PhpMyAdmin\SqlParser\Lexer::lex()

Complexity

Conditions	24
Paths	76

Size

Total Lines	136
Code Lines	68

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	64
CRAP Score	24

Importance

Changes

0

<?php
    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();
    }