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/>.

/**

 * Components (core subsystems + plugins) related code.

 *

 * @package    core

 * @copyright  2013 Petr Skoda {@link http://skodak.org}

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

 */

// Constants used in version.php files, these must exist when core_component executes.

// We make use of error_log as debugging is not always available.

// phpcs:disable moodle.PHP.ForbiddenFunctions.FoundWithAlternative

// We make use of empty if statements to make complex decisions clearer.

// phpcs:disable Generic.CodeAnalysis.EmptyStatement.DetectedIf

/** Software maturity level - internals can be tested using white box techniques. */

define('MATURITY_ALPHA', 50);

/** Software maturity level - feature complete, ready for preview and testing. */

define('MATURITY_BETA', 100);

/** Software maturity level - tested, will be released unless there are fatal bugs. */

define('MATURITY_RC', 150);

/** Software maturity level - ready for production deployment. */

define('MATURITY_STABLE', 200);

/** Any version - special value that can be used in $plugin->dependencies in version.php files. */

define('ANY_VERSION', 'any');

/**

 * Collection of components related methods.

 */

class core_component {

    /** @var array list of ignored directories in plugin type roots - watch out for auth/db exception */

    protected static $ignoreddirs = [

        'CVS' => true,

        '_vti_cnf' => true,

        'amd' => true,

        'classes' => true,

        'db' => true,

        'fonts' => true,

        'lang' => true,

        'pix' => true,

        'simpletest' => true,

        'templates' => true,

        'tests' => true,

        'yui' => true,

    ];

    /** @var array list plugin types that support subplugins, do not add more here unless absolutely necessary */

    protected static $supportsubplugins = ['mod', 'editor', 'tool', 'local'];

    /** @var object JSON source of the component data */

    protected static $componentsource = null;

    /** @var array cache of plugin types */

    protected static $plugintypes = null;

    /** @var array cache of plugin locations */

    protected static $plugins = null;

    /** @var array cache of core subsystems */

    protected static $subsystems = null;

    /** @var array subplugin type parents */

    protected static $parents = null;

    /** @var array subplugins */

    protected static $subplugins = null;

    /** @var array cache of core APIs */

    protected static $apis = null;

    /** @var array list of all known classes that can be autoloaded */

    protected static $classmap = null;

    /** @var array list of all classes that have been renamed to be autoloaded */

    protected static $classmaprenames = null;

    /** @var array list of some known files that can be included. */

    protected static $filemap = null;

    /** @var int|float core version. */

    protected static $version = null;

    /** @var array list of the files to map. */

    protected static $filestomap = ['lib.php', 'settings.php'];

    /** @var array associative array of PSR-0 namespaces and corresponding paths. */

    protected static $psr0namespaces = [

        'Mustache' => 'lib/mustache/src/Mustache',

        'CFPropertyList' => 'lib/plist/classes/CFPropertyList',

    ];

    /** @var array<string|array<string>> associative array of PRS-4 namespaces and corresponding paths. */

    protected static $psr4namespaces = [

        'MaxMind' => 'lib/maxmind/MaxMind',

        'GeoIp2' => 'lib/maxmind/GeoIp2',

        'Sabberworm\\CSS' => 'lib/php-css-parser',

        'MoodleHQ\\RTLCSS' => 'lib/rtlcss',

        'ScssPhp\\ScssPhp' => 'lib/scssphp',

        'OpenSpout' => 'lib/openspout/src',

        'MatthiasMullie\\Minify' => 'lib/minify/matthiasmullie-minify/src/',

        'MatthiasMullie\\PathConverter' => 'lib/minify/matthiasmullie-pathconverter/src/',

