//- This test should not be ran with the current bit values used by the Locksmith class
// I believe it's rather unlikely you want to try to start a quarter million threads
// I usually run this test with the max reader count set to 2047.
// I'll have to make a test that creates a fake lock state so that we can test the new max.
//[Test, Order(3)]
public void Locksmith_WhileNotWriteLocked_AllowsMaxConcurrentReadersToEnter()
{
int numberOfThreadsToCreate = Locksmith.MaxNumberOfActiveReaders;
int numberOfReads = 0;
CountdownEvent readersEnteredEvent = new CountdownEvent(numberOfThreadsToCreate);
ManualResetEvent lockTestedEvent = new ManualResetEvent(false);
for (int i = 0; i < numberOfThreadsToCreate; i++)
{
StartNewThreadThatRuns(IncrementNumReadsInsideReadLock);
}
readersEnteredEvent.Wait();
Assert.That(numberOfReads, Is.EqualTo(numberOfThreadsToCreate));
Assert.That(lockState.NumberOfActiveReaders(), Is.EqualTo(Locksmith.MaxNumberOfActiveReaders));
lockTestedEvent.Set();
return;
void IncrementNumReadsInsideReadLock()
{
Locksmith.EnterReadLock(ref lockState, readLockTestObject);
{
Interlocked.Increment(ref numberOfReads);
readersEnteredEvent.Signal();
lockTestedEvent.WaitOne();
}
Locksmith.ExitReadLock(ref lockState, readLockTestObject, writeLockTestObject);
}
}
public void Locksmith_WhenReadLockReleased_ReleasesAWaitingWriterIfPresent()
{
const int initialValue = 10;
const int successValue = 25;
int writeResult = initialValue;
ManualResetEvent writerExitedEvent = new ManualResetEvent(false);
Locksmith.EnterReadLock(ref lockState, readLockTestObject);
{
StartNewThreadThatRuns(SetWriteResultToFailureValue);
Thread.Sleep(50);
Assert.That(WritersAreWaiting);
Assert.That(writeResult, Is.EqualTo(initialValue));
}
Locksmith.ExitReadLock(ref lockState, readLockTestObject, writeLockTestObject);
writerExitedEvent.WaitOne();
Assert.That(writeResult, Is.EqualTo(successValue));
return;
void SetWriteResultToFailureValue()
{
Locksmith.EnterWriteLock(ref lockState, writeLockTestObject);
{
writeResult = successValue;
}
Locksmith.ExitWriteLock(ref lockState, readLockTestObject, writeLockTestObject);
writerExitedEvent.Set();
}
}
public void Locksmith_WhenReadLockIsUpgradedWithOnlyOneReader_PreventsNewReadersFromEntering()
{
const int failureValue = 25;
const int expectedValue = 10;
int result = expectedValue;
Locksmith.EnterReadLock(ref lockState, readLockTestObject);
Locksmith.Upgrade(ref lockState, writeLockTestObject);
{
StartNewThreadThatRuns(SetReadResultToFailureValue);
Thread.Sleep(1000);
Assert.That(result, Is.EqualTo(expectedValue));
}
Locksmith.ExitWriteLock(ref lockState, readLockTestObject, writeLockTestObject);
return;
void SetReadResultToFailureValue()
{
Locksmith.EnterReadLock(ref lockState, readLockTestObject);
result = failureValue;
Locksmith.ExitReadLock(ref lockState, readLockTestObject, writeLockTestObject);
}
}
public void Locksmith_WhenWriteLockIsDowngraded_AllowsNewReadersToEnter()
{
const int successValue = 25;
const int initialValue = 10;
int readResult = initialValue;
ManualResetEvent readerFinishedEvent = new ManualResetEvent(false);
Locksmith.EnterWriteLock(ref lockState, writeLockTestObject);
Locksmith.Downgrade(ref lockState, readLockTestObject);
{
StartNewThreadThatRuns(SetReadResultToFailureValue);
readerFinishedEvent.WaitOne();
Assert.That(readResult, Is.EqualTo(successValue));
}
Locksmith.ExitReadLock(ref lockState, readLockTestObject, writeLockTestObject);
return;
void SetReadResultToFailureValue()
{
Locksmith.EnterReadLock(ref lockState, readLockTestObject);
{
readResult = successValue;
}
Locksmith.ExitReadLock(ref lockState, readLockTestObject, writeLockTestObject);
readerFinishedEvent.Set();
}
}
public void Locksmith_WhenWriteLockReleased_ReleasesAWaitingReaderIfPresent()
{
const int initialValue = 10;
const int expectedValue = 42;
int readResult = initialValue;
ManualResetEvent readerExitedEvent = new ManualResetEvent(false);
Locksmith.EnterWriteLock(ref lockState, writeLockTestObject);
{
StartNewThreadThatRuns(SetReadResultToExpectedValue);
Thread.Sleep(100);
Assert.That(ReadersAreWaiting);
Assert.That(readResult, Is.EqualTo(initialValue));
}
Locksmith.ExitWriteLock(ref lockState, readLockTestObject, writeLockTestObject);
//- This should be more than enough time for the other thread to wake up and set the value.
