# Django 2.2.9.dev20191202104323 文档

# django.template.loaders.base 源代码

    from django.template import Template, TemplateDoesNotExist

    class Loader:

        def __init__(self, engine):
            self.engine = engine

        def get_template(self, template_name, skip=None):
            """
            Call self.get_template_sources() and return a Template object for
            the first template matching template_name. If skip is provided, ignore
            template origins in skip. This is used to avoid recursion during
            template extending.
            """
            tried = []

            for origin in self.get_template_sources(template_name):
                if skip is not None and origin in skip:
                    tried.append((origin, 'Skipped'))
                    continue

                try:
                    contents = self.get_contents(origin)
                except TemplateDoesNotExist:
                    tried.append((origin, 'Source does not exist'))
                    continue
                else:
                    return Template(
                        contents, origin, origin.template_name, self.engine,
                    )

            raise TemplateDoesNotExist(template_name, tried=tried)

        def get_template_sources(self, template_name):
            """
            An iterator that yields possible matching template paths for a
            template name.
            """
            raise NotImplementedError(
                'subclasses of Loader must provide a get_template_sources() method'
            )

        def reset(self):
            """
            Reset any state maintained by the loader instance (e.g. cached
            templates or cached loader modules).
            """
            pass