        'IMSGlobal\LTI' => 'lib/ltiprovider/src',

        'Packback\\Lti1p3' => 'lib/lti1p3/src',

        'Phpml' => 'lib/mlbackend/php/phpml/src/Phpml',

        'PHPMailer\\PHPMailer' => 'lib/phpmailer/src',

        'RedeyeVentures\\GeoPattern' => 'lib/geopattern-php/GeoPattern',

        'Firebase\\JWT' => 'lib/php-jwt/src',

        'ZipStream' => 'lib/zipstream/src/',

        'MyCLabs\\Enum' => 'lib/php-enum/src',

        'PhpXmlRpc' => 'lib/phpxmlrpc',

        'Psr\\Http\\Client' => 'lib/psr/http-client/src',

        'Psr\\Http\\Message' => [

            'lib/psr/http-message/src',

            'lib/psr/http-factory/src',

        ],

        'Psr\\EventDispatcher' => 'lib/psr/event-dispatcher/src',

        'Psr\\Clock' => 'lib/psr/clock/src',

        'Psr\\Container' => 'lib/psr/container/src',

        'GuzzleHttp\\Psr7' => 'lib/guzzlehttp/psr7/src',

        'GuzzleHttp\\Promise' => 'lib/guzzlehttp/promises/src',

        'GuzzleHttp' => 'lib/guzzlehttp/guzzle/src',

        'Kevinrob\\GuzzleCache' => 'lib/guzzlehttp/kevinrob/guzzlecache/src',

        'Aws' => 'lib/aws-sdk/src',

        'JmesPath' => 'lib/jmespath/src',

        'Laravel\\SerializableClosure' => 'lib/laravel/serializable-closure/src',

        'DI' => 'lib/php-di/php-di/src',

        'Invoker' => 'lib/php-di/invoker/src',

    ];

    /**

     * Class loader for Frankenstyle named classes in standard locations.

     * Frankenstyle namespaces are supported.

     *

     * The expected location for core classes is:

     *    1/ core_xx_yy_zz ---> lib/classes/xx_yy_zz.php

     *    2/ \core\xx_yy_zz ---> lib/classes/xx_yy_zz.php

     *    3/ \core\xx\yy_zz ---> lib/classes/xx/yy_zz.php

     *

     * The expected location for plugin classes is:

     *    1/ mod_name_xx_yy_zz ---> mod/name/classes/xx_yy_zz.php

     *    2/ \mod_name\xx_yy_zz ---> mod/name/classes/xx_yy_zz.php

     *    3/ \mod_name\xx\yy_zz ---> mod/name/classes/xx/yy_zz.php

     *

     * @param string $classname

     */

    public static function classloader($classname) {

        self::init();

        if (isset(self::$classmap[$classname])) {

            // Global $CFG is expected in included scripts.

            global $CFG;

            // Function include would be faster, but for BC it is better to include only once.

            include_once(self::$classmap[$classname]);

            return;

        }

        if (isset(self::$classmaprenames[$classname]) && isset(self::$classmap[self::$classmaprenames[$classname]])) {

            $newclassname = self::$classmaprenames[$classname];

            $debugging = "Class '%s' has been renamed for the autoloader and is now deprecated. Please use '%s' instead.";

            debugging(sprintf($debugging, $classname, $newclassname), DEBUG_DEVELOPER);

            if (PHP_VERSION_ID >= 70000 && preg_match('#\\\null(\\\|$)#', $classname)) {

                throw new \coding_exception("Cannot alias $classname to $newclassname");

            }

            class_alias($newclassname, $classname);

            return;

        }

        $file = self::psr_classloader($classname);

        // If the file is found, require it.

        if (!empty($file)) {

            require($file);

            return;

        }

    }

    /**

     * Return the path to a class from our defined PSR-0 or PSR-4 standard namespaces on

     * demand. Only returns paths to files that exist.

     *

     * Adapated from http://www.php-fig.org/psr/psr-4/examples/ and made PSR-0

     * compatible.

     *

     * @param string $class the name of the class.

     * @return string|bool The full path to the file defining the class. Or false if it could not be resolved or does not exist.

     */

    protected static function psr_classloader($class) {

        // Iterate through each PSR-4 namespace prefix.

        foreach (self::$psr4namespaces as $prefix => $paths) {

            if (!is_array($paths)) {

                $paths = [$paths];

            }

            foreach ($paths as $path) {

                $file = self::get_class_file($class, $prefix, $path, ['\\']);

                if (!empty($file) && file_exists($file)) {

                    return $file;

                }

            }

        }

        // Iterate through each PSR-0 namespace prefix.

        foreach (self::$psr0namespaces as $prefix => $path) {

            $file = self::get_class_file($class, $prefix, $path, ['\\', '_']);

            if (!empty($file) && file_exists($file)) {

                return $file;

            }

        }

        return false;

    }

    /**

     * Return the path to the class based on the given namespace prefix and path it corresponds to.

