Add fast --HEAD option to upstream-diff.

git_upstream_diff.py

Index: git_upstream_diff.py
diff --git a/git_upstream_diff.py b/git_upstream_diff.py
index 9d9db95fd5d64bb1703f15dd38aa6c9270565370..fa0454e057bac0288e0014ac4a5c83dc07e20715 100755
--- a/git_upstream_diff.py
+++ b/git_upstream_diff.py
@@ -19,6 +19,9 @@ def main(args):
                       help=(
                         'Print a colorized wordwise diff '
                         'instead of line-wise diff'))
+  parser.add_argument('--HEAD', action='store_true', default=False,
+                      help=('Diff against HEAD instead of the working copy.'

[agable, 2014/05/07 00:57:48]

No space between this period and 'Much...'

[iannucci, 2014/05/07 01:02:23]

Good catch. Done.

+                            'Much faster for large repos.'))
   opts, extra_args = parser.parse_known_args(args)
 
   cur = git.current_branch()
@@ -34,7 +37,10 @@ def main(args):
   cmd = [git.GIT_EXE, 'diff', '--patience', '-C', '-C']
   if opts.wordwise:
     cmd += ['--word-diff=color', r'--word-diff-regex=(\w+|[^[:space:]])']
-  cmd += [git.get_or_create_merge_base(cur, par)]
+  if opts.HEAD:
+    cmd += ['%s..%s' % (git.get_or_create_merge_base(cur, par), cur)]
+  else:
+    cmd += [git.get_or_create_merge_base(cur, par)]
 
   cmd += extra_args