Merge #279

279: Signals now accept parameters r=Bromeon a=LeaoLuciano

Project for testing: 
- [dodge-the-creeps-signals.zip](https://github.com/godot-rust/gdext/files/11507083/dodge-the-creeps-signals.zip)
- Added a signal named test in Player scene that is emitted when player dies
- This signal is connected in Main scene which calls test_function, printing player's death position



Co-authored-by: Luciano Leão <[email protected]>

Author: bors[bot]

godot-core/src/lib.rs

@@ -53,7 +53,8 @@ pub mod private {
     pub use crate::registry::{callbacks, ClassPlugin, ErasedRegisterFn, PluginComponent};
     pub use crate::storage::as_storage;
     pub use crate::{
-        gdext_register_method, gdext_register_method_inner, gdext_virtual_method_callback,
+        gdext_get_arguments_info, gdext_register_method, gdext_register_method_inner,
+        gdext_virtual_method_callback,
     };
 
     use crate::{log, sys};

godot-core/src/macros.rs

@@ -229,20 +229,7 @@ macro_rules! gdext_register_method_inner {
 
             // Arguments meta-information
             let argument_count = NUM_ARGS as u32;
-            let mut arguments_info: [PropertyInfo; NUM_ARGS] = {
-                let mut i = -1i32;
-                [$(
-                    {
-                        i += 1;
-                        let prop = Sig::property_info(i, stringify!($param));
-                        //OnceArg::new(prop)
-                        prop
-                    },
-                )*]
-            };
-            let mut arguments_info_sys: [sys::GDExtensionPropertyInfo; NUM_ARGS]
-                = std::array::from_fn(|i| arguments_info[i].property_sys());
-//                = std::array::from_fn(|i| arguments_info[i].once_sys());
+            let mut arguments_info: [sys::GDExtensionPropertyInfo; NUM_ARGS] = $crate::gdext_get_arguments_info!(($($RetTy)+, $($ParamTy),*), $( $param, )*);
             let mut arguments_metadata: [sys::GDExtensionClassMethodArgumentMetadata; NUM_ARGS]
                 = std::array::from_fn(|i| Sig::param_metadata(i as i32));
 
@@ -262,7 +249,7 @@ macro_rules! gdext_register_method_inner {
                 return_value_info: std::ptr::addr_of_mut!(return_value_info_sys),
                 return_value_metadata,
                 argument_count,
-                arguments_info: arguments_info_sys.as_mut_ptr(),
+                arguments_info: arguments_info.as_mut_ptr(),
                 arguments_metadata: arguments_metadata.as_mut_ptr(),
                 default_argument_count: 0,
                 default_arguments: std::ptr::null_mut(),
@@ -621,3 +608,25 @@ macro_rules! gdext_ptrcall {
         );
     };
 }
+
+#[doc(hidden)]
+#[macro_export]
+macro_rules! gdext_get_arguments_info {
+    (
+        $Signature:ty,
+        $($param:ident,)*
+    ) => {
+        {
+            use $crate::builtin::meta::*;
+
+            let mut i = -1i32;
+            [$(
+                {
+                    i += 1;
+                    let prop = <$Signature as VarcallSignatureTuple>::property_info(i, stringify!($param)).property_sys();
+                    prop
+                },
+            )*]
+        }
+    };
+}

godot-macros/src/godot_api.rs

@@ -8,7 +8,7 @@ use crate::util;
 use crate::util::bail;
 use proc_macro2::{Ident, TokenStream};
 use quote::quote;
-use venial::{AttributeValue, Declaration, Error, Function, Impl, ImplMember};
+use venial::{AttributeValue, Declaration, Error, FnParam, Function, Impl, ImplMember, TyExpr};
 
 pub fn transform(input_decl: Declaration) -> Result<TokenStream, Error> {
     let decl = match input_decl {
@@ -62,19 +62,41 @@ fn transform_inherent_impl(mut decl: Impl) -> Result<TokenStream, Error> {
     let class_name = util::validate_impl(&decl, None, "godot_api")?;
     let class_name_str = class_name.to_string();
 
-    //let register_fn = format_ident!("__godot_rust_register_{}", class_name_str);
-    //#[allow(non_snake_case)]
-
     let (funcs, signals) = process_godot_fns(&mut decl)?;
-    let signal_name_strs = signals.into_iter().map(|ident| ident.to_string());
+
+    let mut signal_name_strs: Vec<String> = Vec::new();
+    let mut signal_parameters_count: Vec<i64> = Vec::new();
+    let mut signal_parameters: Vec<TokenStream> = Vec::new();
+
+    for signature in signals {
+        let mut param_types: Vec<TyExpr> = Vec::new();
+        let mut param_names: Vec<Ident> = Vec::new();
+
+        for param in signature.params.inner {
+            match &param.0 {
+                FnParam::Typed(param) => {
+                    param_types.push(param.ty.clone());
+                    param_names.push(param.name.clone());
+                }
+                FnParam::Receiver(_) => {}
+            };
+        }
+
+        signal_name_strs.push(signature.name.to_string());
+        signal_parameters_count.push(param_names.len() as i64);
+        signal_parameters.push(
+            quote! {
+                ::godot::private::gdext_get_arguments_info!(((), #(#param_types ),*), #(#param_names, )*).as_ptr()
+            },
+        );
+    }
 
     let prv = quote! { ::godot::private };
 
