public void CanEnterLocksSync()
{
var myLock = new AsyncReaderWriterLockSlim();
myLock.EnterReadLock();
Assert.IsTrue(myLock.TryEnterReadLock(0));
Assert.IsFalse(myLock.TryEnterWriteLock(0));
myLock.ExitReadLock();
myLock.ExitReadLock();
myLock.EnterWriteLock();
Assert.IsFalse(myLock.TryEnterReadLock(0));
Assert.IsFalse(myLock.TryEnterWriteLock(0));
myLock.ExitWriteLock();
}
public async Task WriteTakesPriorityOverRead1()
{
var myLock = new AsyncReaderWriterLockSlim();
// Check that no new read lock can be entered when another thread/task wants
// to enter the write lock while at least one read lock is active.
myLock.EnterReadLock();
using (var cts = new CancellationTokenSource())
{
var enterWriteLockTask = myLock.EnterWriteLockAsync(cts.Token);
Assert.IsFalse(myLock.TryEnterReadLock(0));
cts.Cancel();
try
{
await enterWriteLockTask;
Assert.Fail();
}
catch (OperationCanceledException)
{
}
}
// Verify that now a new read lock can be entered.
Assert.IsTrue(await myLock.TryEnterReadLockAsync(0));
}
public void DowngradeLockAllowsReadLock()
{
var myLock = new AsyncReaderWriterLockSlim();
myLock.EnterWriteLock();
Assert.IsFalse(myLock.TryEnterWriteLock(0));
Assert.IsFalse(myLock.TryEnterReadLock(0));
// After downgrading the lock and after the try to get the write lock is canceled,
// it should be possible to enter another read lock.
myLock.DowngradeWriteLockToReadLock();
Assert.IsFalse(myLock.TryEnterWriteLock(0));
Assert.IsTrue(myLock.TryEnterReadLock(0));
myLock.ExitReadLock();
myLock.ExitReadLock();
}
public void ThrowsOperationCanceledExceptionAfterWait()
{
var myLock = new AsyncReaderWriterLockSlim();
myLock.EnterReadLock();
try
{
using (var cts = new CancellationTokenSource(100))
{
myLock.EnterWriteLock(cts.Token);
}
}
catch (OperationCanceledException)
{
// Check that we can now enter another read lock.
Assert.IsTrue(myLock.TryEnterReadLock(0));
throw;
}
}