readerExitedEvent.WaitOne();
Assert.That(readResult, Is.EqualTo(expectedValue));
return;
void SetReadResultToExpectedValue()
{
Locksmith.EnterReadLock(ref lockState, readLockTestObject);
{
readResult = expectedValue;
}
Locksmith.ExitReadLock(ref lockState, readLockTestObject, writeLockTestObject);
readerExitedEvent.Set();
}
}
public void Locksmith_WhenWriteLockReleased_ReleasesAllWaitingReaders()
{
int numberOfThreadsToCreate = 100;
int numberOfReads = 0;
CountdownEvent readersExitedEvent = new CountdownEvent(numberOfThreadsToCreate);
Locksmith.EnterWriteLock(ref lockState, writeLockTestObject);
{
for (int i = 0; i < numberOfThreadsToCreate; i++)
{
StartNewThreadThatRuns(IncrementNumReadsInsideReadLock);
}
Thread.Sleep(1000);
Assert.That(numberOfReads, Is.EqualTo(0));
}
Locksmith.ExitWriteLock(ref lockState, readLockTestObject, writeLockTestObject);
readersExitedEvent.Wait();
Assert.That(numberOfReads, Is.EqualTo(numberOfThreadsToCreate));
return;
void IncrementNumReadsInsideReadLock()
{
Locksmith.EnterReadLock(ref lockState, readLockTestObject);
{
Interlocked.Increment(ref numberOfReads);
}
Locksmith.ExitReadLock(ref lockState, readLockTestObject, writeLockTestObject);
readersExitedEvent.Signal();
}
}
public void Locksmith_WhenReadLockedAndReservedForWriter_CausesNewReadersToWait()
{
const int initialValue = 10;
const int valueAddedByReader = 50;
const int valueAddedByWriter = 20;
int result = initialValue;
CountdownEvent exitedLocksEvent = new CountdownEvent(2);
Locksmith.EnterReadLock(ref lockState, readLockTestObject);
{
StartNewThreadThatRuns(AddWriterValue);
Thread.Sleep(300);
StartNewThreadThatRuns(AddReaderValue);
Thread.Sleep(300);
Assert.That(result, Is.EqualTo(initialValue));
Assert.That(lockState.IsReservedForWriter());
Assert.That(lockState.HasWaitingReaders());
}
Locksmith.ExitReadLock(ref lockState, readLockTestObject, writeLockTestObject);
exitedLocksEvent.Wait();
return;
void AddReaderValue()
{
Locksmith.EnterReadLock(ref lockState, readLockTestObject); //- You passed the wrong object ya dolt...
{
int currentResult;
int valueToSet;
do
{
currentResult = result;
valueToSet = currentResult + valueAddedByReader;
} while (Interlocked.CompareExchange(ref result, valueToSet, currentResult) != currentResult);
}
Locksmith.ExitReadLock(ref lockState, readLockTestObject, writeLockTestObject);
exitedLocksEvent.Signal();
}
void AddWriterValue()
{
Locksmith.EnterWriteLock(ref lockState, writeLockTestObject);
{
int currentResult, valueToSet;
do
{
currentResult = result;
valueToSet = currentResult + valueAddedByWriter;
}while (Interlocked.CompareExchange(ref result, valueToSet, currentResult) != currentResult);
}
Locksmith.ExitWriteLock(ref lockState, readLockTestObject, writeLockTestObject);
exitedLocksEvent.Signal();
}
}
//- This test should not be ran with the current bit values used by the Locksmith class
// I believe it's rather unlikely you want to try to start a quarter million threads
// I usually run this test with the max reader count set to 2047.
