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- <?php
- /*
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- * This software consists of voluntary contributions made by many individuals
- * and is licensed under the MIT license. For more information, see
- * <http://www.doctrine-project.org>.
- */
- namespace Doctrine\DBAL\Id;
- use Doctrine\DBAL\DriverManager;
- use Doctrine\DBAL\Connection;
- /**
- * 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 (table_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
- *
- * @author Benjamin Eberlei <kontakt@beberlei.de>
- */
- class TableGenerator
- {
- /**
- * @var \Doctrine\DBAL\Connection
- */
- private $conn;
- /**
- * @var string
- */
- private $generatorTableName;
- /**
- * @var array
- */
- private $sequences = array();
- /**
- * @param \Doctrine\DBAL\Connection $conn
- * @param string $generatorTableName
- *
- * @throws \Doctrine\DBAL\DBALException
- */
- public function __construct(Connection $conn, $generatorTableName = 'sequences')
- {
- $params = $conn->getParams();
- if ($params['driver'] == 'pdo_sqlite') {
- throw new \Doctrine\DBAL\DBALException("Cannot use TableGenerator with SQLite.");
- }
- $this->conn = DriverManager::getConnection($params, $conn->getConfiguration(), $conn->getEventManager());
- $this->generatorTableName = $generatorTableName;
- }
- /**
- * Generates the next unused value for the given sequence name.
- *
- * @param string $sequenceName
- *
- * @return integer
- *
- * @throws \Doctrine\DBAL\DBALException
- */
- public function nextValue($sequenceName)
- {
- if (isset($this->sequences[$sequenceName])) {
- $value = $this->sequences[$sequenceName]['value'];
- $this->sequences[$sequenceName]['value']++;
- if ($this->sequences[$sequenceName]['value'] >= $this->sequences[$sequenceName]['max']) {
- unset ($this->sequences[$sequenceName]);
- }
- return $value;
- }
- $this->conn->beginTransaction();
- try {
- $platform = $this->conn->getDatabasePlatform();
- $sql = "SELECT sequence_value, sequence_increment_by " .
- "FROM " . $platform->appendLockHint($this->generatorTableName, \Doctrine\DBAL\LockMode::PESSIMISTIC_WRITE) . " " .
- "WHERE sequence_name = ? " . $platform->getWriteLockSQL();
- $stmt = $this->conn->executeQuery($sql, array($sequenceName));
- if ($row = $stmt->fetch(\PDO::FETCH_ASSOC)) {
- $row = array_change_key_case($row, CASE_LOWER);
- $value = $row['sequence_value'];
- $value++;
- if ($row['sequence_increment_by'] > 1) {
- $this->sequences[$sequenceName] = array(
- '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 = $this->conn->executeUpdate($sql, array($sequenceName, $row['sequence_value']));
- if ($rows != 1) {
- throw new \Doctrine\DBAL\DBALException("Race-condition detected while updating sequence. Aborting generation");
- }
- } else {
- $this->conn->insert(
- $this->generatorTableName,
- array('sequence_name' => $sequenceName, 'sequence_value' => 1, 'sequence_increment_by' => 1)
- );
- $value = 1;
- }
- $this->conn->commit();
- } catch(\Exception $e) {
- $this->conn->rollback();
- throw new \Doctrine\DBAL\DBALException("Error occurred while generating ID with TableGenerator, aborted generation: " . $e->getMessage(), 0, $e);
- }
- return $value;
- }
- }
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