<?php
  
  namespace Guzzle\Service;
  
  use Guzzle\Cache\CacheAdapterInterface;
  
  /**
   * Decorator that adds caching to a service description loader
   */
  class CachingConfigLoader implements ConfigLoaderInterface
  {
      /** @var ConfigLoaderInterface */
      protected $loader;
  
      /** @var CacheAdapterInterface */
      protected $cache;
  
      /**
       * @param ConfigLoaderInterface $loader Loader used to load the config when there is a cache miss
       * @param CacheAdapterInterface $cache  Object used to cache the loaded result
       */
      public function __construct(ConfigLoaderInterface $loader, CacheAdapterInterface $cache)
      {
          $this->loader = $loader;
          $this->cache = $cache;
      }
  
      public function load($config, array $options = array())
      {
          if (!is_string($config)) {
              $key = false;
          } else {
              $key = 'loader_' . crc32($config);
              if ($result = $this->cache->fetch($key)) {
                  return $result;
              }
          }
  
          $result = $this->loader->load($config, $options);
          if ($key) {
              $this->cache->save($key, $result);
          }
  
          return $result;
      }
  }