mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-10-01 14:10:50 +00:00
361 lines
12 KiB
C++
361 lines
12 KiB
C++
#include <Parsers/Lexer.h>
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#include <Common/StringUtils/StringUtils.h>
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#include <common/find_symbols.h>
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namespace DB
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{
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namespace
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{
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/// This must be consistent with functions in ReadHelpers.h
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template <char quote, TokenType success_token, TokenType error_token>
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Token quotedString(const char *& pos, const char * const token_begin, const char * const end)
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{
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++pos;
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while (true)
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{
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pos = find_first_symbols<quote, '\\'>(pos, end);
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if (pos >= end)
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return Token(error_token, token_begin, end);
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if (*pos == quote)
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{
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++pos;
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if (pos < end && *pos == quote)
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{
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++pos;
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continue;
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}
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return Token(success_token, token_begin, pos);
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}
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if (*pos == '\\')
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{
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++pos;
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if (pos >= end)
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return Token(error_token, token_begin, end);
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++pos;
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continue;
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}
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__builtin_unreachable();
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}
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}
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}
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Token Lexer::nextToken()
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{
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Token res = nextTokenImpl();
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if (res.type != TokenType::EndOfStream && max_query_size && res.end > begin + max_query_size)
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res.type = TokenType::ErrorMaxQuerySizeExceeded;
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if (res.isSignificant())
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prev_significant_token_type = res.type;
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return res;
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}
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Token Lexer::nextTokenImpl()
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{
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if (pos >= end)
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return Token(TokenType::EndOfStream, end, end);
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const char * const token_begin = pos;
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auto commentUntilEndOfLine = [&]() mutable
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{
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pos = find_first_symbols<'\n'>(pos, end); /// This means that newline in single-line comment cannot be escaped.
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return Token(TokenType::Comment, token_begin, pos);
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};
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switch (*pos)
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{
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case ' ': [[fallthrough]];
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case '\t': [[fallthrough]];
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case '\n': [[fallthrough]];
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case '\r': [[fallthrough]];
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case '\f': [[fallthrough]];
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case '\v':
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{
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++pos;
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while (pos < end && isWhitespaceASCII(*pos))
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++pos;
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return Token(TokenType::Whitespace, token_begin, pos);
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}
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case '0': [[fallthrough]];
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case '1': [[fallthrough]];
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case '2': [[fallthrough]];
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case '3': [[fallthrough]];
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case '4': [[fallthrough]];
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case '5': [[fallthrough]];
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case '6': [[fallthrough]];
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case '7': [[fallthrough]];
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case '8': [[fallthrough]];
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case '9':
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{
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/// The task is not to parse a number or check correctness, but only to skip it.
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/// Disambiguation: if previous token was dot, then we could parse only simple integer,
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/// for chained tuple access operators (x.1.1) to work.
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// Otherwise it will be tokenized as x . 1.1, not as x . 1 . 1
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if (prev_significant_token_type == TokenType::Dot)
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{
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++pos;
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while (pos < end && isNumericASCII(*pos))
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++pos;
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}
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else
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{
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/// 0x, 0b
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bool hex = false;
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if (pos + 2 < end && *pos == '0' && (pos[1] == 'x' || pos[1] == 'b' || pos[1] == 'X' || pos[1] == 'B'))
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{
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if (pos[1] == 'x' || pos[1] == 'X')
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hex = true;
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pos += 2;
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}
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else
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++pos;
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while (pos < end && (hex ? isHexDigit(*pos) : isNumericASCII(*pos)))
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++pos;
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/// decimal point
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if (pos < end && *pos == '.')
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{
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++pos;
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while (pos < end && (hex ? isHexDigit(*pos) : isNumericASCII(*pos)))
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++pos;
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}
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/// exponentiation (base 10 or base 2)
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if (pos + 1 < end && (hex ? (*pos == 'p' || *pos == 'P') : (*pos == 'e' || *pos == 'E')))
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{
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++pos;
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/// sign of exponent. It is always decimal.
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if (pos + 1 < end && (*pos == '-' || *pos == '+'))
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++pos;
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while (pos < end && isNumericASCII(*pos))
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++pos;
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}
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}
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/// word character cannot go just after number (SELECT 123FROM)
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if (pos < end && isWordCharASCII(*pos))
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{
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++pos;
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while (pos < end && isWordCharASCII(*pos))
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++pos;
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return Token(TokenType::ErrorWrongNumber, token_begin, pos);
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}
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return Token(TokenType::Number, token_begin, pos);
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}
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case '\'':
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return quotedString<'\'', TokenType::StringLiteral, TokenType::ErrorSingleQuoteIsNotClosed>(pos, token_begin, end);
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case '"':
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return quotedString<'"', TokenType::QuotedIdentifier, TokenType::ErrorDoubleQuoteIsNotClosed>(pos, token_begin, end);
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case '`':
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return quotedString<'`', TokenType::QuotedIdentifier, TokenType::ErrorBackQuoteIsNotClosed>(pos, token_begin, end);
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case '(':
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return Token(TokenType::OpeningRoundBracket, token_begin, ++pos);
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case ')':
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return Token(TokenType::ClosingRoundBracket, token_begin, ++pos);
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case '[':
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return Token(TokenType::OpeningSquareBracket, token_begin, ++pos);
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case ']':
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return Token(TokenType::ClosingSquareBracket, token_begin, ++pos);
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case ',':
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return Token(TokenType::Comma, token_begin, ++pos);
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case ';':
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return Token(TokenType::Semicolon, token_begin, ++pos);
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case '.': /// qualifier, tuple access operator or start of floating point number
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{
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/// Just after identifier or complex expression or number (for chained tuple access like x.1.1 to work properly).
