Add ability to prepend code to type generation (#2907)

crates/libs/bindgen/src/args.rs

@@ -10,11 +10,9 @@ where
     Ok(result)
 }
 
+// This function is needed to avoid a recursion limit in the Rust compiler.
 fn from_string(result: &mut Vec<String>, value: &str) -> Result<()> {
-    let value = if let Some((value, _)) = value.split_once('#') { value } else { value };
-
-    from_iter(result, value.split_whitespace().map(|arg| arg.to_string()))?;
-    Ok(())
+    from_iter(result, value.split_whitespace().map(|arg| arg.to_string()))
 }
 
 fn from_iter<I, S>(result: &mut Vec<String>, args: I) -> Result<()>

crates/libs/bindgen/src/rust/mod.rs

@@ -42,6 +42,20 @@ pub fn from_reader(reader: &'static metadata::Reader, mut config: std::collectio
         return Err(Error::new("cannot combine `implement` and `sys` configuration values"));
     }
 
+    config.retain(|key, value| {
+        if let Some(full_name) = key.strip_prefix("prepend:") {
+            if let Some(index) = full_name.rfind('.') {
+                let namespace = &full_name[0..index];
+                let name = &full_name[index + 1..];
+                if let Some(type_def) = reader.get_type_def(namespace, name).next() {
+                    writer.prepend.insert(type_def, value.to_string());
+                    return false;
+                }
+            }
+        }
+        true
+    });
+
     if let Some((key, _)) = config.first_key_value() {
         return Err(Error::new(&format!("invalid configuration value `{key}`")));
     }

crates/libs/bindgen/src/rust/writer.rs

@@ -20,6 +20,7 @@ pub struct Writer {
     pub minimal: bool,             // strips out enumerators - in future possibly other helpers as well
     pub no_inner_attributes: bool, // skips the inner attributes at the start of the file
     pub vtbl: bool,                // include minimal vtbl layout support for interfaces
+    pub prepend: std::collections::HashMap<metadata::TypeDef, String>,
 }
 
 impl Writer {
@@ -36,6 +37,7 @@ impl Writer {
             minimal: false,
             no_inner_attributes: false,
             vtbl: false,
+            prepend: Default::default(),
         }
     }
 
@@ -75,12 +77,20 @@ impl Writer {
         }
     }
     pub fn type_def(&self, def: metadata::TypeDef) -> TokenStream {
-        match def.kind() {
+        let tokens = match def.kind() {
             metadata::TypeKind::Class => classes::writer(self, def),
             metadata::TypeKind::Interface => interfaces::writer(self, def),
             metadata::TypeKind::Enum => enums::writer(self, def),
             metadata::TypeKind::Struct => structs::writer(self, def),
             metadata::TypeKind::Delegate => delegates::writer(self, def),
+        };
+
+        if let Some(prepend) = self.prepend.get(&def) {
+            let mut combined = TokenStream::from(prepend);
+            combined.combine(&tokens);
+            combined
+        } else {
+            tokens
         }
     }
 

crates/libs/windows/src/Windows/Win32/Foundation/mod.rs

@@ -10490,6 +10490,7 @@ impl ::core::fmt::Debug for WAIT_EVENT {
         f.debug_tuple("WAIT_EVENT").field(&self.0).finish()
     }
 }
+#[must_use]
 #[repr(transparent)]
 #[derive(::core::cmp::PartialEq, ::core::cmp::Eq, ::core::marker::Copy, ::core::clone::Clone, ::core::default::Default)]
 pub struct WIN32_ERROR(pub u32);
@@ -10530,6 +10531,7 @@ impl ::core::default::Default for APP_LOCAL_DEVICE_ID {
         unsafe { ::core::mem::zeroed() }
     }
 }
+#[must_use]
 #[repr(transparent)]
 #[derive(::core::cmp::PartialEq, ::core::cmp::Eq)]
 pub struct BOOL(pub i32);
@@ -11161,6 +11163,7 @@ impl ::core::default::Default for LUID {
         unsafe { ::core::mem::zeroed() }
     }
 }
+#[must_use]
 #[repr(transparent)]
 #[derive(::core::cmp::PartialEq, ::core::cmp::Eq)]
 pub struct NTSTATUS(pub i32);

crates/libs/windows/src/Windows/Win32/System/Rpc/mod.rs

@@ -3810,6 +3810,7 @@ impl ::core::fmt::Debug for RPC_NOTIFICATION_TYPES {
         f.debug_tuple("RPC_NOTIFICATION_TYPES").field(&self.0).finish()
     }
 }
+#[must_use]
 #[repr(transparent)]
 #[derive(::core::cmp::PartialEq, ::core::cmp::Eq, ::core::marker::Copy, ::core::clone::Clone, ::core::default::Default)]
 pub struct RPC_STATUS(pub i32);

