Move catch_panic_pad_function() into a generic place for all element subclasses

gst-plugin-togglerecord/src/togglerecord.rs

@@ -259,21 +259,6 @@ impl ToggleRecord {
         Box::new(imp)
     }
 
-    fn catch_panic_pad_function<T, F: FnOnce(&Self, &Element) -> T, G: FnOnce() -> T>(
-        parent: &Option<gst::Object>,
-        fallback: G,
-        f: F,
-    ) -> T {
-        let element = parent
-            .as_ref()
-            .cloned()
-            .unwrap()
-            .downcast::<Element>()
-            .unwrap();
-        let togglerecord = element.get_impl().downcast_ref::<ToggleRecord>().unwrap();
-        element.catch_panic(fallback, |element| f(togglerecord, element))
-    }
-
     fn set_pad_functions(sinkpad: &gst::Pad, srcpad: &gst::Pad) {
         sinkpad.set_chain_function(|pad, parent, buffer| {
             ToggleRecord::catch_panic_pad_function(

gst-plugin/src/element.rs

@@ -53,6 +53,33 @@ pub trait ElementImpl<T: ElementBase>: ObjectImpl<T> + AnyImpl + Send + Sync + '
     }
 }
 
+use std::any::Any;
+
+pub trait ElementImplExt<T> {
+    fn catch_panic_pad_function<R, F: FnOnce(&Self, &T) -> R, G: FnOnce() -> R>(
+            parent: &Option<gst::Object>,
+            fallback: G,
+            f: F,
+        ) -> R;
+}
+
+impl<S: ElementImpl<T>, T: ObjectType + glib::IsA<gst::Element> + glib::IsA<gst::Object>> ElementImplExt<T> for S {
+    fn catch_panic_pad_function<R, F: FnOnce(&Self, &T) -> R, G: FnOnce() -> R>(
+        parent: &Option<gst::Object>,
+        fallback: G,
+        f: F,
+    ) -> R {
+        let element = parent
+            .as_ref()
+            .cloned()
+            .unwrap()
+            .downcast::<T>()
+            .unwrap();
+        let imp = Any::downcast_ref::<Self>(element.get_impl()).unwrap();
+        element.catch_panic(fallback, |element| f(imp, element))
+    }
+}
+
 any_impl!(ElementBase, ElementImpl);
 
 pub unsafe trait ElementBase: IsA<gst::Element> + ObjectType {