ClickHouse/src/Parsers/ASTFunction.cpp
Alexey Milovidov 993f3faefd Miscellaneous
2021-10-31 18:11:46 +03:00

637 lines
23 KiB
C++

#include <string_view>
#include <Parsers/ASTFunction.h>
#include <Common/quoteString.h>
#include <Common/FieldVisitorToString.h>
#include <Common/SipHash.h>
#include <Common/typeid_cast.h>
#include <DataTypes/IDataType.h>
#include <DataTypes/NumberTraits.h>
#include <IO/Operators.h>
#include <IO/WriteBufferFromString.h>
#include <IO/WriteHelpers.h>
#include <Parsers/ASTExpressionList.h>
#include <Parsers/ASTIdentifier.h>
#include <Parsers/ASTLiteral.h>
#include <Parsers/ASTSubquery.h>
#include <Parsers/ASTWithAlias.h>
#include <Parsers/queryToString.h>
using namespace std::literals;
namespace DB
{
namespace ErrorCodes
{
extern const int UNEXPECTED_EXPRESSION;
extern const int UNEXPECTED_AST_STRUCTURE;
}
void ASTFunction::appendColumnNameImpl(WriteBuffer & ostr) const
{
if (name == "view")
throw Exception("Table function view cannot be used as an expression", ErrorCodes::UNEXPECTED_EXPRESSION);
writeString(name, ostr);
if (parameters)
{
writeChar('(', ostr);
for (auto it = parameters->children.begin(); it != parameters->children.end(); ++it)
{
if (it != parameters->children.begin())
writeCString(", ", ostr);
(*it)->appendColumnName(ostr);
}
writeChar(')', ostr);
}
writeChar('(', ostr);
if (arguments)
{
for (auto it = arguments->children.begin(); it != arguments->children.end(); ++it)
{
if (it != arguments->children.begin())
writeCString(", ", ostr);
(*it)->appendColumnName(ostr);
}
}
writeChar(')', ostr);
if (is_window_function)
{
writeCString(" OVER ", ostr);
if (!window_name.empty())
{
ostr << window_name;
}
else
{
FormatSettings format_settings{ostr, true /* one_line */};
FormatState state;
FormatStateStacked frame;
writeCString("(", ostr);
window_definition->formatImpl(format_settings, state, frame);
writeCString(")", ostr);
}
}
}
/** Get the text that identifies this element. */
String ASTFunction::getID(char delim) const
{
return "Function" + (delim + name);
}
ASTPtr ASTFunction::clone() const
{
auto res = std::make_shared<ASTFunction>(*this);
res->children.clear();
if (arguments) { res->arguments = arguments->clone(); res->children.push_back(res->arguments); }
if (parameters) { res->parameters = parameters->clone(); res->children.push_back(res->parameters); }
if (window_definition)
{
res->window_definition = window_definition->clone();
res->children.push_back(res->window_definition);
}
return res;
}
void ASTFunction::updateTreeHashImpl(SipHash & hash_state) const
{
hash_state.update(name.size());
hash_state.update(name);
IAST::updateTreeHashImpl(hash_state);
}
ASTPtr ASTFunction::toLiteral() const
{
if (!arguments) return {};
if (name == "array")
{
Array array;
for (const auto & arg : arguments->children)
{
if (auto * literal = arg->as<ASTLiteral>())
array.push_back(literal->value);
else if (auto * func = arg->as<ASTFunction>())
{
if (auto func_literal = func->toLiteral())
array.push_back(func_literal->as<ASTLiteral>()->value);
}
else
/// Some of the Array arguments is not literal
return {};
}
return std::make_shared<ASTLiteral>(array);
}
return {};
}
/** A special hack. If it's [I]LIKE or NOT [I]LIKE expression and the right hand side is a string literal,
* we will highlight unescaped metacharacters % and _ in string literal for convenience.
* Motivation: most people are unaware that _ is a metacharacter and forgot to properly escape it with two backslashes.
* With highlighting we make it clearly obvious.
*
* Another case is regexp match. Suppose the user types match(URL, 'www.yandex.ru'). It often means that the user is unaware that . is a metacharacter.
