teach rebaseline_server to generate diffs of rendered SKPs

gm/rebaseline_server/imagepairset.py

 #!/usr/bin/python
 
 """
 Copyright 2014 Google Inc.
 
 Use of this source code is governed by a BSD-style license that can be
 found in the LICENSE file.
 
 ImagePairSet class; see its docstring below.
 """
 
 # System-level imports
 import posixpath
 
-# Local imports
+# Must fix up PYTHONPATH before importing from within Skia
+import fix_pythonpath  # pylint: disable=W0611
+
+# Imports from within Skia
 import column
 import imagediffdb
+from py.utils import gs_utils
 
 # Keys used within dictionary representation of ImagePairSet.
 # NOTE: Keep these in sync with static/constants.js
 KEY__ROOT__EXTRACOLUMNHEADERS = 'extraColumnHeaders'
 KEY__ROOT__EXTRACOLUMNORDER = 'extraColumnOrder'
 KEY__ROOT__HEADER = 'header'
 KEY__ROOT__IMAGEPAIRS = 'imagePairs'
 KEY__ROOT__IMAGESETS = 'imageSets'
 KEY__IMAGESETS__FIELD__BASE_URL = 'baseUrl'
 KEY__IMAGESETS__FIELD__DESCRIPTION = 'description'
@@ skipping 127 matching lines @@
       specified_column_ids = set(column_ids_in_order)
       forgotten_column_ids = all_column_ids - specified_column_ids
       assert not forgotten_column_ids, (
           'column_ids_in_order %s missing these column_ids: %s' % (
               column_ids_in_order, forgotten_column_ids))
       column_ids_in_order = [c for c in column_ids_in_order
                              if c in all_column_ids]
 
     key_description = KEY__IMAGESETS__FIELD__DESCRIPTION
     key_base_url = KEY__IMAGESETS__FIELD__BASE_URL
+    # EPOGER: instead of this special handling for GS URLs vs HTTP URLs, maybe come up with an object than can represent either one?  (or even a local file)
+    if gs_utils.GSUtils.is_gs_url(self._image_base_url):
+      value_base_url = imagediffdb.GSObject(
+          gs_url=self._image_base_url).as_http_url()
+    else:
+      value_base_url = self._image_base_url
+
     return {
         KEY__ROOT__EXTRACOLUMNHEADERS: self._column_headers_as_dict(),
         KEY__ROOT__EXTRACOLUMNORDER: column_ids_in_order,
         KEY__ROOT__IMAGEPAIRS: self._image_pair_dicts,
         KEY__ROOT__IMAGESETS: {
             KEY__IMAGESETS__SET__IMAGE_A: {
                 key_description: self._descriptions[0],
-                key_base_url: self._image_base_url,
+                key_base_url: value_base_url,
             },
             KEY__IMAGESETS__SET__IMAGE_B: {
                 key_description: self._descriptions[1],
-                key_base_url: self._image_base_url,
+                key_base_url: value_base_url,
             },
             KEY__IMAGESETS__SET__DIFFS: {
                 key_description: 'color difference per channel',
                 key_base_url: posixpath.join(
                     self._diff_base_url, imagediffdb.RGBDIFFS_SUBDIR),
             },
             KEY__IMAGESETS__SET__WHITEDIFFS: {
                 key_description: 'differing pixels in white',
                 key_base_url: posixpath.join(
                     self._diff_base_url, imagediffdb.WHITEDIFFS_SUBDIR),
             },
         },
     }