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/Makefile b/Makefile
index d74ac93..9f81c73 100644
--- a/Makefile
+++ b/Makefile
@@ -165,6 +165,7 @@
 GITWEB_HOME_LINK_STR = projects
 GITWEB_SITENAME =
 GITWEB_PROJECTROOT = /pub/git
+GITWEB_PROJECT_MAXDEPTH = 2007
 GITWEB_EXPORT_OK =
 GITWEB_STRICT_EXPORT =
 GITWEB_BASE_URL =
@@ -831,6 +832,7 @@
 	    -e 's|++GITWEB_HOME_LINK_STR++|$(GITWEB_HOME_LINK_STR)|g' \
 	    -e 's|++GITWEB_SITENAME++|$(GITWEB_SITENAME)|g' \
 	    -e 's|++GITWEB_PROJECTROOT++|$(GITWEB_PROJECTROOT)|g' \
+	    -e 's|"++GITWEB_PROJECT_MAXDEPTH++"|$(GITWEB_PROJECT_MAXDEPTH)|g' \
 	    -e 's|++GITWEB_EXPORT_OK++|$(GITWEB_EXPORT_OK)|g' \
 	    -e 's|++GITWEB_STRICT_EXPORT++|$(GITWEB_STRICT_EXPORT)|g' \
 	    -e 's|++GITWEB_BASE_URL++|$(GITWEB_BASE_URL)|g' \
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 $projectroot
diff --git a/t/t9500-gitweb-standalone-no-errors.sh b/t/t9500-gitweb-standalone-no-errors.sh
index 642b836..f7bad5b 100755
--- a/t/t9500-gitweb-standalone-no-errors.sh
+++ b/t/t9500-gitweb-standalone-no-errors.sh
@@ -18,6 +18,7 @@
 our \$version = "current";
 our \$GIT = "git";
 our \$projectroot = "$(pwd)";
+our \$project_maxdepth = 8;
 our \$home_link_str = "projects";
 our \$site_name = "[localhost]";
 our \$site_header = "";