Add explicit path support to the interface macro (#2976)

crates/libs/interface/src/lib.rs

@@ -341,41 +341,40 @@ impl Interface {
     }
 
     fn parent_vtable(&self) -> Option<proc_macro2::TokenStream> {
-        if let Some(i) = self.parent_ident() {
-            let i = quote::format_ident!("{}_Vtbl", i);
-            Some(quote!(#i))
+        if let Some((ident, path)) = self.parent_path().split_last() {
+            let ident = quote::format_ident!("{}_Vtbl", ident);
+            Some(quote! { #(#path::)* #ident })
         } else {
             None
         }
     }
 
     fn parent_is_iunknown(&self) -> bool {
-        if let Some(ident) = self.parent_ident() {
+        if let Some(ident) = self.parent_path().last() {
             ident == "IUnknown"
         } else {
             false
         }
     }
 
-    fn parent_ident(&self) -> Option<&syn::Ident> {
+    fn parent_path(&self) -> Vec<syn::Ident> {
         if let Some(parent) = &self.parent {
-            Some(&parent.segments.last().as_ref().expect("segements should never be empty").ident)
+            parent.segments.iter().map(|segment| segment.ident.clone()).collect()
         } else {
-            None
+            vec![]
         }
     }
 
     /// Gets the parent trait constrait which is nothing if the parent is IUnknown
     fn parent_trait_constraint(&self) -> proc_macro2::TokenStream {
-        if let Some(i) = self.parent_ident() {
-            if i == "IUnknown" {
-                return quote!();
+        if let Some((ident, path)) = self.parent_path().split_last() {
+            if ident != "IUnknown" {
+                let ident = quote::format_ident!("{}_Impl", ident);
+                return quote! { #(#path::)* #ident };
             }
-            let i = quote::format_ident!("{}_Impl", i);
-            quote!(#i)
-        } else {
-            quote!()
         }
+
+        quote! {}
     }
 }
 

crates/tests/interface/tests/no_use.rs

@@ -0,0 +1,39 @@
+#![allow(non_snake_case)]
+
+// This is a variant of the interface_core/no_use.rs test for use with more complex paths provided by the windows crate.
+
+#[windows::core::interface("BD1AE5E0-A6AE-11CE-BD37-504200C10000")]
+unsafe trait ITestPersistMemory: windows::Win32::System::Com::IPersist {
+    unsafe fn IsDirty(&self) -> windows::core::HRESULT;
+}
+
+#[windows::core::implement(ITestPersistMemory, windows::Win32::System::Com::IPersist)]
+struct Test;
+
+impl windows::Win32::System::Com::IPersist_Impl for Test {
+    fn GetClassID(&self) -> windows::core::Result<windows::core::GUID> {
+        Ok("CEE1D356-0860-4262-90D4-C77423F0E352".into())
+    }
+}
+
+impl ITestPersistMemory_Impl for Test {
+    unsafe fn IsDirty(&self) -> windows::core::HRESULT {
+        windows::Win32::Foundation::S_FALSE
+    }
+}
+
+#[test]
+fn test() -> windows::core::Result<()> {
+    unsafe {
+        let p: windows::Win32::System::Com::IPersist = Test.into();
+        assert_eq!(
+            p.GetClassID()?,
+            "CEE1D356-0860-4262-90D4-C77423F0E352".into()
+        );
+
+        let m: ITestPersistMemory = windows_core::Interface::cast(&p)?;
+        assert_eq!(m.IsDirty(), windows::Win32::Foundation::S_FALSE);
+
+        Ok(())
+    }
+}

crates/tests/interface_core/tests/test.rs → crates/tests/interface_core/tests/asterisk_use.rs

@@ -1,5 +1,8 @@
 #![allow(non_snake_case)]
 
+// This tests uses `windows_core` via an asterisk to test that the interface/implement macros support this mode
+// as opposed to no_use.rs which tests the opposite.
+
 use windows_core::*;
 
 #[interface("72cd87fa-9c99-42e0-8986-84a76f08fc5a")]

crates/tests/interface_core/tests/no_use.rs

@@ -0,0 +1,26 @@
+#![allow(non_snake_case)]
+
+// This tests uses `windows_core` explicitly to test that the interface/implement macros support this mode
+// as opposed to asterisk_use.rs which tests the opposite.
+
+#[windows_core::interface("72cd87fa-9c99-42e0-8986-84a76f08fc5a")]
+unsafe trait ITest: windows_core::IUnknown {
+    unsafe fn Test(&self) -> windows_core::HRESULT;
+}
+
+#[windows_core::implement(ITest)]
+struct Test;
+
+impl ITest_Impl for Test {
+    unsafe fn Test(&self) -> windows_core::HRESULT {
+        windows_core::HRESULT(123)
+    }
+}
+
+#[test]
+fn test() {
+    unsafe {
+        let test: ITest = Test.into();
+        assert_eq!(test.Test(), windows_core::HRESULT(123));
+    }
+}