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/>.

/**

 * Utility class for browsing of files.

 *

 * @package   core_files

 * @copyright 2008 Petr Skoda (http://skodak.org)

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

 */

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

require_once("$CFG->libdir/filebrowser/file_info.php");

// general area types

require_once("$CFG->libdir/filebrowser/file_info_stored.php");

require_once("$CFG->libdir/filebrowser/virtual_root_file.php");

// description of available areas in each context level

require_once("$CFG->libdir/filebrowser/file_info_context_system.php");

require_once("$CFG->libdir/filebrowser/file_info_context_user.php");

require_once("$CFG->libdir/filebrowser/file_info_context_coursecat.php");

require_once("$CFG->libdir/filebrowser/file_info_context_course.php");

require_once("$CFG->libdir/filebrowser/file_info_context_module.php");

/**

 * This class provides the main entry point for other code wishing to get information about files.

 *

 * The whole file storage for a Moodle site can be seen as a huge virtual tree.

 * The spine of the tree is the tree of contexts (system, course-categories,

 * courses, modules, also users). Then, within each context, there may be any number of

 * file areas, and a file area contains folders and files. The various file_info

 * subclasses return info about the things in this tree. They should be obtained

 * from an instance of this class.

 *

 * This virtual tree is different for each user depending of his/her current permissions.

 * Some branches such as draft areas are hidden, but accessible.

 *

 * Always use this abstraction when you need to access module files from core code.

  *

 * @package   core_files

 * @category  files

 * @copyright 2008 Petr Skoda (http://skodak.org)

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

*/

class file_browser {

    /** @var array cached list of enrolled courses.  */

    protected $enrolledcourses = null;

    /**

     * Looks up file_info instance

     *

     * @param stdClass $context context object

     * @param string $component component

     * @param string $filearea file area

     * @param int $itemid item ID

     * @param string $filepath file path

     * @param string $filename file name

     * @return file_info|null file_info instance or null if not found or access not allowed

     */

    public function get_file_info($context = NULL, $component = NULL, $filearea = NULL, $itemid = NULL, $filepath = NULL, $filename = NULL) {

        if (!$context) {

            $context = context_system::instance();

        }

        switch ($context->contextlevel) {

            case CONTEXT_SYSTEM:

                return $this->get_file_info_context_system($context, $component, $filearea, $itemid, $filepath, $filename);

            case CONTEXT_USER:

                return $this->get_file_info_context_user($context, $component, $filearea, $itemid, $filepath, $filename);

            case CONTEXT_COURSECAT:

                return $this->get_file_info_context_coursecat($context, $component, $filearea, $itemid, $filepath, $filename);

            case CONTEXT_COURSE:

                return $this->get_file_info_context_course($context, $component, $filearea, $itemid, $filepath, $filename);

            case CONTEXT_MODULE:

                return $this->get_file_info_context_module($context, $component, $filearea, $itemid, $filepath, $filename);

        }

        return null;

    }

    /**

     * Returns info about the files at System context

     * @todo MDL-33372 - Provide a way of displaying recent files for blog entries.

     *

     * @param object $context context object

     * @param string $component component

     * @param string $filearea file area

     * @param int $itemid item ID

     * @param string $filepath file path

     * @param string $filename file name

     * @return file_info instance or null if not found or access not allowed

     */

    private function get_file_info_context_system($context, $component, $filearea, $itemid, $filepath, $filename) {

        $level = new file_info_context_system($this, $context);

        return $level->get_file_info($component, $filearea, $itemid, $filepath, $filename);

        // nothing supported at this context yet

    }

    /**

     * Returns info about the files at User context

     *

     * @param stdClass $context context object

     * @param string $component component

     * @param string $filearea file area

     * @param int $itemid item ID

     * @param string $filepath file path

     * @param string $filename file name

     * @return file_info|null file_info instance or null if not found or access not allowed

     */

    private function get_file_info_context_user($context, $component, $filearea, $itemid, $filepath, $filename) {

        global $DB, $USER;

        if ($context->instanceid == $USER->id) {

            $user = $USER;

        } else {

            $user = $DB->get_record('user', array('id'=>$context->instanceid));

        }

        if (isguestuser($user)) {

            // guests do not have any files

            return null;

        }

        if ($user->deleted) {

            return null;

        }

        $level = new file_info_context_user($this, $context, $user);

        return $level->get_file_info($component, $filearea, $itemid, $filepath, $filename);

    }

    /**

     * Returns info about the files at Course category context

     *

     * @param stdClass $context context object

     * @param string $component component

     * @param string $filearea file area

     * @param int $itemid item ID

     * @param string $filepath file path

     * @param string $filename file name

     * @return file_info|null file_info instance or null if not found or access not allowed

     */

    private function get_file_info_context_coursecat($context, $component, $filearea, $itemid, $filepath, $filename) {

        global $DB;

        if (!$category = $DB->get_record('course_categories', array('id'=>$context->instanceid))) {

            return null;

        }

        $level = new file_info_context_coursecat($this, $context, $category);

        return $level->get_file_info($component, $filearea, $itemid, $filepath, $filename);

    }

    /**

     * Returns info about the files at Course category context

     *

     * @param stdClass $context context object

     * @param string $component component

     * @param string $filearea file area

     * @param int $itemid item ID

     * @param string $filepath file path

     * @param string $filename file name

     * @return file_info|null file_info instance or null if not found or access not allowed

     */

    private function get_file_info_context_course($context, $component, $filearea, $itemid, $filepath, $filename) {

        global $DB, $COURSE;

        if ($context->instanceid == $COURSE->id) {

            $course = $COURSE;

        } else if (!$course = $DB->get_record('course', array('id'=>$context->instanceid))) {

            return null;

        }

        $level = new file_info_context_course($this, $context, $course);

        return $level->get_file_info($component, $filearea, $itemid, $filepath, $filename);

    }

    /**

     * Returns info about the files at Course category context

     *

     * @param context $context context object

     * @param string $component component

     * @param string $filearea file area

     * @param int $itemid item ID

     * @param string $filepath file path

     * @param string $filename file name

     * @return file_info|null file_info instance or null if not found or access not allowed

     */

    private function get_file_info_context_module($context, $component, $filearea, $itemid, $filepath, $filename) {

        if (!($context instanceof context_module)) {

            return null;

        }

        $coursecontext = $context->get_course_context();

        $modinfo = get_fast_modinfo($coursecontext->instanceid);

        $cm = $modinfo->get_cm($context->instanceid);

        if (empty($cm->uservisible)) {

            return null;

        }

        $level = new file_info_context_module($this, $context, $cm->get_course(), $cm, $cm->modname);

        return $level->get_file_info($component, $filearea, $itemid, $filepath, $filename);

    }

    /**

     * Check if user is enrolled into the course

     *

     * This function keeps a cache of enrolled courses because it may be called multiple times for many courses in one request

     *

     * @param int $courseid

     * @return bool

     */

    public function is_enrolled($courseid) {

        if ($this->enrolledcourses === null || PHPUNIT_TEST) {

            // Since get_file_browser() returns a statically cached object we can't rely on cache

            // inside the file_browser class in the unittests.

            // TODO MDL-59964 remove this caching when it's implemented inside enrol_get_my_courses().

            $this->enrolledcourses = enrol_get_my_courses(['id']);

        }

        return array_key_exists($courseid, $this->enrolledcourses);

    }

}