graphmanager: can remove property

Add public remove_property to PropertyExt

src/graphmanager/node.rs

@@ -344,6 +344,14 @@ impl PropertyExt for Node {
         self.update_description();
     }
 
+    /// Remove a port property with a name.
+    ///
+    fn remove_property(&self, name: &str) {
+        let private = imp::Node::from_instance(self);
+        trace!("property name={} removed", name);
+        private.properties.borrow_mut().remove(name);
+    }
+
     /// Retrieves node properties.
     ///
     fn properties(&self) -> Ref<HashMap<String, String>> {

src/graphmanager/port.rs

@@ -22,7 +22,7 @@ use gtk::{
     prelude::*,
     subclass::prelude::*,
 };
-use log::info;
+use log::trace;
 use std::cell::RefCell;
 use std::cell::{Cell, Ref};
 use std::collections::HashMap;
@@ -223,17 +223,25 @@ impl SelectionExt for Port {
 }
 
 impl PropertyExt for Port {
-    /// Add a node property with a name and a value.
+    /// Add a port property with a name and a value.
     ///
     fn add_property(&self, name: &str, value: &str) {
         let private = imp::Port::from_instance(self);
-        info!("property name={} updated with value={}", name, value);
+        trace!("property name={} updated with value={}", name, value);
         private
             .properties
             .borrow_mut()
             .insert(name.to_string(), value.to_string());
     }
 
+    /// Remove a port property with a name.
+    ///
+    fn remove_property(&self, name: &str) {
+        let private = imp::Port::from_instance(self);
+        trace!("property name={} removed", name);
+        private.properties.borrow_mut().remove(name);
+    }
+
     /// Retrieves node properties.
     ///
     fn properties(&self) -> Ref<HashMap<String, String>> {

src/graphmanager/property.rs

@@ -28,13 +28,21 @@ pub trait PropertyExt {
     ///
     fn add_property(&self, name: &str, value: &str);
 
+    /// Add a node property with a name and a value.
+    ///
+    fn remove_property(&self, name: &str);
+
     /// Update the properties.
     ///
     /// Update the PropertyExt properties.
     ///
     fn update_properties(&self, new_properties: &HashMap<String, String>) {
         for (key, value) in new_properties {
-            self.add_property(key, value);
+            if value.is_empty() {
+                self.remove_property(key);
+            } else {
+                self.add_property(key, value);
+            }
         }
     }