--- /dev/null
+<?php
+
+namespace Drupal\Core\Extension;
+
+/**
+ * Defines an extension (file) object.
+ */
+class Extension implements \Serializable {
+
+ /**
+ * The type of the extension (e.g., 'module').
+ *
+ * @var string
+ */
+ protected $type;
+
+ /**
+ * The relative pathname of the extension (e.g., 'core/modules/node/node.info.yml').
+ *
+ * @var string
+ */
+ protected $pathname;
+
+ /**
+ * The filename of the main extension file (e.g., 'node.module').
+ *
+ * @var string|null
+ */
+ protected $filename;
+
+ /**
+ * An SplFileInfo instance for the extension's info file.
+ *
+ * Note that SplFileInfo is a PHP resource and resources cannot be serialized.
+ *
+ * @var \SplFileInfo
+ */
+ protected $splFileInfo;
+
+ /**
+ * The app root.
+ *
+ * @var string
+ */
+ protected $root;
+
+ /**
+ * Constructs a new Extension object.
+ *
+ * @param string $root
+ * The app root.
+ * @param string $type
+ * The type of the extension; e.g., 'module'.
+ * @param string $pathname
+ * The relative path and filename of the extension's info file; e.g.,
+ * 'core/modules/node/node.info.yml'.
+ * @param string $filename
+ * (optional) The filename of the main extension file; e.g., 'node.module'.
+ */
+ public function __construct($root, $type, $pathname, $filename = NULL) {
+ $this->root = $root;
+ $this->type = $type;
+ $this->pathname = $pathname;
+ $this->filename = $filename;
+ }
+
+ /**
+ * Returns the type of the extension.
+ *
+ * @return string
+ */
+ public function getType() {
+ return $this->type;
+ }
+
+ /**
+ * Returns the internal name of the extension.
+ *
+ * @return string
+ */
+ public function getName() {
+ return basename($this->pathname, '.info.yml');
+ }
+
+ /**
+ * Returns the relative path of the extension.
+ *
+ * @return string
+ */
+ public function getPath() {
+ return dirname($this->pathname);
+ }
+
+ /**
+ * Returns the relative path and filename of the extension's info file.
+ *
+ * @return string
+ */
+ public function getPathname() {
+ return $this->pathname;
+ }
+
+ /**
+ * Returns the filename of the extension's info file.
+ *
+ * @return string
+ */
+ public function getFilename() {
+ return basename($this->pathname);
+ }
+
+ /**
+ * Returns the relative path of the main extension file, if any.
+ *
+ * @return string|null
+ */
+ public function getExtensionPathname() {
+ if ($this->filename) {
+ return $this->getPath() . '/' . $this->filename;
+ }
+ }
+
+ /**
+ * Returns the name of the main extension file, if any.
+ *
+ * @return string|null
+ */
+ public function getExtensionFilename() {
+ return $this->filename;
+ }
+
+ /**
+ * Loads the main extension file, if any.
+ *
+ * @return bool
+ * TRUE if this extension has a main extension file, FALSE otherwise.
+ */
+ public function load() {
+ if ($this->filename) {
+ include_once $this->root . '/' . $this->getPath() . '/' . $this->filename;
+ return TRUE;
+ }
+ return FALSE;
+ }
+
+ /**
+ * Re-routes method calls to SplFileInfo.
+ *
+ * Offers all SplFileInfo methods to consumers; e.g., $extension->getMTime().
+ */
+ public function __call($method, array $args) {
+ if (!isset($this->splFileInfo)) {
+ $this->splFileInfo = new \SplFileInfo($this->pathname);
+ }
+ return call_user_func_array([$this->splFileInfo, $method], $args);
+ }
+
+ /**
+ * Implements Serializable::serialize().
+ *
+ * Serializes the Extension object in the most optimized way.
+ */
+ public function serialize() {
+ // Don't serialize the app root, since this could change if the install is
+ // moved.
+ $data = [
+ 'type' => $this->type,
+ 'pathname' => $this->pathname,
+ 'filename' => $this->filename,
+ ];
+
+ // @todo ThemeHandler::listInfo(), ThemeHandler::rebuildThemeData(), and
+ // system_list() are adding custom properties to the Extension object.
+ $info = new \ReflectionObject($this);
+ foreach ($info->getProperties(\ReflectionProperty::IS_PUBLIC) as $property) {
+ $data[$property->getName()] = $property->getValue($this);
+ }
+
+ return serialize($data);
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function unserialize($data) {
+ $data = unserialize($data);
+ // Get the app root from the container.
+ $this->root = DRUPAL_ROOT;
+ $this->type = $data['type'];
+ $this->pathname = $data['pathname'];
+ $this->filename = $data['filename'];
+
+ // @todo ThemeHandler::listInfo(), ThemeHandler::rebuildThemeData(), and
+ // system_list() are adding custom properties to the Extension object.
+ foreach ($data as $property => $value) {
+ if (!isset($this->$property)) {
+ $this->$property = $value;
+ }
+ }
+ }
+
+}