     *

     * Will return the path even if the file does not exist. Check the file esists before requiring.

     *

     * @param string $class the name of the class.

     * @param string $prefix The namespace prefix used to identify the base directory of the source files.

     * @param string $path The relative path to the base directory of the source files.

     * @param string[] $separators The characters that should be used for separating.

     * @return string|bool The full path to the file defining the class. Or false if it could not be resolved.

     */

    protected static function get_class_file($class, $prefix, $path, $separators) {

        global $CFG;

        // Does the class use the namespace prefix?

        $len = strlen($prefix);

        if (strncmp($prefix, $class, $len) !== 0) {

            // No, move to the next prefix.

            return false;

        }

        $path = $CFG->dirroot . '/' . $path;

        // Get the relative class name.

        $relativeclass = substr($class, $len);

        // Replace the namespace prefix with the base directory, replace namespace

        // separators with directory separators in the relative class name, append

        // with .php.

        $file = $path . str_replace($separators, '/', $relativeclass) . '.php';

        return $file;

    }

    /**

     * Initialise caches, always call before accessing self:: caches.

     */

    protected static function init() {

        global $CFG;

        // Init only once per request/CLI execution, we ignore changes done afterwards.

        if (isset(self::$plugintypes)) {

            return;

        }

        if (defined('IGNORE_COMPONENT_CACHE') && IGNORE_COMPONENT_CACHE) {

            self::fill_all_caches();

            return;

        }

        if (!empty($CFG->alternative_component_cache)) {

            // Hack for heavily clustered sites that want to manage component cache invalidation manually.

            $cachefile = $CFG->alternative_component_cache;

            if (file_exists($cachefile)) {

                if (CACHE_DISABLE_ALL) {

                    // Verify the cache state only on upgrade pages.

                    $content = self::get_cache_content();

                    if (sha1_file($cachefile) !== sha1($content)) {

                        die('Outdated component cache file defined in $CFG->alternative_component_cache, can not continue');

                    }

                    return;

                }

                $cache = [];

                include($cachefile);

                self::$plugintypes      = $cache['plugintypes'];

                self::$plugins          = $cache['plugins'];

                self::$subsystems       = $cache['subsystems'];

                self::$parents          = $cache['parents'];

                self::$subplugins       = $cache['subplugins'];

                self::$apis             = $cache['apis'];

                self::$classmap         = $cache['classmap'];

                self::$classmaprenames  = $cache['classmaprenames'];

                self::$filemap          = $cache['filemap'];

                return;

            }

            if (!is_writable(dirname($cachefile))) {

                die(

                    'Can not create alternative component cache file defined in ' .

                    '$CFG->alternative_component_cache, can not continue'

                );

            }

            // Lets try to create the file, it might be in some writable directory or a local cache dir.

        } else {

            // Note: $CFG->cachedir MUST be shared by all servers in a cluster,

            // use $CFG->alternative_component_cache if you do not like it.

            $cachefile = "$CFG->cachedir/core_component.php";

        }

        if (!CACHE_DISABLE_ALL && !self::is_developer()) {

            // 1/ Use the cache only outside of install and upgrade.

            // 2/ Let developers add/remove classes in developer mode.

            if (is_readable($cachefile)) {

                $cache = false;

                include($cachefile);

                if (!is_array($cache)) {

                    // Something is very wrong.

                } else if (!isset($cache['version'])) {

                    // Something is very wrong.

                } else if ((float) $cache['version'] !== (float) self::fetch_core_version()) {

                    // Outdated cache. We trigger an error log to track an eventual repetitive failure of float comparison.

                    error_log('Resetting core_component cache after core upgrade to version ' . self::fetch_core_version());

                } else if ($cache['plugintypes']['mod'] !== "$CFG->dirroot/mod") {

                    // phpcs:ignore moodle.Commenting.InlineComment.NotCapital

                    // $CFG->dirroot was changed.

                } else {

                    // The cache looks ok, let's use it.

                    self::$plugintypes      = $cache['plugintypes'];

                    self::$plugins          = $cache['plugins'];

                    self::$subsystems       = $cache['subsystems'];

                    self::$parents          = $cache['parents'];

                    self::$subplugins       = $cache['subplugins'];

                    self::$apis             = $cache['apis'];

                    self::$classmap         = $cache['classmap'];

                    self::$classmaprenames  = $cache['classmaprenames'];

                    self::$filemap          = $cache['filemap'];

                    return;

                }

                // Note: we do not verify $CFG->admin here intentionally,

                // they must visit admin/index.php after any change.

