graphbook: introduce element_factory_exists

This method helps to tell if a factory exists
when loading a graph.
If the factory does not exists, use light mode
to display it and prevent some menu item
and change its description.

ChangeLog.md

@@ -100,3 +100,7 @@
 ### app
  - [x] Add multiple graphviews with tabs.
  - [x] handle the caps setter element
+
+## 0.3.2
+### app
+- [x] check that element exists before creating it on file load.

TODO.md

@@ -15,7 +15,6 @@
 - [ ] unable to connect element with incompatible caps.
 - [ ] Implement graph dot render/load
 
-
 - [ ] Add probes on each pad to monitor the pipeline
 - [ ] Render a media file
 - [ ] Offer compatible element to a pad (autorender)
@@ -32,7 +31,6 @@
 
 ## bugs
 
-- [ ] check that element exists before creating it on file load.
 - [ ] Combo box is not well selected if the value is not linear such as flags. See flags in playbin
 - [ ] opening a graph file can lead a different behavior in the pipeline. See videomixer graph where the zorder
       on pads is not correctly set to right one.

src/gps/element.rs

@@ -46,6 +46,19 @@ impl ElementInfo {
         Ok(elements)
     }
 
+    pub fn element_factory_exists(element_name: &str) -> bool {
+        match ElementInfo::element_feature(element_name) {
+            Some(_feature) => {
+                GPS_DEBUG!("Found element factory name {}", element_name);
+                true
+            }
+            None => {
+                GPS_ERROR!("Unable to find element factory name {}", element_name);
+                false
+            }
+        }
+    }
+
     pub fn element_feature(element_name: &str) -> Option<gst::PluginFeature> {
         let registry = gst::Registry::get();
         gst::Registry::find_feature(&registry, element_name, gst::ElementFactory::static_type())
@@ -60,6 +73,14 @@ impl ElementInfo {
 
     pub fn element_description(element_name: &str) -> anyhow::Result<String> {
         let mut desc = String::from("");
+        if !ElementInfo::element_factory_exists(element_name) {
+            desc.push_str("<b>Factory details:</b>\n");
+            desc.push_str("<b>Name:</b>");
+            desc.push_str(element_name);
+            desc.push('\n');
+            desc.push('\n');
+            desc.push_str("Factory unavailable.");
+        } else {
             let feature = ElementInfo::element_feature(element_name)
                 .ok_or_else(|| glib::bool_error!("Failed get element feature"))?;
             let rank = feature.rank();
@@ -114,6 +135,7 @@ impl ElementInfo {
                     desc.push('\n');
                 }
             }
+        }
         Ok(desc)
     }
 

src/gps/pad.rs

@@ -51,10 +51,9 @@ impl PadInfo {
     }
 
     pub fn pads(element_name: &str, include_on_request: bool) -> (Vec<PadInfo>, Vec<PadInfo>) {
-        let feature = ElementInfo::element_feature(element_name).expect("Unable to get feature");
         let mut input = vec![];
         let mut output = vec![];
-
+        if let Some(feature) = ElementInfo::element_feature(element_name) {
             if let Ok(factory) = feature.downcast::<gst::ElementFactory>() {
                 if factory.num_pad_templates() > 0 {
                     let pads = factory.static_pad_templates();
@@ -87,5 +86,8 @@ impl PadInfo {
                 }
             }
             (input, output)
+        } else {
+            (input, output)
+        }
     }
 }

src/graphbook.rs

@@ -242,6 +242,10 @@ pub fn create_graphtab(app: &GPSApp, id: u32, name: Option<&str>) {
             if let Some(node) = current_graphtab(&app).graphview().node(node_id) {
                 let description = GPS::ElementInfo::element_description(&node.name()).ok();
                 node.set_tooltip_markup(description.as_deref());
+                if  !GPS::ElementInfo::element_factory_exists(&node.name()) {
+                    node.set_light(true);
+                    node.set_tooltip_markup(description.as_deref());
+                }
                 for port in node.all_ports(GM::PortDirection::All) {
                     let caps = PropertyExt::property(&port,"_caps");
                     GPS_DEBUG!("caps={} for port id {}", caps.clone().unwrap_or_else(|| "caps unknown".to_string()), port.id());
@@ -382,6 +386,8 @@ pub fn create_graphtab(app: &GPSApp, id: u32, name: Option<&str>) {
             glib::clone!(@weak graphbook =>  @default-return None, move |values: &[Value]| {
                 let app = upgrade_weak!(app_weak, None);
                 let node_id = values[1].get::<u32>().expect("node id args[1]");
+                let node = current_graphtab(&app).graphview().node(node_id).unwrap();
+                let element_exists = GPS::ElementInfo::element_factory_exists(&node.name());
                 let point = values[2].get::<graphene::Point>().expect("point in args[2]");
                 let pop_menu = app.app_pop_menu_at_position(&*current_graphtab(&app).graphview(), point.to_vec2().x() as f64, point.to_vec2().y() as f64);
                 let menu: gio::MenuModel = app
@@ -390,6 +396,16 @@ pub fn create_graphtab(app: &GPSApp, id: u32, name: Option<&str>) {
                     .expect("Couldn't get menu model for node");
                 pop_menu.set_menu_model(Some(&menu));
 
+
+                let app_weak = app.downgrade();
+                app.connect_app_menu_action("node.delete",
+                    move |_,_| {
+                        let app = upgrade_weak!(app_weak);
+                        GPS_DEBUG!("node.delete id: {}", node_id);
+                        current_graphtab(&app).graphview().remove_node(node_id);
+                    }
+                );
+                if element_exists {
                     let app_weak = app.downgrade();
                     app.connect_app_menu_action("node.add-to-favorite",
                         move |_,_| {
@@ -401,14 +417,7 @@ pub fn create_graphtab(app: &GPSApp, id: u32, name: Option<&str>) {
                         }
                     );
 
-                let app_weak = app.downgrade();
+
-                app.connect_app_menu_action("node.delete",
-                    move |_,_| {
-                        let app = upgrade_weak!(app_weak);
-                        GPS_DEBUG!("node.delete id: {}", node_id);
-                        current_graphtab(&app).graphview().remove_node(node_id);
-                    }
-                );
                     let node = app.node(node_id);
                     if let Some(input) = GPS::ElementInfo::element_supports_new_pad_request(&node.name(),  GM::PortDirection::Input) {
                         let app_weak = app.downgrade();
@@ -445,6 +454,7 @@ pub fn create_graphtab(app: &GPSApp, id: u32, name: Option<&str>) {
                             GPSUI::properties::display_plugin_properties(&app, &node.name(), node_id);
                         }
                     );
+                }
                 pop_menu.show();
                 None
             }),
@@ -459,7 +469,9 @@ pub fn create_graphtab(app: &GPSApp, id: u32, name: Option<&str>) {
             let node_id = values[1].get::<u32>().expect("node id args[1]");
             GPS_TRACE!("Node double clicked id={}", node_id);
             let node = current_graphtab(&app).graphview().node(node_id).unwrap();
+            if GPS::ElementInfo::element_factory_exists(&node.name()) {
                 GPSUI::properties::display_plugin_properties(&app, &node.name(), node_id);
+            }
             None
         }),
     );