libct: use Namespaces.IsPrivate more

In these cases, this is exactly what we want to find out.

Slightly improves performance and readability.

Signed-off-by: Kir Kolyshkin <[email protected]>

Author: kolyshkin

libcontainer/configs/validate/rootless.go

@@ -34,7 +34,7 @@ func rootlessEUIDMappings(config *configs.Config) error {
 		return errors.New("rootless container requires user namespaces")
 	}
 	// We only require mappings if we are not joining another userns.
-	if path := config.Namespaces.PathOf(configs.NEWUSER); path == "" {
+	if config.Namespaces.IsPrivate(configs.NEWUSER) {
 		if len(config.UIDMappings) == 0 {
 			return errors.New("rootless containers requires at least one UID mapping")
 		}

libcontainer/specconv/spec_linux.go

@@ -415,7 +415,7 @@ func CreateLibcontainerConfig(opts *CreateOpts) (*configs.Config, error) {
 			}
 			config.Namespaces.Add(t, ns.Path)
 		}
-		if config.Namespaces.Contains(configs.NEWNET) && config.Namespaces.PathOf(configs.NEWNET) == "" {
+		if config.Namespaces.IsPrivate(configs.NEWNET) {
 			config.Networks = []*configs.Network{
 				{
 					Type: "loopback",
@@ -481,7 +481,7 @@ func CreateLibcontainerConfig(opts *CreateOpts) (*configs.Config, error) {
 	// Only set it if the container will have its own cgroup
 	// namespace and the cgroupfs will be mounted read/write.
 	//
-	hasCgroupNS := config.Namespaces.Contains(configs.NEWCGROUP) && config.Namespaces.PathOf(configs.NEWCGROUP) == ""
+	hasCgroupNS := config.Namespaces.IsPrivate(configs.NEWCGROUP)
 	hasRwCgroupfs := false
 	if hasCgroupNS {
 		for _, m := range config.Mounts {