            }

        }

        if (!isset(self::$plugintypes)) {

            // This needs to be atomic and self-fixing as much as possible.

            $content = self::get_cache_content();

            if (file_exists($cachefile)) {

                if (sha1_file($cachefile) === sha1($content)) {

                    return;

                }

                // Stale cache detected!

                unlink($cachefile);

            }

            // Permissions might not be setup properly in installers.

            $dirpermissions = !isset($CFG->directorypermissions) ? 02777 : $CFG->directorypermissions;

            $filepermissions = !isset($CFG->filepermissions) ? ($dirpermissions & 0666) : $CFG->filepermissions;

            clearstatcache();

            $cachedir = dirname($cachefile);

            if (!is_dir($cachedir)) {

                mkdir($cachedir, $dirpermissions, true);

            }

            if ($fp = @fopen($cachefile . '.tmp', 'xb')) {

                fwrite($fp, $content);

                fclose($fp);

                @rename($cachefile . '.tmp', $cachefile);

                @chmod($cachefile, $filepermissions);

            }

            @unlink($cachefile . '.tmp'); // Just in case anything fails (race condition).

            self::invalidate_opcode_php_cache($cachefile);

        }

    }

    /**

     * Are we in developer debug mode?

     *

     * Note: You need to set "$CFG->debug = (E_ALL | E_STRICT);" in config.php,

     *       the reason is we need to use this before we setup DB connection or caches for CFG.

     *

     * @return bool

     */

    protected static function is_developer() {

        global $CFG;

        // Note we can not rely on $CFG->debug here because DB is not initialised yet.

        if (isset($CFG->config_php_settings['debug'])) {

            $debug = (int)$CFG->config_php_settings['debug'];

        } else {

            return false;

        }

        if ($debug & E_ALL && $debug & E_STRICT) {

            return true;

        }

        return false;

    }

    /**

     * Create cache file content.

     *

     * @private this is intended for $CFG->alternative_component_cache only.

     *

     * @return string

     */

    public static function get_cache_content() {

        if (!isset(self::$plugintypes)) {

            self::fill_all_caches();

        }

        $cache = [

            'subsystems'        => self::$subsystems,

            'plugintypes'       => self::$plugintypes,

            'plugins'           => self::$plugins,

            'parents'           => self::$parents,

            'subplugins'        => self::$subplugins,

            'apis'              => self::$apis,

            'classmap'          => self::$classmap,

            'classmaprenames'   => self::$classmaprenames,

            'filemap'           => self::$filemap,

            'version'           => self::$version,

        ];

        return '<?php

$cache = ' . var_export($cache, true) . ';

';

    }

    /**

     * Fill all caches.

     */

    protected static function fill_all_caches() {

        self::$subsystems = self::fetch_subsystems();

        [self::$plugintypes, self::$parents, self::$subplugins] = self::fetch_plugintypes();

        self::$plugins = [];

        foreach (self::$plugintypes as $type => $fulldir) {

            self::$plugins[$type] = self::fetch_plugins($type, $fulldir);

        }

        self::$apis = self::fetch_apis();

        self::fill_classmap_cache();

        self::fill_classmap_renames_cache();

        self::fill_filemap_cache();

        self::fetch_core_version();

    }

    /**

     * Get the core version.

     *

     * In order for this to work properly, opcache should be reset beforehand.

     *

     * @return float core version.

     */

    protected static function fetch_core_version() {

        global $CFG;

        if (self::$version === null) {

            $version = null; // Prevent IDE complaints.

            require($CFG->dirroot . '/version.php');

            self::$version = $version;

        }

        return self::$version;

    }

    /**

     * Returns list of core subsystems.

     * @return array

     */

    protected static function fetch_subsystems() {

        global $CFG;

        // NOTE: Any additions here must be verified to not collide with existing add-on modules and subplugins!!!

