Add downcasting

KDAB · Feb 7, 2025 · f6c1f8c · f6c1f8c
1 parent 9f08e5a
commit f6c1f8c
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Showing 11 changed files with 181 additions and 30 deletions.
diff --git a/crates/cxx-qt-gen/src/generator/rust/qobject.rs b/crates/cxx-qt-gen/src/generator/rust/qobject.rs
@@ -16,7 +16,7 @@ use crate::{
     naming::TypeNames,
 };
 use quote::{format_ident, quote};
-use syn::{parse_quote, Attribute, Ident, Result};
+use syn::{parse_quote, Attribute, Result};
 
 impl GeneratedRustFragment {
     // Might need to be refactored to use a StructuredQObject instead (confirm with Leon)
@@ -30,11 +30,7 @@ impl GeneratedRustFragment {
         let namespace_idents = NamespaceName::from(qobject);
 
         let mut generated = vec![
-            generate_qobject_definitions(
-                &qobject_names,
-                qobject.base_class.clone(),
-                type_names,
-            )?,
+            generate_qobject_definitions(&qobject_names, &qobject.cfgs)?,
             generate_rust_properties(
                 &qobject.properties,
                 &qobject_names,
@@ -67,18 +63,7 @@ impl GeneratedRustFragment {
             )?);
         }
 
-        generated.extend(vec![
-            constructor::generate(
-                &structured_qobject.constructors,
-                &qobject_names,
-                &namespace_idents,
-                type_names,
-                &qobject.cfgs,
-            )?,
-            cxxqttype::generate(&qobject_names, type_names, &qobject.cfgs)?,
-        ]);
         // Generate casting impl
-        let mut blocks = GeneratedRustFragment::default();
         let base = structured_qobject
             .declaration
             .base_class
@@ -88,7 +73,7 @@ impl GeneratedRustFragment {
             .cloned()
             .unwrap_or(
                 Name::new(format_ident!("QObject")).with_module(parse_quote! {::cxx_qt::qobject}),
-            ); // TODO! is this default module here causing the issues in the threading examples
+            );
 
         let base_unqualified = base.rust_unqualified();
         let base_qualified = base.rust_qualified();
@@ -98,39 +83,55 @@ impl GeneratedRustFragment {
         let (upcast_fn, upcast_fn_attrs, upcast_fn_qualified) = qobject_names
             .cxx_qt_ffi_method("upcastPtr")
             .into_cxx_parts();
-        let fragment = GeneratedRustFragment {
+        let (downcast_fn, downcast_fn_attrs, downcast_fn_qualified) = qobject_names
+            .cxx_qt_ffi_method("downcastPtr")
+            .into_cxx_parts();
+
+        generated.push(GeneratedRustFragment {
             cxx_mod_contents: vec![parse_quote! {
                 extern "C++" {
                     #[doc(hidden)]
                     #(#upcast_fn_attrs)*
                     unsafe fn #upcast_fn(thiz: *const #struct_name_unqualified) -> *const #base_unqualified;
+
+                    #[doc(hidden)]
+                    #(#downcast_fn_attrs)*
+                    unsafe fn #downcast_fn(base: *const #base_unqualified) -> *const #struct_name_unqualified;
                 }
             }],
             cxx_qt_mod_contents: vec![parse_quote! {
                 impl ::cxx_qt::Upcast<#base_qualified> for #struct_name{
                     unsafe fn upcast_ptr(this: *const Self) -> *const #base_qualified {
                         #upcast_fn_qualified(this)
                     }
+
+                    unsafe fn from_base_ptr(base: *const #base_qualified) -> *const Self {
+                        #downcast_fn_qualified(base)
+                    }
                 }
             }],
-        };
+        });
 
-        generated.push(fragment);
-        generated.push(blocks);
-
-        generated.push(constructor::generate(
-            &structured_qobject.constructors,
-            &qobject_names,
-            &namespace_idents,
-            type_names,
-        )?);
+        generated.extend(vec![
+            constructor::generate(
+                &structured_qobject.constructors,
+                &qobject_names,
+                &namespace_idents,
+                type_names,
+                &qobject.cfgs,
+            )?,
+            cxxqttype::generate(&qobject_names, type_names, &qobject.cfgs)?,
+        ]);
 
