Replace manual upcast impl for C++ type with generation

Author: BenFordTytherington

crates/cxx-qt-gen/src/generator/rust/externcxxqt.rs

@@ -31,7 +31,6 @@ impl GeneratedRustFragment {
             .iter()
             .map(|ty| -> Result<GeneratedRustFragment> {
                 let mut generated = vec![];
-
                 let qobject_names = QObjectNames::from_extern_qobject(ty, type_names)?;
 
                 generated.push(GeneratedRustFragment::generate_casting_impl(

crates/cxx-qt-lib/src/gui/qguiapplication.rs

@@ -6,9 +6,8 @@
 
 use crate::{QByteArray, QFont, QString, QStringList, QVector};
 use core::pin::Pin;
-use cxx_qt::Upcast;
 
-#[cxx::bridge]
+#[cxx_qt::bridge]
 mod ffi {
     unsafe extern "C++" {
         include!("cxx-qt-lib/qbytearray.h");
@@ -22,25 +21,15 @@ mod ffi {
         include!("cxx-qt-lib/qfont.h");
         type QFont = crate::QFont;
 
-        include!("cxx-qt-lib/qguiapplication.h");
-        type QGuiApplication;
-
         include!("cxx-qt-lib/qcoreapplication.h");
         type QCoreApplication;
+    }
 
-        include!("cxx-qt/casting.h");
-
-        #[doc(hidden)]
-        #[rust_name = "upcast_qguiapplication"]
-        #[cxx_name = "upcastPtr"]
-        #[namespace = "rust::cxxqt1"]
-        unsafe fn upcast(thiz: *const QGuiApplication) -> *const QCoreApplication;
-
-        #[doc(hidden)]
-        #[rust_name = "downcast_qcoreapplication"]
-        #[cxx_name = "downcastPtr"]
-        #[namespace = "rust::cxxqt1"]
-        unsafe fn downcast(base: *const QCoreApplication) -> *const QGuiApplication;
+    unsafe extern "C++Qt" {
+        include!("cxx-qt-lib/qguiapplication.h");
+        #[qobject]
+        #[base = QCoreApplication]
+        type QGuiApplication;
     }
 
     #[namespace = "rust::cxxqtlib1"]
@@ -116,19 +105,7 @@ mod ffi {
     impl UniquePtr<QGuiApplication> {}
 }
 
-pub use ffi::{
-    downcast_qcoreapplication, upcast_qguiapplication, QCoreApplication, QGuiApplication,
-};
-
-impl Upcast<QCoreApplication> for QGuiApplication {
-    unsafe fn upcast_ptr(this: *const Self) -> *const QCoreApplication {
-        upcast_qguiapplication(this)
-    }
-
-    unsafe fn from_base_ptr(base: *const QCoreApplication) -> *const Self {
-        downcast_qcoreapplication(base)
-    }
-}
+pub use ffi::QGuiApplication;
 
 impl QGuiApplication {
     /// Prepends path to the beginning of the library path list,

crates/cxx-qt-lib/src/qml/qqmlapplicationengine.rs

@@ -3,7 +3,7 @@
 //
 // SPDX-License-Identifier: MIT OR Apache-2.0
 
-#[cxx::bridge]
+#[cxx_qt::bridge]
 mod ffi {
     unsafe extern "C++" {
         include!("cxx-qt-lib/qstring.h");
@@ -13,23 +13,6 @@ mod ffi {
         include!("cxx-qt-lib/qurl.h");
         type QUrl = crate::QUrl;
 
-        include!("cxx-qt-lib/qqmlapplicationengine.h");
-        type QQmlApplicationEngine;
-
-        include!("cxx-qt/casting.h");
-
-        #[doc(hidden)]
-        #[rust_name = "upcast_qqmlapplication_engine"]
-        #[cxx_name = "upcastPtr"]
-        #[namespace = "rust::cxxqt1"]
-        unsafe fn upcast(thiz: *const QQmlApplicationEngine) -> *const QQmlEngine;
-
-        #[doc(hidden)]
-        #[rust_name = "downcast_qqml_engine"]
-        #[cxx_name = "downcastPtr"]
-        #[namespace = "rust::cxxqt1"]
-        unsafe fn downcast(base: *const QQmlEngine) -> *const QQmlApplicationEngine;
-
         /// Adds path as a directory where the engine searches for installed modules in a URL-based directory structure.
         #[rust_name = "add_import_path"]
         fn addImportPath(self: Pin<&mut QQmlApplicationEngine>, path: &QString);
@@ -75,6 +58,13 @@ mod ffi {
         fn setOfflineStoragePath(self: Pin<&mut QQmlApplicationEngine>, dir: &QString);
     }
 
+    unsafe extern "C++Qt" {
+        include!("cxx-qt-lib/qqmlapplicationengine.h");
+        #[qobject]
+        #[base = QQmlEngine]
+        type QQmlApplicationEngine;
+    }
+
     unsafe extern "C++" {
         include!("cxx-qt-lib/qqmlengine.h");
         type QQmlEngine = crate::QQmlEngine;
@@ -94,21 +84,8 @@ mod ffi {
     impl UniquePtr<QQmlApplicationEngine> {}
 }
 
-use crate::QQmlEngine;
-use cxx_qt::Upcast;
-
 pub use ffi::QQmlApplicationEngine;
 
-impl Upcast<QQmlEngine> for QQmlApplicationEngine {
-    unsafe fn upcast_ptr(this: *const Self) -> *const QQmlEngine {
-        ffi::upcast_qqmlapplication_engine(this)
-    }
-
-    unsafe fn from_base_ptr(base: *const QQmlEngine) -> *const Self {
-        ffi::downcast_qqml_engine(base)
-    }
-}
-
 impl QQmlApplicationEngine {
     /// Create a new QQmlApplicationEngine
     pub fn new() -> cxx::UniquePtr<Self> {