/* ---- many producers ---- */
public override void Produce(T t)
{
if (_size == 0)
{
return;
}
long produceNumber = _produceCount.AndIncrement;
int offset = ( int )(produceNumber & _mask);
VolatileRef <T> volatileRef = _data[offset];
if (AssertPreviousCompleted(produceNumber, volatileRef))
{
volatileRef.Ref = t;
volatileRef.ProduceNumber = produceNumber;
}
else
{
// If we don't manage to wait for the previous produce to complete even after
// all the yields in `assertPreviousCompleted`, we drop `t` to avoid causing
// a problem in db operation. We increment dropEvents to so the RecentBuffer
// consumer can detect that there has been a drop.
_dropEvents.incrementAndGet();
}
}
public override void Foreach(System.Action <T> consumer)
{
if (_size == 0)
{
return;
}
long snapshotProduce = _produceCount.get();
long snapshotConsume = Math.Max(_consumeCount.get(), snapshotProduce - _size);
for (long i = snapshotConsume; i < snapshotProduce; i++)
{
int offset = ( int )(i & _mask);
VolatileRef <T> volatileRef = _data[offset];
if (volatileRef.ProduceNumber < i)
{
return;
}
consumer(volatileRef.Ref);
}
}
public RingRecentBuffer(int size)
{
if (size > 0)
{
Preconditions.requirePowerOfTwo(size);
}
this._size = size;
_mask = size - 1;
//noinspection unchecked
_data = new VolatileRef[size];
for (int i = 0; i < size; i++)
{
_data[i] = new VolatileRef <T>();
_data[i].produceNumber = i - size;
}
_produceCount = new AtomicLong(0);
_consumeCount = new AtomicLong(0);
_dropEvents = new AtomicLong(0);
}
private bool AssertPreviousCompleted(long produceNumber, VolatileRef <T> volatileRef)
{
int attempts = 100;
long prevProduceNumber = volatileRef.ProduceNumber;
while (prevProduceNumber != produceNumber - _size && attempts > 0)
{
// Coming in here is expected to be very rare, because it means that producers have
// circled around the ring buffer, and the producer `size` elements ago hasn't finished
// writing to the buffer. We yield and hope the previous produce is done when we get back.
try
{
Thread.Sleep(0, 1000);
}
catch (InterruptedException)
{
// continue
}
prevProduceNumber = volatileRef.ProduceNumber;
attempts--;
}
return(attempts > 0);
}
