Proyectos de Subversion Moodle

<?php

// This file is part of Moodle - http://moodle.org/

//

// Moodle is free software: you can redistribute it and/or modify

// it under the terms of the GNU General Public License as published by

// the Free Software Foundation, either version 3 of the License, or

// (at your option) any later version.

//

// Moodle is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

// GNU General Public License for more details.

//

// You should have received a copy of the GNU General Public License

// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**

 * Abstract class for loading records from the DB.

 *

 * @package    mod_forum

 * @copyright  2019 Ryan Wyllie <ryan@moodle.com>

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

namespace mod_forum\local\vaults;

defined('MOODLE_INTERNAL') || die();

use mod_forum\local\factories\entity as entity_factory;

use moodle_database;

/**

 * Abstract class for loading records from the DB.

 *

 * @copyright  2019 Ryan Wyllie <ryan@moodle.com>

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

abstract class db_table_vault {

    /** @var moodle_database $db A moodle database */

    private $db;

    /** @var entity_factory $entityfactory Entity factory */

    private $entityfactory;

    /** @var object $legacyfactory Entity->legacy factory */

    private $legacyfactory;

    /**

     * Constructor.

     *

     * @param moodle_database $db A moodle database

     * @param entity_factory $entityfactory Entity factory

     * @param object $legacyfactory Legacy factory

     */

    public function __construct(

        moodle_database $db,

        entity_factory $entityfactory,

        $legacyfactory

    ) {

        $this->db = $db;

        $this->entityfactory = $entityfactory;

        $this->legacyfactory = $legacyfactory;

    }

    /**

     * Get the table alias.

     *

     * @return string

     */

    abstract protected function get_table_alias(): string;

    /**

     * Build the SQL to be used in get_records_sql.

     *

     * @param string|null $wheresql Where conditions for the SQL

     * @param string|null $sortsql Order by conditions for the SQL

     * @param object|null $user The user object

     * @return string

     */

    abstract protected function generate_get_records_sql(string $wheresql = null, string $sortsql = null,

        ?int $userid = null): string;

    /**

     * Convert the DB records into entities. The list of records will have been

     * passed through any preprocessors that may be defined before being given to

     * this function.

     *

     * Each result will from the list will be an associative array where the key

     * is set to the identifier given to the preprocessor and the result is the value

     * generated by the preprocessor.

     *

     * All results will have a 'record' key who's value is the original DB record.

     *

     * @param array $results The DB records

     */

    abstract protected function from_db_records(array $results);

    /**

     * Get the list of preprocessors to run on the DB record results. The preprocessors

     * should be defined using an associative array. The key used to identify the

     * preprocessor in this list will be used to identify the value of that preprocessor

     * in the list of results when passed to the from_db_records function.

     *

     * @return array

     */

    protected function get_preprocessors(): array {

        return [];

    }

    /**

     * Get the moodle database.

     *

     * @return moodle_database

     */

    protected function get_db(): moodle_database {

        return $this->db;

    }

    /**

     * Get the entity factory.

     *

     * @return entity_factory

     */

    protected function get_entity_factory(): entity_factory {

        return $this->entityfactory;

    }

    /**

     * Get the legacy factory

     *

     * @return object

     */

    protected function get_legacy_factory() {

        return $this->legacyfactory;

    }

    /**

     * Execute the defined preprocessors on the DB record results and then convert

     * them into entities.

     *

     * @param stdClass[] $records List of DB results

     * @return array

     */

    protected function transform_db_records_to_entities(array $records) {

        $preprocessors = $this->get_preprocessors();

        $result = array_map(function($record) {

            return ['record' => $record];

        }, $records);

        $result = array_reduce(array_keys($preprocessors), function($carry, $preprocessor) use ($records, $preprocessors) {

            $step = $preprocessors[$preprocessor];

            $dependencies = $step->execute($records);

            foreach ($dependencies as $index => $dependency) {

                // Add the new dependency to the list.

                $carry[$index] = array_merge($carry[$index], [$preprocessor => $dependency]);

            }

            return $carry;

        }, $result);

        return $this->from_db_records($result);

    }

    /**

     * Get the entity for the given id.

     *

     * @param int $id Identifier for the entity

     * @return object|null

     */

    public function get_from_id(int $id) {

        $records = $this->get_from_ids([$id]);

        return count($records) ? array_shift($records) : null;

    }

    /**

     * Get the list of entities for the given ids.

     *

     * @param int[] $ids Identifiers

     * @return array

     */

    public function get_from_ids(array $ids) {

        $alias = $this->get_table_alias();

        list($insql, $params) = $this->get_db()->get_in_or_equal($ids);

        $wheresql = $alias . '.id ' . $insql;

        $sql = $this->generate_get_records_sql($wheresql);

        $records = $this->get_db()->get_records_sql($sql, $params);

        return $this->transform_db_records_to_entities($records);

    }

}