        $info = [];

        foreach (self::fetch_component_source('subsystems') as $subsystem => $path) {

            // Replace admin/ directory with the config setting.

            if ($CFG->admin !== 'admin') {

                if ($path === 'admin') {

                    $path = $CFG->admin;

                }

                if (strpos($path, 'admin/') === 0) {

                    $path = $CFG->admin . substr($path, 5);

                }

            }

            $info[$subsystem] = empty($path) ? null : "{$CFG->dirroot}/{$path}";

        }

        return $info;

    }

    /**

     * Returns list of core APIs.

     * @return stdClass[]

     */

    protected static function fetch_apis() {

        return (array) json_decode(file_get_contents(__DIR__ . '/../apis.json'));

    }

    /**

     * Returns list of known plugin types.

     * @return array

     */

    protected static function fetch_plugintypes() {

        global $CFG;

        $types = [];

        foreach (self::fetch_component_source('plugintypes') as $plugintype => $path) {

            // Replace admin/ with the config setting.

            if ($CFG->admin !== 'admin' && strpos($path, 'admin/') === 0) {

                $path = $CFG->admin . substr($path, 5);

            }

            $types[$plugintype] = "{$CFG->dirroot}/{$path}";

        }

        $parents = [];

        $subplugins = [];

        if (!empty($CFG->themedir) && is_dir($CFG->themedir)) {

            $types['theme'] = $CFG->themedir;

        } else {

            $types['theme'] = $CFG->dirroot . '/theme';

        }

        foreach (self::$supportsubplugins as $type) {

            if ($type === 'local') {

                // Local subplugins must be after local plugins.

                continue;

            }

            $plugins = self::fetch_plugins($type, $types[$type]);

            foreach ($plugins as $plugin => $fulldir) {

                $subtypes = self::fetch_subtypes($fulldir);

                if (!$subtypes) {

                    continue;

                }

                $subplugins[$type . '_' . $plugin] = [];

                foreach ($subtypes as $subtype => $subdir) {

                    if (isset($types[$subtype])) {

                        error_log("Invalid subtype '$subtype', duplicate detected.");

                        continue;

                    }

                    $types[$subtype] = $subdir;

                    $parents[$subtype] = $type . '_' . $plugin;

                    $subplugins[$type . '_' . $plugin][$subtype] = array_keys(self::fetch_plugins($subtype, $subdir));

                }

            }

        }

        // Local is always last!

        $types['local'] = $CFG->dirroot . '/local';

        if (in_array('local', self::$supportsubplugins)) {

            $type = 'local';

            $plugins = self::fetch_plugins($type, $types[$type]);

            foreach ($plugins as $plugin => $fulldir) {

                $subtypes = self::fetch_subtypes($fulldir);

                if (!$subtypes) {

                    continue;

                }

                $subplugins[$type . '_' . $plugin] = [];

                foreach ($subtypes as $subtype => $subdir) {

                    if (isset($types[$subtype])) {

                        error_log("Invalid subtype '$subtype', duplicate detected.");

                        continue;

                    }

                    $types[$subtype] = $subdir;

                    $parents[$subtype] = $type . '_' . $plugin;

                    $subplugins[$type . '_' . $plugin][$subtype] = array_keys(self::fetch_plugins($subtype, $subdir));

                }

            }

        }

        return [$types, $parents, $subplugins];

    }

    /**

     * Returns the component source content as loaded from /lib/components.json.

     *

     * @return array

     */

    protected static function fetch_component_source(string $key) {

        if (null === self::$componentsource) {

            self::$componentsource = (array) json_decode(file_get_contents(__DIR__ . '/../components.json'));

        }

        return (array) self::$componentsource[$key];

    }

    /**

     * Returns list of subtypes.

     * @param string $ownerdir

     * @return array

     */

    protected static function fetch_subtypes($ownerdir) {

        global $CFG;

        $types = [];

        $subplugins = [];

        if (file_exists("$ownerdir/db/subplugins.json")) {

            $subplugins = [];

            $subpluginsjson = json_decode(file_get_contents("$ownerdir/db/subplugins.json"));

            if (json_last_error() === JSON_ERROR_NONE) {

                if (!empty($subpluginsjson->plugintypes)) {

                    $subplugins = (array) $subpluginsjson->plugintypes;

                } else {

                    error_log("No plugintypes defined in $ownerdir/db/subplugins.json");

                }

            } else {

                $jsonerror = json_last_error_msg();

                error_log("$ownerdir/db/subplugins.json is invalid ($jsonerror)");

            }

        } else if (file_exists("$ownerdir/db/subplugins.php")) {

            error_log('Use of subplugins.php has been deprecated. ' .