         Ok(GeneratedRustFragment::flatten(generated))
     }
 }
 
 /// Generate the C++ and Rust CXX definitions for the QObject
-fn generate_qobject_definitions(qobject_idents: &QObjectNames) -> Result<GeneratedRustFragment> {
+fn generate_qobject_definitions(
+    qobject_idents: &QObjectNames,
+    cfgs: &[Attribute],
+) -> Result<GeneratedRustFragment> {
     let cpp_class_name_rust = &qobject_idents.name.rust_unqualified();
     let cpp_class_name_cpp = &qobject_idents.name.cxx_unqualified();
 
@@ -264,6 +265,11 @@ mod tests {
                     #[cxx_name = "upcastPtr"]
                     #[namespace = "rust::cxxqt1"]
                     unsafe fn cxx_qt_ffi_MyObject_upcastPtr(thiz: *const MyObject) -> *const QObject;
+
+                    #[doc(hidden)]
+                    #[cxx_name = "downcastPtr"]
+                    #[namespace = "rust::cxxqt1"]
+                    unsafe fn cxx_qt_ffi_MyObject_downcastPtr(base: *const QObject) -> *const MyObject;
                 }
             },
         );

diff --git a/crates/cxx-qt-gen/test_outputs/cfgs.h b/crates/cxx-qt-gen/test_outputs/cfgs.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include <cstdint>
+#include <cxx-qt/casting.h>
 #include <cxx-qt/signalhandler.h>
 #include <cxx-qt/type.h>
 

diff --git a/crates/cxx-qt-gen/test_outputs/cfgs.rs b/crates/cxx-qt-gen/test_outputs/cfgs.rs
@@ -158,6 +158,20 @@ mod ffi {
             self_value: Pin<&mut QObjectEnabled>,
         );
     }
+    extern "C++" {
+        #[doc(hidden)]
+        #[cxx_name = "upcastPtr"]
+        #[namespace = "rust::cxxqt1"]
+        unsafe fn cxx_qt_ffi_QObjectEnabled_upcastPtr(
+            thiz: *const QObjectEnabled,
+        ) -> *const QObject;
+        #[doc(hidden)]
+        #[cxx_name = "downcastPtr"]
+        #[namespace = "rust::cxxqt1"]
+        unsafe fn cxx_qt_ffi_QObjectEnabled_downcastPtr(
+            base: *const QObject,
+        ) -> *const QObjectEnabled;
+    }
     extern "Rust" {
         #[cxx_name = "createRs"]
         #[namespace = "cxx_qt_QObjectEnabled"]
@@ -284,6 +298,20 @@ mod ffi {
             self_value: Pin<&mut QObjectDisabled>,
         );
     }
+    extern "C++" {
+        #[doc(hidden)]
+        #[cxx_name = "upcastPtr"]
+        #[namespace = "rust::cxxqt1"]
+        unsafe fn cxx_qt_ffi_QObjectDisabled_upcastPtr(
+            thiz: *const QObjectDisabled,
+        ) -> *const QObject;
+        #[doc(hidden)]
+        #[cxx_name = "downcastPtr"]
+        #[namespace = "rust::cxxqt1"]
+        unsafe fn cxx_qt_ffi_QObjectDisabled_downcastPtr(
+            base: *const QObject,
+        ) -> *const QObjectDisabled;
+    }
     extern "Rust" {
         #[cxx_name = "createRs"]
         #[namespace = "cxx_qt_QObjectDisabled"]
@@ -450,6 +478,11 @@ mod ffi {
             self_value: Pin<&mut QObjectExternDisabled>,
         );
     }
+    extern "C++" {
+        #[doc(hidden)]
+        #[namespace = ""]
+        type QObject = cxx_qt::qobject::QObject;
+    }
 }
 #[cfg(not(enabled))]
 impl ffi::QObjectEnabled {
@@ -599,6 +632,14 @@ cxx_qt::static_assertions::assert_eq_size!(
     cxx_qt::signalhandler::CxxQtSignalHandler<QObjectEnabledCxxQtSignalClosuresignal_enabled>,
     [usize; 2]
 );
+impl ::cxx_qt::Upcast<::cxx_qt::qobject::QObject> for ffi::QObjectEnabled {
+    unsafe fn upcast_ptr(this: *const Self) -> *const ::cxx_qt::qobject::QObject {
+        ffi::cxx_qt_ffi_QObjectEnabled_upcastPtr(this)
+    }
+    unsafe fn from_base_ptr(base: *const ::cxx_qt::qobject::QObject) -> *const Self {
+        ffi::cxx_qt_ffi_QObjectEnabled_downcastPtr(base)
+    }
+}
 #[doc(hidden)]
 #[allow(clippy::unnecessary_box_returns)]
 #[cfg(enabled)]
@@ -770,6 +811,14 @@ cxx_qt::static_assertions::assert_eq_size!(
     cxx_qt::signalhandler::CxxQtSignalHandler<QObjectDisabledCxxQtSignalClosuresignal_enabled>,
     [usize; 2]
 );
+impl ::cxx_qt::Upcast<::cxx_qt::qobject::QObject> for ffi::QObjectDisabled {
+    unsafe fn upcast_ptr(this: *const Self) -> *const ::cxx_qt::qobject::QObject {
+        ffi::cxx_qt_ffi_QObjectDisabled_upcastPtr(this)
+    }
+    unsafe fn from_base_ptr(base: *const ::cxx_qt::qobject::QObject) -> *const Self {
+        ffi::cxx_qt_ffi_QObjectDisabled_downcastPtr(base)
+    }
+}
 #[doc(hidden)]
 #[allow(clippy::unnecessary_box_returns)]
 #[cfg(not(enabled))]

