1#pragma once
2
3#include <Processors/IProcessor.h>
4
5
6namespace DB
7{
8
9/** Has one input and one output.
10 * Simply pull a block from input, transform it, and push it to output.
11 */
12class ISimpleTransform : public IProcessor
13{
14protected:
15 InputPort & input;
16 OutputPort & output;
17
18 Port::Data current_data;
19 bool has_input = false;
20 bool transformed = false;
21 bool no_more_data_needed = false;
22 const bool skip_empty_chunks;
23
24 /// Set input port NotNeeded after chunk was pulled.
25 /// Input port will become needed again only after data was transformed.
26 /// This allows to escape caching chunks in input port, which can lead to uneven data distribution.
27 bool set_input_not_needed_after_read = false;
28
29 virtual void transform(Chunk & chunk) = 0;
30 void stopReading() { no_more_data_needed = true; }
31
32public:
33 ISimpleTransform(Block input_header_, Block output_header_, bool skip_empty_chunks_);
34
35 Status prepare() override;
36 void work() override;
37
38 InputPort & getInputPort() { return input; }
39 OutputPort & getOutputPort() { return output; }
40
41 void setInputNotNeededAfterRead(bool value) { set_input_not_needed_after_read = value; }
42};
43
44}
45