                "Please update your '$ownerdir' plugin to provide a subplugins.json file instead.");

            include("$ownerdir/db/subplugins.php");

        }

        foreach ($subplugins as $subtype => $dir) {

            if (!preg_match('/^[a-z][a-z0-9]*$/', $subtype)) {

                error_log("Invalid subtype '$subtype'' detected in '$ownerdir', invalid characters present.");

                continue;

            }

            if (isset(self::$subsystems[$subtype])) {

                error_log("Invalid subtype '$subtype'' detected in '$ownerdir', duplicates core subsystem.");

                continue;

            }

            if ($CFG->admin !== 'admin' && strpos($dir, 'admin/') === 0) {

                $dir = preg_replace('|^admin/|', "$CFG->admin/", $dir);

            }

            if (!is_dir("$CFG->dirroot/$dir")) {

                error_log("Invalid subtype directory '$dir' detected in '$ownerdir'.");

                continue;

            }

            $types[$subtype] = "$CFG->dirroot/$dir";

        }

        return $types;

    }

    /**

     * Returns list of plugins of given type in given directory.

     * @param string $plugintype

     * @param string $fulldir

     * @return array

     */

    protected static function fetch_plugins($plugintype, $fulldir) {

        global $CFG;

        $fulldirs = (array)$fulldir;

        if ($plugintype === 'theme') {

            if (realpath($fulldir) !== realpath($CFG->dirroot . '/theme')) {

                // Include themes in standard location too.

                array_unshift($fulldirs, $CFG->dirroot . '/theme');

            }

        }

        $result = [];

        foreach ($fulldirs as $fulldir) {

            if (!is_dir($fulldir)) {

                continue;

            }

            $items = new \DirectoryIterator($fulldir);

            foreach ($items as $item) {

                if ($item->isDot() || !$item->isDir()) {

                    continue;

                }

                $pluginname = $item->getFilename();

                if ($plugintype === 'auth' && $pluginname === 'db') {

                    // Special exception for this wrong plugin name.

                } else if (isset(self::$ignoreddirs[$pluginname])) {

                    continue;

                }

                if (!self::is_valid_plugin_name($plugintype, $pluginname)) {

                    // Always ignore plugins with problematic names here.

                    continue;

                }

                $result[$pluginname] = $fulldir . '/' . $pluginname;

                unset($item);

            }

            unset($items);

        }

        ksort($result);

        return $result;

    }

    /**

     * Find all classes that can be autoloaded including frankenstyle namespaces.

     */

    protected static function fill_classmap_cache() {

        global $CFG;

        self::$classmap = [];

        self::load_classes('core', "$CFG->dirroot/lib/classes");

        foreach (self::$subsystems as $subsystem => $fulldir) {

            if (!$fulldir) {

                continue;

            }

            self::load_classes('core_' . $subsystem, "$fulldir/classes");

        }

        foreach (self::$plugins as $plugintype => $plugins) {

            foreach ($plugins as $pluginname => $fulldir) {

                self::load_classes($plugintype . '_' . $pluginname, "$fulldir/classes");

            }

        }

        ksort(self::$classmap);

    }

    /**

     * Fills up the cache defining what plugins have certain files.

     *

     * @see self::get_plugin_list_with_file

     * @return void

     */

    protected static function fill_filemap_cache() {

        global $CFG;

        self::$filemap = [];

        foreach (self::$filestomap as $file) {

            if (!isset(self::$filemap[$file])) {

                self::$filemap[$file] = [];

            }

            foreach (self::$plugins as $plugintype => $plugins) {

                if (!isset(self::$filemap[$file][$plugintype])) {

                    self::$filemap[$file][$plugintype] = [];

                }

                foreach ($plugins as $pluginname => $fulldir) {

                    if (file_exists("$fulldir/$file")) {

                        self::$filemap[$file][$plugintype][$pluginname] = "$fulldir/$file";

                    }

                }

            }

        }

    }

    /**

     * Find classes in directory and recurse to subdirs.

