Merge pull request #991 from godot-rust/feature/compat-virtual-methods

Godot FFI: postinit create, compat virtual methods, icon paths

Author: Bromeon

godot-codegen/src/context.rs

@@ -69,14 +69,14 @@ impl<'a> Context<'a> {
             // Populate derived-to-base relations
             if let Some(base) = class.inherits.as_ref() {
                 let base_name = TyName::from_godot(base);
-                println!(
-                    "* Add engine class {} <- inherits {}",
-                    class_name.description(),
-                    base_name.description()
-                );
+                // println!(
+                //     "* Add engine class {} <- inherits {}",
+                //     class_name.description(),
+                //     base_name.description()
+                // );
                 ctx.inheritance_tree.insert(class_name.clone(), base_name);
             } else {
-                println!("* Add engine class {}", class_name.description());
+                // println!("* Add engine class {}", class_name.description());
             }
 
             // Populate notification constants (first, only for classes that declare them themselves).
@@ -347,6 +347,11 @@ impl InheritanceTree {
         assert!(existing.is_none(), "Duplicate inheritance insert");
     }
 
+    #[allow(unused)] // Currently 4.4 gated, for virtual method hashes.
+    pub fn direct_base(&self, derived_name: &TyName) -> Option<TyName> {
+        self.derived_to_base.get(derived_name).cloned()
+    }
+
     /// Returns all base classes, without the class itself, in order from nearest to furthest (object).
     pub fn collect_all_bases(&self, derived_name: &TyName) -> Vec<TyName> {
         let mut upgoer = derived_name;

godot-codegen/src/generator/functions_common.rs

@@ -8,7 +8,7 @@
 use crate::generator::default_parameters;
 use crate::models::domain::{ArgPassing, FnParam, FnQualifier, Function, RustTy};
 use crate::special_cases;
-use crate::util::{lifetime, safe_ident};
+use crate::util::lifetime;
 use proc_macro2::{Ident, TokenStream};
 use quote::{format_ident, quote};
 
@@ -155,11 +155,11 @@ pub fn make_function_definition(
         make_params_exprs(sig.params().iter(), passing)
     };
 
-    let rust_function_name_str = sig.name();
+    let rust_function_name = sig.name_ident();
 
     let (primary_fn_name, default_fn_code, default_structs_code);
     if has_default_params {
-        primary_fn_name = format_ident!("{}_full", safe_ident(rust_function_name_str));
+        primary_fn_name = format_ident!("{}_full", rust_function_name);
 
         (default_fn_code, default_structs_code) =
             default_parameters::make_function_definition_with_defaults(
@@ -169,7 +169,7 @@ pub fn make_function_definition(
                 cfg_attributes,
             );
     } else {
-        primary_fn_name = safe_ident(rust_function_name_str);
+        primary_fn_name = rust_function_name.clone();
         default_fn_code = TokenStream::new();
         default_structs_code = TokenStream::new();
     };
@@ -227,7 +227,7 @@ pub fn make_function_definition(
             }
         } else {
             let try_return_decl = &sig.return_value().call_result_decl();
-            let try_fn_name = format_ident!("try_{}", rust_function_name_str);
+            let try_fn_name = format_ident!("try_{}", rust_function_name);
 
             // Note: all varargs functions are non-static, which is why there are some shortcuts in try_*() argument forwarding.
             // This can be made more complex if ever necessary.

godot-codegen/src/generator/method_tables.rs

@@ -159,8 +159,8 @@ pub fn make_utility_function_table(api: &ExtensionApi) -> TokenStream {
     };
 
     for function in api.utility_functions.iter() {
+        let field = generator::utility_functions::make_utility_function_ptr_name(function);
         let fn_name_str = function.name();
-        let field = generator::utility_functions::make_utility_function_ptr_name(fn_name_str);
         let hash = function.hash();
 
         table.method_decls.push(quote! {
@@ -191,7 +191,7 @@ struct NamedMethodTable {
     method_count: usize,
 }
 
