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#include "stdafx.h"
#include "../../relacy/relacy_std.hpp"
// THE TEST IS EXPECTED TO FAIL WITH "DEADLOCK"
class CondVar
{
public:
CondVar();
~CondVar();
void Enter();
void Wait();
void Release();
void ReleaseAll();
void Leave();
private:
std::atomic<int> m_lMutex;
std::atomic<unsigned> m_dwWaitingForSignal;
HANDLE m_xhEvtEnter;
HANDLE m_xhSemRelease;
};
CondVar::CondVar()
: m_xhEvtEnter(CreateEvent(0, 0, 0, 0))
, m_xhSemRelease(CreateSemaphore(0, 0, 0x7FFFFFFF, 0))
{
m_lMutex.store(0, std::memory_order_relaxed);
m_dwWaitingForSignal.store(0, std::memory_order_relaxed);
}
CondVar::~CondVar()
{
CloseHandle(m_xhEvtEnter);
CloseHandle(m_xhSemRelease);
}
void CondVar::Enter()
{
int lMutex = m_lMutex.load(std::memory_order_seq_cst);
for (;;)
{
if( lMutex >= 0 )
{
if (m_lMutex.compare_exchange_weak(lMutex, lMutex | 0x80000000u, std::memory_order_seq_cst))
break;
}
else
{
if (false == m_lMutex.compare_exchange_weak(lMutex, lMutex + 1, std::memory_order_seq_cst))
continue;
WaitForSingleObject(m_xhEvtEnter, INFINITE);
RL_ASSERT(m_lMutex.load(std::memory_order_seq_cst) < 0);
break;
}
}
}
void CondVar::Wait()
{
unsigned dwWaitingForSignal = m_dwWaitingForSignal.load(std::memory_order_seq_cst);
m_dwWaitingForSignal.store(dwWaitingForSignal + 1, std::memory_order_seq_cst);
RL_ASSERT(m_lMutex.load(std::memory_order_seq_cst) < 0);
int lMutex = m_lMutex.load(std::memory_order_seq_cst);
for (;;)
{
unsigned dwWaitingToOwn = lMutex & 0x7FFFFFFFu;
RL_ASSERT(dwWaitingToOwn >= dwWaitingForSignal);
if (dwWaitingToOwn == dwWaitingForSignal)
{
if (m_lMutex.compare_exchange_weak(lMutex, dwWaitingToOwn + 1, std::memory_order_seq_cst))
break;
}
else
{
SetEvent(m_xhEvtEnter);
break;
}
}
WaitForSingleObject(m_xhSemRelease, INFINITE);
WaitForSingleObject(m_xhEvtEnter, INFINITE);
RL_ASSERT(m_lMutex.load(std::memory_order_seq_cst) < 0);
}
void CondVar::Release()
{
RL_ASSERT(m_lMutex.load(std::memory_order_seq_cst) < 0);
unsigned dwWaitingForSignal = m_dwWaitingForSignal.load(std::memory_order_seq_cst);
if (dwWaitingForSignal != 0)
{
m_dwWaitingForSignal.store(dwWaitingForSignal - 1, std::memory_order_seq_cst);
ReleaseSemaphore(m_xhSemRelease, 1, 0);
}
}
void CondVar::ReleaseAll()
{
RL_ASSERT(m_lMutex.load(std::memory_order_seq_cst) < 0);
unsigned dwWaitingForSignal = m_dwWaitingForSignal.load(std::memory_order_seq_cst);
if (dwWaitingForSignal != 0)
{
m_dwWaitingForSignal.store(0, std::memory_order_seq_cst);
ReleaseSemaphore(m_xhSemRelease, dwWaitingForSignal, 0);
}
}
void CondVar::Leave()
{
int lMutex = m_lMutex.load(std::memory_order_seq_cst);
RL_ASSERT(lMutex < 0);
for (;;)
{
unsigned dwWaitingToOwn = lMutex & 0x7FFFFFFFu;
unsigned dwWaitingForSignal = m_dwWaitingForSignal.load(std::memory_order_seq_cst);
RL_ASSERT(dwWaitingToOwn >= dwWaitingForSignal);
if (dwWaitingToOwn == dwWaitingForSignal)
{
if (m_lMutex.compare_exchange_weak(lMutex, lMutex & 0x7FFFFFFF, std::memory_order_seq_cst))
break;
}
else
{
if (false == m_lMutex.compare_exchange_weak(lMutex, lMutex - 1, std::memory_order_seq_cst))
continue;
SetEvent(m_xhEvtEnter);
break;
}
}
}
struct CondVarTest : rl::test_suite<CondVarTest, 3>
{
VAR_T(int) stage;
CondVar cv;
void before()
{
VAR(stage) = 0;
}
void thread(unsigned index)
{
if (0 == index)
{
cv.Enter();
VAR(stage) += 1;
cv.ReleaseAll();
while (VAR(stage) != 2)
cv.Wait();
cv.Leave();
}
else if (1 == index)
{
cv.Enter();
while (VAR(stage) != 1)
cv.Wait();
VAR(stage) += 1;
cv.ReleaseAll();
cv.Leave();
}
else if (2 == index)
{
cv.Enter();
while (VAR(stage) != 2)
cv.Wait();
cv.Leave();
}
}
};
int main()
{
rl::simulate<CondVarTest>();
}
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