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   1  <?php
   2  /**
   3  *
   4  * This file is part of the phpBB Forum Software package.
   5  *
   6  * @copyright (c) phpBB Limited <https://www.phpbb.com>
   7  * @license GNU General Public License, version 2 (GPL-2.0)
   8  *
   9  * For full copyright and license information, please see
  10  * the docs/CREDITS.txt file.
  11  *
  12  */
  13  
  14  namespace phpbb;
  15  
  16  /**
  17  * The class loader resolves class names to file system paths and loads them if
  18  * necessary.
  19  *
  20  * Classes have to be of the form phpbb_(dir_)*(classpart_)*, so directory names
  21  * must never contain underscores. Example: phpbb_dir_subdir_class_name is a
  22  * valid class name, while phpbb_dir_sub_dir_class_name is not.
  23  *
  24  * If every part of the class name is a directory, the last directory name is
  25  * also used as the filename, e.g. phpbb_dir would resolve to dir/dir.php.
  26  */
  27  class class_loader
  28  {
  29      private $namespace;
  30      private $path;
  31      private $php_ext;
  32      private $cache;
  33  
  34      /**
  35      * A map of looked up class names to paths relative to $this->path.
  36      * This map is stored in cache and looked up if the cache is available.
  37      *
  38      * @var array
  39      */
  40      private $cached_paths = array();
  41  
  42      /**
  43      * Creates a new \phpbb\class_loader, which loads files with the given
  44      * file extension from the given path.
  45      *
  46      * @param string $namespace Required namespace for files to be loaded
  47      * @param string $path    Directory to load files from
  48      * @param string $php_ext The file extension for PHP files
  49      * @param \phpbb\cache\driver\driver_interface $cache An implementation of the phpBB cache interface.
  50      */
  51  	public function __construct($namespace, $path, $php_ext = 'php', \phpbb\cache\driver\driver_interface $cache = null)
  52      {
  53          if ($namespace[0] !== '\\')
  54          {
  55              $namespace = '\\' . $namespace;
  56          }
  57  
  58          $this->namespace = $namespace;
  59          $this->path = $path;
  60          $this->php_ext = $php_ext;
  61  
  62          $this->set_cache($cache);
  63      }
  64  
  65      /**
  66      * Provide the class loader with a cache to store paths. If set to null, the
  67      * the class loader will resolve paths by checking for the existence of every
  68      * directory in the class name every time.
  69      *
  70      * @param \phpbb\cache\driver\driver_interface $cache An implementation of the phpBB cache interface.
  71      */
  72  	public function set_cache(\phpbb\cache\driver\driver_interface $cache = null)
  73      {
  74          if ($cache)
  75          {
  76              $this->cached_paths = $cache->get('class_loader_' . str_replace('\\', '__', $this->namespace));
  77  
  78              if ($this->cached_paths === false)
  79              {
  80                  $this->cached_paths = array();
  81              }
  82          }
  83  
  84          $this->cache = $cache;
  85      }
  86  
  87      /**
  88      * Registers the class loader as an autoloader using SPL.
  89      */
  90  	public function register()
  91      {
  92          spl_autoload_register(array($this, 'load_class'));
  93      }
  94  
  95      /**
  96      * Removes the class loader from the SPL autoloader stack.
  97      */
  98  	public function unregister()
  99      {
 100          spl_autoload_unregister(array($this, 'load_class'));
 101      }
 102  
 103      /**
 104      * Resolves a phpBB class name to a relative path which can be included.
 105      *
 106      * @param string       $class The class name to resolve, must be in the
 107      *                            namespace the loader was constructed with.
 108      *                            Has to begin with \
 109      * @return string|bool        A relative path to the file containing the
 110      *                            class or false if looking it up failed.
 111      */
 112  	public function resolve_path($class)
 113      {
 114          if (isset($this->cached_paths[$class]))
 115          {
 116              return $this->path . $this->cached_paths[$class] . '.' . $this->php_ext;
 117          }
 118  
 119          if (!preg_match('/^' . preg_quote($this->namespace, '/') . '[a-zA-Z0-9_\\\\]+$/', $class))
 120          {
 121              return false;
 122          }
 123  
 124          $relative_path = str_replace('\\', '/', substr($class, strlen($this->namespace)));
 125  
 126          if (!file_exists($this->path . $relative_path . '.' . $this->php_ext))
 127          {
 128              return false;
 129          }
 130  
 131          if ($this->cache)
 132          {
 133              $this->cached_paths[$class] = $relative_path;
 134              $this->cache->put('class_loader_' . str_replace('\\', '__', $this->namespace), $this->cached_paths);
 135          }
 136  
 137          return $this->path . $relative_path . '.' . $this->php_ext;
 138      }
 139  
 140      /**
 141      * Resolves a class name to a path and then includes it.
 142      *
 143      * @param string $class The class name which is being loaded.
 144      */
 145  	public function load_class($class)
 146      {
 147          // In general $class is not supposed to contain a leading backslash,
 148          // but sometimes it does. See tickets PHP-50731 and HHVM-1840.
 149          if ($class[0] !== '\\')
 150          {
 151              $class = '\\' . $class;
 152          }
 153  
 154          if (substr($class, 0, strlen($this->namespace)) === $this->namespace)
 155          {
 156              $path = $this->resolve_path($class);
 157  
 158              if ($path)
 159              {
 160                  require $path;
 161              }
 162          }
 163      }
 164  }