-#[allow(dead_code)] // for lazy feature
+#[allow(dead_code)] // Individual fields would need to be cfg'ed with: feature = "codegen-lazy-fptrs".
 struct IndexedMethodTable {
     table_name: Ident,
     imports: TokenStream,

godot-codegen/src/generator/mod.rs

@@ -28,6 +28,9 @@ pub mod notifications;
 pub mod utility_functions;
 pub mod virtual_traits;
 
+#[cfg(since_api = "4.4")]
+pub mod virtual_hashes;
+
 // ----------------------------------------------------------------------------------------------------------------------------------------------
 
 // Some file generation functions are in specific modules:
@@ -44,6 +47,8 @@ pub fn generate_sys_module_file(sys_gen_path: &Path, submit_fn: &mut SubmitFn) {
         pub mod table_scene_classes;
         pub mod table_editor_classes;
         pub mod table_utilities;
+        #[cfg(since_api = "4.4")]
+        pub mod virtual_hashes;
 
         pub mod central;
         pub mod gdextension_interface;
@@ -77,6 +82,15 @@ pub fn generate_sys_classes_file(
         submit_fn(sys_gen_path.join(filename), code);
         watch.record(format!("generate_classes_{}_file", api_level.lower()));
     }
+
+    // From 4.4 onward, generate table that maps all virtual methods to their known hashes.
+    // This allows Godot to fall back to an older compatibility function if one is not supported.
+    #[cfg(since_api = "4.4")]
+    {
+        let code = virtual_hashes::make_virtual_hashes_file(api, ctx);
+        submit_fn(sys_gen_path.join("virtual_hashes.rs"), code);
+        watch.record("generate_virtual_hashes_file");
+    }
 }
 
 pub fn generate_sys_utilities_file(

godot-codegen/src/generator/utility_functions.rs

@@ -35,16 +35,16 @@ pub(crate) fn generate_utilities_file(
     submit_fn(gen_path.join("utilities.rs"), tokens);
 }
 
-pub(crate) fn make_utility_function_ptr_name(godot_function_name: &str) -> Ident {
-    util::safe_ident(godot_function_name)
+pub(crate) fn make_utility_function_ptr_name(function: &dyn Function) -> Ident {
+    function.name_ident()
 }
 
 pub(crate) fn make_utility_function_definition(function: &UtilityFunction) -> TokenStream {
+    let function_ident = make_utility_function_ptr_name(function);
     let function_name_str = function.name();
-    let fn_ptr = make_utility_function_ptr_name(function_name_str);
 
     let ptrcall_invocation = quote! {
-        let utility_fn = sys::utility_function_table().#fn_ptr;
+        let utility_fn = sys::utility_function_table().#function_ident;
 
         <CallSig as PtrcallSignatureTuple>::out_utility_ptrcall(
             utility_fn,
@@ -54,7 +54,7 @@ pub(crate) fn make_utility_function_definition(function: &UtilityFunction) -> To
     };
 
     let varcall_invocation = quote! {
-        let utility_fn = sys::utility_function_table().#fn_ptr;
+        let utility_fn = sys::utility_function_table().#function_ident;
 
         <CallSig as VarcallSignatureTuple>::out_utility_ptrcall_varargs(
             utility_fn,