// I'll have to make a test that creates a fake lock state so that we can test the new max.
//[Test, Order(4), ]
public void Locksmith_WhenReadLockedAndAtMaxActiveReaders_CausesNewReadersToWait()
{
//- Since we need all of the reader slots in order to run this test, we'll use a separate
// set of objects than the rest.
int methodsLockState = 0;
object methodsReadLockObject = new object();
object methodsWriteLockObject = new object();
int numberOfThreadsToCreate = Locksmith.MaxNumberOfActiveReaders - 1;
int numberOfIncrementingThreads = numberOfThreadsToCreate + 1;
int numberOfReads = 0;
Barrier barrierToKeepReadersInLock = new Barrier(numberOfIncrementingThreads);
Locksmith.EnterReadLock(ref methodsLockState, methodsReadLockObject);
{
for (int i = 0; i < numberOfThreadsToCreate; i++)
{
StartNewThreadThatRuns(IncrementNumReadsInsideReadLock);
}
Thread.Sleep(200);
Assert.AreEqual(numberOfReads, numberOfThreadsToCreate);
Assert.AreEqual(Locksmith.NumberOfActiveReaders(methodsLockState), Locksmith.MaxNumberOfActiveReaders);
Thread setValueThread = new Thread(IncrementNumReadsInsideReadLock)
{
IsBackground = false
};
setValueThread.Start();
Thread.Sleep(200);
while (true)
{
if ((setValueThread.ThreadState & ThreadState.WaitSleepJoin) == ThreadState.WaitSleepJoin)
{
Assert.AreEqual(Locksmith.NumberOfActiveReaders(methodsLockState), Locksmith.MaxNumberOfActiveReaders);
Assert.That(methodsLockState.HasWaitingReaders(), $"{methodsLockState}");
break;
}
}
barrierToKeepReadersInLock.SignalAndWait();
}
Locksmith.ExitReadLock(ref methodsLockState, methodsReadLockObject, methodsWriteLockObject);
return;
void IncrementNumReadsInsideReadLock()
{
Locksmith.EnterReadLock(ref methodsLockState, methodsReadLockObject);
{
Interlocked.Increment(ref numberOfReads);
barrierToKeepReadersInLock.SignalAndWait();
}
Locksmith.ExitReadLock(ref methodsLockState, methodsReadLockObject, methodsWriteLockObject);
}
}
public void Locksmith_WhileUnlocked_AllowsAWriterToEnter()
{
Locksmith.EnterWriteLock(ref lockState, writeLockTestObject);
{
Thread.SpinWait(1);
}
Locksmith.ExitWriteLock(ref lockState, readLockTestObject, writeLockTestObject);
}
public void Locksmith_WhenWriteLocked_ThrowsIfExitReadLockIsCalled()
{
Locksmith.EnterWriteLock(ref lockState, writeLockTestObject);
Assert.Throws <SynchronizationLockException>(ExitLockWithExitReadLock);
Locksmith.ExitWriteLock(ref lockState, readLockTestObject, writeLockTestObject);
return;
void ExitLockWithExitReadLock() =>
Locksmith.ExitReadLock(ref lockState, readLockTestObject, writeLockTestObject);
}
public void Locksmith_WhenReadLockIsUpgraded_ThrowsIfExitReadLockIsCalled()
{
Locksmith.EnterReadLock(ref lockState, readLockTestObject);
Locksmith.Upgrade(ref lockState, writeLockTestObject);
Assert.Throws <SynchronizationLockException>(TryToCallExitReadLock);
Locksmith.ExitWriteLock(ref lockState, readLockTestObject, writeLockTestObject);
return;
void TryToCallExitReadLock() =>
Locksmith.ExitReadLock(ref lockState, readLockTestObject, writeLockTestObject);
}
public void Locksmith_WhenReadLockIsUpgradedWhileOtherReadersAreActive_WaitsUntilAllOtherReadersExitToConvertLock()
{
const int numberOfOtherReaders = 10;
int numberOfReads = 0;
int numberOfExits = 0;
CountdownEvent readEvent = new CountdownEvent(numberOfOtherReaders);
CountdownEvent exitEvent = new CountdownEvent(numberOfOtherReaders);
