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#include <Databases/MySQL/tryQuoteUnrecognizedTokens.h>
#include <Parsers/CommonParsers.h>
#include <Common/quoteString.h>
namespace DB
{
/// Checks if there are no any tokens (like whitespaces) between current and previous pos
static bool noWhitespaces(const char * to, const char * from)
{
return static_cast<size_t>(from - to) == 0;
}
/// Checks if the token should be quoted too together with unrecognized
static bool isWordOrNumber(TokenType type)
{
return type == TokenType::BareWord || type == TokenType::Number;
}
static void quoteLiteral(
IParser::Pos & pos,
IParser::Pos & pos_prev,
const char *& pos_unrecognized,
const char *& copy_from,
String & rewritten_query)
{
/// Copy also whitespaces if any
const auto * end =
isWordOrNumber(pos->type) && noWhitespaces(pos_prev->end, pos->begin)
? pos->end
: pos_prev->end;
String literal(pos_unrecognized, static_cast<size_t>(end - pos_unrecognized));
rewritten_query.append(copy_from, pos_unrecognized - copy_from).append(backQuoteMySQL(literal));
copy_from = end;
}
bool tryQuoteUnrecognizedTokens(const String & query, String & res)
{
Tokens tokens(query.data(), query.data() + query.size());
IParser::Pos pos(tokens, 0);
Expected expected;
String rewritten_query;
const char * copy_from = query.data();
auto pos_prev = pos;
const char * pos_unrecognized = nullptr;
for (;pos->type != TokenType::EndOfStream; ++pos)
{
/// Commit quotes if any whitespaces found or the token is not a word
bool commit = !noWhitespaces(pos_prev->end, pos->begin) || (pos->type != TokenType::Error && !isWordOrNumber(pos->type));
if (pos_unrecognized && commit)
{
quoteLiteral(
pos,
pos_prev,
pos_unrecognized,
copy_from,
rewritten_query);
pos_unrecognized = nullptr;
}
if (pos->type == TokenType::Error)
{
/// Find first appearance of the error token
if (!pos_unrecognized)
{
pos_unrecognized =
isWordOrNumber(pos_prev->type) && noWhitespaces(pos_prev->end, pos->begin)
? pos_prev->begin
: pos->begin;
}
}
pos_prev = pos;
}
/// There was EndOfStream but not committed unrecognized token
if (pos_unrecognized)
{
quoteLiteral(
pos,
pos_prev,
pos_unrecognized,
copy_from,
rewritten_query);
pos_unrecognized = nullptr;
}
/// If no Errors found
if (copy_from == query.data())
return false;
auto size = static_cast<size_t>(pos->end - copy_from);
rewritten_query.append(copy_from, size);
res = rewritten_query;
return true;
}
}
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