text: """
  Scrapy extension for collecting scraping stats
  """
  import pprint
  import logging
  
  logger = logging.getLogger(__name__)
  
  
  class StatsCollector:
  
      def __init__(self, crawler):
          self._dump = crawler.settings.getbool('STATS_DUMP')
          self._stats = {}
  
      def get_value(self, key, default=None, spider=None):
          return self._stats.get(key, default)
  
      def get_stats(self, spider=None):
          return self._stats
  
      def set_value(self, key, value, spider=None):
          self._stats[key] = value
  
      def set_stats(self, stats, spider=None):
          self._stats = stats
  
      def inc_value(self, key, count=1, start=0, spider=None):
          d = self._stats
          d[key] = d.setdefault(key, start) + count
  
      def max_value(self, key, value, spider=None):
          self._stats[key] = max(self._stats.setdefault(key, value), value)
  
      def min_value(self, key, value, spider=None):
          self._stats[key] = min(self._stats.setdefault(key, value), value)
  
      def clear_stats(self, spider=None):
          self._stats.clear()
  
      def open_spider(self, spider):
          pass
  
      def close_spider(self, spider, reason):
          if self._dump:
              logger.info("Dumping Scrapy stats:\n" + pprint.pformat(self._stats),
                          extra={'spider': spider})
          self._persist_stats(self._stats, spider)
  
      def _persist_stats(self, stats, spider):
          pass
  
  
  class MemoryStatsCollector(StatsCollector):
  
      def __init__(self, crawler):
          super(MemoryStatsCollector, self).__init__(crawler)
          self.spider_stats = {}
  
      def _persist_stats(self, stats, spider):
          self.spider_stats[spider.name] = stats
  
  
  class DummyStatsCollector(StatsCollector):
  
      def get_value(self, key, default=None, spider=None):
          return default
  
      def set_value(self, key, value, spider=None):
          pass
  
      def set_stats(self, stats, spider=None):
          pass
  
      def inc_value(self, key, count=1, start=0, spider=None):
          pass
  
      def max_value(self, key, value, spider=None):
          pass
  
      def min_value(self, key, value, spider=None):
          pass
  