gecko/mfbt/tests/TestTypeTraits.cpp

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "mozilla/Assertions.h"
#include "mozilla/TypeTraits.h"
using mozilla::IsBaseOf;
using mozilla::IsConvertible;
namespace CPlusPlus11IsBaseOf {
// Adapted from C++11 ยง 20.9.6.
struct B {};
struct B1 : B {};
struct B2 : B {};
struct D : private B1, private B2 {};
static void
StandardIsBaseOfTests()
{
MOZ_ASSERT((IsBaseOf<B, D>::value) == true);
MOZ_ASSERT((IsBaseOf<const B, D>::value) == true);
MOZ_ASSERT((IsBaseOf<B, const D>::value) == true);
MOZ_ASSERT((IsBaseOf<B, const B>::value) == true);
MOZ_ASSERT((IsBaseOf<D, B>::value) == false);
MOZ_ASSERT((IsBaseOf<B&, D&>::value) == false);
MOZ_ASSERT((IsBaseOf<B[3], D[3]>::value) == false);
// We fail at the following test. To fix it, we need to specialize IsBaseOf
// for all built-in types.
// MOZ_ASSERT((IsBaseOf<int, int>::value) == false);
}
} /* namespace CPlusPlus11IsBaseOf */
class A { };
class B : public A { };
class C : private A { };
class D { };
class E : public A { };
class F : public B, public E { };
static void
TestIsBaseOf()
{
MOZ_ASSERT((IsBaseOf<A, B>::value),
"A is a base of B");
MOZ_ASSERT((!IsBaseOf<B, A>::value),
"B is not a base of A");
MOZ_ASSERT((IsBaseOf<A, C>::value),
"A is a base of C");
MOZ_ASSERT((!IsBaseOf<C, A>::value),
"C is not a base of A");
MOZ_ASSERT((IsBaseOf<A, F>::value),
"A is a base of F");
MOZ_ASSERT((!IsBaseOf<F, A>::value),
"F is not a base of A");
MOZ_ASSERT((!IsBaseOf<A, D>::value),
"A is not a base of D");
MOZ_ASSERT((!IsBaseOf<D, A>::value),
"D is not a base of A");
MOZ_ASSERT((IsBaseOf<B, B>::value),
"B is the same as B (and therefore, a base of B)");
}
static void
TestIsConvertible()
{
// Pointer type convertibility
MOZ_ASSERT((IsConvertible<A*, A*>::value),
"A* should convert to A*");
MOZ_ASSERT((IsConvertible<B*, A*>::value),
"B* should convert to A*");
MOZ_ASSERT((!IsConvertible<A*, B*>::value),
"A* shouldn't convert to B*");
MOZ_ASSERT((!IsConvertible<A*, C*>::value),
"A* shouldn't convert to C*");
MOZ_ASSERT((!IsConvertible<A*, D*>::value),
"A* shouldn't convert to unrelated D*");
MOZ_ASSERT((!IsConvertible<D*, A*>::value),
"D* shouldn't convert to unrelated A*");
// Instance type convertibility
MOZ_ASSERT((IsConvertible<A, A>::value),
"A is A");
MOZ_ASSERT((IsConvertible<B, A>::value),
"B converts to A");
MOZ_ASSERT((!IsConvertible<D, A>::value),
"D and A are unrelated");
MOZ_ASSERT((!IsConvertible<A, D>::value),
"A and D are unrelated");
// These cases seem to require C++11 support to properly implement them, so
// for now just disable them.
//MOZ_ASSERT((!IsConvertible<C*, A*>::value),
// "C* shouldn't convert to A* (private inheritance)");
//MOZ_ASSERT((!IsConvertible<C, A>::value),
// "C doesn't convert to A (private inheritance)");
}
int
main()
{
CPlusPlus11IsBaseOf::StandardIsBaseOfTests();
TestIsBaseOf();
TestIsConvertible();
}