gitweb - option to disable rename detection

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

Hi all,

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

so here is a proposal patch to add an option to disable rename
detection on selected project.

# please bear with me! I _know_ my perl code sucks.  this is just to
# show my idea.

regards,
--
         yashi

diff --git a/gitweb.cgi b/gitweb.cgi
--- a/gitweb.cgi
+++ b/gitweb.cgi
@@ -40,6 +40,11 @@ my $home_text =              "indextext.html";
 #my $projects_list = $projectroot;
 my $projects_list = "index/index.aux";
 
+# rename detection on big change require a lot of memory. If your tree
+# has big change commit, list those project names to disable rename
+# detection. most sane project doesn't need to disable this feature.
+my $projects_disable_rename_detection = "";
+
 # input validation and dispatch
 my $action = $cgi->param('a');
 if (defined $action) {
@@ -1572,6 +1577,17 @@ sub git_log {
        git_footer_html();
 }
 
+sub git_diff_tree_options {
+       my $found = 0;
+       my @list = split(/ /, $projects_disable_rename_detection);
+       foreach my $p (@list) {
+               if ($project eq $p) {
+                       $found = 1;
+               }
+       }
+       $found ? "" : "-M";
+}
+
 sub git_commit {
        my %co = git_read_commit($hash);
        if (!%co) {
@@ -1587,7 +1603,8 @@ 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 $opts = git_diff_tree_options();
+       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();