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<?php
/**
* Parses an Index hint.
*/
declare(strict_types=1);
namespace PhpMyAdmin\SqlParser\Components;
use PhpMyAdmin\SqlParser\Component;
use PhpMyAdmin\SqlParser\Parser;
use PhpMyAdmin\SqlParser\Token;
use PhpMyAdmin\SqlParser\TokensList;
/**
* Parses an Index hint.
*/
class IndexHint extends Component
{
/**
* The type of hint (USE/FORCE/IGNORE)
*
* @var string
*/
public $type;
/**
* What the hint is for (INDEX/KEY)
*
* @var string
*/
public $indexOrKey;
/**
* The clause for which this hint is (JOIN/ORDER BY/GROUP BY)
*
* @var string
*/
public $for;
/**
* List of indexes in this hint
*
* @var array
*/
public $indexes = [];
/**
* @param string $type the type of hint (USE/FORCE/IGNORE)
* @param string $indexOrKey What the hint is for (INDEX/KEY)
* @param string $for the clause for which this hint is (JOIN/ORDER BY/GROUP BY)
* @param array $indexes List of indexes in this hint
*/
public function __construct(string $type = null, string $indexOrKey = null, string $for = null, array $indexes = [])
{
$this->type = $type;
$this->indexOrKey = $indexOrKey;
$this->for = $for;
$this->indexes = $indexes;
}
/**
* @param Parser $parser the parser that serves as context
* @param TokensList $list the list of tokens that are being parsed
* @param array $options parameters for parsing
*
* @return IndexHint|Component[]
*/
public static function parse(Parser $parser, TokensList $list, array $options = [])
{
$ret = [];
$expr = new static();
$expr->type = isset($options['type']) ? $options['type'] : null;
/**
* The state of the parser.
*
* Below are the states of the parser.
* 0 ----------------- [ USE/IGNORE/FORCE ]-----------------> 1
* 1 -------------------- [ INDEX/KEY ] --------------------> 2
* 2 ----------------------- [ FOR ] -----------------------> 3
* 2 -------------------- [ expr_list ] --------------------> 0
* 3 -------------- [ JOIN/GROUP BY/ORDER BY ] -------------> 4
* 4 -------------------- [ expr_list ] --------------------> 0
*
* @var int
*/
$state = 0;
// By design, the parser will parse first token after the keyword. So, the keyword
// must be analyzed too, in order to determine the type of this index hint.
if ($list->idx > 0) {
--$list->idx;
}
for (; $list->idx < $list->count; ++$list->idx) {
/**
* Token parsed at this moment.
*
* @var Token
*/
$token = $list->tokens[$list->idx];
// End of statement.
if ($token->type === Token::TYPE_DELIMITER) {
break;
}
// Skipping whitespaces and comments.
if (($token->type === Token::TYPE_WHITESPACE) || ($token->type === Token::TYPE_COMMENT)) {
continue;
}
switch ($state) {
case 0:
if ($token->type === Token::TYPE_KEYWORD) {
if ($token->keyword === 'USE' || $token->keyword === 'IGNORE' || $token->keyword === 'FORCE') {
$expr->type = $token->keyword;
$state = 1;
} else {
break 2;
}
}
break;
case 1:
if ($token->type === Token::TYPE_KEYWORD) {
if ($token->keyword === 'INDEX' || $token->keyword === 'KEY') {
$expr->indexOrKey = $token->keyword;
} else {
$parser->error('Unexpected keyword.', $token);
}
$state = 2;
} else {
// we expect the token to be a keyword
$parser->error('Unexpected token.', $token);
}
break;
case 2:
if ($token->type === Token::TYPE_KEYWORD && $token->keyword === 'FOR') {
$state = 3;
} else {
$expr->indexes = ExpressionArray::parse($parser, $list);
$state = 0;
$ret[] = $expr;
$expr = new static();
}
break;
case 3:
if ($token->type === Token::TYPE_KEYWORD) {
if ($token->keyword === 'JOIN' || $token->keyword === 'GROUP BY' || $token->keyword === 'ORDER BY') {
$expr->for = $token->keyword;
} else {
$parser->error('Unexpected keyword.', $token);
}
$state = 4;
} else {
// we expect the token to be a keyword
$parser->error('Unexpected token.', $token);
}
break;
case 4:
$expr->indexes = ExpressionArray::parse($parser, $list);
$state = 0;
$ret[] = $expr;
$expr = new static();
break;
}
}
--$list->idx;
return $ret;
}
/**
* @param IndexHint|IndexHint[] $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);
}
$ret = $component->type . ' ' . $component->indexOrKey . ' ';
if ($component->for !== null) {
$ret .= 'FOR ' . $component->for . ' ';
}
return $ret . ExpressionArray::build($component->indexes);
}
}
|
