folly/test/TraitsTest.cpp

   1 /*
   2  * Copyright 2016 Facebook, Inc.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *   http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #include <folly/Traits.h>
  18
  19 #include <gtest/gtest.h>
  20
  21 using namespace folly;
  22 using namespace std;
  23
  24 struct T1 {}; // old-style IsRelocatable, below
  25 struct T2 {}; // old-style IsRelocatable, below
  26 struct T3 { typedef std::true_type IsRelocatable; };
  27 struct T4 { typedef std::true_type IsTriviallyCopyable; };
  28 struct T5 : T3 {};
  29
  30 struct F1 {};
  31 struct F2 { typedef int IsRelocatable; };
  32 struct F3 : T3 { typedef std::false_type IsRelocatable; };
  33 struct F4 : T1 {};
  34
  35 namespace folly {
  36   template <> struct IsRelocatable<T1> : std::true_type {};
  37   template <> FOLLY_ASSUME_RELOCATABLE(T2);
  38 }
  39
  40 TEST(Traits, scalars) {
  41   EXPECT_TRUE(IsRelocatable<int>::value);
  42   EXPECT_TRUE(IsRelocatable<bool>::value);
  43   EXPECT_TRUE(IsRelocatable<double>::value);
  44   EXPECT_TRUE(IsRelocatable<void*>::value);
  45 }
  46
  47 TEST(Traits, containers) {
  48   EXPECT_TRUE  (IsRelocatable<vector<F1>>::value);
  49   EXPECT_FALSE((IsRelocatable<pair<F1, F1>>::value));
  50   EXPECT_TRUE ((IsRelocatable<pair<T1, T2>>::value));
  51 }
  52
  53 TEST(Traits, original) {
  54   EXPECT_TRUE(IsRelocatable<T1>::value);
  55   EXPECT_TRUE(IsRelocatable<T2>::value);
  56 }
  57
  58 TEST(Traits, typedefd) {
  59   EXPECT_TRUE (IsRelocatable<T3>::value);
  60   EXPECT_TRUE (IsRelocatable<T5>::value);
  61   EXPECT_FALSE(IsRelocatable<F2>::value);
  62   EXPECT_FALSE(IsRelocatable<F3>::value);
  63 }
  64
  65 TEST(Traits, unset) {
  66   EXPECT_FALSE(IsRelocatable<F1>::value);
  67   EXPECT_FALSE(IsRelocatable<F4>::value);
  68 }
  69
  70 TEST(Traits, bitprop) {
  71   EXPECT_TRUE(IsTriviallyCopyable<T4>::value);
  72   EXPECT_TRUE(IsRelocatable<T4>::value);
  73 }
  74
  75 TEST(Traits, bitAndInit) {
  76   EXPECT_TRUE (IsTriviallyCopyable<int>::value);
  77   EXPECT_FALSE(IsTriviallyCopyable<vector<int>>::value);
  78   EXPECT_TRUE (IsZeroInitializable<int>::value);
  79   EXPECT_FALSE(IsZeroInitializable<vector<int>>::value);
  80 }
  81
  82 TEST(Traits, is_negative) {
  83   EXPECT_TRUE(folly::is_negative(-1));
  84   EXPECT_FALSE(folly::is_negative(0));
  85   EXPECT_FALSE(folly::is_negative(1));
  86   EXPECT_FALSE(folly::is_negative(0u));
  87   EXPECT_FALSE(folly::is_negative(1u));
  88
  89   EXPECT_TRUE(folly::is_non_positive(-1));
  90   EXPECT_TRUE(folly::is_non_positive(0));
  91   EXPECT_FALSE(folly::is_non_positive(1));
  92   EXPECT_TRUE(folly::is_non_positive(0u));
  93   EXPECT_FALSE(folly::is_non_positive(1u));
  94 }
  95
  96 TEST(Traits, relational) {
  97   // We test, especially, the edge cases to make sure we don't
  98   // trip -Wtautological-comparisons
  99
 100   EXPECT_FALSE((folly::less_than<uint8_t, 0u,   uint8_t>(0u)));
 101   EXPECT_FALSE((folly::less_than<uint8_t, 0u,   uint8_t>(254u)));
 102   EXPECT_FALSE((folly::less_than<uint8_t, 255u, uint8_t>(255u)));
 103   EXPECT_TRUE( (folly::less_than<uint8_t, 255u, uint8_t>(254u)));
 104
 105   EXPECT_FALSE((folly::greater_than<uint8_t, 0u,   uint8_t>(0u)));
 106   EXPECT_TRUE( (folly::greater_than<uint8_t, 0u,   uint8_t>(254u)));
 107   EXPECT_FALSE((folly::greater_than<uint8_t, 255u, uint8_t>(255u)));
 108   EXPECT_FALSE((folly::greater_than<uint8_t, 255u, uint8_t>(254u)));
 109 }
 110
 111 struct membership_no {};
 112 struct membership_yes { using x = void; };
 113 FOLLY_CREATE_HAS_MEMBER_TYPE_TRAITS(has_member_type_x, x);
 114
 115 TEST(Traits, has_member_type) {
 116   EXPECT_FALSE(bool(has_member_type_x<membership_no>::value));
 117   EXPECT_TRUE(bool(has_member_type_x<membership_yes>::value));
 118 }