libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/swap.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 // <memory>
  10
  11 // shared_ptr
  12
  13 // void swap(shared_ptr& r);
  14
  15 #include <memory>
  16 #include <cassert>
  17
  18 #include "test_macros.h"
  19
  20 struct A
  21 {
  22     static int count;
  23
  24     A() {++count;}
  25     A(const A&) {++count;}
  26     ~A() {--count;}
  27 };
  28
  29 int A::count = 0;
  30
  31 int main(int, char**)
  32 {
  33     {
  34         A* ptr1 = new A;
  35         A* ptr2 = new A;
  36         std::shared_ptr<A> p1(ptr1);
  37         {
  38             std::shared_ptr<A> p2(ptr2);
  39             p1.swap(p2);
  40             assert(p1.use_count() == 1);
  41             assert(p1.get() == ptr2);
  42             assert(p2.use_count() == 1);
  43             assert(p2.get() == ptr1);
  44             assert(A::count == 2);
  45         }
  46         assert(p1.use_count() == 1);
  47         assert(p1.get() == ptr2);
  48         assert(A::count == 1);
  49     }
  50     assert(A::count == 0);
  51     {
  52         A* ptr1 = new A;
  53         A* ptr2 = 0;
  54         std::shared_ptr<A> p1(ptr1);
  55         {
  56             std::shared_ptr<A> p2;
  57             p1.swap(p2);
  58             assert(p1.use_count() == 0);
  59             assert(p1.get() == ptr2);
  60             assert(p2.use_count() == 1);
  61             assert(p2.get() == ptr1);
  62             assert(A::count == 1);
  63         }
  64         assert(p1.use_count() == 0);
  65         assert(p1.get() == ptr2);
  66         assert(A::count == 0);
  67     }
  68     assert(A::count == 0);
  69     {
  70         A* ptr1 = 0;
  71         A* ptr2 = new A;
  72         std::shared_ptr<A> p1;
  73         {
  74             std::shared_ptr<A> p2(ptr2);
  75             p1.swap(p2);
  76             assert(p1.use_count() == 1);
  77             assert(p1.get() == ptr2);
  78             assert(p2.use_count() == 0);
  79             assert(p2.get() == ptr1);
  80             assert(A::count == 1);
  81         }
  82         assert(p1.use_count() == 1);
  83         assert(p1.get() == ptr2);
  84         assert(A::count == 1);
  85     }
  86     assert(A::count == 0);
  87     {
  88         A* ptr1 = 0;
  89         A* ptr2 = 0;
  90         std::shared_ptr<A> p1;
  91         {
  92             std::shared_ptr<A> p2;
  93             p1.swap(p2);
  94             assert(p1.use_count() == 0);
  95             assert(p1.get() == ptr2);
  96             assert(p2.use_count() == 0);
  97             assert(p2.get() == ptr1);
  98             assert(A::count == 0);
  99         }
 100         assert(p1.use_count() == 0);
 101         assert(p1.get() == ptr2);
 102         assert(A::count == 0);
 103     }
 104     assert(A::count == 0);
 105
 106   return 0;
 107 }