gitweb: optimize per-file history generation

The rev-list command that is recent enough can filter commits
based on paths they touch, so use it instead of generating the
full list and limiting it by passing it with diff-tree --stdin.

[jc: The patch originally came from Luben Tuikov but the it was
 corrupt, but it was short enough to be applied by hand.  I
 added the --full-history to make the output compatible with the
 original while doing so.]

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/gitweb/gitweb.cgi b/gitweb/gitweb.cgi
index 035e76d..1007742 100755 (executable)
--- a/gitweb/gitweb.cgi
+++ b/gitweb/gitweb.cgi
@@ -2295,16 +2295,13 @@ sub git_history {
              "</div>\n";
        print "<div class=\"page_path\"><b>/" . esc_html($file_name) . "</b><br/></div>\n";
 
-       open my $fd, "-|", "$gitbin/git-rev-list $hash | $gitbin/git-diff-tree -r --stdin -- \'$file_name\'";
-       my $commit;
+       open my $fd, "-|",
+               "$gitbin/git-rev-list --full-history $hash -- \'$file_name\'";
        print "<table cellspacing=\"0\">\n";
        my $alternate = 0;
        while (my $line = <$fd>) {
                if ($line =~ m/^([0-9a-fA-F]{40})/){
-                       $commit = $1;
-                       next;
-               }
-               if ($line =~ m/^:([0-7]{6}) ([0-7]{6}) ([0-9a-fA-F]{40}) ([0-9a-fA-F]{40}) (.)\t(.*)$/ && (defined $commit)) {
+                       my $commit = $1;
                        my %co = git_read_commit($commit);
                        if (!%co) {
                                next;
@@ -2336,7 +2333,6 @@ sub git_history {
                        }
                        print "</td>\n" .
                              "</tr>\n";
-                       undef $commit;
                }
        }
        print "</table>\n";