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<?php
namespace Doctrine\DBAL\Id;
use Doctrine\DBAL\Connection;
use Doctrine\DBAL\Driver;
use Doctrine\DBAL\DriverManager;
use Doctrine\DBAL\Exception;
use Doctrine\DBAL\LockMode;
use Doctrine\Deprecations\Deprecation;
use Throwable;
use function array_change_key_case;
use function assert;
use function is_int;
use const CASE_LOWER;
/**
* Table ID Generator for those poor languages that are missing sequences.
*
* WARNING: The Table Id Generator clones a second independent database
* connection to work correctly. This means using the generator requests that
* generate IDs will have two open database connections. This is necessary to
* be safe from transaction failures in the main connection. Make sure to only
* ever use one TableGenerator otherwise you end up with many connections.
*
* TableID Generator does not work with SQLite.
*
* The TableGenerator does not take care of creating the SQL Table itself. You
* should look at the `TableGeneratorSchemaVisitor` to do this for you.
* Otherwise the schema for a table looks like:
*
* CREATE sequences (
* sequence_name VARCHAR(255) NOT NULL,
* sequence_value INT NOT NULL DEFAULT 1,
* sequence_increment_by INT NOT NULL DEFAULT 1,
* PRIMARY KEY (sequence_name)
* );
*
* Technically this generator works as follows:
*
* 1. Use a robust transaction serialization level.
* 2. Open transaction
* 3. Acquire a read lock on the table row (SELECT .. FOR UPDATE)
* 4. Increment current value by one and write back to database
* 5. Commit transaction
*
* If you are using a sequence_increment_by value that is larger than one the
* ID Generator will keep incrementing values until it hits the incrementation
* gap before issuing another query.
*
* If no row is present for a given sequence a new one will be created with the
* default values 'value' = 1 and 'increment_by' = 1
*
* @deprecated
*/
class TableGenerator
{
private Connection $conn;
/** @var string */
private $generatorTableName;
/** @var mixed[][] */
private array $sequences = [];
/**
* @param string $generatorTableName
*
* @throws Exception
*/
public function __construct(Connection $conn, $generatorTableName = 'sequences')
{
Deprecation::trigger(
'doctrine/dbal',
'https://github.com/doctrine/dbal/pull/4681',
'The TableGenerator class is is deprecated.',
);
if ($conn->getDriver() instanceof Driver\PDO\SQLite\Driver) {
throw new Exception('Cannot use TableGenerator with SQLite.');
}
$this->conn = DriverManager::getConnection(
$conn->getParams(),
$conn->getConfiguration(),
$conn->getEventManager(),
);
$this->generatorTableName = $generatorTableName;
}
/**
* Generates the next unused value for the given sequence name.
*
* @param string $sequence
*
* @return int
*
* @throws Exception
*/
public function nextValue($sequence)
{
if (isset($this->sequences[$sequence])) {
$value = $this->sequences[$sequence]['value'];
$this->sequences[$sequence]['value']++;
if ($this->sequences[$sequence]['value'] >= $this->sequences[$sequence]['max']) {
unset($this->sequences[$sequence]);
}
return $value;
}
$this->conn->beginTransaction();
try {
$platform = $this->conn->getDatabasePlatform();
$sql = 'SELECT sequence_value, sequence_increment_by'
. ' FROM ' . $platform->appendLockHint($this->generatorTableName, LockMode::PESSIMISTIC_WRITE)
. ' WHERE sequence_name = ? ' . $platform->getWriteLockSQL();
$row = $this->conn->fetchAssociative($sql, [$sequence]);
if ($row !== false) {
$row = array_change_key_case($row, CASE_LOWER);
$value = $row['sequence_value'];
$value++;
assert(is_int($value));
if ($row['sequence_increment_by'] > 1) {
$this->sequences[$sequence] = [
'value' => $value,
'max' => $row['sequence_value'] + $row['sequence_increment_by'],
];
}
$sql = 'UPDATE ' . $this->generatorTableName . ' ' .
'SET sequence_value = sequence_value + sequence_increment_by ' .
'WHERE sequence_name = ? AND sequence_value = ?';
$rows = $this->conn->executeStatement($sql, [$sequence, $row['sequence_value']]);
if ($rows !== 1) {
throw new Exception('Race-condition detected while updating sequence. Aborting generation');
}
} else {
$this->conn->insert(
$this->generatorTableName,
['sequence_name' => $sequence, 'sequence_value' => 1, 'sequence_increment_by' => 1],
);
$value = 1;
}
$this->conn->commit();
} catch (Throwable $e) {
$this->conn->rollBack();
throw new Exception(
'Error occurred while generating ID with TableGenerator, aborted generation: ' . $e->getMessage(),
0,
$e,
);
}
return $value;
}
}
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