1 | #pragma once |
---|---|
2 | |
3 | #include <TableFunctions/ITableFunction.h> |
4 | #include <Common/IFactoryWithAliases.h> |
5 | #include <Common/NamePrompter.h> |
6 | |
7 | |
8 | #include <functional> |
9 | #include <memory> |
10 | #include <string> |
11 | #include <unordered_map> |
12 | #include <boost/noncopyable.hpp> |
13 | |
14 | |
15 | namespace DB |
16 | { |
17 | |
18 | class Context; |
19 | |
20 | using TableFunctionCreator = std::function<TableFunctionPtr()>; |
21 | |
22 | /** Lets you get a table function by its name. |
23 | */ |
24 | class TableFunctionFactory final: private boost::noncopyable, public IFactoryWithAliases<TableFunctionCreator> |
25 | { |
26 | public: |
27 | |
28 | static TableFunctionFactory & instance(); |
29 | |
30 | /// Register a function by its name. |
31 | /// No locking, you must register all functions before usage of get. |
32 | void registerFunction(const std::string & name, Creator creator, CaseSensitiveness case_sensitiveness = CaseSensitive); |
33 | |
34 | template <typename Function> |
35 | void registerFunction(CaseSensitiveness case_sensitiveness = CaseSensitive) |
36 | { |
37 | auto creator = [] () -> TableFunctionPtr |
38 | { |
39 | return std::make_shared<Function>(); |
40 | }; |
41 | registerFunction(Function::name, std::move(creator), case_sensitiveness); |
42 | } |
43 | |
44 | /// Throws an exception if not found. |
45 | TableFunctionPtr get(const std::string & name, const Context & context) const; |
46 | |
47 | /// Returns nullptr if not found. |
48 | TableFunctionPtr tryGet(const std::string & name, const Context & context) const; |
49 | |
50 | bool isTableFunctionName(const std::string & name) const; |
51 | |
52 | private: |
53 | using TableFunctions = std::unordered_map<std::string, Creator>; |
54 | |
55 | const TableFunctions & getCreatorMap() const override { return table_functions; } |
56 | |
57 | const TableFunctions & getCaseInsensitiveCreatorMap() const override { return case_insensitive_table_functions; } |
58 | |
59 | String getFactoryName() const override { return "TableFunctionFactory"; } |
60 | |
61 | TableFunctions table_functions; |
62 | TableFunctions case_insensitive_table_functions; |
63 | }; |
64 | |
65 | } |
66 |