[2093] doxygen for getAbsoluteLabelSequence()

src/lib/datasrc/rbtree.h

@@ -221,7 +221,26 @@ public:
         return (dns::LabelSequence(getLabelsData()));
     }
 
+    /// \brief Return the absolute label sequence of the node.
     ///
+    /// This method returns the label sequence corresponding to the full
+    /// name of the node; i.e. the entire name as it appears in the zone.
+    ///
+    /// It takes the (partial) name of the node itself, and extends it
+    /// with all upper nodes.
+    ///
+    /// The label sequence that is returned should therefore always be
+    /// absolute.
+    ///
+    /// \note Care must be taken with the buffer that is used here; this
+    /// method overwrites its data, so it should not be associated with
+    /// any other LabelSequence during the lifetime of the LabelSequence
+    /// returned by this method. See LabelSequence::extend(), which is used
+    /// by this method.
+    ///
+    /// \param buf A data buffer where the label sequence will be built.
+    ///            The data in this buffer will be overwritten by this call,
+    /// \return A LabelSequence with the absolute name of this node.
     isc::dns::LabelSequence getAbsoluteLabelSequence(
         uint8_t buf[isc::dns::LabelSequence::MAX_SERIALIZED_LENGTH]) const;