ClickHouse/dbms/src/Parsers/ASTFunction.cpp
2019-06-17 01:51:09 +03:00

372 lines
14 KiB
C++

#include <Common/typeid_cast.h>
#include <Parsers/ASTLiteral.h>
#include <Parsers/ASTFunction.h>
#include <Parsers/ASTWithAlias.h>
#include <Parsers/ASTSubquery.h>
#include <IO/WriteHelpers.h>
#include <IO/WriteBufferFromString.h>
namespace DB
{
void ASTFunction::appendColumnNameImpl(WriteBuffer & ostr) const
{
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);
for (auto it = arguments->children.begin(); it != arguments->children.end(); ++it)
{
if (it != arguments->children.begin())
writeCString(", ", ostr);
(*it)->appendColumnName(ostr);
}
writeChar(')', 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); }
return res;
}
/** A special hack. If it's LIKE or NOT 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;
}
void ASTFunction::formatImplWithoutAlias(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const
{
FormatStateStacked nested_need_parens = frame;
FormatStateStacked nested_dont_need_parens = frame;
nested_need_parens.need_parens = true;
nested_dont_need_parens.need_parens = false;
/// Should this function to be written as operator?
bool written = false;
if (arguments && !parameters)
{
if (arguments->children.size() == 1)
{
const char * operators[] =
{
"negate", "-",
"not", "NOT ",
nullptr
};
for (const char ** func = operators; *func; func += 2)
{
if (0 == strcmp(name.c_str(), func[0]))
{
if (frame.need_parens)
settings.ostr << '(';
settings.ostr << (settings.hilite ? hilite_operator : "") << func[1] << (settings.hilite ? hilite_none : "");
/** A particularly stupid case. If we have a unary minus before a literal that is a negative number
* "-(-1)" or "- -1", this can not be formatted as `--1`, since this will be interpreted as a comment.
* Instead, add a space.
* PS. You can not just ask to add parentheses - see formatImpl for ASTLiteral.
*/
if (name == "negate" && arguments->children[0]->as<ASTLiteral>())
settings.ostr << ' ';
arguments->formatImpl(settings, state, nested_need_parens);
written = true;
if (frame.need_parens)
settings.ostr << ')';
}
}
}
/** 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 ",
"notLike", " NOT LIKE ",
"in", " IN ",
"notIn", " NOT IN ",
"globalIn", " GLOBAL IN ",
"globalNotIn", " GLOBAL NOT IN ",
nullptr
};
for (const char ** func = operators; *func; func += 2)
{
if (0 == strcmp(name.c_str(), 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")
&& 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_func->name == "tuple")
&& !(second_arg_literal && second_arg_literal->value.getType() == Field::Types::Tuple)
&& !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 && 0 == strcmp(name.c_str(), "arrayElement"))
{
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 && 0 == strcmp(name.c_str(), "tupleElement"))
{
/// It can be printed in a form of 'x.1' only if right hand side is unsigned integer literal.
if (const auto * lit = arguments->children[1]->as<ASTLiteral>())
{
if (lit->value.getType() == Field::Types::UInt64)
{
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 && 0 == strcmp(name.c_str(), "lambda"))
{
/// 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[0]->formatImpl(settings, state, nested_need_parens);
}
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 (0 == strcmp(name.c_str(), 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 && 0 == strcmp(name.c_str(), "array"))
{
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 && 0 == strcmp(name.c_str(), "tuple"))
{
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)
{
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)
{
settings.ostr << '(' << (settings.hilite ? hilite_none : "");
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);
}
settings.ostr << (settings.hilite ? hilite_function : "") << ')';
}
settings.ostr << (settings.hilite ? hilite_none : "");
}
}
}