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8b9778ebb6
In case of ambiguity, lambda functions should prefer its arguments to other aliases or identifiers
88 lines
2.5 KiB
C++
88 lines
2.5 KiB
C++
#pragma once
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#include <map>
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#include <Parsers/IAST.h>
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#include <Interpreters/Aliases.h>
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#include <Core/Names.h>
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namespace DB
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{
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class ASTSelectQuery;
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class ASTIdentifier;
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struct ASTTablesInSelectQueryElement;
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class Context;
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class QueryNormalizer
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{
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/// Extracts settings, mostly to show which are used and which are not.
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struct ExtractedSettings
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{
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const UInt64 max_ast_depth;
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const UInt64 max_expanded_ast_elements;
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bool prefer_column_name_to_alias;
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template <typename T>
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ExtractedSettings(const T & settings)
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: max_ast_depth(settings.max_ast_depth)
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, max_expanded_ast_elements(settings.max_expanded_ast_elements)
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, prefer_column_name_to_alias(settings.prefer_column_name_to_alias)
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{
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}
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};
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public:
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struct Data
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{
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using SetOfASTs = std::set<const IAST *>;
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using MapOfASTs = std::map<ASTPtr, ASTPtr>;
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Aliases & aliases;
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const NameSet & source_columns_set;
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ExtractedSettings settings;
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/// tmp data
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size_t level;
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MapOfASTs finished_asts; /// already processed vertices (and by what they replaced)
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SetOfASTs current_asts; /// vertices in the current call stack of this method
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std::string current_alias; /// the alias referencing to the ancestor of ast (the deepest ancestor with aliases)
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const bool ignore_alias; /// normalize query without any aliases
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/// It's Ok to have "c + 1 AS c" in queries, but not in table definition
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const bool allow_self_aliases; /// for constructs like "SELECT column + 1 AS column"
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Data(Aliases & aliases_, const NameSet & source_columns_set_, bool ignore_alias_, ExtractedSettings && settings_, bool allow_self_aliases_)
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: aliases(aliases_)
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, source_columns_set(source_columns_set_)
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, settings(settings_)
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, level(0)
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, ignore_alias(ignore_alias_)
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, allow_self_aliases(allow_self_aliases_)
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{}
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};
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explicit QueryNormalizer(Data & data)
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: visitor_data(data)
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{}
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void visit(ASTPtr & ast)
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{
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visit(ast, visitor_data);
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}
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private:
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Data & visitor_data;
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static void visit(ASTPtr & ast, Data & data);
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static void visit(ASTIdentifier &, ASTPtr &, Data &);
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static void visit(ASTTablesInSelectQueryElement &, const ASTPtr &, Data &);
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static void visit(ASTSelectQuery &, const ASTPtr &, Data &);
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static void visitChildren(IAST * node, Data & data);
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};
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}
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