ClickHouse

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#include <Processors/Sources/TemporaryFileLazySource.h>
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#include <Formats/TemporaryFileStreamLegacy.h>
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namespace DB
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{
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TemporaryFileLazySource::~TemporaryFileLazySource() = default;
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TemporaryFileLazySource::TemporaryFileLazySource(const std::string & path_, const Block & header_)
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    : ISource(header_, true)
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    , path(path_)
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    , done(false)
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{}
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Chunk TemporaryFileLazySource::generate()
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{
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    if (done)
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        return {};
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    if (!stream)
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        stream = std::make_unique<TemporaryFileStreamLegacy>(path, header);
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    auto block = stream->block_in->read();
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    if (!block)
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    {
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        done = true;
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        stream.reset();
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    }
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    return Chunk(block.getColumns(), block.rows());
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}
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}
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