1 | #pragma once |
2 | |
3 | #include <string> |
4 | #include <Processors/IProcessor.h> |
5 | #include <IO/Progress.h> |
6 | |
7 | |
8 | namespace DB |
9 | { |
10 | |
11 | class WriteBuffer; |
12 | |
13 | /** Output format have three inputs and no outputs. It writes data from WriteBuffer. |
14 | * |
15 | * First input is for main resultset, second is for "totals" and third is for "extremes". |
16 | * It's not necessarily to connect "totals" or "extremes" ports (they may remain dangling). |
17 | * |
18 | * Data from input ports are pulled in order: first, from main input, then totals, then extremes. |
19 | * |
20 | * By default, data for "totals" and "extremes" is ignored. |
21 | */ |
22 | class IOutputFormat : public IProcessor |
23 | { |
24 | public: |
25 | enum PortKind { Main = 0, Totals = 1, Extremes = 2 }; |
26 | |
27 | protected: |
28 | WriteBuffer & out; |
29 | |
30 | Chunk current_chunk; |
31 | PortKind current_block_kind = PortKind::Main; |
32 | bool has_input = false; |
33 | bool finished = false; |
34 | bool finalized = false; |
35 | |
36 | virtual void consume(Chunk) = 0; |
37 | virtual void consumeTotals(Chunk) {} |
38 | virtual void consumeExtremes(Chunk) {} |
39 | virtual void finalize() {} |
40 | |
41 | public: |
42 | IOutputFormat(const Block & , WriteBuffer & out_); |
43 | |
44 | Status prepare() override; |
45 | void work() override; |
46 | |
47 | /// Flush output buffers if any. |
48 | virtual void flush(); |
49 | |
50 | /// Value for rows_before_limit_at_least field. |
51 | virtual void setRowsBeforeLimit(size_t /*rows_before_limit*/) {} |
52 | |
53 | /// Notify about progress. Method could be called from different threads. |
54 | /// Passed value are delta, that must be summarized. |
55 | virtual void onProgress(const Progress & /*progress*/) {} |
56 | |
57 | /// Content-Type to set when sending HTTP response. |
58 | virtual std::string getContentType() const { return "text/plain; charset=UTF-8" ; } |
59 | |
60 | InputPort & getPort(PortKind kind) { return *std::next(inputs.begin(), kind); } |
61 | |
62 | public: |
63 | /// Compatible to IBlockOutputStream interface |
64 | |
65 | void write(const Block & block) { consume(Chunk(block.getColumns(), block.rows())); } |
66 | |
67 | virtual void doWritePrefix() {} |
68 | virtual void doWriteSuffix() { finalize(); } |
69 | |
70 | void setTotals(const Block & totals) { consumeTotals(Chunk(totals.getColumns(), totals.rows())); } |
71 | void setExtremes(const Block & extremes) { consumeExtremes(Chunk(extremes.getColumns(), extremes.rows())); } |
72 | }; |
73 | } |
74 | |
75 | |