diff --git a/crates/cxx-qt-gen/test_outputs/inheritance.rs b/crates/cxx-qt-gen/test_outputs/inheritance.rs
@@ -67,6 +67,12 @@ mod inheritance {
         #[namespace = "rust::cxxqt1"]
         unsafe fn cxx_qt_ffi_MyObject_upcastPtr(thiz: *const MyObject)
             -> *const QAbstractItemModel;
+        #[doc(hidden)]
+        #[cxx_name = "downcastPtr"]
+        #[namespace = "rust::cxxqt1"]
+        unsafe fn cxx_qt_ffi_MyObject_downcastPtr(
+            base: *const QAbstractItemModel,
+        ) -> *const MyObject;
     }
     extern "Rust" {
         #[cxx_name = "createRs"]
@@ -90,6 +96,9 @@ impl ::cxx_qt::Upcast<inheritance::QAbstractItemModel> for inheritance::MyObject
     unsafe fn upcast_ptr(this: *const Self) -> *const inheritance::QAbstractItemModel {
         inheritance::cxx_qt_ffi_MyObject_upcastPtr(this)
     }
+    unsafe fn from_base_ptr(base: *const inheritance::QAbstractItemModel) -> *const Self {
+        inheritance::cxx_qt_ffi_MyObject_downcastPtr(base)
+    }
 }
 #[doc(hidden)]
 #[allow(clippy::unnecessary_box_returns)]

diff --git a/crates/cxx-qt-gen/test_outputs/invokables.rs b/crates/cxx-qt-gen/test_outputs/invokables.rs
@@ -151,6 +151,10 @@ mod ffi {
         #[cxx_name = "upcastPtr"]
         #[namespace = "rust::cxxqt1"]
         unsafe fn cxx_qt_ffi_MyObject_upcastPtr(thiz: *const MyObject) -> *const QObject;
+        #[doc(hidden)]
+        #[cxx_name = "downcastPtr"]
+        #[namespace = "rust::cxxqt1"]
+        unsafe fn cxx_qt_ffi_MyObject_downcastPtr(base: *const QObject) -> *const MyObject;
     }
     #[namespace = "cxx_qt::my_object::cxx_qt_MyObject"]
     #[cxx_name = "CxxQtConstructorArguments0"]
@@ -315,6 +319,9 @@ impl ::cxx_qt::Upcast<::cxx_qt::qobject::QObject> for ffi::MyObject {
     unsafe fn upcast_ptr(this: *const Self) -> *const ::cxx_qt::qobject::QObject {
         ffi::cxx_qt_ffi_MyObject_upcastPtr(this)
     }
+    unsafe fn from_base_ptr(base: *const ::cxx_qt::qobject::QObject) -> *const Self {
+        ffi::cxx_qt_ffi_MyObject_downcastPtr(base)
+    }
 }
 #[doc(hidden)]
 pub fn route_arguments_MyObject_0<'a>(

