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Direktori : /var/www/projetos/admin.iigd.com.br/vendor/phpmyadmin/sql-parser/src/ |
Current File : /var/www/projetos/admin.iigd.com.br/vendor/phpmyadmin/sql-parser/src/Lexer.php |
<?php /** * Defines the lexer of the library. * * This is one of the most important components, along with the parser. * * Depends on context to extract lexemes. */ declare(strict_types=1); namespace PhpMyAdmin\SqlParser; use PhpMyAdmin\SqlParser\Exceptions\LexerException; use function define; use function defined; use function in_array; use function mb_strlen; use function sprintf; use function strlen; use function substr; if (! defined('USE_UTF_STRINGS')) { // NOTE: In previous versions of PHP (5.5 and older) the default // internal encoding is "ISO-8859-1". // All `mb_` functions must specify the correct encoding, which is // 'UTF-8' in order to work properly. /* * Forces usage of `UtfString` if the string is multibyte. * `UtfString` may be slower, but it gives better results. * * @var bool */ define('USE_UTF_STRINGS', true); } /** * Performs lexical analysis over a SQL statement and splits it in multiple * tokens. * * The output of the lexer is affected by the context of the SQL statement. * * @see Context */ class Lexer extends Core { /** * A list of methods that are used in lexing the SQL query. * * @var array */ public static $PARSER_METHODS = [ // It is best to put the parsers in order of their complexity // (ascending) and their occurrence rate (descending). // // Conflicts: // // 1. `parseDelimiter`, `parseUnknown`, `parseKeyword`, `parseNumber` // They fight over delimiter. The delimiter may be a keyword, a // number or almost any character which makes the delimiter one of // the first tokens that must be parsed. // // 1. `parseNumber` and `parseOperator` // They fight over `+` and `-`. // // 2. `parseComment` and `parseOperator` // They fight over `/` (as in ```/*comment*/``` or ```a / b```) // // 3. `parseBool` and `parseKeyword` // They fight over `TRUE` and `FALSE`. // // 4. `parseKeyword` and `parseUnknown` // They fight over words. `parseUnknown` does not know about // keywords. 'parseDelimiter', 'parseWhitespace', 'parseNumber', 'parseComment', 'parseOperator', 'parseBool', 'parseString', 'parseSymbol', 'parseKeyword', 'parseLabel', 'parseUnknown', ]; /** * The string to be parsed. * * @var string|UtfString */ public $str = ''; /** * The length of `$str`. * * By storing its length, a lot of time is saved, because parsing methods * would call `strlen` everytime. * * @var int */ public $len = 0; /** * The index of the last parsed character. * * @var int */ public $last = 0; /** * Tokens extracted from given strings. * * @var TokensList */ public $list; /** * The default delimiter. This is used, by default, in all new instances. * * @var string */ public static $DEFAULT_DELIMITER = ';'; /** * Statements delimiter. * This may change during lexing. * * @var string */ public $delimiter; /** * The length of the delimiter. * * Because `parseDelimiter` can be called a lot, it would perform a lot of * calls to `strlen`, which might affect performance when the delimiter is * big. * * @var int */ public $delimiterLen; /** * Gets the tokens list parsed by a new instance of a lexer. * * @param string|UtfString $str the query to be lexed * @param bool $strict whether strict mode should be * enabled or not * @param string $delimiter the delimiter to be used * * @return TokensList */ public static function getTokens($str, $strict = false, $delimiter = null) { $lexer = new self($str, $strict, $delimiter); return $lexer->list; } /** * @param string|UtfString $str the query to be lexed * @param bool $strict whether strict mode should be * enabled or not * @param string $delimiter the delimiter to be used */ public function __construct($str, $strict = false, $delimiter = null) { // `strlen` is used instead of `mb_strlen` because the lexer needs to // parse each byte of the input. $len = $str instanceof UtfString ? $str->length() : strlen($str); // For multi-byte strings, a new instance of `UtfString` is // initialized (only if `UtfString` usage is forced. if (! $str instanceof UtfString && USE_UTF_STRINGS && $len !