fix path issues on mac and win for skpdiff_server.py

tools/skpdiff/skpdiff_server.py

 #!/usr/bin/python
 # -*- coding: utf-8 -*-
 
 from __future__ import print_function
 import argparse
 import BaseHTTPServer
 import json
 import os
 import os.path
 import re
@@ skipping 50 matching lines @@
     skpdiff_path = None
     possible_paths = []
 
     # Use the user given path, or try out some good default paths.
     if user_path:
         possible_paths.append(user_path)
     else:
         possible_paths.append(os.path.join(SKIA_ROOT_DIR, 'out',
                                            'Release', 'skpdiff'))
         possible_paths.append(os.path.join(SKIA_ROOT_DIR, 'out',
+                                           'Release', 'skpdiff.exe'))
+        possible_paths.append(os.path.join(SKIA_ROOT_DIR, 'out',
                                            'Debug', 'skpdiff'))
+        possible_paths.append(os.path.join(SKIA_ROOT_DIR, 'out',
+                                           'Debug', 'skpdiff.exe'))
     # Use the first path that actually points to the binary
     for possible_path in possible_paths:
         if os.path.isfile(possible_path):
             skpdiff_path = possible_path
             break
 
     # If skpdiff was not found, print out diagnostic info for the user.
     if skpdiff_path is None:
         print('Could not find skpdiff binary. Either build it into the ' +
               'default directory, or specify the path on the command line.')
@@ skipping 70 matching lines @@
 
 def get_head_version(path):
     """Get the version of the file at the given path stored inside the HEAD of
     the git repository. It is returned as a string.
 
     @param path The path of the file whose HEAD is returned. It is assumed the
     path is inside a git repo rooted at SKIA_ROOT_DIR.
     """
 
     # git-show will not work with absolute paths. This ensures we give it a path
-    # relative to the skia root.
-    git_path = os.path.relpath(path, SKIA_ROOT_DIR)
+    # relative to the skia root. This path also has to use forward slashes, even
+    # on windows.
+    git_path = os.path.relpath(path, SKIA_ROOT_DIR).replace('\\', '/')
     git_show_proc = subprocess.Popen(['git', 'show', 'HEAD:' + git_path],
                                      stdout=subprocess.PIPE)
 
     # When invoked outside a shell, git will output the last committed version
     # of the file directly to stdout.
     git_version_content, _ = git_show_proc.communicate()
     return git_version_content
 
 
 class GMInstance:
@@ skipping 40 matching lines @@
            - determine which GMs changed
            - download the changed images
            - compare them with skpdiff
         """
 
         # Get the expectations and compare them with actual hashes
         self._get_expectations()
 
 
         # Create a temporary file tree that makes sense for skpdiff to operate
-        # on.
-        image_output_dir = tempfile.mkdtemp('skpdiff')
+        # on. We take the realpath of the new temp directory because some OSs
+        # (*cough* osx) put the temp directory behind a symlink that gets
+        # resolved later down the pipeline and breaks the image map.
+        image_output_dir = os.path.realpath(tempfile.mkdtemp('skpdiff'))
         expected_image_dir = os.path.join(image_output_dir, 'expected')
         actual_image_dir = os.path.join(image_output_dir, 'actual')
         os.mkdir(expected_image_dir)
         os.mkdir(actual_image_dir)
 
         # Download expected and actual images that differed into the temporary
         # file tree.
         self._download_expectation_images(expected_image_dir, actual_image_dir)
 
         # Invoke skpdiff with our downloaded images and place its results in the
@@ skipping 328 matching lines @@
 
     expectations_manager = ExpectationsManager(args['expectations_dir'],
                                                args['expected'],
                                                args['updated'],
                                                skpdiff_path)
 
     run_server(expectations_manager, port=args['port'])
 
 if __name__ == '__main__':
     main()