
        };
        EXPECT_DEATH(workaround_macro(), deathstring);
    }

    {
        int* p = nullptr;

        EXPECT_DEATH(helper(not_null{p}), deathstring);
        EXPECT_DEATH(helper_const(not_null{p}), deathstring);
    }

#ifdef CONFIRM_COMPILATION_ERRORS
    {
        not_null x{nullptr};
        helper(not_null{nullptr});
        helper_const(not_null{nullptr});
    }
#endif
}
#endif // #if defined(__cplusplus) && (__cplusplus >= 201703L)

TEST(notnull_tests, TestMakeNotNull)
{
    {
        int i = 42;

        const auto x = make_not_null(&i);
        helper(make_not_null(&i));
        helper_const(make_not_null(&i));

        EXPECT_TRUE(*x == 42);
    }

    {
        int i = 42;
        int* p = &i;

        const auto x = make_not_null(p);
        helper(make_not_null(p));
        helper_const(make_not_null(p));

        EXPECT_TRUE(*x == 42);
    }

    std::set_terminate([] {
        std::cerr << "Expected Death. TestMakeNotNull";
        std::abort();
    });

    {
        const auto workaround_macro = []() {
            int* p1 = nullptr;
            const auto x = make_not_null(p1);
            EXPECT_TRUE(*x == 42);
        };
        EXPECT_DEATH(workaround_macro(), deathstring);
    }

    {
        const auto workaround_macro = []() {
            const int* p1 = nullptr;
            const auto x = make_not_null(p1);
            EXPECT_TRUE(*x == 42);
        };
        EXPECT_DEATH(workaround_macro(), deathstring);
    }

    {
        int* p = nullptr;

        EXPECT_DEATH(helper(make_not_null(p)), deathstring);
        EXPECT_DEATH(helper_const(make_not_null(p)), deathstring);
    }

#ifdef CONFIRM_COMPILATION_ERRORS
    {
        EXPECT_DEATH(make_not_null(nullptr), deathstring);
        EXPECT_DEATH(helper(make_not_null(nullptr)), deathstring);
        EXPECT_DEATH(helper_const(make_not_null(nullptr)), deathstring);
    }
#endif
}

TEST(notnull_tests, TestStdHash)
{
    int x = 42;
    int y = 99;
    not_null<int*> nn{&x};
    const not_null<int*> cnn{&x};

    std::hash<not_null<int*>> hash_nn;
    std::hash<int*> hash_intptr;

    EXPECT_TRUE(hash_nn(nn) == hash_intptr(&x));
    EXPECT_FALSE(hash_nn(nn) == hash_intptr(&y));
    EXPECT_FALSE(hash_nn(nn) == hash_intptr(nullptr));
}