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Reduce an unnecessary O(N^3) loop in lexer.
The lexer's handling of operators contained an O(N^3) hazard when dealing with long strings of + or - characters; it seems hard to prevent this case from being O(N^2), but the additional N multiplier was not needed. Backpatch all the way since this has been there since 7.x, and it presents at least a mild hazard in that trying to do Bind, PREPARE or EXPLAIN on a hostile query could take excessive time (without honouring cancels or timeouts) even if the query was never executed.
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@ -881,20 +881,33 @@ other .
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* to forbid operator names like '?-' that could not be
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* to forbid operator names like '?-' that could not be
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* sequences of SQL operators.
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* sequences of SQL operators.
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*/
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*/
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while (nchars > 1 &&
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if (nchars > 1 &&
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(yytext[nchars - 1] == '+' ||
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(yytext[nchars - 1] == '+' ||
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yytext[nchars - 1] == '-'))
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yytext[nchars - 1] == '-'))
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{
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{
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int ic;
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int ic;
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for (ic = nchars - 2; ic >= 0; ic--)
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for (ic = nchars - 2; ic >= 0; ic--)
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{
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{
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if (strchr("~!@#^&|`?%", yytext[ic]))
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char c = yytext[ic];
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if (c == '~' || c == '!' || c == '@' ||
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c == '#' || c == '^' || c == '&' ||
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c == '|' || c == '`' || c == '?' ||
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c == '%')
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break;
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break;
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}
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}
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if (ic >= 0)
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if (ic < 0)
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break; /* found a char that makes it OK */
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{
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nchars--; /* else remove the +/-, and check again */
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/*
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* didn't find a qualifying character, so remove
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* all trailing [+-]
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*/
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do {
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nchars--;
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} while (nchars > 1 &&
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(yytext[nchars - 1] == '+' ||
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yytext[nchars - 1] == '-'));
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}
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}
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}
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SET_YYLLOC();
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SET_YYLLOC();
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@ -798,20 +798,33 @@ other .
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* to forbid operator names like '?-' that could not be
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* to forbid operator names like '?-' that could not be
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* sequences of SQL operators.
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* sequences of SQL operators.
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*/
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*/
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while (nchars > 1 &&
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if (nchars > 1 &&
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(yytext[nchars - 1] == '+' ||
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(yytext[nchars - 1] == '+' ||
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yytext[nchars - 1] == '-'))
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yytext[nchars - 1] == '-'))
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{
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{
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int ic;
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int ic;
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for (ic = nchars - 2; ic >= 0; ic--)
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for (ic = nchars - 2; ic >= 0; ic--)
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{
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{
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if (strchr("~!@#^&|`?%", yytext[ic]))
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char c = yytext[ic];
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if (c == '~' || c == '!' || c == '@' ||
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c == '#' || c == '^' || c == '&' ||
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c == '|' || c == '`' || c == '?' ||
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c == '%')
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break;
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break;
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}
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}
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if (ic >= 0)
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if (ic < 0)
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break; /* found a char that makes it OK */
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{
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nchars--; /* else remove the +/-, and check again */
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/*
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* didn't find a qualifying character, so remove
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* all trailing [+-]
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*/
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do {
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nchars--;
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} while (nchars > 1 &&
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(yytext[nchars - 1] == '+' ||
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yytext[nchars - 1] == '-'));
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}
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}
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}
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if (nchars < yyleng)
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if (nchars < yyleng)
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@ -687,20 +687,33 @@ cppline {space}*#([^i][A-Za-z]*|{if}|{ifdef}|{ifndef}|{import})((\/\*[^*/]*\*+
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* to forbid operator names like '?-' that could not be
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* to forbid operator names like '?-' that could not be
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* sequences of SQL operators.
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* sequences of SQL operators.
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*/
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*/
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while (nchars > 1 &&
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if (nchars > 1 &&
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(yytext[nchars-1] == '+' ||
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(yytext[nchars - 1] == '+' ||
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yytext[nchars-1] == '-'))
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yytext[nchars - 1] == '-'))
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{
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{
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int ic;
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int ic;
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for (ic = nchars-2; ic >= 0; ic--)
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for (ic = nchars - 2; ic >= 0; ic--)
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{
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{
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if (strchr("~!@#^&|`?%", yytext[ic]))
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char c = yytext[ic];
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if (c == '~' || c == '!' || c == '@' ||
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c == '#' || c == '^' || c == '&' ||
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c == '|' || c == '`' || c == '?' ||
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c == '%')
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break;
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break;
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}
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}
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if (ic >= 0)
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if (ic < 0)
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break; /* found a char that makes it OK */
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{
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nchars--; /* else remove the +/-, and check again */
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/*
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* didn't find a qualifying character, so remove
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* all trailing [+-]
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*/
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do {
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nchars--;
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} while (nchars > 1 &&
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(yytext[nchars - 1] == '+' ||
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yytext[nchars - 1] == '-'));
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}
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}
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}
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if (nchars < yyleng)
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if (nchars < yyleng)
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