public async Task AsyncReaderWriterLock_ReaderThenReader()
{
// Verify that obtaining a reader lock does not block
// another reader.
var rwLock = new AsyncReaderWriterLock();
var haveLock = false;
var inTask = false;
var readLock = await rwLock.GetReadLockAsync();
Task.Run(
async() =>
{
inTask = true;
using (await rwLock.GetReadLockAsync())
{
haveLock = true;
}
});
Helper.WaitFor(() => inTask, defaultTimeout);
await Task.Delay(taskWait);
Assert.IsTrue(haveLock);
readLock.Dispose();
Helper.WaitFor(() => haveLock, defaultTimeout);
rwLock.Dispose();
}
public async Task ReaderThenReader_Delay()
{
// Verify that obtaining a reader lock does not block
// another reader. We'll add delay to mix things up.
var rwLock = new AsyncReaderWriterLock();
var haveLock = false;
var inTask = false;
var readLock = await rwLock.GetReadLockAsync();
var task = Task.Run(
async() =>
{
inTask = true;
using (await rwLock.GetReadLockAsync())
{
await Task.Delay(250);
haveLock = true;
}
});
NeonHelper.WaitFor(() => inTask, defaultTimeout);
await Task.Delay(taskWait);
Assert.True(haveLock);
readLock.Dispose();
NeonHelper.WaitFor(() => haveLock, defaultTimeout);
rwLock.Dispose();
}
public async Task AsyncReaderWriterLock_ReaderThenReader_Repeat_Delay()
{
// Verify that obtaining a reader lock does not block
// another reader. We'll add delay to mix things up.
using (var rwLock = new AsyncReaderWriterLock())
{
for (int i = 0; i < repeatCount; i++)
{
var haveLock = false;
var inTask = false;
var readLock = await rwLock.GetReadLockAsync();
Task.Run(
async() =>
{
inTask = true;
using (await rwLock.GetReadLockAsync())
{
await Task.Delay(100);
haveLock = true;
}
});
Helper.WaitFor(() => inTask, defaultTimeout);
await Task.Delay(taskWait);
Assert.IsTrue(haveLock);
readLock.Dispose();
Helper.WaitFor(() => haveLock, defaultTimeout);
}
}
}
public async Task AsyncReaderWriterLock_Basic_Repeat_Delay()
{
using (var rwLock = new AsyncReaderWriterLock())
{
var haveLock = false;
for (int i = 0; i < repeatCount; i++)
{
// Verify that we can obtain a reader lock.
// We'll add delay to mix things up.
using (await rwLock.GetReadLockAsync())
{
await Task.Delay(100);
haveLock = true;
}
Assert.IsTrue(haveLock);
haveLock = false;
// Verify that we can obtain a writer lock.
// We'll add delay to mix things up.
using (await rwLock.GetWriteLockAsync())
{
await Task.Delay(100);
haveLock = true;
}
Assert.IsTrue(haveLock);
}
}
}
public async Task AsyncReaderWriterLock_ReaderThenWriter()
{
// Verify that obtaining a reader lock blocks a writer lock and then
// that releasing the read lock, unblocks the writer.
var rwLock = new AsyncReaderWriterLock();
var haveLock = false;
var inTask = false;
var readLock = await rwLock.GetReadLockAsync();
Task.Run(
async() =>
{
inTask = true;
using (await rwLock.GetWriteLockAsync())
{
haveLock = true;
}
});
Helper.WaitFor(() => inTask, defaultTimeout);
await Task.Delay(taskWait);
Assert.IsFalse(haveLock);
readLock.Dispose();
Helper.WaitFor(() => haveLock, defaultTimeout);
rwLock.Dispose();
}
public async Task AsyncReaderWriterLock_WriterThenReader_Repeat()
{
// Verify that obtaining a writer lock blocks a reader lock and then
// that releasing the write lock, unblocks the reader.