*/
static bool highlightStringLiteralWithMetacharacters(const ASTPtr & node, const IAST::FormatSettings & settings, const char * metacharacters)
{
if (const auto * literal = node->as<ASTLiteral>())
{
if (literal->value.getType() == Field::Types::String)
{
auto string = applyVisitor(FieldVisitorToString(), literal->value);
unsigned escaping = 0;
for (auto c : string)
{
if (c == '\\')
{
settings.ostr << c;
if (escaping == 2)
escaping = 0;
++escaping;
}
else if (nullptr != strchr(metacharacters, c))
{
if (escaping == 2) /// Properly escaped metacharacter
settings.ostr << c;
else /// Unescaped metacharacter
settings.ostr << "\033[1;35m" << c << "\033[0m";
escaping = 0;
}
else
{
settings.ostr << c;
escaping = 0;
}
}
return true;
}
}
return false;
}
ASTSelectWithUnionQuery * ASTFunction::tryGetQueryArgument() const
{
if (arguments && arguments->children.size() == 1)
{
return arguments->children[0]->as<ASTSelectWithUnionQuery>();
}
return nullptr;
}
void ASTFunction::formatImplWithoutAlias(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const
{
frame.expression_list_prepend_whitespace = false;
FormatStateStacked nested_need_parens = frame;
FormatStateStacked nested_dont_need_parens = frame;
nested_need_parens.need_parens = true;
nested_dont_need_parens.need_parens = false;
if (auto * query = tryGetQueryArgument())
{
std::string nl_or_nothing = settings.one_line ? "" : "\n";
std::string indent_str = settings.one_line ? "" : std::string(4u * frame.indent, ' ');
settings.ostr << (settings.hilite ? hilite_function : "") << name << "(" << nl_or_nothing;
FormatStateStacked frame_nested = frame;
frame_nested.need_parens = false;
++frame_nested.indent;
query->formatImpl(settings, state, frame_nested);
settings.ostr << nl_or_nothing << indent_str << ")";
return;
}
/// Should this function to be written as operator?
bool written = false;
if (arguments && !parameters)
{
/// Unary prefix operators.
if (arguments->children.size() == 1)
{
const char * operators[] =
{
"negate", "-",
"not", "NOT ",
nullptr
};
for (const char ** func = operators; *func; func += 2)
{
if (strcasecmp(name.c_str(), func[0]) != 0)
{
continue;
}
const auto * literal = arguments->children[0]->as<ASTLiteral>();
const auto * function = arguments->children[0]->as<ASTFunction>();
bool negate = name == "negate";
bool is_tuple = literal && literal->value.getType() == Field::Types::Tuple;
// do not add parentheses for tuple literal, otherwise extra parens will be added `-((3, 7, 3), 1)` -> `-(((3, 7, 3), 1))`
bool literal_need_parens = literal && !is_tuple;
// negate always requires parentheses, otherwise -(-1) will be printed as --1
bool negate_need_parens = negate && (literal_need_parens || (function && function->name == "negate"));
// We don't need parentheses around a single literal.
bool need_parens = !literal && frame.need_parens && !negate_need_parens;
// do not add extra parentheses for functions inside negate, i.e. -(-toUInt64(-(1)))
if (negate_need_parens)
nested_need_parens.need_parens = false;
if (need_parens)
settings.ostr << '(';
settings.ostr << (settings.hilite ? hilite_operator : "") << func[1] << (settings.hilite ? hilite_none : "");
if (negate_need_parens)
settings.ostr << '(';
arguments->formatImpl(settings, state, nested_need_parens);
written = true;
if (negate_need_parens)
settings.ostr << ')';
if (need_parens)
settings.ostr << ')';
break;
}
}
/// Unary postfix operators.
if (!written && arguments->children.size() == 1)
{
const char * operators[] =
{
"isNull", " IS NULL",
"isNotNull", " IS NOT NULL",
nullptr
};
for (const char ** func = operators; *func; func += 2)
{
if (strcasecmp(name.c_str(), func[0]) != 0)
{
continue;
}
if (frame.need_parens)
settings.ostr << '(';
arguments->formatImpl(settings, state, nested_need_parens);
settings.ostr << (settings.hilite ? hilite_operator : "") << func[1] << (settings.hilite ? hilite_none : "");
if (frame.need_parens)
settings.ostr << ')';
written = true;
break;
}
}
/** need_parens - do we need parentheses around the expression with the operator.
* They are needed only if this expression is included in another expression with the operator.
*/
if (!written && arguments->children.size() == 2)
{
const char * operators[] =
{
"multiply", " * ",
"divide", " / ",
"modulo", " % ",
"plus", " + ",
"minus", " - ",
"notEquals", " != ",
"lessOrEquals", " <= ",
"greaterOrEquals", " >= ",
"less", " < ",
"greater", " > ",
"equals", " = ",
"like", " LIKE ",
"ilike", " ILIKE ",
"notLike", " NOT LIKE ",
"notILike", " NOT ILIKE ",
"in", " IN ",
"notIn", " NOT IN ",
"globalIn", " GLOBAL IN ",
"globalNotIn", " GLOBAL NOT IN ",
nullptr
};
for (const char ** func = operators; *func; func += 2)
{
if (name == std::string_view(func[0]))
{
if (frame.need_parens)
settings.ostr << '(';
arguments->children[0]->formatImpl(settings, state, nested_need_parens);
settings.ostr << (settings.hilite ? hilite_operator : "") << func[1] << (settings.hilite ? hilite_none : "");
bool special_hilite = settings.hilite
&& (name == "like" || name == "notLike" || name == "ilike" || name == "notILike")
&& highlightStringLiteralWithMetacharacters(arguments->children[1], settings, "%_");
/// Format x IN 1 as x IN (1): put parens around rhs even if there is a single element in set.