     * @param string $component

     * @param string $fulldir

     * @param string $namespace

     */

    protected static function load_classes($component, $fulldir, $namespace = '') {

        if (!is_dir($fulldir)) {

            return;

        }

        if (!is_readable($fulldir)) {

            // TODO: MDL-51711 We should generate some diagnostic debugging information in this case

            // because its pretty likely to lead to a missing class error further down the line.

            // But our early setup code can't handle errors this early at the moment.

            return;

        }

        $items = new \DirectoryIterator($fulldir);

        foreach ($items as $item) {

            if ($item->isDot()) {

                continue;

            }

            if ($item->isDir()) {

                $dirname = $item->getFilename();

                self::load_classes($component, "$fulldir/$dirname", $namespace . '\\' . $dirname);

                continue;

            }

            $filename = $item->getFilename();

            $classname = preg_replace('/\.php$/', '', $filename);

            if ($filename === $classname) {

                // Not a php file.

                continue;

            }

            if ($namespace === '') {

                // Legacy long frankenstyle class name.

                self::$classmap[$component . '_' . $classname] = "$fulldir/$filename";

            }

            // New namespaced classes.

            self::$classmap[$component . $namespace . '\\' . $classname] = "$fulldir/$filename";

        }

        unset($item);

        unset($items);

    }

    /**

     * List all core subsystems and their location

     *

     * This is a list of components that are part of the core and their

     * language strings are defined in /lang/en/<<subsystem>>.php. If a given

     * plugin is not listed here and it does not have proper plugintype prefix,

     * then it is considered as course activity module.

     *

     * The location is absolute file path to dir. NULL means there is no special

     * directory for this subsystem. If the location is set, the subsystem's

     * renderer.php is expected to be there.

     *

     * @return array of (string)name => (string|null)full dir location

     */

    public static function get_core_subsystems() {

        self::init();

        return self::$subsystems;

    }

    /**

     * List all core APIs and their attributes.

     *

     * This is a list of all the existing / allowed APIs in moodle, each one with the

     * following attributes:

     *   - component: the component, usually a subsystem or core, the API belongs to.

     *   - allowedlevel2: if the API is allowed as level2 namespace or no.

     *   - allowedspread: if the API can spread out from its component or no.

     *

     * @return stdClass[] array of APIs (as keys) with their attributes as object instances.

     */

    public static function get_core_apis() {

        self::init();

        return self::$apis;

    }

    /**

     * Get list of available plugin types together with their location.

     *

     * @return array as (string)plugintype => (string)fulldir

     */

    public static function get_plugin_types() {

        self::init();

        return self::$plugintypes;

    }

    /**

     * Get list of plugins of given type.

     *

     * @param string $plugintype

     * @return array as (string)pluginname => (string)fulldir

     */

    public static function get_plugin_list($plugintype) {

        self::init();

        if (!isset(self::$plugins[$plugintype])) {

            return [];

        }

        return self::$plugins[$plugintype];

    }

    /**

     * Get a list of all the plugins of a given type that define a certain class

     * in a certain file. The plugin component names and class names are returned.

     *

     * @param string $plugintype the type of plugin, e.g. 'mod' or 'report'.

     * @param string $class the part of the name of the class after the

     *      frankenstyle prefix. e.g 'thing' if you are looking for classes with

     *      names like report_courselist_thing. If you are looking for classes with

     *      the same name as the plugin name (e.g. qtype_multichoice) then pass ''.

     *      Frankenstyle namespaces are also supported.

     * @param string $file the name of file within the plugin that defines the class.

     * @return array with frankenstyle plugin names as keys (e.g. 'report_courselist', 'mod_forum')

     *      and the class names as values (e.g. 'report_courselist_thing', 'qtype_multichoice').

     */

    public static function get_plugin_list_with_class($plugintype, $class, $file = null) {

        global $CFG; // Necessary in case it is referenced by included PHP scripts.

        if ($class) {

            $suffix = '_' . $class;

        } else {

            $suffix = '';

        }

        $pluginclasses = [];

        $plugins = self::get_plugin_list($plugintype);

        foreach ($plugins as $plugin => $fulldir) {

            // Try class in frankenstyle namespace.

            if ($class) {

                $classname = '\\' . $plugintype . '_' . $plugin . '\\' . $class;

                if (class_exists($classname, true)) {

                    $pluginclasses[$plugintype . '_' . $plugin] = $classname;

                    continue;

                }

            }

            // Try autoloading of class with frankenstyle prefix.

