[PATCH 2/6] gitweb: Improve "next" link in commitdiff view

[Jakub Narebski <jnareb@gmail.com>]

Check if 'hp' (hash_parent) parameter to 'commitdiff' view is one of
'h' (hash) commit parents, i.e. if commitdiff is of the form
"<commit>^<n> <commit>", and mark it as such in the bottom part of
navigation bar. The "next" link in commitdiff view was introduced
in commit 151602df00b8e5c5b4a8193f59a94b85f9b5aebc

If 'hb' is n-th parent of 'h', show the following at the bottom
of navigation bar:
  (from parent n: _commit_)

Signed-off-by: Jakub Narebski <jnareb@gmail.com>
---
This is sort of companion to previous commit, meaning thatI'd like to
see if I came from link to diff to one of parents in a merge commit.
Purely decoration, but I think it is nice.

 gitweb/gitweb.perl |    9 ++++++++-
 1 files changed, 8 insertions(+), 1 deletions(-)

diff --git a/gitweb/gitweb.perl b/gitweb/gitweb.perl
index e2d5222..4561d4e 100755
--- a/gitweb/gitweb.perl
+++ b/gitweb/gitweb.perl
@@ -4479,7 +4479,14 @@ sub git_commitdiff {
 				$hash_parent_short = substr($hash_parent, 0, 7);
 			}
 			$formats_nav .=
-				' (from: ' .
+				' (from';
+			for (my $i = 0; $i < @{$co{'parents'}}; $i++) {
+				if ($co{'parents'}[$i] eq $hash_parent) {
+					$formats_nav .= ' parent ' . ($i+1);
+					last;
+				}
+			}
+			$formats_nav .= ': ' .
 				$cgi->a({-href => href(action=>"commitdiff",
 				                       hash=>$hash_parent)},
 				        esc_html($hash_parent_short)) .