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<?php
/**
* `LOCK` statement.
*/
namespace PhpMyAdmin\SqlParser\Statements;
use PhpMyAdmin\SqlParser\Components\LockExpression;
use PhpMyAdmin\SqlParser\Parser;
use PhpMyAdmin\SqlParser\Statement;
use PhpMyAdmin\SqlParser\Token;
use PhpMyAdmin\SqlParser\TokensList;
/**
* `LOCK` statement.
*
* @category Statements
*
* @license https://www.gnu.org/licenses/gpl-2.0.txt GPL-2.0+
*/
class LockStatement extends Statement
{
/**
* Tables with their Lock expressions.
*
* @var LockExpression[]
*/
public $locked = array();
/**
* Whether it's a LOCK statement
* if false, it's an UNLOCK statement
*/
public $isLock = true;
/**
* @param Parser $parser the instance that requests parsing
* @param TokensList $list the list of tokens to be parsed
*/
public function parse(Parser $parser, TokensList $list)
{
if ($list->tokens[$list->idx]->value === 'UNLOCK') {
// this is in fact an UNLOCK statement
$this->isLock = false;
}
++$list->idx; // Skipping `LOCK`.
/**
* The state of the parser.
*
* Below are the states of the parser.
*
* 0 ---------------- [ TABLES ] -----------------> 1
* 1 -------------- [ lock_expr ] ----------------> 2
* 2 ------------------ [ , ] --------------------> 1
*
* @var int
*/
$state = 0;
/**
* Previous parsed token
*/
$prevToken = null;
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) || ($token->type === Token::TYPE_COMMENT)) {
continue;
}
if ($state === 0) {
if ($token->type === Token::TYPE_KEYWORD) {
if ($token->keyword !== 'TABLES') {
$parser->error('Unexpected keyword.', $token);
break;
}
$state = 1;
continue;
} else {
$parser->error('Unexpected token.', $token);
break;
}
} elseif ($state === 1) {
if (!$this->isLock) {
// UNLOCK statement should not have any more tokens
$parser->error('Unexpected token.', $token);
break;
}
$this->locked[] = LockExpression::parse($parser, $list);
$state = 2;
} elseif ($state === 2) {
if ($token->value === ',') {
// move over to parsing next lock expression
$state = 1;
}
}
$prevToken = $token;
}
if ($state !== 2 && $prevToken != null) {
$parser->error('Unexpected end of LOCK statement.', $prevToken);
}
}
/**
* @return string
*/
public function build()
{
return trim(($this->isLock ? 'LOCK' : 'UNLOCK')
. ' TABLES ' . LockExpression::build($this->locked));
}
}
|