qom: Add recursive version of object_child_for_each

Useful for iterating through an entire QOM subtree.

Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Tested-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Message-id: 1441383782-24378-2-git-send-email-peter.maydell@linaro.org

include/qom/object.h

@@ -1493,6 +1493,21 @@ void object_property_set_description(Object *obj, const char *name,
 int object_child_foreach(Object *obj, int (*fn)(Object *child, void *opaque),
                          void *opaque);
 
+/**
+ * object_child_foreach_recursive:
+ * @obj: the object whose children will be navigated
+ * @fn: the iterator function to be called
+ * @opaque: an opaque value that will be passed to the iterator
+ *
+ * Call @fn passing each child of @obj and @opaque to it, until @fn returns
+ * non-zero. Calls recursively, all child nodes of @obj will also be passed
+ * all the way down to the leaf nodes of the tree. Depth first ordering.
+ *
+ * Returns: The last value returned by @fn, or 0 if there is no child.
+ */
+int object_child_foreach_recursive(Object *obj,
+                                   int (*fn)(Object *child, void *opaque),
+                                   void *opaque);
 /**
  * container_get:
  * @root: root of the #path, e.g., object_get_root()

qom/object.c

@@ -775,23 +775,42 @@ void object_class_foreach(void (*fn)(ObjectClass *klass, void *opaque),
     enumerating_types = false;
 }
 
-int object_child_foreach(Object *obj, int (*fn)(Object *child, void *opaque),
+static int do_object_child_foreach(Object *obj,
-                         void *opaque)
+                                   int (*fn)(Object *child, void *opaque),
+                                   void *opaque, bool recurse)
 {
     ObjectProperty *prop, *next;
     int ret = 0;
 
     QTAILQ_FOREACH_SAFE(prop, &obj->properties, node, next) {
         if (object_property_is_child(prop)) {
-            ret = fn(prop->opaque, opaque);
+            Object *child = prop->opaque;
+
+            ret = fn(child, opaque);
             if (ret != 0) {
                 break;
             }
+            if (recurse) {
+                do_object_child_foreach(child, fn, opaque, true);
+            }
         }
     }
     return ret;
 }
 
+int object_child_foreach(Object *obj, int (*fn)(Object *child, void *opaque),
+                         void *opaque)
+{
+    return do_object_child_foreach(obj, fn, opaque, false);
+}
+
+int object_child_foreach_recursive(Object *obj,
+                                   int (*fn)(Object *child, void *opaque),
+                                   void *opaque)
+{
+    return do_object_child_foreach(obj, fn, opaque, true);
+}
+
 static void object_class_get_list_tramp(ObjectClass *klass, void *opaque)
 {
     GSList **list = opaque;