ManualResetEvent upgradeEvent = new ManualResetEvent(false);
Locksmith.EnterReadLock(ref lockState, readLockTestObject);
for (int i = 0; i < numberOfOtherReaders; i++)
{
StartNewThreadThatRuns(IncrementNumReadsInsideReadLock);
}
readEvent.Wait();
Assert.That(numberOfReads, Is.EqualTo(numberOfOtherReaders));
upgradeEvent.Set();
Locksmith.Upgrade(ref lockState, writeLockTestObject);
{
Assert.That(lockState.IsReadLocked() == false, $"{lockState}");
exitEvent.Wait();
Assert.That(numberOfExits, Is.EqualTo(numberOfOtherReaders));
}
Locksmith.ExitWriteLock(ref lockState, readLockTestObject, writeLockTestObject);
return;
void IncrementNumReadsInsideReadLock()
{
Locksmith.EnterReadLock(ref lockState, readLockTestObject);
{
Interlocked.Increment(ref numberOfReads);
readEvent.Signal();
upgradeEvent.WaitOne();
Thread.Sleep(1000);
Assert.That(ReservedForUpgrade && IsReadLocked);
}
Locksmith.ExitReadLock(ref lockState, readLockTestObject, writeLockTestObject);
Interlocked.Increment(ref numberOfExits);
exitEvent.Signal();
}
}
public bool IfValueEqualsFirstSetToSecond(T valueToTestFor, T valueToSetTo)
{
Locksmith.EnterReadLock(ref lockState, readLockobject);
{
if (lockedValue.Equals(valueToTestFor))
{
Locksmith.Upgrade(ref lockState, this);
{
lockedValue = valueToSetTo;
}
Locksmith.ExitWriteLock(ref lockState, readLockobject, this);
return(true);
}
}
Locksmith.ExitReadLock(ref lockState, readLockobject, this);
return(false);
}
public void Locksmith_WhenReadLockReleased_ReleasesOnlyOneWaitingWriter()
{
const int initialValue = 10;
const int valueToAdd = 15;
const int successValue = initialValue + valueToAdd;
int result = initialValue;
ManualResetEvent resultTestedEvent = new ManualResetEvent(false);
Locksmith.EnterReadLock(ref lockState, readLockTestObject);
{
StartNewThreadThatRuns(SetWriteResultToFailureValue);
StartNewThreadThatRuns(SetWriteResultToFailureValue);
Thread.Sleep(300);
Assert.That(NumberOfWaitingWriters, Is.EqualTo(2));
Assert.That(result, Is.EqualTo(initialValue));
}
Locksmith.ExitReadLock(ref lockState, readLockTestObject, writeLockTestObject);
Thread.Sleep(500);
Assert.That(result, Is.EqualTo(successValue));
resultTestedEvent.Set();
return;
void SetWriteResultToFailureValue()
{
Locksmith.EnterWriteLock(ref lockState, writeLockTestObject);
{
int currentResult;
int valueToSet;
do
{
currentResult = result;
valueToSet = currentResult + valueToAdd;
}while (Interlocked.CompareExchange(ref result, valueToSet, currentResult) != currentResult);
resultTestedEvent.WaitOne();
}
Locksmith.ExitWriteLock(ref lockState, readLockTestObject, writeLockTestObject);
}
}
public void Locksmith_WhenAReaderHasDecidedToWait_WillNotDeadlockIfTheReaderCantCallWaitBeforeAWriterExits()
{
const int initialValue = 10;
const int expectedValue = 42;
int valueBeingTested = initialValue;
ManualResetEvent readerExitedEvent = new ManualResetEvent(false);
Locksmith.EnterWriteLock(ref lockState, writeLockTestObject);
lock (readLockTestObject) //- This should prevent the reader from being able to lock the same object, which it needs to do in order to call Monitor.Wait()
{
StartNewThreadThatRuns(SetReadResultToTestInt);
//- Hold the lock long enough that the reader will decide to start waiting
Thread.Sleep(500);
Assert.That(ReadersAreWaiting);
//- Make sure they didn't manage to set the value despite the lock somehow.
