Add support for .xlf (#496)

An Alternative .xliff file extension

pontoon/base/models.py

@@ -1115,6 +1115,7 @@ class Resource(models.Model):
     FORMAT_CHOICES = (
         ('po', 'po'),
         ('xliff', 'xliff'),
+        ('xlf', 'xliff'),
         ('properties', 'properties'),
         ('dtd', 'dtd'),
         ('inc', 'inc'),
@@ -1158,7 +1159,12 @@ def get_path_format(self, path):
         path_format = extension[1:].lower()
 
         # Special case: pot files are considered the po format
-        return 'po' if path_format == 'pot' else path_format
+        if path_format == 'pot':
+            return 'po'
+        elif path_format == 'xlf':
+            return 'xliff'
+        else:
+            return path_format
 
 
 class Subpage(models.Model):

pontoon/sync/formats/__init__.py

@@ -14,6 +14,7 @@
     '.lang': lang.parse,
     '.po': po.parse,
     '.pot': po.parse,
+    '.xlf': xliff.parse,
     '.xliff': xliff.parse,
     '.dtd': silme.parse_dtd,
     '.properties': silme.parse_properties,

pontoon/sync/vcs/models.py

@@ -343,10 +343,7 @@ def relative_resource_paths(self):
         """
         path = self.source_directory_path
         for absolute_path in self.resources_for_path(path):
-            # .pot files in the source directory need to be renamed to
-            # .po files for the locale directories.
-            if absolute_path.endswith('.pot'):
-                absolute_path = absolute_path[:-1]
+            absolute_path = source_to_locale_path(absolute_path)
 
             yield os.path.relpath(absolute_path, path)