/// <summary>
/// Poll for new messages in a stream. If new messages are found beyond the last consumed position then they
/// will be delivered to the <seealso cref="IBlockHandler"/> up to a limited number of bytes.
///
/// A scan will terminate if a padding frame is encountered. If first frame in a scan is padding then a block
/// for the padding is notified. If the padding comes after the first frame in a scan then the scan terminates
/// at the offset the padding frame begins. Padding frames are delivered singularly in a block.
///
/// Padding frames may be for a greater range than the limit offset but only the header needs to be valid so
/// relevant length of the frame is <see cref="DataHeaderFlyweight.HEADER_LENGTH"/>
/// </summary>
/// <param name="handler"> to which block is delivered. </param>
/// <param name="blockLengthLimit"> up to which a block may be in length. </param>
/// <returns> the number of bytes that have been consumed. </returns>
public int BlockPoll(BlockHandler handler, int blockLengthLimit)
{
if (_isClosed)
{
return(0);
}
var position = _subscriberPosition.Get();
var offset = (int)position & _termLengthMask;
var termBuffer = ActiveTermBuffer(position);
var limitOffset = Math.Min(offset + blockLengthLimit, termBuffer.Capacity);
var resultingOffset = TermBlockScanner.Scan(termBuffer, offset, limitOffset);
var length = resultingOffset - offset;
if (resultingOffset > offset)
{
try
{
var termId = termBuffer.GetInt(offset + DataHeaderFlyweight.TERM_ID_FIELD_OFFSET);
handler(termBuffer, offset, length, SessionId, termId);
}
catch (Exception t)
{
_errorHandler(t);
}
finally
{
_subscriberPosition.SetOrdered(position + length);
}
}
return(length);
}
public void ShouldReadBlockOfThreeMessagesThatFillBuffer()
{
const int offset = 0;
int limit = _termBuffer.Capacity;
const int messageLength = 50;
int alignedMessageLength = BitUtil.Align(messageLength, FrameDescriptor.FRAME_ALIGNMENT);
int thirdMessageLength = limit - (alignedMessageLength * 2);
A.CallTo(() => _termBuffer.GetIntVolatile(FrameDescriptor.LengthOffset(offset)))
.Returns(messageLength);
A.CallTo(() => _termBuffer.GetShort(FrameDescriptor.TypeOffset(offset)))
.Returns((short)HeaderFlyweight.HDR_TYPE_DATA);
A.CallTo(() => _termBuffer.GetIntVolatile(FrameDescriptor.LengthOffset(alignedMessageLength)))
.Returns(messageLength);
A.CallTo(() => _termBuffer.GetShort(FrameDescriptor.TypeOffset(alignedMessageLength)))
.Returns((short)HeaderFlyweight.HDR_TYPE_DATA);
A.CallTo(() => _termBuffer.GetIntVolatile(FrameDescriptor.LengthOffset(alignedMessageLength * 2)))
.Returns(thirdMessageLength);
A.CallTo(() => _termBuffer.GetShort(FrameDescriptor.TypeOffset(alignedMessageLength * 2)))
.Returns((short)HeaderFlyweight.HDR_TYPE_DATA);
int newOffset = TermBlockScanner.Scan(_termBuffer, offset, limit);
Assert.That(newOffset, Is.EqualTo(limit));
}
/// <summary>
/// Poll for new messages in a stream. If new messages are found beyond the last consumed position then they
/// will be delivered to the <seealso cref="IBlockHandler"/> up to a limited number of bytes.