== mb_strlen($str, 'UTF-8')) { $str = new UtfString($str); } $this->str = $str; $this->len = $str instanceof UtfString ? $str->length() : $len; $this->strict = $strict; // Setting the delimiter. $this->setDelimiter(! empty($delimiter) ? $delimiter : static::$DEFAULT_DELIMITER); $this->lex(); } /** * Sets the delimiter. * * @param string $delimiter the new delimiter */ public function setDelimiter($delimiter) { $this->delimiter = $delimiter; $this->delimiterLen = strlen($delimiter); } /** * Parses the string and extracts lexemes. */ public function lex() { // TODO: Sometimes, static::parse* functions make unnecessary calls to // is* functions. For a better performance, some rules can be deduced // from context. // For example, in `parseBool` there is no need to compare the token // every time with `true` and `false`. The first step would be to // compare with 'true' only and just after that add another letter from // context and compare again with `false`. // Another example is `parseComment`. $list = new TokensList(); /** * Last processed token. * * @var Token */ $lastToken = null; for ($this->last = 0, $lastIdx = 0; $this->last < $this->len; $lastIdx = ++$this->last) { /** * The new token. * * @var Token */ $token = null; foreach (static::$PARSER_METHODS as $method) { $token = $this->$method(); if ($token) { break; } } if ($token === null) { // @assert($this->last === $lastIdx); $token = new Token($this->str[$this->last]); $this->error('Unexpected character.', $this->str[$this->last], $this->last); } elseif ( $lastToken !== null && $token->type === Token::TYPE_SYMBOL && $token->flags & Token::FLAG_SYMBOL_VARIABLE && ( $lastToken->type === Token::TYPE_STRING || ( $lastToken->type === Token::TYPE_SYMBOL && $lastToken->flags & Token::FLAG_SYMBOL_BACKTICK ) ) ) { // Handles ```... FROM 'user'@'%' ...```. $lastToken->token .= $token->token; $lastToken->type = Token::TYPE_SYMBOL; $lastToken->flags = Token::FLAG_SYMBOL_USER; $lastToken->value .= '@' . $token->value; continue; } elseif ( $lastToken !== null && $token->type === Token::TYPE_KEYWORD && $lastToken->type === Token::TYPE_OPERATOR && $lastToken->value === '.' ) { // Handles ```... tbl.FROM ...```. In this case, FROM is not // a reserved word. $token->type = Token::TYPE_NONE; $token->flags = 0; $token->value = $token->token; } $token->position = $lastIdx; $list->tokens[$list->count++] = $token; // Handling delimiters. if ($token->type === Token::TYPE_NONE && $token->value === 'DELIMITER') { if ($this->last + 1 >= $this->len) { $this->error('Expected whitespace(s) before delimiter.', '', $this->last + 1); continue; } // Skipping last R (from `delimiteR`) and whitespaces between // the keyword `DELIMITER` and the actual delimiter. $pos = ++$this->last; $token = $this->parseWhitespace(); if ($token !== null) { $token->position = $pos; $list->tokens[$list->count++] = $token; } // Preparing the token that holds the new delimiter. if ($this->last + 1 >= $this->len) { $this->error('Expected delimiter.', '', $this->last + 1); continue; } $pos = $this->last + 1; // Parsing the delimiter. $this->delimiter = null; $delimiterLen = 0; while ( ++$this->last < $this->len && ! Context::isWhitespace($this->str[$this->last]) && $delimiterLen < 15 ) { $this->delimiter .= $this->str[$this->last]; ++$delimiterLen; } if (empty($this->delimiter)) { $this->error('Expected delimiter.', '', $this->last); $this->delimiter = ';'; } --$this->last; // Saving the delimiter and its token. $this->delimiterLen = strlen($this->delimiter); $token = new Token($this->delimiter, Token::TYPE_DELIMITER); $token->position = $pos; $list->tokens[$list->count++] = $token; } $lastToken = $token; } // Adding a final delimiter to mark the ending. $list->tokens[$list->count++] = new Token(null, Token::TYPE_DELIMITER); // Saving the tokens list. $this->list = $list; $this->solveAmbiguityOnStarOperator(); } /** * Resolves the ambiguity when dealing with the "*" operator. * * In SQL statements, the "*" operator can be an arithmetic operator (like in 2*3) or an SQL wildcard (like in * SELECT a.