Assert.That(valueBeingTested, Is.EqualTo(initialValue));
//- Exit the write lock, which should call Monitor.PulseAll().
// lock() is re-entrant so the fact that we already locked the read lock object,
// shouldn't prevent this thread from reacquiring the lock to call Monitor.PulseAll().
Locksmith.ExitWriteLock(ref lockState, readLockTestObject, writeLockTestObject);
}
//- Give the reader time to work if they managed to avoid the deadlock
readerExitedEvent.WaitOne();
Assert.That(valueBeingTested, Is.EqualTo(expectedValue));
return;
void SetReadResultToTestInt()
{
Locksmith.EnterReadLock(ref lockState, readLockTestObject);
{
valueBeingTested = expectedValue;
}
Locksmith.ExitReadLock(ref lockState, readLockTestObject, writeLockTestObject);
readerExitedEvent.Set();
}
}
public void Locksmith_WhileWriteLocked_PreventsOtherWritersFromEntering()
{
const int initialValue = 10;
const int expectedValue = 42;
int valueBeingTested = initialValue;
Locksmith.EnterWriteLock(ref lockState, writeLockTestObject);
{
StartNewThreadThatRuns(SetValueBeingTestedToExpectedValue);
Thread.Sleep(1000);
Assert.That(valueBeingTested, Is.EqualTo(initialValue));
}
Locksmith.ExitWriteLock(ref lockState, readLockTestObject, writeLockTestObject);
void SetValueBeingTestedToExpectedValue()
{
Locksmith.EnterWriteLock(ref lockState, writeLockTestObject);
valueBeingTested = expectedValue;
Locksmith.ExitWriteLock(ref lockState, readLockTestObject, writeLockTestObject);
}
}
public void Locksmith_WhileReadLocked_PreventsWritersFromEntering()
{
const int failureValue = 25;
const int expectedValue = 10;
int writeResult = expectedValue;
Locksmith.EnterReadLock(ref lockState, readLockTestObject);
{
StartNewThreadThatRuns(SetWriteResultToFailureValue);
Thread.Sleep(1000);
Assert.That(writeResult, Is.EqualTo(expectedValue));
}
Locksmith.ExitReadLock(ref lockState, readLockTestObject, writeLockTestObject);
return;
void SetWriteResultToFailureValue()
{
Locksmith.EnterWriteLock(ref lockState, writeLockTestObject);
writeResult = failureValue;
Locksmith.ExitWriteLock(ref lockState, readLockTestObject, writeLockTestObject);
}
}
public void Locksmith_WhenWriteLockReleased_ReleasesAWaitingWriterIfPresent()
{
const int initialValue = 10;
const int expectedValue = 42;
int valueBeingTested = initialValue;
ManualResetEvent writerExitedEvent = new ManualResetEvent(false);
Locksmith.EnterWriteLock(ref lockState, writeLockTestObject);
{
StartNewThreadThatRuns(SetValueBeingTestedToExpectedValue);
//- We'll wait a while to give the other thread a chance to set the value, so we can see if the lock works.
Thread.Sleep(100);
Assert.That(WritersAreWaiting);
Assert.That(valueBeingTested, Is.EqualTo(initialValue));
}
Locksmith.ExitWriteLock(ref lockState, readLockTestObject, writeLockTestObject);
//- This should be more than enough time for the other thread to wake up and set the value.
