Re: gitweb - option to disable rename detection

[Yasushi SHOJI <yashi@atmark-techno.com>]

At Mon, 15 Aug 2005 11:53:20 -0700 (PDT),
Linus Torvalds wrote:
> 
> On Tue, 16 Aug 2005, Yasushi SHOJI wrote:
> > 
> > It seems to me that git-diff-tree needs huge memory if you try to diff
> > on big change with rename detection enabled.
> > 
> > This isn't problem for sane project but if you create a repo with only
> > major releases imports, git-diff-tree run by git_commit() eats system
> > memory and die ;P
> 
> Instead of disabling it entirely, how about just having some limit on it?

ah, that's a good idea.  here is a quick and dirty patch.
--
          yashi

diff --git a/gitweb.cgi b/gitweb.cgi
--- a/gitweb.cgi
+++ b/gitweb.cgi
@@ -40,6 +40,9 @@ my $home_text =               "indextext.html";
 #my $projects_list = $projectroot;
 my $projects_list = "index/index.aux";
 
+# max number of changes to use rename detection on git-diff-tree
+my $rename_detection_threshold = 1000;
+
 # input validation and dispatch
 my $action = $cgi->param('a');
 if (defined $action) {
@@ -1587,7 +1590,18 @@ sub git_commit {
                $root = " --root";
                $parent = "";
        }
-       open my $fd, "-|", "$gitbin/git-diff-tree -r -M $root $parent $hash" or die_error(undef, "Open failed.");
+       my $nr_files;
+       my $opts = "";
+       my $disabled_notice;
+       open my $fd, "-|", "$gitbin/git-diff-tree -r $root $parent $hash" or die_error(undef, "Open failed.");
+       $nr_files++ while <$fd>;
+       close $fd or die_error(undef, "Counting diff-tree failed.");
+       if ($nr_files <  $rename_detection_threshold) {
+               $opts .= " -M";
+       } else {
+               $disabled_notice = "(Rename detection disabled)";
+       }
+       open my $fd, "-|", "$gitbin/git-diff-tree -r $opts $root $parent $hash" or die_error(undef, "Open failed.");
        @difftree = map { chomp; $_ } <$fd>;
        close $fd or die_error(undef, "Reading diff-tree failed.");
        git_header_html();
@@ -1671,7 +1685,7 @@ sub git_commit {
        print "</div>\n";
        print "<div class=\"list_head\">\n";
        if ($#difftree > 10) {
-               print(($#difftree + 1) . " files changed:\n");
+               print(($#difftree + 1) . " files changed" . $disabled_notice  . ":\n");
        }
        print "</div>\n";
        print "<table cellspacing=\"0\">\n";