[core] Attribute: Add notion of depth for attributes with parents

For attributes in `GroupAttribute` and `ListAttribute`, the notion of
parent attribute exists through the `root` property. As a parent can
itself have a parent, the `depth` property describes how many levels
there are between the attribute and the root level.

A value of 0 means that the attribute is at the root level, and it
increases as it gets deeper.

Author: cbentejac

meshroom/core/attribute.py

@@ -61,6 +61,13 @@ def __init__(self, node, attributeDesc, isOutput, root=None, parent=None):
         self._description = attributeDesc.description
         self._invalidate = False if self._isOutput else attributeDesc.invalidate
 
+        self._depth = 0
+        if root is not None:
+            current = self
+            while current.root is not None:
+                self._depth += 1
+                current = current.root
+
         # invalidation value for output attributes
         self._invalidationValue = ""
 
@@ -77,6 +84,9 @@ def node(self):
     def root(self):
         return self._root() if self._root else None
 
+    def getDepth(self):
+        return self._depth
+
     def getName(self):
         """ Attribute name """
         return self._name
@@ -454,6 +464,7 @@ def updateInternals(self):
     validValueChanged = Signal()
     validValue = Property(bool, getValidValue, setValidValue, notify=validValueChanged)
     root = Property(BaseObject, root.fget, constant=True)
+    depth = Property(int, getDepth, constant=True)
 
 
 def raiseIfLink(func):