writerExitedEvent.WaitOne();
Assert.That(valueBeingTested, Is.EqualTo(expectedValue));
return;
void SetValueBeingTestedToExpectedValue()
{
Locksmith.EnterWriteLock(ref lockState, writeLockTestObject);
{
valueBeingTested = expectedValue;
}
Locksmith.ExitWriteLock(ref lockState, readLockTestObject, writeLockTestObject);
writerExitedEvent.Set();
}
}
void SetIntToValueInsideWriteLock(ref int intToSet, int valueToSetTo)
{
Locksmith.EnterWriteLock(ref lockState, writeLockTestObject);
intToSet = valueToSetTo;
Locksmith.ExitWriteLock(ref lockState, readLockTestObject, writeLockTestObject);
}
public void Locksmith_WhenReadLockIsUpgradedWhileOtherReadersAreActive_PreventsNewReadersFromEntering()
{
const int numberOfOtherReaders = 10;
int numberOfReadersEntered = 0;
int numberOfExits = 0;
CountdownEvent readEvent = new CountdownEvent(numberOfOtherReaders);
CountdownEvent exitEvent = new CountdownEvent(numberOfOtherReaders);
ManualResetEvent outerUpgradeEvent = new ManualResetEvent(false);
ManualResetEvent innerUpgradeEvent = new ManualResetEvent(false);
for (int i = 0; i < numberOfOtherReaders; i++)
{
StartNewThreadThatRuns(IncrementNumReadsInsideReadLock_FirstSet);
}
readEvent.Wait();
Assert.That(numberOfReadersEntered, Is.EqualTo(numberOfOtherReaders));
StartNewThreadThatRuns(EnterReadLockAndUpgrade);
exitEvent.Wait();
Assert.That(numberOfExits, Is.EqualTo(numberOfOtherReaders));
for (int i = 0; i < numberOfOtherReaders; i++)
{
StartNewThreadThatRuns(IncrementNumReadsInsideReadLock_SecondSet);
}
Thread.Sleep(1000);
Assert.That(numberOfReadersEntered, Is.EqualTo(numberOfOtherReaders));
innerUpgradeEvent.Set();
return;
void EnterReadLockAndUpgrade()
{
Locksmith.EnterReadLock(ref lockState, readLockTestObject);
outerUpgradeEvent.Set();
Locksmith.Upgrade(ref lockState, writeLockTestObject);
{
innerUpgradeEvent.WaitOne();
Assert.That(numberOfExits, Is.EqualTo(numberOfOtherReaders));
}
Locksmith.ExitWriteLock(ref lockState, readLockTestObject, writeLockTestObject);
}
void IncrementNumReadsInsideReadLock_FirstSet()
{
Locksmith.EnterReadLock(ref lockState, readLockTestObject);
{
Interlocked.Increment(ref numberOfReadersEntered);
readEvent.Signal();
outerUpgradeEvent.WaitOne();
Thread.Sleep(1000);
}
Locksmith.ExitReadLock(ref lockState, readLockTestObject, writeLockTestObject);
Interlocked.Increment(ref numberOfExits);
exitEvent.Signal();
}
void IncrementNumReadsInsideReadLock_SecondSet()
{
Locksmith.EnterReadLock(ref lockState, readLockTestObject);
{
Interlocked.Increment(ref numberOfReadersEntered);
}
Locksmith.ExitReadLock(ref lockState, readLockTestObject, writeLockTestObject);
Interlocked.Increment(ref numberOfExits);
}
}
//- This test should not be ran with the current bit values used by the Locksmith class
// I believe it's rather unlikely you want to try to start a quarter million threads
// I usually run this test with the max reader count set to 2047.
// I'll have to make a test that creates a fake lock state so that we can test the new max.
//[Test, Order(5)]
public void Locksmith_WhenReadLockReleased_ReleasesAllWaitingReaders()
{
//- Since we need all of the reader slots in order to run this test, we'll use a separate
// set of lock variables than the rest.
