class LibrariesDirectoryFileFinder

class LibrariesDirectoryFileFinder {
    
    /**
     * The app root.
     *
     * @var string
     */
    protected $root;
    
    /**
     * The site path.
     *
     * @var string
     */
    protected $sitePath;
    
    /**
     * The profile extension list.
     *
     * @var \Drupal\Core\Extension\ExtensionList
     */
    protected $profileExtensionList;
    
    /**
     * The install profile.
     *
     * @var string|false|null
     */
    protected $installProfile;
    
    /**
     * Constructs a new LibrariesDirectoryFileFinder instance.
     *
     * @param string $root
     *   The app root.
     * @param string $site_path
     *   The site path.
     * @param \Drupal\Core\Extension\ProfileExtensionList $profile_extension_list
     *   The profile extension list.
     * @param string $install_profile
     *   The install profile.
     */
    public function __construct($root, $site_path, ProfileExtensionList $profile_extension_list, $install_profile) {
        $this->root = $root;
        $this->sitePath = $site_path;
        $this->profileExtensionList = $profile_extension_list;
        $this->installProfile = $install_profile;
    }
    
    /**
     * Finds files that are located in the supported 'libraries' directories.
     *
     * It searches the following locations:
     * - A libraries directory in the current site directory, for example:
     *   sites/default/libraries.
     * - The root libraries directory.
     * - A libraries directory in the selected installation profile, for example:
     *   profiles/my_install_profile/libraries.
     * If the same library is present in multiple locations the first location
     * found will be used. The locations are searched in the order listed.
     *
     * @param string $path
     *   The path for the library file to find.
     *
     * @return string|false
     *   The real path to the library file relative to the root directory. If the
     *   library cannot be found then FALSE.
     */
    public function find($path) {
        // Search sites/<domain>/*.
        $directories[] = "{$this->sitePath}/libraries/";
        // Always search the root 'libraries' directory.
        $directories[] = 'libraries/';
        // Installation profiles can place libraries into a 'libraries' directory.
        if ($this->installProfile) {
            $profile_path = $this->profileExtensionList
                ->getPath($this->installProfile);
            $directories[] = "{$profile_path}/libraries/";
        }
        foreach ($directories as $dir) {
            if (file_exists($this->root . '/' . $dir . $path)) {
                return $dir . $path;
            }
        }
        // The library has not been found.
        return FALSE;
    }

}