[PATCH 3/7] gitweb: Use @hist_opts as git-rev-list parameters in git_history

[Jakub Narebski <jnareb@gmail.com>]

Add new global configuration variable @hist_opts, which holds
additional, history specific options (parameters) to git-rev-list
called in git_history subroutine.  Default value is '--full-history',
as it was.

Signed-off-by: Jakub Narebski <jnareb@gmail.com>
---
 gitweb/gitweb.perl |   18 ++++++++++++++++--
 1 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/gitweb/gitweb.perl b/gitweb/gitweb.perl
index 4c76032..2191853 100755
--- a/gitweb/gitweb.perl
+++ b/gitweb/gitweb.perl
@@ -176,9 +176,23 @@ # - more costly is '-C' (or '-C', '-M'),
 #   (number of changed files + number of removed files) * (number of new files)
 # - even more costly is '-C', '--find-copies-harder' with cost
 #   (number of files in the original tree) * (number of new files)
-# - one might want to include '-B' option, e.g. '-B', '-M'
+# - one might want to include '-B' option, e.g. have it ('-B', '-M'),
+#   or for example '-l<num>' together with '-M' and perhaps '-C'
 our @diff_opts = ('-M'); # taken from git_commit
 
+# options fo git-rev-list used in git_history
+# - default is '--full-history', which is slowest but works with merges,
+#   and was done to not change the output from previous version when
+#   path limiting was done by piping revisions to git-diff-tree --stdin
+# - less costly is (), i.e. without '--full-history', which of course
+#   changes output and provides _simplified_ history of a file
+# - for files which appeared late in the history less costly is
+#   --full-history, --remove-empty, although it changes output in
+#   the rare case when name vanished the appeared thorough the history;
+#   it improves performance of course only the last page of history
+# - least costly, but changing output, is having --remove-mepty only
+our @hist_opts = ('--full-history');
+
 our $GITWEB_CONFIG = $ENV{'GITWEB_CONFIG'} || "++GITWEB_CONFIG++";
 do $GITWEB_CONFIG if -e $GITWEB_CONFIG;
 
@@ -3137,7 +3151,7 @@ sub git_history {
 	}
 
 	open my $fd, "-|",
-		git_cmd(), "rev-list", $limit, "--full-history", $hash_base, "--", $file_name
+		git_cmd(), "rev-list", $limit, @hist_opts, $hash_base, "--", $file_name
 			or die_error(undef, "Open git-rev-list-failed");
 	my @revlist = map { chomp; $_ } <$fd>;
 	close $fd
-- 
1.4.2