int methodsLockState = 0;
object methodsReadLockObject = new object();
object methodsWriteLockObject = new object();
int initialNumberOfThreadsToCreate = Locksmith.MaxNumberOfActiveReaders - 1;
int numberWaitingOfThreadsToCreate = 3;
int numberOfIncrementingThreads = initialNumberOfThreadsToCreate + numberWaitingOfThreadsToCreate;
int numberOfReads = 0;
ManualResetEvent waitingReadersEvent = new ManualResetEvent(false);
CountdownEvent readersExitedEvent = new CountdownEvent(initialNumberOfThreadsToCreate);
Locksmith.EnterReadLock(ref methodsLockState, methodsReadLockObject);
{
for (int i = 0; i < initialNumberOfThreadsToCreate; i++)
{
StartNewThreadThatRuns(IncrementNumReadsInsideReadLock);
}
Thread.Sleep(300);
Assert.AreEqual(Locksmith.NumberOfActiveReaders(methodsLockState), Locksmith.MaxNumberOfActiveReaders);
Assert.AreEqual(initialNumberOfThreadsToCreate, numberOfReads);
for (int i = 0; i < numberWaitingOfThreadsToCreate; i++)
{
Thread setValueThread = new Thread(IncrementNumReadsInsideReadLock)
{
IsBackground = false
};
setValueThread.Start();
}
Thread.Sleep(200);
Assert.That(methodsLockState.HasWaitingReaders(), $"{methodsLockState}");
waitingReadersEvent.Set(); //- We should be the last one needed to trigger the barrier to drop
readersExitedEvent.Wait();
readersExitedEvent.Reset(numberWaitingOfThreadsToCreate);
//- Ensure the waiting readers are still waiting
Assert.That(Locksmith.NumberOfActiveReaders(methodsLockState), Is.EqualTo(1));
Assert.AreEqual(numberOfReads, initialNumberOfThreadsToCreate);
Assert.That(methodsLockState.HasWaitingReaders(), $"{methodsLockState}");
}
Locksmith.ExitReadLock(ref methodsLockState, methodsReadLockObject, methodsWriteLockObject); //- This should release the waiting readers
//- Give them time to wake up and do their work.
readersExitedEvent.Wait();
//- Check the outcome to make sure they woke up and incremented the count.
Assert.That(numberOfReads, Is.EqualTo(numberOfIncrementingThreads));
return;
void IncrementNumReadsInsideReadLock()
{
Locksmith.EnterReadLock(ref methodsLockState, methodsReadLockObject);
{
Interlocked.Increment(ref numberOfReads);
waitingReadersEvent.WaitOne();
}
Locksmith.ExitReadLock(ref methodsLockState, methodsReadLockObject, methodsWriteLockObject);
readersExitedEvent.Signal();
}
}
public void Locksmith_WhenWriteLockReleased_ReleasesWaitingWritersBeforeWaitingReaders()
{
const int initialValue = 10;
const int valueAddedByReader = 50;
const int valueAddedByWriter = 20;
const int successValue = initialValue + valueAddedByWriter;
int result = initialValue;
ManualResetEvent valueSetEvent = new ManualResetEvent(false);
ManualResetEvent valueTestedEvent = new ManualResetEvent(false);
Locksmith.EnterWriteLock(ref lockState, writeLockTestObject);
{
StartNewThreadThatRuns(AddWriterValue);
Thread.Sleep(200);
Assert.That(WritersAreWaiting);
StartNewThreadThatRuns(AddReaderValue);
Thread.Sleep(200);
Assert.That(ReadersAreWaiting);
Assert.That(result, Is.EqualTo(initialValue));
}
Locksmith.ExitWriteLock(ref lockState, readLockTestObject, writeLockTestObject);
valueSetEvent.WaitOne();
Assert.That(ReadersAreWaiting);
Assert.That(WritersAreWaiting == false);
Assert.That(result, Is.EqualTo(successValue));
valueTestedEvent.Set();
return;
void AddReaderValue()
{
Locksmith.EnterReadLock(ref lockState, readLockTestObject);
{
int currentResult, valueToSet;
do
{
currentResult = result;
valueToSet = currentResult + valueAddedByReader;
} while (Interlocked.CompareExchange(ref result, valueToSet, currentResult) != currentResult);
}
Locksmith.ExitReadLock(ref lockState, readLockTestObject, writeLockTestObject);
}
void AddWriterValue()
{
Locksmith.EnterWriteLock(ref lockState, writeLockTestObject);
{
int currentResult;
int valueToSet;
do
{
currentResult = result;
valueToSet = currentResult + valueAddedByWriter;
}while (Interlocked.CompareExchange(ref result, valueToSet, currentResult) != currentResult);
valueSetEvent.Set();
valueTestedEvent.WaitOne();
}
Locksmith.ExitWriteLock(ref lockState, readLockTestObject, writeLockTestObject);
}
}
public void PickLock(Locksmith lockpicker)
{
lockpicker.WriteDownCombination(_safeCombination);
}
public void PickLocker(Locksmith lockpicker)
{
lockpicker.WriteDownCombination(safeCombination);
}