/// <summary>
/// Try to claim a range in the publication log into which a message can be written with zero copy semantics.
/// Once the message has been written then <seealso cref="BufferClaim#commit()"/> should be called thus making it available.
/// <para>
/// <b>Note:</b> This method can only be used for message lengths less than MTU length minus header.
///
/// <pre>{@code
/// final BufferClaim bufferClaim = new BufferClaim(); // Can be stored and reused to avoid allocation
///
/// if (publication.tryClaim(messageLength, bufferClaim) > 0L)
/// {
/// try
/// {
/// final MutableDirectBuffer buffer = bufferClaim.buffer();
/// final int offset = bufferClaim.offset();
///
/// // Work with buffer directly or wrap with a flyweight
/// }
/// finally
/// {
/// bufferClaim.commit();
/// }
/// }
/// }</pre>
///
/// </para>
/// </summary>
/// <param name="length"> of the range to claim, in bytes.. </param>
/// <param name="bufferClaim"> to be populated if the claim succeeds. </param>
/// <returns> The new stream position, otherwise <seealso cref="NOT_CONNECTED"/>, <seealso cref="BACK_PRESSURED"/>,
/// <seealso cref="ADMIN_ACTION"/> or <seealso cref="CLOSED"/>. </returns>
/// <exception cref="ArgumentException"> if the length is greater than max payload length within an MTU. </exception>
/// <seealso cref="BufferClaim.Commit()" />
/// <seealso cref="BufferClaim.Abort()" />
public long TryClaim(int length, BufferClaim bufferClaim)
{
var newPosition = CLOSED;
if (!_isClosed)
{
CheckForMaxPayloadLength(length);
var limit = _positionLimit.Volatile;
var partitionIndex = LogBufferDescriptor.ActivePartitionIndex(_logMetaDataBuffer);
var termAppender = _termAppenders[partitionIndex];
var rawTail = termAppender.RawTailVolatile();
var termOffset = rawTail & 0xFFFFFFFFL;
var position = LogBufferDescriptor.ComputeTermBeginPosition(LogBufferDescriptor.TermId(rawTail), _positionBitsToShift, InitialTermId) + termOffset;
if (position < limit)
{
var result = termAppender.Claim(_headerWriter, length, bufferClaim);
newPosition = NewPosition(partitionIndex, (int)termOffset, position, result);
}
else if (_clientConductor.IsPublicationConnected(LogBufferDescriptor.TimeOfLastStatusMessage(_logMetaDataBuffer)))
{
newPosition = BACK_PRESSURED;
}
else
{
newPosition = NOT_CONNECTED;
}
}
return(newPosition);
}
public long TryClaim(int length, BufferClaim bufferClaim)
{
CheckForMaxPayloadLength(length);
var newPosition = CLOSED;
if (!_isClosed)
{
var limit = _positionLimit.Volatile;
var partitionIndex = LogBufferDescriptor.ActivePartitionIndex(_logMetaDataBuffer);
var termAppender = _termAppenders[partitionIndex];
var rawTail = termAppender.RawTailVolatile();
var termOffset = rawTail & 0xFFFFFFFFL;
var position = LogBufferDescriptor.ComputeTermBeginPosition(LogBufferDescriptor.TermId(rawTail), _positionBitsToShift, InitialTermId) + termOffset;
if (position < limit)
{
var result = termAppender.Claim(_headerWriter, length, bufferClaim);
newPosition = NewPosition(partitionIndex, (int)termOffset, position, result);
}
else
{
newPosition = BackPressureStatus(position, length);
}
}
return(newPosition);
}
public unsafe void CouldCreateLogBuffers()
{
var sw = new Stopwatch();
var l1 = new LogBuffers("../AeronLogBufferTests");
Assert.IsTrue(l1.TermLength >= LogBufferDescriptor.TERM_MIN_LENGTH);
Console.WriteLine($"TermLength: {l1.TermLength}");
var activePartitionIndex = LogBufferDescriptor.ActivePartitionIndex(l1.LogMetaData);
Console.WriteLine($"Active partition: {activePartitionIndex}");
var activePartition = l1.Partitions[activePartitionIndex];
var rawTail = activePartition.RawTailVolatile;
Console.WriteLine($"Raw tail: {rawTail}");
