public void EnterExit()
{
using (ReaderWriterLockSlim rwls = new ReaderWriterLockSlim())
{
Assert.IsFalse(rwls.IsReadLockHeld);
rwls.EnterReadLock();
Assert.IsTrue(rwls.IsReadLockHeld);
rwls.ExitReadLock();
Assert.IsFalse(rwls.IsReadLockHeld);
Assert.IsFalse(rwls.IsUpgradeableReadLockHeld);
rwls.EnterUpgradeableReadLock();
Assert.IsTrue(rwls.IsUpgradeableReadLockHeld);
rwls.ExitUpgradeableReadLock();
Assert.IsFalse(rwls.IsUpgradeableReadLockHeld);
Assert.IsFalse(rwls.IsWriteLockHeld);
rwls.EnterWriteLock();
Assert.IsTrue(rwls.IsWriteLockHeld);
rwls.ExitWriteLock();
Assert.IsFalse(rwls.IsWriteLockHeld);
Assert.IsFalse(rwls.IsUpgradeableReadLockHeld);
rwls.EnterUpgradeableReadLock();
Assert.IsFalse(rwls.IsWriteLockHeld);
Assert.IsTrue(rwls.IsUpgradeableReadLockHeld);
rwls.EnterWriteLock();
Assert.IsTrue(rwls.IsWriteLockHeld);
rwls.ExitWriteLock();
Assert.IsFalse(rwls.IsWriteLockHeld);
Assert.IsTrue(rwls.IsUpgradeableReadLockHeld);
rwls.ExitUpgradeableReadLock();
Assert.IsFalse(rwls.IsUpgradeableReadLockHeld);
Assert.IsTrue(rwls.TryEnterReadLock(0));
rwls.ExitReadLock();
Assert.IsTrue(rwls.TryEnterReadLock(Timeout2.InfiniteTimeSpan));
rwls.ExitReadLock();
Assert.IsTrue(rwls.TryEnterUpgradeableReadLock(0));
rwls.ExitUpgradeableReadLock();
Assert.IsTrue(rwls.TryEnterUpgradeableReadLock(Timeout2.InfiniteTimeSpan));
rwls.ExitUpgradeableReadLock();
Assert.IsTrue(rwls.TryEnterWriteLock(0));
rwls.ExitWriteLock();
Assert.IsTrue(rwls.TryEnterWriteLock(Timeout2.InfiniteTimeSpan));
rwls.ExitWriteLock();
}
}
public void InvalidTimeouts()
{
using (ReaderWriterLockSlim rwls = new ReaderWriterLockSlim())
{
AssertExtensions.Throws <ArgumentOutOfRangeException>(() => rwls.TryEnterReadLock(-2));
AssertExtensions.Throws <ArgumentOutOfRangeException>(() => rwls.TryEnterUpgradeableReadLock(-3));
AssertExtensions.Throws <ArgumentOutOfRangeException>(() => rwls.TryEnterWriteLock(-4));
AssertExtensions.Throws <ArgumentOutOfRangeException>(() => rwls.TryEnterReadLock(TimeSpan.MaxValue));
AssertExtensions.Throws <ArgumentOutOfRangeException>(() => rwls.TryEnterUpgradeableReadLock(TimeSpan.MinValue));
AssertExtensions.Throws <ArgumentOutOfRangeException>(() => rwls.TryEnterWriteLock(TimeSpan.FromMilliseconds(-2)));
}
}
public void Dispose()
{
ReaderWriterLockSlim rwls;
rwls = new ReaderWriterLockSlim();
rwls.Dispose();
AssertExtensions.Throws <ObjectDisposedException>(() => rwls.TryEnterReadLock(0));
AssertExtensions.Throws <ObjectDisposedException>(() => rwls.TryEnterUpgradeableReadLock(0));
AssertExtensions.Throws <ObjectDisposedException>(() => rwls.TryEnterWriteLock(0));
rwls.Dispose();
for (int i = 0; i < 3; i++)
{
rwls = new ReaderWriterLockSlim();
switch (i)
{
case 0: rwls.EnterReadLock(); break;
case 1: rwls.EnterUpgradeableReadLock(); break;
case 2: rwls.EnterWriteLock(); break;
}
AssertExtensions.Throws <SynchronizationLockException>(() => rwls.Dispose());
}
}
public void WriterToWriterChain()
{