using (var rwLock = new AsyncReaderWriterLock())
{
for (int i = 0; i < repeatCount; i++)
{
var haveLock = false;
var inTask = false;
var writeLock = await rwLock.GetWriteLockAsync();
Task.Run(
async() =>
{
inTask = true;
using (await rwLock.GetReadLockAsync())
{
haveLock = true;
}
});
Helper.WaitFor(() => inTask, defaultTimeout);
await Task.Delay(taskWait);
Assert.IsFalse(haveLock);
writeLock.Dispose();
Helper.WaitFor(() => haveLock, defaultTimeout);
}
}
}
public async Task AsyncReaderWriterLock_Basic()
{
var rwLock = (AsyncReaderWriterLock)null;
var haveLock = false;
// Verify that we can obtain a reader lock.
rwLock = new AsyncReaderWriterLock();
haveLock = false;
using (await rwLock.GetReadLockAsync())
{
haveLock = true;
}
Assert.IsTrue(haveLock);
rwLock.Dispose();
// Verify that we can obtain a writer lock.
rwLock = new AsyncReaderWriterLock();
haveLock = false;
using (await rwLock.GetWriteLockAsync())
{
haveLock = true;
}
Assert.IsTrue(haveLock);
rwLock.Dispose();
}
public async Task AsyncReaderWriterLock_Basic_Repeat()
{
using (var rwLock = new AsyncReaderWriterLock())
{
var haveLock = false;
for (int i = 0; i < repeatCount; i++)
{
// Verify that we can obtain a reader lock.
using (await rwLock.GetReadLockAsync())
{
haveLock = true;
}
Assert.IsTrue(haveLock);
haveLock = false;
// Verify that we can obtain a writer lock.
using (await rwLock.GetWriteLockAsync())
{
haveLock = true;
}
Assert.IsTrue(haveLock);
}
}
}
public async Task WriterThenReader_Delay()
{
// Verify that obtaining a writer lock blocks a reader lock and then
// that releasing the write lock, unblocks the reader. We'll add delay
// to mix things up.
var rwLock = new AsyncReaderWriterLock();
var haveLock = false;
var inTask = false;
var writeLock = await rwLock.GetWriteLockAsync();
var task = Task.Run(
async() =>
{
inTask = true;
using (await rwLock.GetReadLockAsync())
{
await Task.Delay(250);
haveLock = true;
}
});
NeonHelper.WaitFor(() => inTask, defaultTimeout);
await Task.Delay(taskWait);
Assert.False(haveLock);
writeLock.Dispose();
NeonHelper.WaitFor(() => haveLock, defaultTimeout);
rwLock.Dispose();
}
public async Task AsyncReaderWriterLock_WriterThenMultipleReaders_Repeat_Delay()
{
// Verify that obtaining a writer lock blocks multiple readers and then
// that releasing the write lock, unblocks all of the readers. We'll add
// delay to mix things up.
const int readerCount = 10;
using (var rwLock = new AsyncReaderWriterLock())
{
for (int i = 0; i < repeatCount; i++)
{
var waitCount = 0;
var acquireCount = 0;
var writeLock = await rwLock.GetWriteLockAsync();
for (int j = 0; j < readerCount; j++)
{
Task.Run(
async() =>
{
Interlocked.Increment(ref waitCount);
using (await rwLock.GetReadLockAsync())
{
await Task.Delay(100);
Interlocked.Increment(ref acquireCount);
}
});
}
Helper.WaitFor(() => waitCount == readerCount, defaultTimeout);
await Task.Delay(taskWait);
Assert.AreEqual(0, acquireCount);
writeLock.Dispose();
Helper.WaitFor(() => acquireCount == readerCount, defaultTimeout);
}
}
}
public async Task AsyncReaderWriterLock_Basic_Delay()
{
var rwLock = (AsyncReaderWriterLock)null;
var haveLock = false;
// Verify that we can obtain a reader lock. We'll add delay
// to mix things up.
rwLock = new AsyncReaderWriterLock();
haveLock = false;
using (await rwLock.GetReadLockAsync())
{
await Task.Delay(250);
haveLock = true;
}
Assert.IsTrue(haveLock);
rwLock.Dispose();
// Verify that we can obtain a writer lock.