godot-codegen/src/generator/virtual_hashes.rs

@@ -0,0 +1,61 @@
+/*
+ * Copyright (c) godot-rust; Bromeon and contributors.
+ * 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 crate::context::Context;
+use crate::models::domain::{Class, ClassLike, ExtensionApi, FnDirection, Function};
+use proc_macro2::TokenStream;
+use quote::quote;
+
+pub fn make_virtual_hashes_file(api: &ExtensionApi, ctx: &mut Context) -> TokenStream {
+    make_virtual_hashes_for_all_classes(&api.classes, ctx)
+}
+
+fn make_virtual_hashes_for_all_classes(all_classes: &[Class], ctx: &mut Context) -> TokenStream {
+    let modules = all_classes
+        .iter()
+        .map(|class| make_virtual_hashes_for_class(class, ctx));
+
+    quote! {
+        #![allow(non_snake_case, non_upper_case_globals, unused_imports)]
+
+        #( #modules )*
+    }
+}
+
+fn make_virtual_hashes_for_class(class: &Class, ctx: &mut Context) -> TokenStream {
+    let class_name = class.name();
+
+    // Import all base class hashes via `use` statements.
+    let use_base_class = if let Some(base_class) = ctx.inheritance_tree().direct_base(class_name) {
+        quote! {
+            pub use super::#base_class::*;
+        }
+    } else {
+        TokenStream::new()
+    };
+
+    let constants = class.methods.iter().filter_map(|method| {
+        let FnDirection::Virtual { hash } = method.direction() else {
+            return None;
+        };
+
+        let method_name = method.name_ident();
+        let constant = quote! {
+            pub const #method_name: u32 = #hash;
+        };
+
+        Some(constant)
+    });
+
+    // Even if there are no virtual methods, we need to generate the module, to enable base class imports via `use`.
+    quote! {
+        pub mod #class_name {
+            #use_base_class
+            #( #constants )*
+        }
+    }
+}

godot-codegen/src/models/domain.rs

@@ -291,9 +291,14 @@ pub trait Function: fmt::Display {
     fn surrounding_class(&self) -> Option<&TyName>;
 
     // Default:
+    /// Rust name as string slice.
     fn name(&self) -> &str {
         &self.common().name
     }
+    /// Rust name as `Ident`. Might be cached in future.
+    fn name_ident(&self) -> Ident {
+        safe_ident(self.name())
+    }
     fn godot_name(&self) -> &str {
         &self.common().godot_name
     }
@@ -310,7 +315,7 @@ pub trait Function: fmt::Display {
         self.common().is_private
     }
     fn is_virtual(&self) -> bool {
-        matches!(self.direction(), FnDirection::Virtual)
+        matches!(self.direction(), FnDirection::Virtual { .. })
     }
     fn direction(&self) -> FnDirection {
         self.common().direction
@@ -330,7 +335,7 @@ pub struct UtilityFunction {
 impl UtilityFunction {
     pub fn hash(&self) -> i64 {
         match self.direction() {
-            FnDirection::Virtual => unreachable!("utility function cannot be virtual"),
+            FnDirection::Virtual { .. } => unreachable!("utility function cannot be virtual"),
             FnDirection::Outbound { hash } => hash,
         }
     }
@@ -370,7 +375,7 @@ pub struct BuiltinMethod {
 impl BuiltinMethod {
     pub fn hash(&self) -> i64 {
         match self.direction() {
-            FnDirection::Virtual => unreachable!("builtin method cannot be virtual"),
+            FnDirection::Virtual { .. } => unreachable!("builtin method cannot be virtual"),
             FnDirection::Outbound { hash } => hash,
         }
     }
@@ -441,7 +446,11 @@ impl fmt::Display for ClassMethod {
 #[derive(Copy, Clone, Debug)]
 pub enum FnDirection {
     /// Godot -> Rust.
-    Virtual,
+    Virtual {
+        // Since PR https://github.com/godotengine/godot/pull/100674, virtual methods have a compat hash, too.
+        #[cfg(since_api = "4.4")]
+        hash: u32,
+    },
 