const auto * second_arg_func = arguments->children[1]->as<ASTFunction>();
const auto * second_arg_literal = arguments->children[1]->as<ASTLiteral>();
bool extra_parents_around_in_rhs = (name == "in" || name == "notIn" || name == "globalIn" || name == "globalNotIn")
&& !second_arg_func
&& !(second_arg_literal
&& (second_arg_literal->value.getType() == Field::Types::Tuple
|| second_arg_literal->value.getType() == Field::Types::Array))
&& !arguments->children[1]->as<ASTSubquery>();
if (extra_parents_around_in_rhs)
{
settings.ostr << '(';
arguments->children[1]->formatImpl(settings, state, nested_dont_need_parens);
settings.ostr << ')';
}
if (!special_hilite && !extra_parents_around_in_rhs)
arguments->children[1]->formatImpl(settings, state, nested_need_parens);
if (frame.need_parens)
settings.ostr << ')';
written = true;
}
}
if (!written && name == "arrayElement"sv)
{
if (frame.need_parens)
settings.ostr << '(';
arguments->children[0]->formatImpl(settings, state, nested_need_parens);
settings.ostr << (settings.hilite ? hilite_operator : "") << '[' << (settings.hilite ? hilite_none : "");
arguments->children[1]->formatImpl(settings, state, nested_dont_need_parens);
settings.ostr << (settings.hilite ? hilite_operator : "") << ']' << (settings.hilite ? hilite_none : "");
written = true;
if (frame.need_parens)
settings.ostr << ')';
}
if (!written && name == "tupleElement"sv)
{
// fuzzer sometimes may insert tupleElement() created from ASTLiteral:
//
// Function_tupleElement, 0xx
// -ExpressionList_, 0xx
// --Literal_Int64_255, 0xx
// --Literal_Int64_100, 0xx
//
// And in this case it will be printed as "255.100", which
// later will be parsed as float, and formatting will be
// inconsistent.
//
// So instead of printing it as regular tuple,
// let's print it as ExpressionList instead (i.e. with ", " delimiter).
bool tuple_arguments_valid = true;
const auto * lit_left = arguments->children[0]->as<ASTLiteral>();
const auto * lit_right = arguments->children[1]->as<ASTLiteral>();
if (lit_left)
{
Field::Types::Which type = lit_left->value.getType();
if (type != Field::Types::Tuple && type != Field::Types::Array)
{
tuple_arguments_valid = false;
}
}
// It can be printed in a form of 'x.1' only if right hand side
// is an unsigned integer lineral. We also allow nonnegative
// signed integer literals, because the fuzzer sometimes inserts
// them, and we want to have consistent formatting.
if (tuple_arguments_valid && lit_right)
{
if (isInt64OrUInt64FieldType(lit_right->value.getType())
&& lit_right->value.get<Int64>() >= 0)
{
if (frame.need_parens)
settings.ostr << '(';
arguments->children[0]->formatImpl(settings, state, nested_need_parens);
settings.ostr << (settings.hilite ? hilite_operator : "") << "." << (settings.hilite ? hilite_none : "");
arguments->children[1]->formatImpl(settings, state, nested_dont_need_parens);
written = true;
if (frame.need_parens)
settings.ostr << ')';
}
}
}
if (!written && name == "lambda"sv)
{
/// Special case: zero elements tuple in lhs of lambda is printed as ().
/// Special case: one-element tuple in lhs of lambda is printed as its element.
