feat: expose Buffer/Block on {Msg}DataReader (#151)#152
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The generated zero-copy reader already held the source span as a private field but didn't surface it. SbeDispatcher consumers that need to forward or buffer the raw bytes (e.g. snapshot-heal flows that stash messages into an ArrayPool slot for later replay) had no way to recover them after parsing — forcing a parallel manual templateId switch just to capture the body. Adds three readonly properties: - Buffer full source ReadOnlySpan<byte> the reader was built from - Block slice sized to the wire blockLength - BlockLength the wire blockLength int All readonly => no defensive copies through 'in' parameters. No codegen size or runtime cost change — only public accessors over fields that already existed. Bumps version to 1.3.0 (additive feature). 187 + 128 tests green (2 new ReaderBufferAccessTests covering fixed-layout and variable-data messages). Closes #151. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Closes #151.
Problema
{Msg}DataReaderguarda o buffer-fonte num campo privado mas não expõe. Consumidores que migram paraSbeDispatcher(#147) e precisam encaminhar/buffer os bytes brutos (ex.: fluxo de snapshot-heal do B3 UMDF que enfileira a mensagem num slot doArrayPoolpara replay posterior) ficam sem recurso — precisariam manter um switch manual paralelo só para capturar o body.Mudança
Adiciona 3 properties
readonlyem todo{Msg}DataReadergerado:BufferReadOnlySpan<byte>BytesConsumedapósReadGroupspara fatiar exato)BlockReadOnlySpan<byte>blockLengthdo wireBlockLengthintblockLengthque construiu o readerTodas
readonlypara evitar defensive copies quando o reader chega viain.Custo
Zero — os dados já existem no campo privado
_buffer/_blockLength. São apenas accessors públicos. Sem mudança no tamanho do struct, sem branch novo, sem virtual.Estratégia alternativa considerada
Expor uma fábrica tipo
reader.AsBytes(int blockLengthOverride)? Descartado: não há ganho sobre slicing direto e adiciona superfície de API. Manter spans crus dá ao consumidor 100% de controle.Testes
tests/SbeCodeGenerator.IntegrationTests/ReaderBufferAccessTests.cs:Edge.Cases.Test.V0.TradeData): validaBlock/Buffer/BlockLengthespelham o que o encoder escreveu.Integration.Test.V0.OrderBookData): valida queBuffer.Slice(0, BytesConsumed)apósReadGroupsrecupera o footprint completo da mensagem com groups.187 + 128 testes verdes.