Allow delta links for large files but give appropriate error message when viewing

appengine/chromium_rietveld/codereview/models.py

 # Copyright 2008 Google Inc.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at
 #
 #     http://www.apache.org/licenses/LICENSE-2.0
 #
 # Unless required by applicable law or agreed to in writing, software
 # distributed under the License is distributed on an "AS IS" BASIS,
@@ skipping 452 matching lines @@
 
   Args:
     patch: The file to compare.
     patchset_id: The file's patchset's key id.
     patchsets: A list of existing patchsets.
 
   Returns:
     A list of patchset ids.
   """
   delta = []
-  if patch.no_base_file:
-    return delta
   for other in patchsets:
     if patchset_id == other.key.id():
       break
     if not hasattr(other, 'parsed_patches'):
       other.parsed_patches = None  # cache variable for already parsed patches
     if other.data or other.parsed_patches:
       # Loading all the Patch entities in every PatchSet takes too long
       # (DeadLineExceeded) and consumes a lot of memory (MemoryError) so instead
       # just parse the patchset's data.  Note we can only do this if the
       # patchset was small enough to fit in the data property.
@@ skipping 531 matching lines @@
     Raises:
       FetchError: If there was a problem fetching it.
     """
     try:
       if self.content_key is not None:
         content = self.content_key.get()
         if content.is_bad:
           msg = 'Bad content. Try to upload again.'
           logging.warn('Patch.get_content: %s', msg)
           raise FetchError(msg)
+        if content.file_too_large:
+          msg = 'File too large.'
+          logging.warn('Patch.get_content: %s', msg)
+          raise FetchError(msg)
         if content.is_uploaded and content.text == None:
           msg = 'Upload in progress.'
           logging.warn('Patch.get_content: %s', msg)
           raise FetchError(msg)
         else:
           return content
     except db.Error:
       # This may happen when a Content entity was deleted behind our back.
       self.content_key = None
 
@@ skipping 790 matching lines @@
   out.issues = sum((i.issues for i in items), [])
   out.latencies = sum((i.latencies for i in items), [])
   out.lgtms = sum((i.lgtms for i in items), [])
   out.review_types = sum((i.review_types for i in items), [])
   out.score = compute_score(out)
   return (
       prev_issues != out.issues or
       prev_latencies != out.latencies or
       prev_lgtms != out.lgtms or
       prev_review_types != out.review_types)