UniversalClassLoader.php

<?php

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier <fabien@symfony.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */
namespace Symfony\Component\ClassLoader;


/**
 * UniversalClassLoader implements a "universal" autoloader for PHP 5.3.
 *
 * It is able to load classes that use either:
 *
 *  * The technical interoperability standards for PHP 5.3 namespaces and
 *    class names (https://github.com/php-fig/fig-standards/blob/master/accepted/PSR-0.md);
 *
 *  * The PEAR naming convention for classes (http://pear.php.net/).
 *
 * Classes from a sub-namespace or a sub-hierarchy of PEAR classes can be
 * looked for in a list of locations to ease the vendoring of a sub-set of
 * classes for large projects.
 *
 * Example usage:
 *
 *     $loader = new UniversalClassLoader();
 *
 *     // register classes with namespaces
 *     $loader->registerNamespaces(array(
 *         'Symfony\Component' => __DIR__.'/component',
 *         'Symfony'           => __DIR__.'/framework',
 *         'Sensio'            => array(__DIR__.'/src', __DIR__.'/vendor'),
 *     ));
 *
 *     // register a library using the PEAR naming convention
 *     $loader->registerPrefixes(array(
 *         'Swift_' => __DIR__.'/Swift',
 *     ));
 *
 *
 *     // to enable searching the include path (e.g. for PEAR packages)
 *     $loader->useIncludePath(true);
 *
 *     // activate the autoloader
 *     $loader->register();
 *
 * In this example, if you try to use a class in the Symfony\Component
 * namespace or one of its children (Symfony\Component\Console for instance),
 * the autoloader will first look for the class under the component/
 * directory, and it will then fallback to the framework/ directory if not
 * found before giving up.
 *
 * @author Fabien Potencier <fabien@symfony.com>
 *
 * @api
 */
class UniversalClassLoader {
  private $namespaces = array();
  private $prefixes = array();
  private $namespaceFallbacks = array();
  private $prefixFallbacks = array();
  private $useIncludePath = false;

  /**
   * Turns on searching the include for class files. Allows easy loading
   * of installed PEAR packages
   *
   * @param Boolean $useIncludePath
   */
  public function useIncludePath($useIncludePath) {
    $this->useIncludePath = $useIncludePath;
  }

  /**
   * Can be used to check if the autoloader uses the include path to check
   * for classes.
   *
   * @return Boolean
   */
  public function getUseIncludePath() {
    return $this->useIncludePath;
  }

  /**
   * Gets the configured namespaces.
   *
   * @return array A hash with namespaces as keys and directories as values
   */
  public function getNamespaces() {
    return $this->namespaces;
  }

  /**
   * Gets the configured class prefixes.
   *
   * @return array A hash with class prefixes as keys and directories as values
   */
  public function getPrefixes() {
    return $this->prefixes;
  }

  /**
   * Gets the directory(ies) to use as a fallback for namespaces.
   *
   * @return array An array of directories
   */
  public function getNamespaceFallbacks() {
    return $this->namespaceFallbacks;
  }

  /**
   * Gets the directory(ies) to use as a fallback for class prefixes.
   *
   * @return array An array of directories
   */
  public function getPrefixFallbacks() {
    return $this->prefixFallbacks;
  }

  /**
   * Registers the directory to use as a fallback for namespaces.
   *
   * @param array $dirs An array of directories
   *
   * @api
   */
  public function registerNamespaceFallbacks(array $dirs) {
    $this->namespaceFallbacks = $dirs;
  }

  /**
   * Registers a directory to use as a fallback for namespaces.
   *
   * @param string $dir A directory
   */
  public function registerNamespaceFallback($dir) {
    $this->namespaceFallbacks[] = $dir;
  }

  /**
   * Registers directories to use as a fallback for class prefixes.
   *
   * @param array $dirs An array of directories
   *
   * @api
   */
  public function registerPrefixFallbacks(array $dirs) {
    $this->prefixFallbacks = $dirs;
  }

