text: from __future__ import absolute_import
  import hashlib
  
  from django.template.base import TemplateDoesNotExist
  from django.template.loader import BaseLoader, get_template_from_string, find_template_loader, make_origin
  import os
  
  from django.conf import settings
  from .compiler import Compiler
  from pyjade import Parser
  
  from pyjade.utils import process
  # from django.template.loaders.cached import Loader
  
  class Loader(BaseLoader):
      is_usable = True
  
      def __init__(self, loaders):
          self.template_cache = {}
          self._loaders = loaders
          self._cached_loaders = []
  
      @property
      def loaders(self):
          # Resolve loaders on demand to avoid circular imports
          if not self._cached_loaders:
              # Set self._cached_loaders atomically. Otherwise, another thread
              # could see an incomplete list. See #17303.
              cached_loaders = []
              for loader in self._loaders:
                  cached_loaders.append(find_template_loader(loader))
              self._cached_loaders = cached_loaders
          return self._cached_loaders
  
      def find_template(self, name, dirs=None):
          for loader in self.loaders:
              try:
                  template, display_name = loader(name, dirs)
                  return (template, make_origin(display_name, loader, name, dirs))
              except TemplateDoesNotExist:
                  pass
          raise TemplateDoesNotExist(name)
  
      def load_template_source(self, template_name, template_dirs=None):
          for loader in self.loaders:
              try:
                  return loader.load_template_source(template_name,template_dirs)
              except TemplateDoesNotExist:
                  pass
          raise TemplateDoesNotExist(template_name)
  
      def load_template(self, template_name, template_dirs=None):
          key = template_name
          if template_dirs:
              # If template directories were specified, use a hash to differentiate
              key = '-'.join([template_name, hashlib.sha1('|'.join(template_dirs)).hexdigest()])
  
          
          if settings.DEBUG or key not in self.template_cache:
  
              if os.path.splitext(template_name)[1] in ('.jade',):
                  try:
                      source, display_name = self.load_template_source(template_name, template_dirs)
                      source=process(source,filename=template_name,compiler=Compiler)
                      origin = make_origin(display_name, self.load_template_source, template_name, template_dirs)
                      template = get_template_from_string(source, origin, template_name)
                  except NotImplementedError:
                      template, origin = self.find_template(template_name, template_dirs)
              else:
                  template, origin = self.find_template(template_name, template_dirs)
              if not hasattr(template, 'render'):
                  try:
                      template = get_template_from_string(process(source,filename=template_name,compiler=Compiler), origin, template_name)
                  except (TemplateDoesNotExist, UnboundLocalError):
                      # If compiling the template we found raises TemplateDoesNotExist,
                      # back off to returning he source and display name for the template
                      # we were asked to load. This allows for correct identification (later)
                      # of the actual template that does not exist.
                      return template, origin
              self.template_cache[key] = template
          return self.template_cache[key], None
  
      # def _preprocess(self, source, name, filename=None):
      #     parser = Parser(source,filename=filename)
      #     block = parser.parse()
      #     compiler = Compiler(block)
      #     return compiler.compile().strip()
  
      def reset(self):
          "Empty the template cache."
          self.template_cache.clear()
  