/// </summary>
/// <param name="blockHandler"> to which block is delivered. </param>
/// <param name="blockLengthLimit"> up to which a block may be in length. </param>
/// <returns> the number of bytes that have been consumed. </returns>
public int BlockPoll(IBlockHandler blockHandler, int blockLengthLimit)
{
if (_isClosed)
{
return(0);
}
var position = _subscriberPosition.Get();
var termOffset = (int)position & _termLengthMask;
var termBuffer = ActiveTermBuffer(position);
var limit = Math.Min(termOffset + blockLengthLimit, termBuffer.Capacity);
var resultingOffset = TermBlockScanner.Scan(termBuffer, termOffset, limit);
var bytesConsumed = resultingOffset - termOffset;
if (resultingOffset > termOffset)
{
try
{
var termId = termBuffer.GetInt(termOffset + DataHeaderFlyweight.TERM_ID_FIELD_OFFSET);
blockHandler.OnBlock(termBuffer, termOffset, bytesConsumed, SessionId, termId);
}
catch (Exception t)
{
_errorHandler(t);
}
_subscriberPosition.SetOrdered(position + bytesConsumed);
}
return(bytesConsumed);
}
public void ShouldScanEmptyBuffer()
{
const int offset = 0;
int limit = _termBuffer.Capacity;
int newOffset = TermBlockScanner.Scan(_termBuffer, offset, limit);
Assert.AreEqual(offset, newOffset);
}
public void ShouldReadFirstMessage()
{
const int offset = 0;
int limit = _termBuffer.Capacity;
const int messageLength = 50;
int alignedMessageLength = BitUtil.Align(messageLength, FrameDescriptor.FRAME_ALIGNMENT);
A.CallTo(() => _termBuffer.GetIntVolatile(FrameDescriptor.LengthOffset(offset)))
.Returns(messageLength);
int newOffset = TermBlockScanner.Scan(_termBuffer, offset, limit);
Assert.That(newOffset, Is.EqualTo(alignedMessageLength));
}
public void ShouldReadOneMessageOnLimit()
{
const int offset = 0;
const int messageLength = 50;
int alignedMessageLength = BitUtil.Align(messageLength, FrameDescriptor.FRAME_ALIGNMENT);
int limit = alignedMessageLength;
A.CallTo(() => _termBuffer.GetIntVolatile(FrameDescriptor.LengthOffset(offset)))
.Returns(messageLength);
int newOffset = TermBlockScanner.Scan(_termBuffer, offset, limit);
Assert.AreEqual(alignedMessageLength, newOffset);
}
public void ShouldReadFirstMessage()
{
const int offset = 0;
int limit = _termBuffer.Capacity;
const int messageLength = 50;
int alignedMessageLength = BitUtil.Align(messageLength, FrameDescriptor.FRAME_ALIGNMENT);
A.CallTo(() => _termBuffer.GetIntVolatile(FrameDescriptor.LengthOffset(offset)))
.Returns(messageLength);
A.CallTo(() => _termBuffer.GetShort(FrameDescriptor.TypeOffset(offset)))
.Returns((short)HeaderFlyweight.HDR_TYPE_DATA);
int newOffset = TermBlockScanner.Scan(_termBuffer, offset, limit);
Assert.AreEqual(alignedMessageLength, newOffset);
}
public void ShouldReadBlockOfOneMessageThenPadding()
{
const int offset = 0;
int limit = _termBuffer.Capacity;
int messageLength = 50;
int alignedMessageLength = BitUtil.Align(messageLength, FrameDescriptor.FRAME_ALIGNMENT);
A.CallTo(() => _termBuffer.GetIntVolatile(FrameDescriptor.LengthOffset(offset))).Returns(messageLength);
A.CallTo(() => _termBuffer.GetShort(FrameDescriptor.TypeOffset(offset))).Returns((short)HeaderFlyweight.HDR_TYPE_DATA);
A.CallTo(() => _termBuffer.GetIntVolatile(FrameDescriptor.LengthOffset(alignedMessageLength))).Returns(messageLength);
A.CallTo(() => _termBuffer.GetShort(FrameDescriptor.TypeOffset(alignedMessageLength))).Returns((short)HeaderFlyweight.HDR_TYPE_PAD);
int firstOffset = TermBlockScanner.Scan(_termBuffer, offset, limit);
Assert.That(firstOffset, Is.EqualTo(alignedMessageLength));
int secondOffset = TermBlockScanner.Scan(_termBuffer, firstOffset, limit);
Assert.That(secondOffset, Is.EqualTo(alignedMessageLength * 2));
}
