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<?php
declare(strict_types=1);
namespace PhpMyAdmin\SqlParser\Statements;
use PhpMyAdmin\SqlParser\Components\OptionsArray;
use PhpMyAdmin\SqlParser\Parser;
use PhpMyAdmin\SqlParser\Statement;
use PhpMyAdmin\SqlParser\Token;
use PhpMyAdmin\SqlParser\TokensList;
use function array_slice;
use function count;
/**
* `EXPLAIN` statement.
*/
class ExplainStatement extends Statement
{
/**
* Options for `EXPLAIN` statements.
*
* @var array<string, int|array<int, int|string>>
* @psalm-var array<string, (positive-int|array{positive-int, ('var'|'var='|'expr'|'expr=')})>
*/
public static $OPTIONS = [
'EXTENDED' => 1,
'PARTITIONS' => 1,
'FORMAT' => [
1,
'var',
],
];
/**
* The parser of the statement to be explained
*
* @var Parser|null
*/
public $bodyParser = null;
/**
* The statement alias, could be any of the following:
* - {EXPLAIN | DESCRIBE | DESC}
* - {EXPLAIN | DESCRIBE | DESC} ANALYZE
* - ANALYZE
*
* @var string
*/
public $statementAlias;
/**
* The connection identifier, if used.
*
* @var int|null
*/
public $connectionId = null;
/**
* The explained table's name, if used.
*
* @var string|null
*/
public $explainedTable = null;
/**
* @param Parser $parser the instance that requests parsing
* @param TokensList $list the list of tokens to be parsed
*/
public function parse(Parser $parser, TokensList $list)
{
/**
* The state of the parser.
*
* Below are the states of the parser.
*
* 0 -------------------[ EXPLAIN/EXPLAIN ANALYZE/ANALYZE ]-----------------------> 1
*
* 1 ------------------------------[ OPTIONS ]------------------------------------> 2
*
* 2 --------------[ tablename / STATEMENT / FOR CONNECTION ]---------------------> 2
*
* @var int
*/
$state = 0;
/**
* To Differentiate between ANALYZE / EXPLAIN / EXPLAIN ANALYZE
* 0 -> ANALYZE ( used by mariaDB https://mariadb.com/kb/en/analyze-statement)
* 1 -> {EXPLAIN | DESCRIBE | DESC}
* 2 -> {EXPLAIN | DESCRIBE | DESC} ANALYZE
*/
$miniState = 0;
for (; $list->idx < $list->count; ++$list->idx) {
/**
* Token parsed at this moment.
*/
$token = $list->tokens[$list->idx];
// Skipping whitespaces and comments.
if ($token->type === Token::TYPE_WHITESPACE || $token->type === Token::TYPE_COMMENT) {
continue;
}
if ($state === 0) {
if ($token->keyword === 'ANALYZE' && $miniState === 0) {
$state = 1;
$this->statementAlias = 'ANALYZE';
} elseif (
$token->keyword === 'EXPLAIN'
|| $token->keyword === 'DESC'
|| $token->keyword === 'DESCRIBE'
) {
$miniState = 1;
$this->statementAlias = $token->keyword;
$lastIdx = $list->idx;
$nextKeyword = $list->getNextOfTypeAndValue(Token::TYPE_KEYWORD, 'ANALYZE');
if ($nextKeyword && $nextKeyword->keyword !== null) {
$miniState = 2;
$this->statementAlias .= ' ANALYZE';
} else {
$list->idx = $lastIdx;
}
$state = 1;
}
} elseif ($state === 1) {
// Parsing options.
$this->options = OptionsArray::parse($parser, $list, static::$OPTIONS);
$state = 2;
} elseif ($state === 2) {
$currIdx = $list->idx;
$list->idx++; // Ignore the current token
$nextToken = $list->getNext();
$list->idx = $currIdx;
if ($token->keyword === 'FOR' && $nextToken->keyword === 'CONNECTION') {
$list->idx++; // Ignore the current token
$list->getNext(); // CONNECTION
$nextToken = $list->getNext(); // Identifier
$this->connectionId = $nextToken->value;
break;
}
// To support EXPLAIN tablename
if ($token->type === Token::TYPE_NONE) {
$this->explainedTable = $token->value;
break;
}
if (
$token->keyword !== 'SELECT'
&& $token->keyword !== 'INSERT'
&& $token->keyword !== 'UPDATE'
&& $token->keyword !== 'DELETE'
) {
$parser->error('Unexpected token.', $token);
break;
}
// Index of the last parsed token by default would be the last token in the $list, because we're
// assuming that all remaining tokens at state 2, are related to the to-be-explained statement.
$idxOfLastParsedToken = $list->count - 1;
$subList = new TokensList(array_slice($list->tokens, $list->idx));
$this->bodyParser = new Parser($subList);
if (count($this->bodyParser->errors)) {
foreach ($this->bodyParser->errors as $error) {
$parser->errors[] = $error;
}
break;
}
$list->idx = $idxOfLastParsedToken;
break;
}
}
}
public function build(): string
{
$str = $this->statementAlias;
if (count($this->options->options)) {
$str .= ' ';
}
$str .= OptionsArray::build($this->options) . ' ';
if ($this->bodyParser) {
foreach ($this->bodyParser->statements as $statement) {
$str .= $statement->build();
}
} elseif ($this->connectionId) {
$str .= 'FOR CONNECTION ' . $this->connectionId;
} elseif ($this->explainedTable) {
$str .= $this->explainedTable;
}
return $str;
}
}
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