1 files changed, 87 insertions, 0 deletions
diff --git a/pystache/spec_loader.py b/pystache/spec_loader.py
new file mode 100644
index 0000000..3cb0f1a
--- /dev/null
+++ b/pystache/spec_loader.py
@@ -0,0 +1,87 @@
+# coding: utf-8
+
+"""
+This module supports customized (aka special or specified) template loading.
+
+"""
+
+import os.path
+
+from pystache.loader import Loader
+
+
+# TODO: add test cases for this class.
+class SpecLoader(object):
+
+    """
+    Supports loading custom-specified templates (from TemplateSpec instances).
+
+    """
+
+    def __init__(self, loader=None):
+        if loader is None:
+            loader = Loader()
+
+        self.loader = loader
+
+    def _find_relative(self, spec):
+        """
+        Return the path to the template as a relative (dir, file_name) pair.
+
+        The directory returned is relative to the directory containing the
+        class definition of the given object.  The method returns None for
+        this directory if the directory is unknown without first searching
+        the search directories.
+
+        """
+        if spec.template_rel_path is not None:
+            return os.path.split(spec.template_rel_path)
+        # Otherwise, determine the file name separately.
+
+        locator = self.loader._make_locator()
+
+        # We do not use the ternary operator for Python 2.4 support.
+        if spec.template_name is not None:
+            template_name = spec.template_name
+        else:
+            template_name = locator.make_template_name(spec)
+
+        file_name = locator.make_file_name(template_name, spec.template_extension)
+
+        return (spec.template_rel_directory, file_name)
+
+    def _find(self, spec):
+        """
+        Find and return the path to the template associated to the instance.
+
+        """
+        dir_path, file_name = self._find_relative(spec)
+
+        locator = self.loader._make_locator()
+
+        if dir_path is None:
+            # Then we need to search for the path.
+            path = locator.find_object(spec, self.loader.search_dirs, file_name=file_name)
+        else:
+            obj_dir = locator.get_object_directory(spec)
+            path = os.path.join(obj_dir, dir_path, file_name)
+
+        return path
+
+    def load(self, spec):
+        """
+        Find and return the template associated to a TemplateSpec instance.
+
+        Returns the template as a unicode string.
+
+        Arguments:
+
+          spec: a TemplateSpec instance.
+
+        """
+        if spec.template is not None:
+            return self.loader.unicode(spec.template, spec.template_encoding)
+
+        path = self._find(spec)
+
+        return self.loader.read(path, spec.template_encoding)