cakephp/src/Database/Statement/BufferedStatement.php

<?php
/**
 * CakePHP(tm) : Rapid Development Framework (https://cakephp.org)
 * Copyright (c) Cake Software Foundation, Inc. (https://cakefoundation.org)
 *
 * Licensed under The MIT License
 * For full copyright and license information, please see the LICENSE.txt
 * Redistributions of files must retain the above copyright notice.
 *
 * @copyright     Copyright (c) Cake Software Foundation, Inc. (https://cakefoundation.org)
 * @link          https://cakephp.org CakePHP(tm) Project
 * @since         3.0.0
 * @license       https://opensource.org/licenses/mit-license.php MIT License
 */
namespace Cake\Database\Statement;

use CachingIterator;
use IteratorIterator;

/**
 * A statement decorator that implements buffered results.
 *
 * This statement decorator will save fetched results in memory, allowing
 * the iterator to be rewound and reused.
 */
class BufferedStatement extends StatementDecorator
{

    /**
     * Records count
     *
     * @var int
     */
    protected $_count = 0;

    /**
     * Array of results
     *
     * @var array
     */
    protected $_records = [];

    /**
     * If true, all rows were fetched
     *
     * @var bool
     */
    protected $_allFetched = false;

    /**
     * Current record pointer
     *
     * @var int
     */
    protected $_counter = 0;

    /**
     * Execute the statement and return the results.
     *
     * @param array|null $params list of values to be bound to query
     * @return bool true on success, false otherwise
     */
    public function execute($params = null)
    {
        $this->_reset();

        return parent::execute($params);
    }

    /**
     * {@inheritDoc}
     *
     * @param string $type The type to fetch.
     * @return array|false
     */
    public function fetch($type = parent::FETCH_TYPE_NUM)
    {
        if ($this->_allFetched) {
            $row = ($this->_counter < $this->_count) ? $this->_records[$this->_counter++] : false;
            $row = ($row && $type === static::FETCH_TYPE_NUM) ? array_values($row) : $row;

            return $row;
        }

        $record = parent::fetch($type);

        if ($record === false) {
            $this->_allFetched = true;
            $this->_counter = $this->_count + 1;
            $this->_statement->closeCursor();

            return false;
        }

        $this->_count++;

        return $this->_records[] = $record;
    }

    /**
     * {@inheritdoc}
     */
    public function fetchAssoc()
    {
        $result = $this->fetch(static::FETCH_TYPE_ASSOC);

        return $result ?: [];
    }

    /**
     * {@inheritDoc}
     *
     * @param string $type The type to fetch.
     * @return array
     */
    public function fetchAll($type = parent::FETCH_TYPE_NUM)
    {
        if ($this->_allFetched) {
            return $this->_records;
        }

        $this->_records = parent::fetchAll($type);
        $this->_count = count($this->_records);
        $this->_allFetched = true;
        $this->_statement->closeCursor();

        return $this->_records;
    }

    /**
     * {@inheritDoc}
     */
    public function rowCount()
    {
        if (!$this->_allFetched) {
            $counter = $this->_counter;
            while ($this->fetch(static::FETCH_TYPE_ASSOC)) {
            }
            $this->_counter = $counter;
        }

        return $this->_count;
    }

    /**
     * Rewind the _counter property
     *
     * @return void
     */
    public function rewind()
    {
        $this->_counter = 0;
    }

    /**
     * Reset all properties
     *
     * @return void
     */
    protected function _reset()
    {
        $this->_count = $this->_counter = 0;
        $this->_records = [];
        $this->_allFetched = false;
    }

    /**
     * Get an iterator that buffers results.
     *
     * @return Traversable
     */
    public function getIterator()
    {
        $statement = parent::getIterator();
        if (!$this->_iterator) {
            $this->_iterator = new BufferedIterator(new IteratorIterator($statement));
        }

        return $this->_iterator;
    }
}