* FROM ...). To solve this ambiguity, the solution is to find the next token, excluding whitespaces and * comments, right after the "*" position. The "*" is for sure an SQL wildcard if the next token found is any of: * - "FROM" (the FROM keyword like in "SELECT * FROM..."); * - "USING" (the USING keyword like in "DELETE table_name.* USING..."); * - "," (a comma separator like in "SELECT *, field FROM..."); * - ")" (a closing parenthesis like in "COUNT(*)"). * This methods will change the flag of the "*" tokens when any of those condition above is true. Otherwise, the * default flag (arithmetic) will be kept. * * @return void */ private function solveAmbiguityOnStarOperator() { $iBak = $this->list->idx; while (($starToken = $this->list->getNextOfTypeAndValue(Token::TYPE_OPERATOR, '*')) !== null) { // getNext() already gets rid of whitespaces and comments. $next = $this->list->getNext(); if ($next === null) { continue; } if ( ($next->type !== Token::TYPE_KEYWORD || ! in_array($next->value, ['FROM', 'USING'], true)) && ($next->type !== Token::TYPE_OPERATOR || ! in_array($next->value, [',', ')'], true)) ) { continue; } $starToken->flags = Token::FLAG_OPERATOR_SQL; } $this->list->idx = $iBak; } /** * Creates a new error log. * * @param string $msg the error message * @param string $str the character that produced the error * @param int $pos the position of the character * @param int $code the code of the error * * @throws LexerException throws the exception, if strict mode is enabled. */ public function error($msg, $str = '', $pos = 0, $code = 0) { $error = new LexerException( Translator::gettext($msg), $str, $pos, $code ); parent::error($error); } /** * Parses a keyword. * * @return Token|null */ public function parseKeyword() { $token = ''; /** * Value to be returned. * * @var Token */ $ret = null; /** * The value of `$this->last` where `$token` ends in `$this->str`. * * @var int */ $iEnd = $this->last; /** * Whether last parsed character is a whitespace. * * @var bool */ $lastSpace = false; for ($j = 1; $j < Context::KEYWORD_MAX_LENGTH && $this->last < $this->len; ++$j, ++$this->last) { // Composed keywords shouldn't have more than one whitespace between // keywords. if (Context::isWhitespace($this->str[$this->last])) { if ($lastSpace) { --$j; // The size of the keyword didn't increase. continue; } $lastSpace = true; } else { $lastSpace = false; } $token .= $this->str[$this->last]; $flags = Context::isKeyword($token); if (($this->last + 1 !== $this->len && ! Context::isSeparator($this->str[$this->last + 1])) || ! $flags) { continue; } $ret = new Token($token, Token::TYPE_KEYWORD, $flags); $iEnd = $this->last; // We don't break so we find longest keyword. // For example, `OR` and `ORDER` have a common prefix `OR`. // If we stopped at `OR`, the parsing would be invalid. } $this->last = $iEnd; return $ret; } /** * Parses a label. * * @return Token|null */ public function parseLabel() { $token = ''; /** * Value to be returned. * * @var Token */ $ret = null; /** * The value of `$this->last` where `$token` ends in `$this->str`. * * @var int */ $iEnd = $this->last; for ($j = 1; $j < Context::LABEL_MAX_LENGTH && $this->last < $this->len; ++$j, ++$this->last) { if ($this->str[$this->last] === ':' && $j > 1) { // End of label $token .= $this->str[$this->last]; $ret = new Token($token, Token::TYPE_LABEL); $iEnd = $this->last; break; } if (Context::isWhitespace($this->str[$this->last]) && $j > 1) { // Whitespace between label and : // The size of the keyword didn't increase. --$j; } elseif (Context::isSeparator($this->str[$this->last])) { // Any other separator break; } $token .