var ta = new TermAppender(activePartition);
var defaultHeader = DataHeaderFlyweight.CreateDefaultHeader(0, 0, activePartition.TermId);
var headerWriter = new HeaderWriter(defaultHeader);
BufferClaim claim;
ta.Claim(headerWriter, 100, out claim);
claim.Commit();
}
internal ExclusivePublication(
ClientConductor clientConductor,
string channel,
int streamId,
int sessionId,
IReadablePosition positionLimit,
LogBuffers logBuffers,
long originalRegistrationId,
long registrationId)
{
var buffers = logBuffers.TermBuffers();
var logMetaDataBuffer = logBuffers.MetaDataBuffer();
for (var i = 0; i < LogBufferDescriptor.PARTITION_COUNT; i++)
{
_termAppenders[i] = new ExclusiveTermAppender(buffers[i], logMetaDataBuffer, i);
}
var termLength = logBuffers.TermLength();
_termBufferLength = termLength;
MaxPayloadLength = LogBufferDescriptor.MtuLength(logMetaDataBuffer) - DataHeaderFlyweight.HEADER_LENGTH;
MaxMessageLength = FrameDescriptor.ComputeExclusiveMaxMessageLength(termLength);
_maxPossiblePosition = termLength * (1L << 31);
_conductor = clientConductor;
Channel = channel;
StreamId = streamId;
SessionId = sessionId;
_logMetaDataBuffer = logMetaDataBuffer;
_originalRegistrationId = originalRegistrationId;
RegistrationId = registrationId;
_positionLimit = positionLimit;
_logBuffers = logBuffers;
_positionBitsToShift = IntUtil.NumberOfTrailingZeros(termLength);
_headerWriter = new HeaderWriter(LogBufferDescriptor.DefaultFrameHeader(logMetaDataBuffer));
InitialTermId = LogBufferDescriptor.InitialTermId(logMetaDataBuffer);
var activeIndex = LogBufferDescriptor.ActivePartitionIndex(logMetaDataBuffer);
_activePartitionIndex = activeIndex;
long rawTail = LogBufferDescriptor.RawTail(_logMetaDataBuffer, activeIndex);
_termId = LogBufferDescriptor.TermId(rawTail);
_termOffset = LogBufferDescriptor.TermOffset(rawTail, termLength);
_termBeginPosition =
LogBufferDescriptor.ComputeTermBeginPosition(_termId, _positionBitsToShift, InitialTermId);
}
public long Offer(
UnsafeBuffer buffer,
int offset,
int length,
ReservedValueSupplier reservedValueSupplier = null)
{
var newPosition = CLOSED;
if (!_isClosed)
{
var limit = _positionLimit.Volatile;
var partitionIndex = LogBufferDescriptor.ActivePartitionIndex(_logMetaDataBuffer);
var termAppender = _termAppenders[partitionIndex];
var rawTail = termAppender.RawTailVolatile();
var termOffset = rawTail & 0xFFFFFFFFL;
var position = LogBufferDescriptor.ComputeTermBeginPosition(LogBufferDescriptor.TermId(rawTail), _positionBitsToShift, InitialTermId) + termOffset;
if (position < limit)
{
long result;
if (length <= MaxPayloadLength)
{
result = termAppender.AppendUnfragmentedMessage(_headerWriter, buffer, offset, length, reservedValueSupplier);
}
else
{
CheckForMaxMessageLength(length);
result = termAppender.AppendFragmentedMessage(_headerWriter, buffer, offset, length, MaxPayloadLength, reservedValueSupplier);
}
newPosition = NewPosition(partitionIndex, (int)termOffset, position, result);
}
else if (_conductor.IsPublicationConnected(LogBufferDescriptor.TimeOfLastStatusMessage(_logMetaDataBuffer)))
{
newPosition = BACK_PRESSURED;
}
else
{
newPosition = NOT_CONNECTED;
}
}
return(newPosition);
}
private long NewPosition(int index, int currentTail, long position, long result)
{
var newPosition = ADMIN_ACTION;
var termOffset = TermAppender.TermOffset(result);
if (termOffset > 0)
{
newPosition = (position - currentTail) + termOffset;
}
else if (termOffset == TermAppender.TRIPPED)
{
var nextIndex = LogBufferDescriptor.NextPartitionIndex(index);
_termAppenders[nextIndex].TailTermId(TermAppender.TermId(result) + 1);
LogBufferDescriptor.ActivePartitionIndex(_logMetaDataBuffer, nextIndex);
}
return(newPosition);
}