  /**
   * Registers a directory to use as a fallback for class prefixes.
   *
   * @param string $dir A directory
   */
  public function registerPrefixFallback($dir) {
    $this->prefixFallbacks[] = $dir;
  }

  /**
   * Registers an array of namespaces
   *
   * @param array $namespaces An array of namespaces (namespaces as keys and locations as values)
   *
   * @api
   */
  public function registerNamespaces(array $namespaces) {
    foreach ($namespaces as $namespace => $locations) {
      $this->namespaces[$namespace] = (array) $locations;
    }
  }

  /**
   * Registers a namespace.
   *
   * @param string       $namespace The namespace
   * @param array|string $paths     The location(s) of the namespace
   *
   * @api
   */
  public function registerNamespace($namespace, $paths) {
    $this->namespaces[$namespace] = (array) $paths;
  }

  /**
   * Registers an array of classes using the PEAR naming convention.
   *
   * @param array $classes An array of classes (prefixes as keys and locations as values)
   *
   * @api
   */
  public function registerPrefixes(array $classes) {
    foreach ($classes as $prefix => $locations) {
      $this->prefixes[$prefix] = (array) $locations;
    }
  }

  /**
   * Registers a set of classes using the PEAR naming convention.
   *
   * @param string       $prefix The classes prefix
   * @param array|string $paths  The location(s) of the classes
   *
   * @api
   */
  public function registerPrefix($prefix, $paths) {
    $this->prefixes[$prefix] = (array) $paths;
  }

  /**
   * Registers this instance as an autoloader.
   *
   * @param Boolean $prepend Whether to prepend the autoloader or not
   *
   * @api
   */
  public function register($prepend = false) {
    spl_autoload_register(array(
      $this,
      'loadClass',
    ), true, $prepend);
  }

  /**
   * Loads the given class or interface.
   *
   * @param string $class The name of the class
   */
  public function loadClass($class) {
    if ($file = $this
      ->findFile($class)) {
      require $file;
    }
  }

  /**
   * Finds the path to the file where the class is defined.
   *
   * @param string $class The name of the class
   *
   * @return string|null The path, if found
   */
  public function findFile($class) {
    if ('\\' == $class[0]) {
      $class = substr($class, 1);
    }
    if (false !== ($pos = strrpos($class, '\\'))) {

      // namespaced class name
      $namespace = substr($class, 0, $pos);
      $className = substr($class, $pos + 1);
      $normalizedClass = str_replace('\\', DIRECTORY_SEPARATOR, $namespace) . DIRECTORY_SEPARATOR . str_replace('_', DIRECTORY_SEPARATOR, $className) . '.php';
      foreach ($this->namespaces as $ns => $dirs) {
        if (0 !== strpos($namespace, $ns)) {
          continue;
        }
        foreach ($dirs as $dir) {
          $file = $dir . DIRECTORY_SEPARATOR . $normalizedClass;
          if (is_file($file)) {
            return $file;
          }
        }
      }
      foreach ($this->namespaceFallbacks as $dir) {
        $file = $dir . DIRECTORY_SEPARATOR . $normalizedClass;
        if (is_file($file)) {
          return $file;
        }
      }
    }
    else {

      // PEAR-like class name
      $normalizedClass = str_replace('_', DIRECTORY_SEPARATOR, $class) . '.php';
      foreach ($this->prefixes as $prefix => $dirs) {
        if (0 !== strpos($class, $prefix)) {
          continue;
        }
        foreach ($dirs as $dir) {
          $file = $dir . DIRECTORY_SEPARATOR . $normalizedClass;
          if (is_file($file)) {
            return $file;
          }
        }
      }
      foreach ($this->prefixFallbacks as $dir) {
        $file = $dir . DIRECTORY_SEPARATOR . $normalizedClass;
        if (is_file($file)) {
          return $file;
        }
      }
    }
    if ($this->useIncludePath && ($file = stream_resolve_include_path($normalizedClass))) {
      return $file;
    }
  }

}