= $this->str[$this->last]; } $this->last = $iEnd; return $ret; } /** * Parses an operator. * * @return Token|null */ public function parseOperator() { $token = ''; /** * Value to be returned. * * @var Token */ $ret = null; /** * The value of `$this->last` where `$token` ends in `$this->str`. * * @var int */ $iEnd = $this->last; for ($j = 1; $j < Context::OPERATOR_MAX_LENGTH && $this->last < $this->len; ++$j, ++$this->last) { $token .= $this->str[$this->last]; $flags = Context::isOperator($token); if (! $flags) { continue; } $ret = new Token($token, Token::TYPE_OPERATOR, $flags); $iEnd = $this->last; } $this->last = $iEnd; return $ret; } /** * Parses a whitespace. * * @return Token|null */ public function parseWhitespace() { $token = $this->str[$this->last]; if (! Context::isWhitespace($token)) { return null; } while (++$this->last < $this->len && Context::isWhitespace($this->str[$this->last])) { $token .= $this->str[$this->last]; } --$this->last; return new Token($token, Token::TYPE_WHITESPACE); } /** * Parses a comment. * * @return Token|null */ public function parseComment() { $iBak = $this->last; $token = $this->str[$this->last]; // Bash style comments. (#comment\n) if (Context::isComment($token)) { while (++$this->last < $this->len && $this->str[$this->last] !== "\n") { $token .= $this->str[$this->last]; } // Include trailing \n as whitespace token if ($this->last < $this->len) { --$this->last; } return new Token($token, Token::TYPE_COMMENT, Token::FLAG_COMMENT_BASH); } // C style comments. (/*comment*\/) if (++$this->last < $this->len) { $token .= $this->str[$this->last]; if (Context::isComment($token)) { // There might be a conflict with "*" operator here, when string is "*/*". // This can occurs in the following statements: // - "SELECT */* comment */ FROM ..." // - "SELECT 2*/* comment */3 AS `six`;" $next = $this->last + 1; if (($next < $this->len) && $this->str[$next] === '*') { // Conflict in "*/*": first "*" was not for ending a comment. // Stop here and let other parsing method define the true behavior of that first star. $this->last = $iBak; return null; } $flags = Token::FLAG_COMMENT_C; // This comment already ended. It may be a part of a // previous MySQL specific command. if ($token === '*/') { return new Token($token, Token::TYPE_COMMENT, $flags); } // Checking if this is a MySQL-specific command. if ($this->last + 1 < $this->len && $this->str[$this->last + 1] === '!') { $flags |= Token::FLAG_COMMENT_MYSQL_CMD; $token .= $this->str[++$this->last]; while ( ++$this->last < $this->len && $this->str[$this->last] >= '0' && $this->str[$this->last] <= '9' ) { $token .= $this->str[$this->last]; } --$this->last; // We split this comment and parse only its beginning // here. return new Token($token, Token::TYPE_COMMENT, $flags); } // Parsing the comment. while ( ++$this->last < $this->len && ( $this->str[$this->last - 1] !== '*' || $this->str[$this->last] !== '/' ) ) { $token .= $this->str[$this->last]; } // Adding the ending. if ($this->last < $this->len) { $token .= $this->str[$this->last]; } return new Token($token, Token::TYPE_COMMENT, $flags); } } // SQL style comments. (-- comment\n) if (++$this->last < $this->len) { $token .= $this->str[$this->last]; $end = false; } else { --$this->last; $end = true; } if (Context::isComment($token, $end)) { // Checking if this comment did not end already (```--\n```). if ($this->str[$this->last] !== "\n") { while (++$this->last < $this->len && $this->str[$this->last] !== "\n") { $token .= $this->str[$this->last]; } } // Include trailing \n as whitespace token if ($this->last < $this->len) { --$this->last; } return new Token($token, Token::TYPE_COMMENT, Token::FLAG_COMMENT_SQL); } $this->last = $iBak; return null; } /** * Parses a boolean. * * @return Token|null */ public function parseBool() { if ($this->last + 3 >= $this->len) { // At least `min(strlen('TRUE'), strlen('FALSE'))` characters are // required. return null; } $iBak = $this->last; $token = $this->str[$this->last] . $this->str[++$this->last] . $this->str[++$this->last] . $this->str[++$this->last]; // _TRUE_ or _FALS_e if (Context::isBool($token)) { return new Token($token, Token::TYPE_BOOL); } if (++$this->last < $this->len) { $token .