$options parameters for parsing * * @return LockExpression */ public static function parse(Parser $parser, TokensList $list, array $options = []) { $ret = new static(); /** * The state of the parser. * * Below are the states of the parser. * * 0 ---------------- [ tbl_name ] -----------------> 1 * 1 ---------------- [ lock_type ] ----------------> 2 * 2 -------------------- [ , ] --------------------> break * * @var int */ $state = 0; $prevToken = null; for (; $list->idx < $list->count; ++$list->idx) { /** * Token parsed at this moment. */ $token = $list->tokens[$list->idx]; // End of statement. if ( $token->type === Token::TYPE_DELIMITER || ($token->type === Token::TYPE_OPERATOR && $token->value === ',') ) { break; } if ($state === 0) { $ret->table = Expression::parse($parser, $list, ['parseField' => 'table']); $state = 1; } elseif ($state === 1) { // parse lock type $ret->type = self::parseLockType($parser, $list); $state = 2; } $prevToken = $token; } // 2 is the only valid end state if ($state !== 2) { $parser->error('Unexpected end of LOCK expression.', $prevToken); } --$list->idx; return $ret; } /** * @param LockExpression|LockExpression[] $component the component to be built * @param array $options parameters for building * * @return string */ public static function build($component, array $options = []) { if (is_array($component)) { return implode(', ', $component); } return $component->table . ' ' . $component->type; } /** * @return string */ private static function parseLockType(Parser $parser, TokensList $list) { $lockType = ''; /** * The state of the parser while parsing for lock type. * * Below are the states of the parser. * * 0 ---------------- [ READ ] -----------------> 1 * 0 ------------- [ LOW_PRIORITY ] ------------> 2 * 0 ---------------- [ WRITE ] ----------------> 3 * 1 ---------------- [ LOCAL ] ----------------> 3 * 2 ---------------- [ WRITE ] ----------------> 3 * * @var int */ $state = 0; $prevToken = null; for (; $list->idx < $list->count; ++$list->idx) { /** * Token parsed at this moment. */ $token = $list->tokens[$list->idx]; // End of statement. if ( $token->type === Token::TYPE_DELIMITER || ($token->type === Token::TYPE_OPERATOR && $token->value === ',') ) { --$list->idx; break; } // Skipping whitespaces and comments. if ($token->type === Token::TYPE_WHITESPACE || $token->type === Token::TYPE_COMMENT) { continue; } // We only expect keywords if ($token->type !== Token::TYPE_KEYWORD) { $parser->error('Unexpected token.', $token); break; } if ($state === 0) { if ($token->keyword === 'READ') { $state = 1; } elseif ($token->keyword === 'LOW_PRIORITY') { $state = 2; } elseif ($token->keyword === 'WRITE') { $state = 3; } else { $parser->error('Unexpected keyword.', $token); break; } $lockType .= $token->keyword; } elseif ($state === 1) { if ($token->keyword !== 'LOCAL') { $parser->error('Unexpected keyword.', $token); break; } $lockType .= ' ' . $token->keyword; $state = 3; } elseif ($state === 2) { if ($token->keyword !== 'WRITE') { $parser->error('Unexpected keyword.', $token); break; } $lockType .= ' ' . $token->keyword; $state = 3; // parsing over } $prevToken = $token; } // Only two possible end states if ($state !== 1 && $state !== 3) { $parser->error('Unexpected end of Lock expression.', $prevToken); } return $lockType; } }