| public CompareAndSet ( long expectedSequence, long nextSequence ) : bool | ||
| expectedSequence | long | the expected value for the sequence |
| nextSequence | long | the new value for the sequence |
| return | bool | |
internal long NextInternal(int n)
{
long current;
long next;
var spinWait = default(AggressiveSpinWait);
do
{
current = _cursor.Value;
next = current + n;
long wrapPoint = next - _bufferSize;
long cachedGatingSequence = _gatingSequenceCache.Value;
if (wrapPoint > cachedGatingSequence || cachedGatingSequence > current)
{
long gatingSequence = Util.GetMinimumSequence(Volatile.Read(ref _gatingSequences), current);
if (wrapPoint > gatingSequence)
{
spinWait.SpinOnce();
continue;
}
_gatingSequenceCache.SetValue(gatingSequence);
}
else if (_cursor.CompareAndSet(current, next))
{
break;
}
} while (true);
return(next);
}
///<summary>
/// Serialise publishers in sequence and set cursor to latest available sequence.
///</summary>
///<param name="sequence">sequence to be applied</param>
///<param name="cursor">cursor to serialise against.</param>
///<param name="batchSize">batchSize of the sequence.</param>
public override void SerialisePublishing(long sequence, Sequence cursor, long batchSize)
{
var spinWait = default(SpinWait);
while (sequence - cursor.Value > _pendingPublication.Length)
{
spinWait.SpinOnce();
}
long expectedSequence = sequence - batchSize;
for (long pendingSequence = expectedSequence + 1; pendingSequence <= sequence; pendingSequence++)
{
_pendingPublication.WriteCompilerOnlyFence((int)pendingSequence & _pendingMask, pendingSequence);
}
_pendingPublication.WriteFullFence((int)sequence & _pendingMask, sequence);
long cursorSequence = cursor.Value;
if (cursorSequence >= sequence)
{
return;
}
expectedSequence = Math.Max(expectedSequence, cursorSequence);
long nextSequence = expectedSequence + 1;
while (cursor.CompareAndSet(expectedSequence, nextSequence))
{
expectedSequence = nextSequence;
nextSequence++;
if (_pendingPublication.ReadFullFence((int)nextSequence & _pendingMask) != nextSequence)
{
break;
}
}
}
///<summary>
/// Serialise publishers in sequence and set cursor to latest available sequence.
///</summary>
///<param name="sequence">sequence to be applied</param>
///<param name="cursor">cursor to serialise against.</param>
///<param name="batchSize">batchSize of the sequence.</param>
public void SerialisePublishing(long sequence, Sequence cursor, long batchSize)
{
var spinWait = default(SpinWait);
while (sequence - cursor.Value > _pendingPublication.Length)
{
spinWait.SpinOnce();
}
long expectedSequence = sequence - batchSize;
for (long pendingSequence = expectedSequence + 1; pendingSequence <= sequence; pendingSequence++)
{
_pendingPublication.WriteFullFence((int)pendingSequence & _pendingMask, pendingSequence);
}
if (cursor.Value != expectedSequence)
{
return;
}
long nextSequence = expectedSequence + 1;
while (cursor.CompareAndSet(expectedSequence, nextSequence))
{
expectedSequence = nextSequence;
nextSequence++;
if (_pendingPublication.ReadFullFence((int)nextSequence & _pendingMask) != nextSequence)
{
break;
}
}
}
/// <summary>
/// Atomically checks the available capacity of the ring buffer and claims the next sequence. Will
/// throw InsufficientCapacityException if the capacity not available.
/// </summary>
/// <param name="availableCapacity">the capacity that should be available before claiming the next slot</param>
/// <param name="delta">the number of slots to claim</param>
/// <param name="dependentSequences">the set of sequences to check to ensure capacity is available</param>
/// <returns>the slot after incrementing</returns>
public long CheckAndIncrement(int availableCapacity, int delta, Sequence[] dependentSequences)
{
for (;;)
{
long sequence = _claimSequence.Value;
if (HasAvailableCapacity(sequence, availableCapacity, dependentSequences))
{
long nextSequence = sequence + delta;
if (_claimSequence.CompareAndSet(sequence, nextSequence))
{
return(nextSequence);
}
}
else
{
throw InsufficientCapacityException.Instance;
}
}
}
internal bool TryNextInternal(int n, out long sequence)
{
long current;
long next;
do
{
current = _cursor.Value;
next = current + n;
if (!HasAvailableCapacity(n, current))
{
sequence = default;
return(false);
}
}while (!_cursor.CompareAndSet(current, next));
sequence = next;
return(true);
}
