libcxx/test/std/utilities/utility/mem.res/mem.res.global/null_memory_resource.pass.cpp

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 // UNSUPPORTED: c++03, c++11, c++14
  10 // TODO: Change to XFAIL once https://github.com/llvm/llvm-project/issues/40340 is fixed
  11 // UNSUPPORTED: availability-pmr-missing
  12
  13 // <memory_resource>
  14
  15 // memory_resource *null_memory_resource()
  16
  17 #include <memory_resource>
  18 #include <cassert>
  19 #include <cstddef> // size_t
  20 #include <new>
  21 #include <type_traits>
  22
  23 #include "count_new.h"
  24 #include "test_macros.h"
  25
  26 struct assert_on_compare : public std::pmr::memory_resource {
  27   void* do_allocate(std::size_t, size_t) override {
  28     assert(false);
  29     return nullptr;
  30   }
  31
  32   void do_deallocate(void*, std::size_t, size_t) override { assert(false); }
  33
  34   bool do_is_equal(const std::pmr::memory_resource&) const noexcept override {
  35     assert(false);
  36     return true;
  37   }
  38 };
  39
  40 void test_return() {
  41   { ASSERT_SAME_TYPE(decltype(std::pmr::null_memory_resource()), std::pmr::memory_resource*); }
  42   // Test that the returned value is not null
  43   { assert(std::pmr::null_memory_resource()); }
  44   // Test the same value is returned by repeated calls.
  45   { assert(std::pmr::null_memory_resource() == std::pmr::null_memory_resource()); }
  46 }
  47
  48 void test_equality() {
  49   // Same object
  50   {
  51     std::pmr::memory_resource& r1 = *std::pmr::null_memory_resource();
  52     std::pmr::memory_resource& r2 = *std::pmr::null_memory_resource();
  53     // check both calls returned the same object
  54     assert(&r1 == &r2);
  55     // check for proper equality semantics
  56     assert(r1 == r2);
  57     assert(r2 == r1);
  58     assert(!(r1 != r2));
  59     assert(!(r2 != r1));
  60     // check the is_equal method
  61     assert(r1.is_equal(r2));
  62     assert(r2.is_equal(r1));
  63   }
  64   // Different types
  65   {
  66     std::pmr::memory_resource& r1 = *std::pmr::null_memory_resource();
  67     assert_on_compare c;
  68     std::pmr::memory_resource& r2 = c;
  69     assert(r1 != r2);
  70     assert(!(r1 == r2));
  71     assert(!r1.is_equal(r2));
  72   }
  73 }
  74
  75 void test_allocate() {
  76 #ifndef TEST_HAS_NO_EXCEPTIONS
  77   DisableAllocationGuard g; // null_memory_resource shouldn't allocate.
  78   try {
  79     (void)std::pmr::null_memory_resource()->allocate(1);
  80     assert(false);
  81   } catch (std::bad_alloc const&) {
  82     // do nothing
  83   } catch (...) {
  84     assert(false);
  85   }
  86 #endif
  87 }
  88
  89 void test_deallocate() {
  90   globalMemCounter.reset();
  91
  92   int x = 42;
  93   std::pmr::null_memory_resource()->deallocate(&x, 0);
  94
  95   assert(globalMemCounter.checkDeleteCalledEq(0));
  96   assert(globalMemCounter.checkDeleteArrayCalledEq(0));
  97 }
  98
  99 int main(int, char**) {
 100   test_return();
 101   test_equality();
 102   test_allocate();
 103   test_deallocate();
 104
 105   return 0;
 106 }