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33 lines
693 B
C++
33 lines
693 B
C++
#pragma once
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#include <memory>
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#include <IO/ReadBuffer.h>
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namespace DB
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{
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struct IReadableWriteBuffer
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{
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/// At the first time returns getReadBufferImpl(). Next calls return nullptr.
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inline std::shared_ptr<ReadBuffer> tryGetReadBuffer()
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{
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if (!can_reread)
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return nullptr;
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can_reread = false;
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return getReadBufferImpl();
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}
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virtual ~IReadableWriteBuffer() {}
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protected:
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/// Creates read buffer from current write buffer.
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/// Returned buffer points to the first byte of original buffer.
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/// Original stream becomes invalid.
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virtual std::shared_ptr<ReadBuffer> getReadBufferImpl() = 0;
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bool can_reread = true;
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};
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}
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