Add cxx_qt::init_crate! and init_qml_module!

crates/cxx-qt-macro/Cargo.toml

@@ -22,6 +22,7 @@ proc-macro = true
 cxx-qt-gen.workspace = true
 proc-macro2.workspace = true
 syn.workspace = true
+quote.workspace = true
 
 [dev-dependencies]
 cxx.workspace = true

crates/cxx-qt-macro/src/lib.rs

@@ -117,6 +117,36 @@ pub fn qobject(_args: TokenStream, _input: TokenStream) -> TokenStream {
     unreachable!("qobject should not be used as a macro by itself. Instead it should be used within a cxx_qt::bridge definition")
 }
 
+/// Force a crate to be initialized
+#[proc_macro]
+pub fn init_crate(args: TokenStream) -> TokenStream {
+    let crate_name = syn::parse_macro_input!(args as syn::Ident);
+    let function_name = quote::format_ident!("cxx_qt_init_crate_{crate_name}");
+    quote::quote! {
+        extern "C" {
+            fn #function_name() -> bool;
+        }
+        unsafe { #function_name(); }
+    }
+    .into()
+}
+
+/// Force a QML module with the given URI to be initialized
+#[proc_macro]
+pub fn init_qml_module(args: TokenStream) -> TokenStream {
+    let module_uri = syn::parse_macro_input!(args as syn::LitStr);
+    let module_name = syn::Ident::new(&module_uri.value().replace('.', "_"), module_uri.span());
+
+    let function_name = quote::format_ident!("cxx_qt_init_qml_module_{module_name}");
+    quote::quote! {
+        extern "C" {
+            fn #function_name() -> bool;
+        }
+        unsafe { #function_name(); }
+    }
+    .into()
+}
+
 // Take the module and C++ namespace and generate the rust code
 fn extract_and_generate(module: ItemMod) -> TokenStream {
     Parser::from(module)

crates/cxx-qt/src/lib.rs

@@ -18,6 +18,8 @@ pub mod signalhandler;
 mod threading;
 
 pub use cxx_qt_macro::bridge;
+pub use cxx_qt_macro::init_crate;
+pub use cxx_qt_macro::init_qml_module;
 pub use cxx_qt_macro::qobject;
 
 pub use connection::{ConnectionType, QMetaObjectConnection};

examples/meta_project/rust/main/src/main.rs

@@ -4,25 +4,12 @@
 // SPDX-License-Identifier: MIT OR Apache-2.0
 
 extern crate qml_meta_project;
-// mod main_object;
-// extern crate sub1;
-// extern crate sub2;
 
 use cxx_qt_lib::{QGuiApplication, QQmlApplicationEngine, QUrl};
 
 fn main() {
-    // extern "C" {
-    //     fn cxx_qt_init_crate_qml_meta_project() -> bool;
-    // }
-
-    // extern "C" {
-    //     fn cxx_qt_init_qml_module_com_kdab_cxx_qt_demo() -> bool;
-    // }
-
-    // unsafe {
-    //     cxx_qt_init_crate_qml_meta_project();
-    //     cxx_qt_init_qml_module_com_kdab_cxx_qt_demo();
-    // }
+    cxx_qt::init_crate!(qml_meta_project);
+    cxx_qt::init_qml_module!("com.kdab.cxx_qt.demo");
 
     // Create the application and engine
     let mut app = QGuiApplication::new();
@@ -48,3 +35,14 @@ fn main() {
         app.exec();
     }
 }
+
+#[cfg(test)]
+mod tests {
+    // In the test cfg there needs to be at least one test that calls the crate initialization.
+    // Otherwise linking will fail!
+    #[test]
+    fn init_dependencies() {
+        cxx_qt::init_crate!(qml_meta_project);
+        cxx_qt::init_qml_module!("com.kdab.cxx_qt.demo");
+    }
+}