gitweb: speed up project listing on large work trees by limiting find depth

Signed-off-by: Luke Lu <git@vicaya.com>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
diff --git a/gitweb/gitweb.perl b/gitweb/gitweb.perl
index 3064298..48e21da 100755
--- a/gitweb/gitweb.perl
+++ b/gitweb/gitweb.perl
@@ -35,6 +35,10 @@
 #our $projectroot = "/pub/scm";
 our $projectroot = "++GITWEB_PROJECTROOT++";
 
+# fs traversing limit for getting project list
+# the number is relative to the projectroot
+our $project_maxdepth = "++GITWEB_PROJECT_MAXDEPTH++";
+
 # target of the home link on top of all pages
 our $home_link = $my_uri || "/";
 
@@ -1509,6 +1513,7 @@
 		# remove the trailing "/"
 		$dir =~ s!/+$!!;
 		my $pfxlen = length("$dir");
+		my $pfxdepth = ($dir =~ tr!/!!);
 
 		File::Find::find({
 			follow_fast => 1, # follow symbolic links
@@ -1519,6 +1524,11 @@
 				return if (m!^[/.]$!);
 				# only directories can be git repositories
 				return unless (-d $_);
+				# don't traverse too deep (Find is super slow on os x)
+				if (($File::Find::name =~ tr!/!!) - $pfxdepth > $project_maxdepth) {
+					$File::Find::prune = 1;
+					return;
+				}
 
 				my $subdir = substr($File::Find::name, $pfxlen + 1);
 				# we check related file in $projectroot