Treat Callable as by-ref in APIs

Author: Bromeon

examples/dodge-the-creeps/rust/src/hud.rs

@@ -26,7 +26,7 @@ impl Hud {
         self.show_message("Game Over".into());
 
         let mut timer = self.base().get_tree().unwrap().create_timer(2.0).unwrap();
-        timer.connect("timeout", self.base().callable("show_start_button"));
+        timer.connect("timeout", &self.base().callable("show_start_button"));
     }
 
     #[func]

examples/dodge-the-creeps/rust/src/main_scene.rs

@@ -102,7 +102,7 @@ impl Main {
         mob.set_linear_velocity(Vector2::new(range, 0.0).rotated(real::from_f32(direction)));
 
         let mut hud = self.base().get_node_as::<Hud>("Hud");
-        hud.connect("start_game", mob.callable("on_start_game"));
+        hud.connect("start_game", &mob.callable("on_start_game"));
     }
 
     fn music(&mut self) -> &mut AudioStreamPlayer {

godot-codegen/src/context.rs

@@ -247,9 +247,12 @@ impl<'a> Context<'a> {
         // Already handled separately.
         debug_assert!(!godot_ty.ty.starts_with("Packed"));
 
+        // IMPORTANT: Keep this in sync with impl_ffi_variant!() macros taking `ref` or not.
+
         // Arrays are also handled separately, and use ByRef.
         match godot_ty.ty.as_str() {
-            "Variant" | "Array" | "Dictionary" => ArgPassing::ByRef,
+            // Note: Signal is currently not used in any parameter, but this may change.
+            "Variant" | "Array" | "Dictionary" | "Callable" | "Signal" => ArgPassing::ByRef,
             "String" | "StringName" | "NodePath" => ArgPassing::ImplAsArg,
             _ => ArgPassing::ByValue,
         }

godot-core/src/builtin/collections/array.rs

@@ -614,7 +614,7 @@ impl<T: ArrayElement> Array<T> {
     ///
     /// Consider using `sort_custom()` to ensure the sorting order is compatible with
     /// your callable's ordering
-    pub fn bsearch_custom(&self, value: impl AsArg<T>, func: Callable) -> usize {
+    pub fn bsearch_custom(&self, value: impl AsArg<T>, func: &Callable) -> usize {
         meta::arg_into_ref!(value: T);
 
         to_usize(
@@ -646,7 +646,7 @@ impl<T: ArrayElement> Array<T> {
     /// Note: The sorting algorithm used is not [stable](https://en.wikipedia.org/wiki/Sorting_algorithm#Stability).
     /// This means that values considered equal may have their order changed when using `sort_unstable_custom`.
     #[doc(alias = "sort_custom")]
-    pub fn sort_unstable_custom(&mut self, func: Callable) {
+    pub fn sort_unstable_custom(&mut self, func: &Callable) {
         // SAFETY: We do not write any values that don't already exist in the array, so all values have the correct type.
         unsafe { self.as_inner_mut() }.sort_custom(func);
     }

godot-core/src/builtin/signal.rs

@@ -74,7 +74,7 @@ impl Signal {
     /// returns [`Error::ERR_INVALID_PARAMETER`] and
     /// pushes an error message, unless the signal is connected with [`ConnectFlags::REFERENCE_COUNTED`](crate::classes::object::ConnectFlags::REFERENCE_COUNTED).
     /// To prevent this, use [`Self::is_connected`] first to check for existing connections.
-    pub fn connect(&self, callable: Callable, flags: i64) -> Error {
+    pub fn connect(&self, callable: &Callable, flags: i64) -> Error {
         let error = self.as_inner().connect(callable, flags);
 
         Error::from_godot(error as i32)
@@ -83,7 +83,7 @@ impl Signal {
     /// Disconnects this signal from the specified [`Callable`].
     ///
     /// If the connection does not exist, generates an error. Use [`Self::is_connected`] to make sure that the connection exists.
-    pub fn disconnect(&self, callable: Callable) {
+    pub fn disconnect(&self, callable: &Callable) {
         self.as_inner().disconnect(callable);
     }
 