rwLock = new AsyncReaderWriterLock();
haveLock = false;
using (await rwLock.GetWriteLockAsync())
{
await Task.Delay(250);
haveLock = true;
}
Assert.IsTrue(haveLock);
rwLock.Dispose();
}
public async Task WriterThenMultipleReaders()
{
// Verify that obtaining a writer lock blocks multiple readers and then
// that releasing the write lock, unblocks all of the readers.
const int readerCount = 10;
var waitCount = 0;
var acquireCount = 0;
var rwLock = new AsyncReaderWriterLock();
var writeLock = await rwLock.GetWriteLockAsync();
for (int i = 0; i < readerCount; i++)
{
var task = Task.Run(
async() =>
{
Interlocked.Increment(ref waitCount);
using (await rwLock.GetReadLockAsync())
{
Interlocked.Increment(ref acquireCount);
}
});
}
NeonHelper.WaitFor(() => waitCount == readerCount, defaultTimeout);
await Task.Delay(taskWait);
Assert.Equal(0, acquireCount);
writeLock.Dispose();
NeonHelper.WaitFor(() => acquireCount == readerCount, defaultTimeout);
rwLock.Dispose();
}
public void AsyncReaderWriterLock_ReaderWriters()
{
// Verify that multiple pending locks work.
using (var rwLock = new AsyncReaderWriterLock())
{
var read1LockTask = rwLock.GetReadLockAsync();
var write1LockTask = rwLock.GetWriteLockAsync();
var read2LockTask = rwLock.GetReadLockAsync();
var write2LockTask = rwLock.GetWriteLockAsync();
var haveLock = false;
Task t;
// Wait for the first read lock.
haveLock = false;
t = Task.Run(async() =>
{
var lk = await read1LockTask;
haveLock = true;
lk.Dispose();
});
Helper.WaitFor(() => haveLock, defaultTimeout);
// Wait for the first write lock.
haveLock = false;
t = Task.Run(async() =>
{
var lk = await write1LockTask;
haveLock = true;
lk.Dispose();
});
Helper.WaitFor(() => haveLock, defaultTimeout);
// Wait for the second write lock. Not that write lock 2
// is favored over read lock 2.
haveLock = false;
t = Task.Run(async() =>
{
var lk = await write2LockTask;
haveLock = true;
lk.Dispose();
});
Helper.WaitFor(() => haveLock, defaultTimeout);
// Wait for the second read lock.
haveLock = false;
t = Task.Run(async() =>
{
var lk = await read2LockTask;
haveLock = true;
lk.Dispose();
});
Helper.WaitFor(() => haveLock, defaultTimeout);
}
}
public async Task AsyncReaderWriterLock_MultipleTasks()
{
// Verify that we can acquire and release both read and write
// locks over an extended period of time from several parallel
// tasks. We're also going to verify that only one writer is
// allowed at a time and that readers aren't allowed when a writer
// has the lock.
const int readTaskCount = 50;
const int writeTaskCount = 10;
var readers = 0;
var writers = 0;
var delay = TimeSpan.FromMilliseconds(50);
using (var rwLock = new AsyncReaderWriterLock())
{
var exit = false;
var tasks = new List <Task>();
var error = false;
for (int i = 0; i < readTaskCount; i++)
{
tasks.Add(Task.Run(
async() =>
{
while (!exit)
{
using (await rwLock.GetReadLockAsync())
{
if (writers > 0)
{
error = true;
}
Interlocked.Increment(ref readers);
await Task.Delay(delay);
Interlocked.Decrement(ref readers);
}
}
}));
}
for (int i = 0; i < writeTaskCount; i++)
{
tasks.Add(Task.Run(
async() =>
{
while (!exit)
{
using (await rwLock.GetWriteLockAsync())
{
if (writers > 0)
{
error = true;
}
if (readers > 0)
{
error = true;
}
Interlocked.Increment(ref writers);
await Task.Delay(delay);
Interlocked.Decrement(ref writers);
}
}
}));
}
await Task.Delay(TimeSpan.FromSeconds(60));
exit = true;
await Helper.WaitAllAsync(tasks.ToArray(), defaultTimeout);
Assert.IsFalse(error);
}
}