     /// Rust -> Godot.
     Outbound { hash: i64 },

godot-codegen/src/models/domain_mapping.rs

@@ -419,20 +419,34 @@ impl ClassMethod {
         ctx: &mut Context,
     ) -> Option<Self> {
         assert!(method.is_virtual);
-        assert!(
-            method.hash.is_none(),
-            "hash present for virtual class method"
-        );
+
+        // Hash for virtual methods is available from Godot 4.4, see https://github.com/godotengine/godot/pull/100674.
+        let direction = FnDirection::Virtual {
+            #[cfg(since_api = "4.4")]
+            hash: {
+                // TODO(v0.3,virtual-compat): re-enable this in favor of 0 fallback.
+                /*let hash_i64 = method.hash.unwrap_or_else(|| {
+                    panic!(
+                        "virtual class methods must have a hash since Godot 4.4; missing: {}.{}",
+                        class_name.godot_ty, method.name
+                    )
+                });*/
+                // Temporarily use hash 0 until upstream PR is merged.
+                let hash_i64 = method.hash.unwrap_or(0);
+
+                // TODO see if we can use u32 everywhere.
+                hash_i64.try_into().unwrap_or_else(|_| {
+                    panic!(
+                        "virtual method {}.{} has hash {} that is out of range for u32",
+                        class_name.godot_ty, method.name, hash_i64
+                    )
+                })
+            },
+        };
 
         let rust_method_name = Self::make_virtual_method_name(class_name, &method.name);
 
-        Self::from_json_inner(
-            method,
-            rust_method_name,
-            class_name,
-            FnDirection::Virtual,
-            ctx,
-        )
+        Self::from_json_inner(method, rust_method_name, class_name, direction, ctx)
     }
 
     fn from_json_inner(

godot-core/src/obj/bounds.rs

@@ -49,7 +49,6 @@
 
 use crate::obj::cap::GodotDefault;
 use crate::obj::{Bounds, Gd, GodotClass, RawGd};
-use crate::registry::callbacks;
 use crate::storage::{InstanceCache, Storage};
 use crate::{out, sys};
 use private::Sealed;
@@ -418,10 +417,7 @@ impl Declarer for DeclUser {
     where
         T: GodotDefault + Bounds<Declarer = Self>,
     {
-        unsafe {
-            let object_ptr = callbacks::create::<T>(std::ptr::null_mut());
-            Gd::from_obj_sys(object_ptr)
-        }
+        Gd::default_instance()
     }
 }
 

godot-core/src/obj/gd.rs

@@ -454,7 +454,12 @@ impl<T: GodotClass> Gd<T> {
         T: cap::GodotDefault,
     {
         unsafe {
+            // Default value (and compat one) for `p_notify_postinitialize` is true in Godot.
+            #[cfg(since_api = "4.4")]
+            let object_ptr = callbacks::create::<T>(std::ptr::null_mut(), sys::conv::SYS_TRUE);
+            #[cfg(before_api = "4.4")]
             let object_ptr = callbacks::create::<T>(std::ptr::null_mut());
+
             Gd::from_obj_sys(object_ptr)
         }
     }

godot-core/src/obj/traits.rs

@@ -162,7 +162,10 @@ pub trait UserClass: Bounds<Declarer = bounds::DeclUser> {
     fn __before_ready(&mut self);
 
     #[doc(hidden)]
-    fn __default_virtual_call(_method_name: &str) -> sys::GDExtensionClassCallVirtual {
+    fn __default_virtual_call(
+        _method_name: &str,
+        #[cfg(since_api = "4.4")] _hash: u32,
+    ) -> sys::GDExtensionClassCallVirtual {
         None
     }
 }
@@ -586,6 +589,9 @@ pub mod cap {
     /// Auto-implemented for `#[godot_api] impl XyVirtual for MyClass` blocks
     pub trait ImplementsGodotVirtual: GodotClass {
         #[doc(hidden)]
-        fn __virtual_call(_name: &str) -> sys::GDExtensionClassCallVirtual;
+        fn __virtual_call(
+            name: &str,
+            #[cfg(since_api = "4.4")] hash: u32,
+        ) -> sys::GDExtensionClassCallVirtual;
     }
 }