            $classname = $plugintype . '_' . $plugin . $suffix;

            if (class_exists($classname, true)) {

                $pluginclasses[$plugintype . '_' . $plugin] = $classname;

                continue;

            }

            // Fall back to old file location and class name.

            if ($file && file_exists("$fulldir/$file")) {

                include_once("$fulldir/$file");

                if (class_exists($classname, false)) {

                    $pluginclasses[$plugintype . '_' . $plugin] = $classname;

                    continue;

                }

            }

        }

        return $pluginclasses;

    }

    /**

     * Get a list of all the plugins of a given type that contain a particular file.

     *

     * @param string $plugintype the type of plugin, e.g. 'mod' or 'report'.

     * @param string $file the name of file that must be present in the plugin.

     *                     (e.g. 'view.php', 'db/install.xml').

     * @param bool $include if true (default false), the file will be include_once-ed if found.

     * @return array with plugin name as keys (e.g. 'forum', 'courselist') and the path

     *               to the file relative to dirroot as value (e.g. "$CFG->dirroot/mod/forum/view.php").

     */

    public static function get_plugin_list_with_file($plugintype, $file, $include = false) {

        global $CFG; // Necessary in case it is referenced by included PHP scripts.

        $pluginfiles = [];

        if (isset(self::$filemap[$file])) {

            // If the file was supposed to be mapped, then it should have been set in the array.

            if (isset(self::$filemap[$file][$plugintype])) {

                $pluginfiles = self::$filemap[$file][$plugintype];

            }

        } else {

            // Old-style search for non-cached files.

            $plugins = self::get_plugin_list($plugintype);

            foreach ($plugins as $plugin => $fulldir) {

                $path = $fulldir . '/' . $file;

                if (file_exists($path)) {

                    $pluginfiles[$plugin] = $path;

                }

            }

        }

        if ($include) {

            foreach ($pluginfiles as $path) {

                include_once($path);

            }

        }

        return $pluginfiles;

    }

    /**

     * Returns all classes in a component matching the provided namespace.

     *

     * It checks that the class exists.

     *

     * e.g. get_component_classes_in_namespace('mod_forum', 'event')

     *

     * @param string|null $component A valid moodle component (frankenstyle) or null if searching all components

     * @param string $namespace Namespace from the component name or empty string if all $component classes.

     * @return array The full class name as key and the class path as value, empty array if $component is `null`

     * and $namespace is empty.

     */

    public static function get_component_classes_in_namespace($component = null, $namespace = '') {

        $classes = [];

        // Only look for components if a component name is set or a namespace is set.

        if (isset($component) || !empty($namespace)) {

            // If a component parameter value is set we only want to look in that component.

            // Otherwise we want to check all components.

            $component = (isset($component)) ? self::normalize_componentname($component) : '\w+';

            if ($namespace) {

                // We will add them later.

                $namespace = trim($namespace, '\\');

                // We need add double backslashes as it is how classes are stored into self::$classmap.

                $namespace = implode('\\\\', explode('\\', $namespace));

                $namespace = $namespace . '\\\\';

            }

            $regex = '|^' . $component . '\\\\' . $namespace . '|';

            $it = new RegexIterator(new ArrayIterator(self::$classmap), $regex, RegexIterator::GET_MATCH, RegexIterator::USE_KEY);

            // We want to be sure that they exist.

            foreach ($it as $classname => $classpath) {

                if (class_exists($classname)) {

                    $classes[$classname] = $classpath;

                }

            }

        }

        return $classes;

    }

    /**

     * Returns the exact absolute path to plugin directory.

     *

     * @param string $plugintype type of plugin

     * @param string $pluginname name of the plugin

     * @return string full path to plugin directory; null if not found

     */

    public static function get_plugin_directory($plugintype, $pluginname) {

        if (empty($pluginname)) {

            // Invalid plugin name, sorry.

            return null;

        }

        self::init();

        if (!isset(self::$plugins[$plugintype][$pluginname])) {

            return null;

        }

        return self::$plugins[$plugintype][$pluginname];