using (AutoResetEvent are = new AutoResetEvent(false))
using (ReaderWriterLockSlim rwls = new ReaderWriterLockSlim())
{
rwls.EnterWriteLock();
Task t = Task.Factory.StartNew(() =>
{
Assert.IsFalse(rwls.TryEnterWriteLock(10));
Task.Run(() => are.Set()); // ideally this won't fire until we've called EnterWriteLock, but it's a benign race in that the test will succeed either way
rwls.EnterWriteLock();
rwls.ExitWriteLock();
}, CancellationToken.None, TaskCreationOptions.LongRunning, TaskScheduler.Default);
are.WaitOne();
rwls.ExitWriteLock();
t.GetAwaiter().GetResult();
}
}
public void WritersAreMutuallyExclusiveFromWriters()
{
using (Barrier barrier = new Barrier(2))
using (ReaderWriterLockSlim rwls = new ReaderWriterLockSlim())
{
Task.WaitAll(
Task.Run(() =>
{
rwls.EnterWriteLock();
barrier.SignalAndWait();
Assert.IsTrue(rwls.IsWriteLockHeld);
barrier.SignalAndWait();
rwls.ExitWriteLock();
}),
Task.Run(() =>
{
barrier.SignalAndWait();
Assert.IsFalse(rwls.TryEnterWriteLock(0));
Assert.IsFalse(rwls.IsReadLockHeld);
barrier.SignalAndWait();
}));
}
}
//[OuterLoop]
//[SkipOnTargetFramework(TargetFrameworkMonikers.NetFramework, "Hangs in desktop, issue dotnet/corefx#3364 is not fixed there")]
public void ReleaseReadersWhenWaitingWriterTimesOut()
{
using (var rwls = new ReaderWriterLockSlim())
{
// Enter the read lock
rwls.EnterReadLock();
// Typical order of execution: 0
Thread writeWaiterThread;
using (var beforeTryEnterWriteLock = new ManualResetEvent(false))
{
writeWaiterThread =
new Thread(() =>
{
// Typical order of execution: 1
// Add a writer to the wait list for enough time to allow successive readers to enter the wait list while this
// writer is waiting
beforeTryEnterWriteLock.Set();
if (rwls.TryEnterWriteLock(1000))
{
// The typical order of execution is not guaranteed, as sleep times are not guaranteed. For
// instance, before this write lock is added to the wait list, the two new read locks may be
// acquired. In that case, the test may complete before or while the write lock is taken.
rwls.ExitWriteLock();
}
// Typical order of execution: 4
});
writeWaiterThread.IsBackground = true;
writeWaiterThread.Start();
beforeTryEnterWriteLock.WaitOne();
}
Thread.Sleep(500); // wait for TryEnterWriteLock to enter the wait list
// A writer should now be waiting, add readers to the wait list. Since a read lock is still acquired, the writer
// should time out waiting, then these readers should enter and exit the lock.
ThreadStart EnterAndExitReadLock = () =>
{
// Typical order of execution: 2, 3
rwls.EnterReadLock();
// Typical order of execution: 5, 6
rwls.ExitReadLock();
};
var readerThreads =
new Thread[]
{
new Thread(EnterAndExitReadLock),
new Thread(EnterAndExitReadLock)
};
foreach (var readerThread in readerThreads)
{
readerThread.IsBackground = true;
readerThread.Start();
}
foreach (var readerThread in readerThreads)
{
readerThread.Join();
}
rwls.ExitReadLock();
// Typical order of execution: 7
writeWaiterThread.Join();
}
}