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      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "base/template_util.h"
      6 
      7 #include <string>
      8 
      9 #include "testing/gtest/include/gtest/gtest.h"
     10 
     11 namespace base {
     12 namespace {
     13 
     14 enum SimpleEnum { SIMPLE_ENUM };
     15 enum EnumWithExplicitType : uint64_t { ENUM_WITH_EXPLICIT_TYPE };
     16 enum class ScopedEnum { SCOPED_ENUM };
     17 enum class ScopedEnumWithOperator { SCOPED_ENUM_WITH_OPERATOR };
     18 std::ostream& operator<<(std::ostream& os, ScopedEnumWithOperator v) {
     19   return os;
     20 }
     21 struct SimpleStruct {};
     22 struct StructWithOperator {};
     23 std::ostream& operator<<(std::ostream& os, const StructWithOperator& v) {
     24   return os;
     25 }
     26 
     27 // is_non_const_reference<Type>
     28 static_assert(!is_non_const_reference<int>::value, "IsNonConstReference");
     29 static_assert(!is_non_const_reference<const int&>::value,
     30               "IsNonConstReference");
     31 static_assert(is_non_const_reference<int&>::value, "IsNonConstReference");
     32 
     33 class AssignParent {};
     34 class AssignChild : AssignParent {};
     35 
     36 // is_assignable<Type1, Type2>
     37 static_assert(!is_assignable<int, int>::value, "IsAssignable");  // 1 = 1;
     38 static_assert(!is_assignable<int, double>::value, "IsAssignable");
     39 static_assert(is_assignable<int&, int>::value, "IsAssignable");
     40 static_assert(is_assignable<int&, double>::value, "IsAssignable");
     41 static_assert(is_assignable<int&, int&>::value, "IsAssignable");
     42 static_assert(is_assignable<int&, int const&>::value, "IsAssignable");
     43 static_assert(!is_assignable<int const&, int>::value, "IsAssignable");
     44 static_assert(!is_assignable<AssignParent&, AssignChild>::value,
     45               "IsAssignable");
     46 static_assert(!is_assignable<AssignChild&, AssignParent>::value,
     47               "IsAssignable");
     48 
     49 struct AssignCopy {};
     50 struct AssignNoCopy {
     51   AssignNoCopy& operator=(AssignNoCopy&&) { return *this; }
     52   AssignNoCopy& operator=(const AssignNoCopy&) = delete;
     53 };
     54 struct AssignNoMove {
     55   AssignNoMove& operator=(AssignNoMove&&) = delete;
     56   AssignNoMove& operator=(const AssignNoMove&) = delete;
     57 };
     58 
     59 static_assert(is_copy_assignable<AssignCopy>::value, "IsCopyAssignable");
     60 static_assert(!is_copy_assignable<AssignNoCopy>::value, "IsCopyAssignable");
     61 
     62 static_assert(is_move_assignable<AssignCopy>::value, "IsMoveAssignable");
     63 static_assert(is_move_assignable<AssignNoCopy>::value, "IsMoveAssignable");
     64 static_assert(!is_move_assignable<AssignNoMove>::value, "IsMoveAssignable");
     65 
     66 // A few standard types that definitely support printing.
     67 static_assert(internal::SupportsOstreamOperator<int>::value,
     68               "ints should be printable");
     69 static_assert(internal::SupportsOstreamOperator<const char*>::value,
     70               "C strings should be printable");
     71 static_assert(internal::SupportsOstreamOperator<std::string>::value,
     72               "std::string should be printable");
     73 
     74 // Various kinds of enums operator<< support.
     75 static_assert(internal::SupportsOstreamOperator<SimpleEnum>::value,
     76               "simple enum should be printable by value");
     77 static_assert(internal::SupportsOstreamOperator<const SimpleEnum&>::value,
     78               "simple enum should be printable by const ref");
     79 static_assert(internal::SupportsOstreamOperator<EnumWithExplicitType>::value,
     80               "enum with explicit type should be printable by value");
     81 static_assert(
     82     internal::SupportsOstreamOperator<const EnumWithExplicitType&>::value,
     83     "enum with explicit type should be printable by const ref");
     84 static_assert(!internal::SupportsOstreamOperator<ScopedEnum>::value,
     85               "scoped enum should not be printable by value");
     86 static_assert(!internal::SupportsOstreamOperator<const ScopedEnum&>::value,
     87               "simple enum should not be printable by const ref");
     88 static_assert(internal::SupportsOstreamOperator<ScopedEnumWithOperator>::value,
     89               "scoped enum with operator<< should be printable by value");
     90 static_assert(
     91     internal::SupportsOstreamOperator<const ScopedEnumWithOperator&>::value,
     92     "scoped enum with operator<< should be printable by const ref");
     93 
     94 // operator<< support on structs.
     95 static_assert(!internal::SupportsOstreamOperator<SimpleStruct>::value,
     96               "simple struct should not be printable by value");
     97 static_assert(!internal::SupportsOstreamOperator<const SimpleStruct&>::value,
     98               "simple struct should not be printable by const ref");
     99 static_assert(internal::SupportsOstreamOperator<StructWithOperator>::value,
    100               "struct with operator<< should be printable by value");
    101 static_assert(
    102     internal::SupportsOstreamOperator<const StructWithOperator&>::value,
    103     "struct with operator<< should be printable by const ref");
    104 
    105 // underlying type of enums
    106 static_assert(std::is_integral<underlying_type<SimpleEnum>::type>::value,
    107               "simple enum must have some integral type");
    108 static_assert(
    109     std::is_same<underlying_type<EnumWithExplicitType>::type, uint64_t>::value,
    110     "explicit type must be detected");
    111 static_assert(std::is_same<underlying_type<ScopedEnum>::type, int>::value,
    112               "scoped enum defaults to int");
    113 
    114 struct TriviallyDestructible {
    115   int field;
    116 };
    117 
    118 class NonTriviallyDestructible {
    119   ~NonTriviallyDestructible() {}
    120 };
    121 
    122 static_assert(is_trivially_destructible<int>::value, "IsTriviallyDestructible");
    123 static_assert(is_trivially_destructible<TriviallyDestructible>::value,
    124               "IsTriviallyDestructible");
    125 static_assert(!is_trivially_destructible<NonTriviallyDestructible>::value,
    126               "IsTriviallyDestructible");
    127 
    128 }  // namespace
    129 }  // namespace base
    130