crossroads: Do not output descendants on introspection

Fixes: #412

dbus-crossroads/src/crossroads.rs

@@ -224,17 +224,19 @@ impl Crossroads {
         (&self.registry, &obj.ifaces)
     }
 
-    pub (crate) fn get_children(&self, path: &dbus::Path<'static>) -> Vec<&str> {
+    pub (crate) fn get_children(&self, path: &dbus::Path<'static>, direct_only: bool) -> Vec<&str> {
         use std::ops::Bound;
         let mut range = self.map.range((Bound::Excluded(path), Bound::Unbounded));
         let p2 = path.as_bytes();
         let substart = if &p2 == &b"/" { 0 } else { p2.len() };
-        let mut r = vec!();
+        let mut r: Vec<&str> = vec!();
         while let Some((c, _)) = range.next() {
             if !c.as_bytes().starts_with(p2) { break; }
             let csub: &str = &c[substart..];
             if csub.len() == 0 || csub.as_bytes()[0] != b'/' { continue; }
-            r.push(&csub[1..]);
+            let csub1 = &csub[1..];
+            if direct_only && r.len() > 0 && csub1.as_bytes().starts_with(r[r.len()-1].as_bytes()) { continue; }
+            r.push(csub1);
         };
         r
     }

dbus-crossroads/src/stdimpl.rs

@@ -9,7 +9,7 @@ use std::marker::PhantomData;
 use crate::ifacedesc::EMITS_CHANGED;
 
 fn introspect(cr: &Crossroads, path: &dbus::Path<'static>) -> String {
-    let mut children = cr.get_children(path);
+    let mut children = cr.get_children(path, true);
     let mut childstr = String::new();
     children.sort_unstable();
     for c in children {
@@ -347,7 +347,7 @@ fn get_managed_objects(mut ctx: Context, cr: &mut Crossroads, _: ()) -> Option<C
     // HashMap<dbus::Path<'static>, IfacePropMap>
     let parent = ctx.path();
     let children: Vec<dbus::Path<'static>> =
-        cr.get_children(ctx.path()).into_iter().map(|child_path| {
+        cr.get_children(ctx.path(), false).into_iter().map(|child_path| {
             let mut x = String::from(&**parent);
             if !x.ends_with('/') {
                 x.push_str("/");

dbus-crossroads/src/test.rs

@@ -164,6 +164,7 @@ fn introspect() {
     });
     cr.insert("/com/example/sample_object0", &[token], ());
     cr.insert("/com/example/sample_object0/child_of_sample_object", &[], ());
+    cr.insert("/com/example/sample_object0/child_of_sample_object/subchild", &[], ());
     cr.insert("/com/example/sample_object0123", &[], ());
     cr.insert("/com/example/sample_object0/another_child_of_sample_object", &[], ());