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if (pos > begin
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&& (!(pos + 1 < end && isNumericASCII(pos[1]))
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|| prev_significant_token_type == TokenType::ClosingRoundBracket
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|| prev_significant_token_type == TokenType::ClosingSquareBracket
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|| prev_significant_token_type == TokenType::BareWord
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|| prev_significant_token_type == TokenType::QuotedIdentifier
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|| prev_significant_token_type == TokenType::Number))
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return Token(TokenType::Dot, token_begin, ++pos);
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++pos;
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while (pos < end && isNumericASCII(*pos))
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++pos;
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/// exponentiation
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if (pos + 1 < end && (*pos == 'e' || *pos == 'E'))
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{
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++pos;
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/// sign of exponent
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if (pos + 1 < end && (*pos == '-' || *pos == '+'))
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++pos;
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while (pos < end && isNumericASCII(*pos))
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++pos;
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}
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return Token(TokenType::Number, token_begin, pos);
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}
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case '+':
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return Token(TokenType::Plus, token_begin, ++pos);
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case '-': /// minus (-), arrow (->) or start of comment (--)
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{
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++pos;
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if (pos < end && *pos == '>')
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return Token(TokenType::Arrow, token_begin, ++pos);
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if (pos < end && *pos == '-')
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{
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++pos;
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return commentUntilEndOfLine();
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}
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return Token(TokenType::Minus, token_begin, pos);
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}
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case '*':
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++pos;
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return Token(TokenType::Asterisk, token_begin, pos);
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case '/': /// division (/) or start of comment (//, /*)
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{
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++pos;
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if (pos < end && (*pos == '/' || *pos == '*'))
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{
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if (*pos == '/')
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{
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++pos;
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return commentUntilEndOfLine();
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}
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else
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{
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++pos;
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while (pos + 2 <= end)
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{
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/// This means that nested multiline comments are not supported.
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if (pos[0] == '*' && pos[1] == '/')
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{
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pos += 2;
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return Token(TokenType::Comment, token_begin, pos);
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}
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++pos;
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}
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return Token(TokenType::ErrorMultilineCommentIsNotClosed, token_begin, end);
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}
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}
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return Token(TokenType::Slash, token_begin, pos);
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}
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case '%':
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return Token(TokenType::Percent, token_begin, ++pos);
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case '=': /// =, ==
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{
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++pos;
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if (pos < end && *pos == '=')
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++pos;
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return Token(TokenType::Equals, token_begin, pos);
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}
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case '!': /// !=
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{
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++pos;
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if (pos < end && *pos == '=')
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return Token(TokenType::NotEquals, token_begin, ++pos);
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return Token(TokenType::ErrorSingleExclamationMark, token_begin, pos);
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}
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case '<': /// <, <=, <>
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{
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++pos;
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if (pos < end && *pos == '=')
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return Token(TokenType::LessOrEquals, token_begin, ++pos);
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if (pos < end && *pos == '>')
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return Token(TokenType::NotEquals, token_begin, ++pos);
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return Token(TokenType::Less, token_begin, pos);
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}
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case '>': /// >, >=
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{
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++pos;
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if (pos < end && *pos == '=')
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return Token(TokenType::GreaterOrEquals, token_begin, ++pos);
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return Token(TokenType::Greater, token_begin, pos);
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}
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case '?':
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return Token(TokenType::QuestionMark, token_begin, ++pos);
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case ':':
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return Token(TokenType::Colon, token_begin, ++pos);
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case '|':
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{
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++pos;
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if (pos < end && *pos == '|')
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return Token(TokenType::Concatenation, token_begin, ++pos);
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return Token(TokenType::ErrorSinglePipeMark, token_begin, pos);
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}
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default:
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if (isWordCharASCII(*pos))
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{
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++pos;
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while (pos < end && isWordCharASCII(*pos))
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++pos;
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return Token(TokenType::BareWord, token_begin, pos);
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}
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else
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return Token(TokenType::Error, token_begin, ++pos);
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}
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}
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const char * getTokenName(TokenType type)
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{
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switch (type)
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{
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#define M(TOKEN) \
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case TokenType::TOKEN: return #TOKEN;
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APPLY_FOR_TOKENS(M)
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#undef M
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}
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__builtin_unreachable();
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}
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const char * getErrorTokenDescription(TokenType type)
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{
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switch (type)
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{
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case TokenType::Error:
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return "Unrecognized token";
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case TokenType::ErrorMultilineCommentIsNotClosed:
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return "Multiline comment is not closed";
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case TokenType::ErrorSingleQuoteIsNotClosed:
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return "Single quoted string is not closed";
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case TokenType::ErrorDoubleQuoteIsNotClosed:
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return "Double quoted string is not closed";
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case TokenType::ErrorBackQuoteIsNotClosed:
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return "Back quoted string is not closed";
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case TokenType::ErrorSingleExclamationMark:
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return "Exclamation mark can only occur in != operator";
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case TokenType::ErrorSinglePipeMark:
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return "Pipe symbol could only occur in || operator";
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case TokenType::ErrorWrongNumber:
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return "Wrong number";
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case TokenType::ErrorMaxQuerySizeExceeded:
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return "Max query size exceeded";
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default:
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return "Not an error";
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}
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}
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}
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