Proyectos de Subversion Moodle

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<?php
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// This file is part of Moodle - http://moodle.org/
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//
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// Moodle is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// Moodle is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
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/**
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 * Delegated database transaction support.
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 *
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 * @package    core_dml
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 * @copyright  2009 Petr Skoda (http://skodak.org)
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 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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 */
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defined('MOODLE_INTERNAL') || die();
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/**
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 * Delegated transaction class.
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 *
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 * @package    core_dml
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 * @copyright  2009 Petr Skoda (http://skodak.org)
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 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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 */
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class moodle_transaction {
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    /** @var array The debug_backtrace() returned array.*/
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    private $start_backtrace;
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    /**@var moodle_database The moodle_database instance.*/
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    private $database = null;
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    /**
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     * Delegated transaction constructor,
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     * can be called only from moodle_database class.
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     * Unfortunately PHP's protected keyword is useless.
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     * @param moodle_database $database
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     */
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    public function __construct($database) {
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        $this->database = $database;
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        $this->start_backtrace = debug_backtrace();
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        array_shift($this->start_backtrace);
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    }
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    /**
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     * Returns backtrace of the code starting exception.
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     * @return array
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     */
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    public function get_backtrace() {
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        return $this->start_backtrace;
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    }
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    /**
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     * Is the delegated transaction already used?
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     * @return bool true if commit and rollback allowed, false if already done
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     */
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    public function is_disposed() {
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        return empty($this->database);
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    }
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    /**
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     * Mark transaction as disposed, no more
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     * commits and rollbacks allowed.
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     * To be used only from moodle_database class
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     * @return null
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     */
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    public function dispose() {
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        return $this->database = null;
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    }
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    /**
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     * Commit delegated transaction.
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     * The real database commit SQL is executed
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     * only after committing all delegated transactions.
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     *
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     * Incorrect order of nested commits or rollback
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     * at any level is resulting in rollback of SQL transaction.
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     *
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     * @return void
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     */
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    public function allow_commit() {
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        if ($this->is_disposed()) {
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            throw new dml_transaction_exception('Transactions already disposed', $this);
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        }
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        $this->database->commit_delegated_transaction($this);
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    }
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    /**
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     * Rollback all current delegated transactions.
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     *
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     * @param Exception|Throwable $e mandatory exception/throwable
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     * @return void
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     */
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    public function rollback($e) {
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        if ($this->is_disposed()) {
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            throw new dml_transaction_exception('Transactions already disposed', $this);
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        }
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        $this->database->rollback_delegated_transaction($this, $e);
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    }
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}