libstdc++-v3/testsuite/30_threads/lock/4.cc

   1 // { dg-do run }
   2 // { dg-options "-pthread"  }
   3 // { dg-require-effective-target c++11 }
   4 // { dg-require-effective-target pthread }
   5 // { dg-require-gthreads "" }
   6
   7 // Copyright (C) 2010-2020 Free Software Foundation, Inc.
   8 //
   9 // This file is part of the GNU ISO C++ Library.  This library is free
  10 // software; you can redistribute it and/or modify it under the
  11 // terms of the GNU General Public License as published by the
  12 // Free Software Foundation; either version 3, or (at your option)
  13 // any later version.
  14
  15 // This library is distributed in the hope that it will be useful,
  16 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 // GNU General Public License for more details.
  19
  20 // You should have received a copy of the GNU General Public License along
  21 // with this library; see the file COPYING3.  If not see
  22 // <http://www.gnu.org/licenses/>.
  23
  24
  25 #include <mutex>
  26 #include <testsuite_hooks.h>
  27
  28 struct unreliable_lock
  29 {
  30   std::mutex m;
  31   std::unique_lock<std::mutex> l;
  32
  33   static int count;
  34   static int throw_on;
  35   static int lock_on;
  36
  37   unreliable_lock() : l(m, std::defer_lock) { }
  38
  39   ~unreliable_lock()
  40   {
  41     VERIFY( !l.owns_lock() );
  42   }
  43
  44   void lock()
  45   {
  46     if (count == throw_on)
  47       throw throw_on;
  48     ++count;
  49     l.lock();
  50   }
  51   bool try_lock()
  52   {
  53     if (count == throw_on)
  54       throw throw_on;
  55     std::unique_lock<std::mutex> l2(m, std::defer_lock);
  56     if (count == lock_on)
  57       l2.lock();
  58     ++count;
  59     return l.try_lock();
  60   }
  61
  62   void unlock()
  63   {
  64     VERIFY( l.owns_lock() );
  65     l.unlock();
  66   }
  67
  68 };
  69
  70 int unreliable_lock::count = 0;
  71 int unreliable_lock::throw_on = -1;
  72 int unreliable_lock::lock_on = -1;
  73
  74 void test01()
  75 {
  76   unreliable_lock l1, l2, l3;
  77
  78   try
  79     {
  80       unreliable_lock::count = 0;
  81       std::lock(l1, l2, l3);
  82       VERIFY( unreliable_lock::count == 3 );
  83       l1.unlock();
  84       l2.unlock();
  85       l3.unlock();
  86     }
  87   catch (...)
  88     {
  89       VERIFY( false );
  90     }
  91 }
  92
  93 void test02()
  94 {
  95   // test behaviour when a lock is already held
  96   try
  97     {
  98       unreliable_lock::lock_on = 1;
  99       while (unreliable_lock::lock_on < 3)
 100       {
 101         unreliable_lock::count = 0;
 102         unreliable_lock l1, l2, l3;
 103         std::lock(l1, l2, l3);
 104         VERIFY( unreliable_lock::count > 3 );
 105         l1.unlock();
 106         l2.unlock();
 107         l3.unlock();
 108         ++unreliable_lock::lock_on;
 109       }
 110     }
 111   catch (...)
 112     {
 113       VERIFY( false );
 114     }
 115 }
 116
 117 void test03()
 118 {
 119   // test behaviour when an exception is thrown
 120   unreliable_lock::throw_on = 0;
 121   while (unreliable_lock::throw_on < 3)
 122   {
 123     unreliable_lock::count = 0;
 124     unreliable_lock l1, l2, l3;
 125     bool test = false;
 126     try
 127       {
 128         std::lock(l1, l2, l3);
 129       }
 130     catch (...)
 131       {
 132         test = true;
 133       }
 134     VERIFY( test );
 135     ++unreliable_lock::throw_on;
 136   }
 137 }
 138
 139 int main()
 140 {
 141   test01();
 142   test02();
 143   test03();
 144   return 0;
 145 }