= $this->str[$this->last]; // fals_E_ if (Context::isBool($token)) { return new Token($token, Token::TYPE_BOOL, 1); } } $this->last = $iBak; return null; } /** * Parses a number. * * @return Token|null */ public function parseNumber() { // A rudimentary state machine is being used to parse numbers due to // the various forms of their notation. // // Below are the states of the machines and the conditions to change // the state. // // 1 --------------------[ + or - ]-------------------> 1 // 1 -------------------[ 0x or 0X ]------------------> 2 // 1 --------------------[ 0 to 9 ]-------------------> 3 // 1 -----------------------[ . ]---------------------> 4 // 1 -----------------------[ b ]---------------------> 7 // // 2 --------------------[ 0 to F ]-------------------> 2 // // 3 --------------------[ 0 to 9 ]-------------------> 3 // 3 -----------------------[ . ]---------------------> 4 // 3 --------------------[ e or E ]-------------------> 5 // // 4 --------------------[ 0 to 9 ]-------------------> 4 // 4 --------------------[ e or E ]-------------------> 5 // // 5 ---------------[ + or - or 0 to 9 ]--------------> 6 // // 7 -----------------------[ ' ]---------------------> 8 // // 8 --------------------[ 0 or 1 ]-------------------> 8 // 8 -----------------------[ ' ]---------------------> 9 // // State 1 may be reached by negative numbers. // State 2 is reached only by hex numbers. // State 4 is reached only by float numbers. // State 5 is reached only by numbers in approximate form. // State 7 is reached only by numbers in bit representation. // // Valid final states are: 2, 3, 4 and 6. Any parsing that finished in a // state other than these is invalid. // Also, negative states are invalid states. $iBak = $this->last; $token = ''; $flags = 0; $state = 1; for (; $this->last < $this->len; ++$this->last) { if ($state === 1) { if ($this->str[$this->last] === '-') { $flags |= Token::FLAG_NUMBER_NEGATIVE; } elseif ( $this->last + 1 < $this->len && $this->str[$this->last] === '0' && ( $this->str[$this->last + 1] === 'x' || $this->str[$this->last + 1] === 'X' ) ) { $token .= $this->str[$this->last++]; $state = 2; } elseif ($this->str[$this->last] >= '0' && $this->str[$this->last] <= '9') { $state = 3; } elseif ($this->str[$this->last] === '.') { $state = 4; } elseif ($this->str[$this->last] === 'b') { $state = 7; } elseif ($this->str[$this->last] !== '+') { // `+` is a valid character in a number. break; } } elseif ($state === 2) { $flags |= Token::FLAG_NUMBER_HEX; if ( ! ( ($this->str[$this->last] >= '0' && $this->str[$this->last] <= '9') || ($this->str[$this->last] >= 'A' && $this->str[$this->last] <= 'F') || ($this->str[$this->last] >= 'a' && $this->str[$this->last] <= 'f') ) ) { break; } } elseif ($state === 3) { if ($this->str[$this->last] === '.') { $state = 4; } elseif ($this->str[$this->last] === 'e' || $this->str[$this->last] === 'E') { $state = 5; } elseif ( ($this->str[$this->last] >= 'a' && $this->str[$this->last] <= 'z') || ($this->str[$this->last] >= 'A' && $this->str[$this->last] <= 'Z') ) { // A number can't be directly followed by a letter $state = -$state; } elseif ($this->str[$this->last] < '0' || $this->str[$this->last] > '9') { // Just digits and `.`, `e` and `E` are valid characters. break; } } elseif ($state === 4) { $flags |= Token::FLAG_NUMBER_FLOAT; if ($this->str[$this->last] === 'e' || $this->str[$this->last] === 'E') { $state = 5; } elseif ( ($this->str[$this->last] >= 'a' && $this->str[$this->last] <= 'z') || ($this->str[$this->last] >= 'A' && $this->str[$this->last] <= 'Z') ) { // A number can't be directly followed by a letter $state = -$state; } elseif ($this->str[$this->last] < '0' || $this->str[$this->last] > '9') { // Just digits, `e` and `E` are valid characters. break; } } elseif ($state === 5) { $flags |= Token::FLAG_NUMBER_APPROXIMATE; if ( $this->str[$this->last] === '+' || $this->str[$this->last] === '-' || ($this->str[$this->last] >= '0' && $this->str[$this->last] <= '9') ) { $state = 6; } elseif ( ($this->str[$this->last] >= 'a' && $this->str[$this->last] <= 'z') || ($this->str[$this->last] >= 'A' && $this->str[$this->last] <= 'Z') ) { // A number can't be directly followed by a letter $state = -$state; } else { break; } } elseif ($state === 6) { if ($this->str[$this->last] < '0' || $this->str[$this->last] > '9') { // Just digits are valid characters. break; } } elseif ($state === 7) { $flags |= Token::FLAG_NUMBER_BINARY; if ($this->str[$this->last] !== '\'') { break; } $state = 8; } elseif ($state === 8) { if ($this->str[$this->last] === '\'') { $state = 9; } elseif ($this->str[$this->last] !== '0' && $this->str[$this->last] !== '1') { break; } } elseif ($state === 9) { break; } $token .= $this->str[$this->last]; } if ($state === 2 || $state === 3 || ($token !== '.' && $state === 4) || $state === 6 || $state === 9) { --$this->last; return new Token($token, Token::TYPE_NUMBER, $flags); } $this->last = $iBak; return null; } /** * Parses a string. * * @param string $quote additional starting symbol * * @return Token|null * * @throws LexerException */ public function parseString($quote = '') { $token = $this->str[$this->last]; $flags = Context::isString($token); if (! $flags && $token !== $quote) { return null; } $quote = $token; while (++$this->last < $this->len) { if ( $this->last + 1 < $this->len && ( ($this->str[$this->last] === $quote && $this->str[$this->last + 1] === $quote) || ($this->str[$this->last] === '\\' && $quote !== '`') ) ) { $token .= $this->str[$this->last] . $this->str[++$this->last]; } else { if ($this->str[$this->last] === $quote) { break; } $token .= $this->str[$this->last]; } } if ($this->last >= $this->len || $this->str[$this->last] !== $quote) { $this->error( sprintf( Translator::gettext('Ending quote %1$s was expected.'), $quote ), '', $this->last ); } else { $token .= $this->str[$this->last]; } return new Token($token, Token::TYPE_STRING, $flags); } /** * Parses a symbol. * * @return Token|null * * @throws LexerException */ public function parseSymbol() { $token = $this->str[$this->last]; $flags = Context::isSymbol($token); if (! $flags) { return null; } if ($flags & Token::FLAG_SYMBOL_VARIABLE) { if ($this->last + 1 < $this->len && $this->str[++$this->last] === '@') { // This is a system variable (e.g. `@@hostname`). $token .= $this->str[$this->last++]; $flags |= Token::FLAG_SYMBOL_SYSTEM; } } elseif ($flags & Token::FLAG_SYMBOL_PARAMETER) { if ($token !== '?' && $this->last + 1 < $this->len) { ++$this->last; } } else { $token = ''; } $str = null; if ($this->last < $this->len) { $str = $this->parseString('`'); if ($str === null) { $str = $this->parseUnknown(); if ($str === null) { $this->error('Variable name was expected.', $this->str[$this->last], $this->last); } } } if ($str !== null) { $token .= $str->token; } return new Token($token, Token::TYPE_SYMBOL, $flags); } /** * Parses unknown parts of the query. * * @return Token|null */ public function parseUnknown() { $token = $this->str[$this->last]; if (Context::isSeparator($token)) { return null; } while (++$this->last < $this->len && ! Context::isSeparator($this->str[$this->last])) { $token .= $this->str[$this->last]; // Test if end of token equals the current delimiter. If so, remove it from the token. if (substr($token, -$this->delimiterLen) === $this->delimiter) { $token = substr($token, 0, -$this->delimiterLen); $this->last -= $this->delimiterLen - 1; break; } } --$this->last; return new Token($token); } /** * Parses the delimiter of the query. * * @return Token|null */ public function parseDelimiter() { $idx = 0; while ($idx < $this->delimiterLen && $this->last + $idx < $this->len) { if ($this->delimiter[$idx] !== $this->str[$this->last + $idx]) { return null; } ++$idx; } $this->last += $this->delimiterLen - 1; return new Token($this->delimiter, Token::TYPE_DELIMITER); } }