if (frame.need_parens)
settings.ostr << '(';
const auto * first_arg_func = arguments->children[0]->as<ASTFunction>();
if (first_arg_func
&& first_arg_func->name == "tuple"
&& first_arg_func->arguments
&& (first_arg_func->arguments->children.size() == 1 || first_arg_func->arguments->children.empty()))
{
if (first_arg_func->arguments->children.size() == 1)
first_arg_func->arguments->children[0]->formatImpl(settings, state, nested_need_parens);
else
settings.ostr << "()";
}
else
arguments->children[0]->formatImpl(settings, state, nested_need_parens);
settings.ostr << (settings.hilite ? hilite_operator : "") << " -> " << (settings.hilite ? hilite_none : "");
arguments->children[1]->formatImpl(settings, state, nested_need_parens);
if (frame.need_parens)
settings.ostr << ')';
written = true;
}
}
if (!written && arguments->children.size() >= 2)
{
const char * operators[] =
{
"and", " AND ",
"or", " OR ",
nullptr
};
for (const char ** func = operators; *func; func += 2)
{
if (name == std::string_view(func[0]))
{
if (frame.need_parens)
settings.ostr << '(';
for (size_t i = 0; i < arguments->children.size(); ++i)
{
if (i != 0)
settings.ostr << (settings.hilite ? hilite_operator : "") << func[1] << (settings.hilite ? hilite_none : "");
arguments->children[i]->formatImpl(settings, state, nested_need_parens);
}
if (frame.need_parens)
settings.ostr << ')';
written = true;
}
}
}
if (!written && name == "array"sv)
{
settings.ostr << (settings.hilite ? hilite_operator : "") << '[' << (settings.hilite ? hilite_none : "");
for (size_t i = 0; i < arguments->children.size(); ++i)
{
if (i != 0)
settings.ostr << ", ";
arguments->children[i]->formatImpl(settings, state, nested_dont_need_parens);
}
settings.ostr << (settings.hilite ? hilite_operator : "") << ']' << (settings.hilite ? hilite_none : "");
written = true;
}
if (!written && arguments->children.size() >= 2 && name == "tuple"sv)
{
settings.ostr << (settings.hilite ? hilite_operator : "") << '(' << (settings.hilite ? hilite_none : "");
for (size_t i = 0; i < arguments->children.size(); ++i)
{
if (i != 0)
settings.ostr << ", ";
arguments->children[i]->formatImpl(settings, state, nested_dont_need_parens);
}
settings.ostr << (settings.hilite ? hilite_operator : "") << ')' << (settings.hilite ? hilite_none : "");
written = true;
}
if (!written && name == "map"sv)
{
settings.ostr << (settings.hilite ? hilite_operator : "") << "map(" << (settings.hilite ? hilite_none : "");
for (size_t i = 0; i < arguments->children.size(); ++i)
{
if (i != 0)
settings.ostr << ", ";
arguments->children[i]->formatImpl(settings, state, nested_dont_need_parens);
}
settings.ostr << (settings.hilite ? hilite_operator : "") << ')' << (settings.hilite ? hilite_none : "");
written = true;
}
}
if (written)
{
return;
}
settings.ostr << (settings.hilite ? hilite_function : "") << name;
if (parameters)
{
settings.ostr << '(' << (settings.hilite ? hilite_none : "");
parameters->formatImpl(settings, state, nested_dont_need_parens);
settings.ostr << (settings.hilite ? hilite_function : "") << ')';
}
if ((arguments && !arguments->children.empty()) || !no_empty_args)
settings.ostr << '(' << (settings.hilite ? hilite_none : "");
if (arguments)
{
bool special_hilite_regexp = settings.hilite
&& (name == "match" || name == "extract" || name == "extractAll" || name == "replaceRegexpOne"
|| name == "replaceRegexpAll");
for (size_t i = 0, size = arguments->children.size(); i < size; ++i)
{
if (i != 0)
settings.ostr << ", ";
bool special_hilite = false;
if (i == 1 && special_hilite_regexp)
special_hilite = highlightStringLiteralWithMetacharacters(arguments->children[i], settings, "|()^$.[]?*+{:-");
if (!special_hilite)
arguments->children[i]->formatImpl(settings, state, nested_dont_need_parens);
}
}
if ((arguments && !arguments->children.empty()) || !no_empty_args)
settings.ostr << (settings.hilite ? hilite_function : "") << ')';
settings.ostr << (settings.hilite ? hilite_none : "");
if (!is_window_function)
{
return;
}
settings.ostr << " OVER ";
if (!window_name.empty())
{
settings.ostr << backQuoteIfNeed(window_name);
}
else
{
settings.ostr << "(";
window_definition->formatImpl(settings, state, frame);
settings.ostr << ")";
}
}
String getFunctionName(const IAST * ast)
{
String res;
if (tryGetFunctionNameInto(ast, res))
return res;
throw Exception(ast ? queryToString(*ast) + " is not an function" : "AST node is nullptr", ErrorCodes::UNEXPECTED_AST_STRUCTURE);
}
std::optional<String> tryGetFunctionName(const IAST * ast)
{
String res;
if (tryGetFunctionNameInto(ast, res))
return res;
return {};
}
bool tryGetFunctionNameInto(const IAST * ast, String & name)
{
if (ast)
{
if (const auto * node = ast->as<ASTFunction>())
{
name = node->name;
return true;
}
}
return false;
}
}