Plasma\Drivers\MySQL\StatementCursor

Complexity

Total Complexity

11

Size/Duplication

Total Lines	103
Duplicated Lines	0 %

Test Coverage

Coverage

80%

Importance

Changes	1
Bugs	0	Features	0

6 Methods

Rating	Name	Duplication	Size	Complexity
A	__construct()	0	3	1
A	processOkMessage()	0	4	2
A	__destruct()	0	5	2
A	isClosed()	0	2	1
A	fetch()	0	20	3
A	close()	0	8	2

<?php
/**
 * Plasma Driver MySQL component
 * Copyright 2018-2019 PlasmaPHP, All Rights Reserved
 *
 * Website: https://github.com/PlasmaPHP
 * License: https://github.com/PlasmaPHP/driver-mysql/blob/master/LICENSE
*/

namespace Plasma\Drivers\MySQL;

/**
 * Represents a Statement Cursor.
 */
class StatementCursor implements \Plasma\CursorInterface {
    /**
     * @var \Plasma\Drivers\MySQL\Driver
     */
    protected $driver;
    
    /**
     * @var \Plasma\Drivers\MySQL\Statement
     */
    protected $statement;
    
    /**
     * @var bool
     */
    protected $closed = false;
    
    /**
     * Constructor.
     * @param \Plasma\Drivers\MySQL\Driver     $driver
     * @param \Plasma\Drivers\MySQL\Statement  $statement
     */
    function __construct(\Plasma\Drivers\MySQL\Driver $driver, \Plasma\Drivers\MySQL\Statement $statement) {
        $this->driver = $driver;
        $this->statement = $statement;
    }
    
    /**
     * Destructor. Runs once the instance goes out of scope.
     * Please do not rely on the destructor to properly close your cursor.
     * ALWAYS explicitely close the cursor once you're done.
     * @codeCoverageIgnore
     */
    function __destruct() {
        if(!$this->closed) {
            $this->close()->then(null, function () {
                // Error during implicit close, close the session
                $this->driver->close();
            });
        }
    }
    
    /**
     * Whether the cursor has been closed.
     * @return bool
     */
    function isClosed(): bool {
        return $this->closed;
    }
    
    /**
     * Closes the cursor and frees the associated resources on the server.
     * Closing a cursor more than once has no effect.
     * @return \React\Promise\PromiseInterface
     */
    function close(): \React\Promise\PromiseInterface {
        if($this->closed) {
            return \React\Promise\resolve();
        }
        
        $this->closed = true;
        
        return $this->statement->close();
    }
    
    /**
     * Fetches the given amount of rows using the cursor. Resolves with the row, an array of rows (if amount > 1), or false if no more results exist.
     * @param int  $amount
     * @return \React\Promise\PromiseInterface
     * @throws \LogicException    Thrown if the driver or DBMS does not support cursors.
     * @throws \Plasma\Exception  Thrown if the underlying statement has been closed.
     */
    function fetch(int $amount = 1): \React\Promise\PromiseInterface {
        if($this->closed) {
            return \React\Promise\resolve(false);
        } elseif($this->statement->isClosed()) {
            throw new \Plasma\Exception('Underlying statement has been closed');
        }
        
        $fetch = new \Plasma\Drivers\MySQL\Commands\FetchCommand(
            $this->driver,
            $this,
            $this->statement->getID(),
            $this->statement->getQuery(),
            $this->statement->getParams(),
            array(),
            $this->statement->getColumns(),
            $amount
        );
        $this->driver->executeCommand($fetch);
        
        return $fetch->getPromise();
    }
    
    /**
     * Processes the OK or EOF message.
     * @param \Plasma\Drivers\MySQL\Messages\OkResponseMessage|\Plasma\Drivers\MySQL\Messages\EOFMessage  $message
     * @return void
     * @internal
     */
    function processOkMessage($message): void {
        if(($message->statusFlags & \Plasma\Drivers\MySQL\StatusFlags::SERVER_STATUS_LAST_ROW_SENT) > 0) {
            $this->close()->then(null, function (\Throwable $e) {
                $this->driver->emit('error', array($e));
            });
        }
    }
}