diff --git a/crates/cxx-qt-gen/test_outputs/passthrough_and_naming.rs b/crates/cxx-qt-gen/test_outputs/passthrough_and_naming.rs
@@ -170,6 +170,11 @@ pub mod ffi {
         #[cxx_name = "upcastPtr"]
         #[namespace = "rust::cxxqt1"]
         unsafe fn cxx_qt_ffi_MyObject_upcastPtr(thiz: *const MyObject) -> *const QStringListModel;
+        #[doc(hidden)]
+        #[cxx_name = "downcastPtr"]
+        #[namespace = "rust::cxxqt1"]
+        unsafe fn cxx_qt_ffi_MyObject_downcastPtr(base: *const QStringListModel)
+            -> *const MyObject;
     }
     extern "Rust" {
         #[cxx_name = "createRs"]
@@ -292,6 +297,10 @@ pub mod ffi {
         #[cxx_name = "upcastPtr"]
         #[namespace = "rust::cxxqt1"]
         unsafe fn cxx_qt_ffi_SecondObject_upcastPtr(thiz: *const SecondObject) -> *const QObject;
+        #[doc(hidden)]
+        #[cxx_name = "downcastPtr"]
+        #[namespace = "rust::cxxqt1"]
+        unsafe fn cxx_qt_ffi_SecondObject_downcastPtr(base: *const QObject) -> *const SecondObject;
     }
     extern "Rust" {
         #[cxx_name = "createRs"]
@@ -334,6 +343,10 @@ pub mod ffi {
         #[cxx_name = "upcastPtr"]
         #[namespace = "rust::cxxqt1"]
         unsafe fn cxx_qt_ffi_MyCxxName_upcastPtr(thiz: *const MyRustName) -> *const QObject;
+        #[doc(hidden)]
+        #[cxx_name = "downcastPtr"]
+        #[namespace = "rust::cxxqt1"]
+        unsafe fn cxx_qt_ffi_MyCxxName_downcastPtr(base: *const QObject) -> *const MyRustName;
     }
     extern "Rust" {
         #[cxx_name = "createRs"]
@@ -613,6 +626,9 @@ impl ::cxx_qt::Upcast<ffi::QStringListModel> for ffi::MyObject {
     unsafe fn upcast_ptr(this: *const Self) -> *const ffi::QStringListModel {
         ffi::cxx_qt_ffi_MyObject_upcastPtr(this)
     }
+    unsafe fn from_base_ptr(base: *const ffi::QStringListModel) -> *const Self {
+        ffi::cxx_qt_ffi_MyObject_downcastPtr(base)
+    }
 }
 #[doc(hidden)]
 #[allow(clippy::unnecessary_box_returns)]
@@ -784,6 +800,9 @@ impl ::cxx_qt::Upcast<::cxx_qt::qobject::QObject> for ffi::SecondObject {
     unsafe fn upcast_ptr(this: *const Self) -> *const ::cxx_qt::qobject::QObject {
         ffi::cxx_qt_ffi_SecondObject_upcastPtr(this)
     }
+    unsafe fn from_base_ptr(base: *const ::cxx_qt::qobject::QObject) -> *const Self {
+        ffi::cxx_qt_ffi_SecondObject_downcastPtr(base)
+    }
 }
 #[doc(hidden)]
 #[allow(clippy::unnecessary_box_returns)]
@@ -809,6 +828,9 @@ impl ::cxx_qt::Upcast<::cxx_qt::qobject::QObject> for ffi::MyRustName {
     unsafe fn upcast_ptr(this: *const Self) -> *const ::cxx_qt::qobject::QObject {
         ffi::cxx_qt_ffi_MyCxxName_upcastPtr(this)
     }
+    unsafe fn from_base_ptr(base: *const ::cxx_qt::qobject::QObject) -> *const Self {
+        ffi::cxx_qt_ffi_MyCxxName_downcastPtr(base)
+    }
 }
 #[doc(hidden)]
 #[allow(clippy::unnecessary_box_returns)]

