libc/test/src/__support/CPP/mutex_test.cpp

   1 //===-- Unittests for mutex -----------------------------------------------===//
   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 #include "src/__support/CPP/mutex.h"
  10 #include "test/UnitTest/Test.h"
  11
  12 using LIBC_NAMESPACE::cpp::adopt_lock;
  13 using LIBC_NAMESPACE::cpp::lock_guard;
  14
  15 // Simple struct for testing cpp::lock_guard. It defines methods 'lock' and
  16 // 'unlock' which are required for the cpp::lock_guard class template.
  17 struct Mutex {
  18   // Flag to show whether this mutex is locked.
  19   bool locked = false;
  20
  21   // Flag to show if this mutex has been double locked.
  22   bool double_locked = false;
  23
  24   // Flag to show if this mutex has been double unlocked.
  25   bool double_unlocked = false;
  26
  27   Mutex() {}
  28
  29   void lock() {
  30     if (locked)
  31       double_locked = true;
  32
  33     locked = true;
  34   }
  35
  36   void unlock() {
  37     if (!locked)
  38       double_unlocked = true;
  39
  40     locked = false;
  41   }
  42 };
  43
  44 TEST(LlvmLibcMutexTest, Basic) {
  45   Mutex m;
  46   ASSERT_FALSE(m.locked);
  47   ASSERT_FALSE(m.double_locked);
  48   ASSERT_FALSE(m.double_unlocked);
  49
  50   {
  51     lock_guard lg(m);
  52     ASSERT_TRUE(m.locked);
  53     ASSERT_FALSE(m.double_locked);
  54   }
  55
  56   ASSERT_FALSE(m.locked);
  57   ASSERT_FALSE(m.double_unlocked);
  58 }
  59
  60 TEST(LlvmLibcMutexTest, AcquireLocked) {
  61   Mutex m;
  62   ASSERT_FALSE(m.locked);
  63   ASSERT_FALSE(m.double_locked);
  64   ASSERT_FALSE(m.double_unlocked);
  65
  66   // Lock the mutex before placing a lock guard on it.
  67   m.lock();
  68   ASSERT_TRUE(m.locked);
  69   ASSERT_FALSE(m.double_locked);
  70
  71   {
  72     lock_guard lg(m, adopt_lock);
  73     ASSERT_TRUE(m.locked);
  74     ASSERT_FALSE(m.double_locked);
  75   }
  76
  77   ASSERT_FALSE(m.locked);
  78   ASSERT_FALSE(m.double_unlocked);
  79 }