     let result = quote! {
         #decl
 
         impl ::godot::obj::cap::ImplementsGodotApi for #class_name {
-            //fn __register_methods(_builder: &mut ::godot::builder::ClassBuilder<Self>) {
             fn __register_methods() {
                 #(
                     ::godot::private::gdext_register_method!(#class_name, #funcs);
@@ -83,14 +105,17 @@ fn transform_inherent_impl(mut decl: Impl) -> Result<TokenStream, Error> {
                 unsafe {
                     let class_name = ::godot::builtin::StringName::from(#class_name_str);
                     use ::godot::sys;
+
                     #(
+                        let parameters = #signal_parameters;
                         let signal_name = ::godot::builtin::StringName::from(#signal_name_strs);
+
                         sys::interface_fn!(classdb_register_extension_class_signal)(
                             sys::get_library(),
                             class_name.string_sys(),
                             signal_name.string_sys(),
-                            std::ptr::null(), // NULL only valid for zero parameters, in current impl; maybe better empty slice
-                            0,
+                            parameters,
+                            sys::GDExtensionInt::from(#signal_parameters_count),
                         );
                     )*
                 }
@@ -110,9 +135,9 @@ fn transform_inherent_impl(mut decl: Impl) -> Result<TokenStream, Error> {
     Ok(result)
 }
 
-fn process_godot_fns(decl: &mut Impl) -> Result<(Vec<Function>, Vec<Ident>), Error> {
+fn process_godot_fns(decl: &mut Impl) -> Result<(Vec<Function>, Vec<Function>), Error> {
     let mut func_signatures = vec![];
-    let mut signal_idents = vec![]; // TODO consider signature
+    let mut signal_signatures = vec![];
 
     let mut removed_indexes = vec![];
     for (index, item) in decl.body_items.iter_mut().enumerate() {
@@ -147,11 +172,12 @@ fn process_godot_fns(decl: &mut Impl) -> Result<(Vec<Function>, Vec<Ident>), Err
                     func_signatures.push(sig);
                 }
                 BoundAttrType::Signal(ref _attr_val) => {
-                    if !method.params.is_empty() || method.return_ty.is_some() {
-                        return attr.bail("parameters and return types not yet supported", method);
+                    if method.return_ty.is_some() {
+                        return attr.bail("return types are not supported", method);
                     }
+                    let sig = util::reduce_to_signature(method);
 
-                    signal_idents.push(method.name.clone());
+                    signal_signatures.push(sig.clone());
                     removed_indexes.push(index);
                 }
             }
@@ -164,7 +190,7 @@ fn process_godot_fns(decl: &mut Impl) -> Result<(Vec<Function>, Vec<Ident>), Err
         decl.body_items.remove(index);
     }
 
-    Ok((func_signatures, signal_idents))
+    Ok((func_signatures, signal_signatures))
 }
 
 fn extract_attributes(method: &Function) -> Result<Option<BoundAttr>, Error> {

itest/rust/src/lib.rs

@@ -31,6 +31,7 @@ mod projection_test;
 mod quaternion_test;
 mod rect2i_test;
 mod rid_test;
+mod signal_test;
 mod singleton_test;
 mod string;
 mod transform2d_test;

itest/rust/src/signal_test.rs

@@ -0,0 +1,97 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+use std::cell::Cell;
+
+use godot::bind::{godot_api, GodotClass};
+use godot::builtin::{GodotString, Variant};
+
+use godot::engine::Object;
+use godot::obj::{Base, Gd, Share};
+use godot::sys;
+
+use crate::itest;
+
+#[derive(GodotClass)]
+#[class(init, base=Object)]
+struct Emitter {
+    #[base]
+    base: Base<Object>,
+}
+
+#[godot_api]
+impl Emitter {
+    #[signal]
+    fn signal_0_arg();
+    #[signal]
+    fn signal_1_arg(arg1: i64);
+    #[signal]
+    fn signal_2_arg(arg1: Gd<Object>, arg2: GodotString);
+}
+
+#[derive(GodotClass)]
+#[class(init, base=Object)]
+struct Receiver {
+    used: [Cell<bool>; 3],
+    #[base]
+    base: Base<Object>,
+}
+
+#[godot_api]
+impl Receiver {
+    #[func]
+    fn receive_0_arg(&self) {
+        self.used[0].set(true);
+    }
+    #[func]
+    fn receive_1_arg(&self, arg1: i64) {
+        self.used[1].set(true);
+        assert_eq!(arg1, 987);
+    }
+    #[func]
+    fn receive_2_arg(&self, arg1: Gd<Object>, arg2: GodotString) {
+        assert_eq!(self.base.share(), arg1);
+        assert_eq!(SIGNAL_ARG_STRING, arg2.to_string());
+
+        self.used[2].set(true);
+    }
+}
+
+const SIGNAL_ARG_STRING: &str = "Signal string arg";
+
+#[itest]
+/// Test that godot can call a method that is connect with a signal
+fn signals() {
+    let mut emitter = Gd::<Emitter>::new_default();
+    let receiver = Gd::<Receiver>::new_default();
+
+    let args = [
+        vec![],
+        vec![Variant::from(987)],
+        vec![
+            Variant::from(receiver.share()),
+            Variant::from(SIGNAL_ARG_STRING),
+        ],
+    ];
+
+    for (i, arg) in args.iter().enumerate() {
+        let signal_name = format!("signal_{i}_arg");
+        let receiver_name = format!("receive_{i}_arg");
+
+        emitter.bind_mut().connect(
+            signal_name.clone().into(),
+            receiver.callable(receiver_name),
+            0,
+        );
+
+        emitter.bind_mut().emit_signal(signal_name.into(), arg);
+
+        assert!(receiver.bind().used[i].get());
+    }
+
+    receiver.free();
+    emitter.free();
+}