diff --git a/crates/cxx-qt-gen/test_outputs/properties.rs b/crates/cxx-qt-gen/test_outputs/properties.rs
@@ -394,6 +394,10 @@ mod ffi {
         #[cxx_name = "upcastPtr"]
         #[namespace = "rust::cxxqt1"]
         unsafe fn cxx_qt_ffi_MyObject_upcastPtr(thiz: *const MyObject) -> *const QObject;
+        #[doc(hidden)]
+        #[cxx_name = "downcastPtr"]
+        #[namespace = "rust::cxxqt1"]
+        unsafe fn cxx_qt_ffi_MyObject_downcastPtr(base: *const QObject) -> *const MyObject;
     }
     extern "Rust" {
         #[cxx_name = "createRs"]
@@ -1052,6 +1056,9 @@ impl ::cxx_qt::Upcast<::cxx_qt::qobject::QObject> for ffi::MyObject {
     unsafe fn upcast_ptr(this: *const Self) -> *const ::cxx_qt::qobject::QObject {
         ffi::cxx_qt_ffi_MyObject_upcastPtr(this)
     }
+    unsafe fn from_base_ptr(base: *const ::cxx_qt::qobject::QObject) -> *const Self {
+        ffi::cxx_qt_ffi_MyObject_downcastPtr(base)
+    }
 }
 #[doc(hidden)]
 #[allow(clippy::unnecessary_box_returns)]

diff --git a/crates/cxx-qt-gen/test_outputs/qenum.rs b/crates/cxx-qt-gen/test_outputs/qenum.rs
@@ -95,6 +95,10 @@ mod ffi {
         #[cxx_name = "upcastPtr"]
         #[namespace = "rust::cxxqt1"]
         unsafe fn cxx_qt_ffi_MyObject_upcastPtr(thiz: *const MyObject) -> *const QObject;
+        #[doc(hidden)]
+        #[cxx_name = "downcastPtr"]
+        #[namespace = "rust::cxxqt1"]
+        unsafe fn cxx_qt_ffi_MyObject_downcastPtr(base: *const QObject) -> *const MyObject;
     }
     extern "Rust" {
         #[cxx_name = "createRs"]
@@ -135,6 +139,10 @@ mod ffi {
         #[cxx_name = "upcastPtr"]
         #[namespace = "rust::cxxqt1"]
         unsafe fn cxx_qt_ffi_CxxName_upcastPtr(thiz: *const MyRenamedObject) -> *const QObject;
+        #[doc(hidden)]
+        #[cxx_name = "downcastPtr"]
+        #[namespace = "rust::cxxqt1"]
+        unsafe fn cxx_qt_ffi_CxxName_downcastPtr(base: *const QObject) -> *const MyRenamedObject;
     }
     extern "Rust" {
         #[cxx_name = "createRs"]
@@ -165,6 +173,9 @@ impl ::cxx_qt::Upcast<::cxx_qt::qobject::QObject> for ffi::MyObject {
     unsafe fn upcast_ptr(this: *const Self) -> *const ::cxx_qt::qobject::QObject {
         ffi::cxx_qt_ffi_MyObject_upcastPtr(this)
     }
+    unsafe fn from_base_ptr(base: *const ::cxx_qt::qobject::QObject) -> *const Self {
+        ffi::cxx_qt_ffi_MyObject_downcastPtr(base)
+    }
 }
 #[doc(hidden)]
 #[allow(clippy::unnecessary_box_returns)]
@@ -190,6 +201,9 @@ impl ::cxx_qt::Upcast<::cxx_qt::qobject::QObject> for ffi::MyRenamedObject {
     unsafe fn upcast_ptr(this: *const Self) -> *const ::cxx_qt::qobject::QObject {
         ffi::cxx_qt_ffi_CxxName_upcastPtr(this)
     }
+    unsafe fn from_base_ptr(base: *const ::cxx_qt::qobject::QObject) -> *const Self {
+        ffi::cxx_qt_ffi_CxxName_downcastPtr(base)
+    }
 }
 #[doc(hidden)]
 #[allow(clippy::unnecessary_box_returns)]