@@ -142,7 +142,7 @@ impl Signal {
     }
 
     /// Returns `true` if the specified [`Callable`] is connected to this signal.
-    pub fn is_connected(&self, callable: Callable) -> bool {
+    pub fn is_connected(&self, callable: &Callable) -> bool {
         self.as_inner().is_connected(callable)
     }
 

itest/rust/src/builtin_tests/containers/array_test.rs

@@ -479,7 +479,7 @@ fn array_should_format_with_display() {
 fn array_sort_custom() {
     let mut a = array![1, 2, 3, 4];
     let func = backwards_sort_callable();
-    a.sort_unstable_custom(func);
+    a.sort_unstable_custom(&func);
     assert_eq!(a, array![4, 3, 2, 1]);
 }
 
@@ -488,8 +488,8 @@ fn array_sort_custom() {
 fn array_binary_search_custom() {
     let a = array![5, 4, 2, 1];
     let func = backwards_sort_callable();
-    assert_eq!(a.bsearch_custom(1, func.clone()), 3);
-    assert_eq!(a.bsearch_custom(3, func), 2);
+    assert_eq!(a.bsearch_custom(1, &func), 3);
+    assert_eq!(a.bsearch_custom(3, &func), 2);
 }
 
 #[cfg(since_api = "4.2")]

itest/rust/src/builtin_tests/containers/signal_test.rs

@@ -5,7 +5,7 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/.
  */
 
-use godot::builtin::{Callable, GString, Signal, StringName, Variant};
+use godot::builtin::{Callable, GString, Signal, StringName};
 use godot::meta::ToGodot;
 use godot::register::{godot_api, GodotClass};
 use std::cell::Cell;
@@ -71,18 +71,15 @@ fn signals() {
 
     let args = [
         vec![],
-        vec![Variant::from(987)],
-        vec![
-            Variant::from(receiver.clone()),
-            Variant::from(SIGNAL_ARG_STRING),
-        ],
+        vec![987.to_variant()],
+        vec![receiver.to_variant(), SIGNAL_ARG_STRING.to_variant()],
     ];
 
     for (i, arg) in args.iter().enumerate() {
         let signal_name = format!("signal_{i}_arg");
         let receiver_name = format!("receive_{i}_arg");
 
-        emitter.connect(&signal_name, receiver.callable(receiver_name));
+        emitter.connect(&signal_name, &receiver.callable(receiver_name));
         emitter.emit_signal(&signal_name, arg);
 
         assert!(receiver.bind().used[i].get());
@@ -117,7 +114,7 @@ fn emit_signal() {
 
     object.connect(
         &StringName::from("test_signal"), // explicit StringName
-        Callable::from_object_method(&receiver, "receive_1_arg"),
+        &Callable::from_object_method(&receiver, "receive_1_arg"),
     );
     assert_eq!(signal.connections().len(), 1);
 
@@ -136,7 +133,7 @@ fn connect_signal() {
     let signal = Signal::from_object_signal(&object, "test_signal");
     let receiver = Receiver::new_alloc();
 
-    signal.connect(Callable::from_object_method(&receiver, "receive_1_arg"), 0);
+    signal.connect(&Callable::from_object_method(&receiver, "receive_1_arg"), 0);
     assert_eq!(signal.connections().len(), 1);
 
     object.emit_signal("test_signal", &[987i64.to_variant()]);
@@ -277,7 +274,7 @@ mod custom_callable {
 
         let received = Arc::new(AtomicU32::new(0));
         let callable = callable(received.clone());
-        signal.connect(callable, 0);
+        signal.connect(&callable, 0);
 
         emit(&mut node);
 

itest/rust/src/object_tests/object_test.rs

@@ -1053,7 +1053,7 @@ fn double_use_reference() {
     emitter
         .clone()
         .upcast::<Object>()
-        .connect("do_use", double_use.callable("use_1"));
+        .connect("do_use", &double_use.callable("use_1"));
 
     let guard = double_use.bind();
 

itest/rust/src/object_tests/reentrant_test.rs

@@ -65,7 +65,7 @@ fn reentrant_emit_succeeds() {
     let mut class = ReentrantClass::new_alloc();
 
     let callable = class.callable("second");
-    class.connect("some_signal", callable);
+    class.connect("some_signal", &callable);
 
     assert!(!class.bind().first_called_pre);
     assert!(!class.bind().first_called_post);