crates/samples/windows/create_window/src/main.rs

@@ -53,7 +53,7 @@ extern "system" fn wndproc(window: HWND, message: u32, wparam: WPARAM, lparam: L
         match message {
             WM_PAINT => {
                 println!("WM_PAINT");
-                ValidateRect(window, None);
+                _ = ValidateRect(window, None);
                 LRESULT(0)
             }
             WM_DESTROY => {

crates/samples/windows/direct2d/src/main.rs

@@ -342,7 +342,7 @@ impl Window {
                     let mut ps = PAINTSTRUCT::default();
                     BeginPaint(self.handle, &mut ps);
                     self.render().unwrap();
-                    EndPaint(self.handle, &ps);
+                    _ = EndPaint(self.handle, &ps);
                     LRESULT(0)
                 }
                 WM_SIZE => {
@@ -425,7 +425,7 @@ impl Window {
                         DispatchMessageA(&message);
                     }
                 } else {
-                    GetMessageA(&mut message, None, 0, 0);
+                    _ = GetMessageA(&mut message, None, 0, 0);
 
                     if message.message == WM_QUIT {
                         return Ok(());

crates/samples/windows/direct3d12/src/main.rs

@@ -103,14 +103,14 @@ where
     };
 
     sample.bind_to_window(&hwnd)?;
-    unsafe { ShowWindow(hwnd, SW_SHOW) };
+    unsafe { _ = ShowWindow(hwnd, SW_SHOW) };
 
     loop {
         let mut message = MSG::default();
 
         if unsafe { PeekMessageA(&mut message, None, 0, 0, PM_REMOVE) }.into() {
             unsafe {
-                TranslateMessage(&message);
+                _ = TranslateMessage(&message);
                 DispatchMessageA(&message);
             }
 

crates/tests/lib/tests/win.rs

@@ -14,7 +14,7 @@ fn linker() -> Result<()> {
 #[test]
 fn gdi() {
     unsafe {
-        AlphaBlend(
+        _ = AlphaBlend(
             HDC::default(),
             0,
             0,

crates/tests/standalone/build.rs

@@ -165,6 +165,16 @@ fn main() {
         "src/b_vtbl_4.rs",
         &["Windows.Win32.System.Com.IPersistFile"],
     );
+
+    riddle(
+        "src/b_prepend.rs",
+        &["Windows.Foundation.DateTime"],
+        &[
+            "flatten",
+            "minimal",
+            "prepend:Windows.Foundation.DateTime=#[derive(std::cmp::PartialOrd,std::cmp::Ord)]",
+        ],
+    );
 }
 
 fn write_sys(output: &str, filter: &[&str]) {

crates/tests/standalone/src/b_prepend.rs

@@ -0,0 +1,45 @@
+// Bindings generated by `windows-bindgen` 0.54.0
+
+#![allow(
+    non_snake_case,
+    non_upper_case_globals,
+    non_camel_case_types,
+    dead_code,
+    clippy::all
+)]
+#[derive(std::cmp::PartialOrd, std::cmp::Ord)]
+#[repr(C)]
+pub struct DateTime {
+    pub UniversalTime: i64,
+}
+impl ::core::marker::Copy for DateTime {}
+impl ::core::clone::Clone for DateTime {
+    fn clone(&self) -> Self {
+        *self
+    }
+}
+impl ::core::fmt::Debug for DateTime {
+    fn fmt(&self, f: &mut ::core::fmt::Formatter<'_>) -> ::core::fmt::Result {
+        f.debug_struct("DateTime")
+            .field("UniversalTime", &self.UniversalTime)
+            .finish()
+    }
+}
+impl ::windows_core::TypeKind for DateTime {
+    type TypeKind = ::windows_core::CopyType;
+}
+impl ::windows_core::RuntimeType for DateTime {
+    const SIGNATURE: ::windows_core::imp::ConstBuffer =
+        ::windows_core::imp::ConstBuffer::from_slice(b"struct(Windows.Foundation.DateTime;i8)");
+}
+impl ::core::cmp::PartialEq for DateTime {
+    fn eq(&self, other: &Self) -> bool {
+        self.UniversalTime == other.UniversalTime
+    }
+}
+impl ::core::cmp::Eq for DateTime {}
+impl ::core::default::Default for DateTime {
+    fn default() -> Self {
+        unsafe { ::core::mem::zeroed() }
+    }
+}

crates/tests/standalone/src/lib.rs

@@ -18,6 +18,7 @@ mod b_none;
 mod b_overloads;
 mod b_pcstr;
 mod b_pcwstr;
+mod b_prepend;
 mod b_pstr;
 mod b_pwstr;
 mod b_std;
@@ -184,3 +185,20 @@ fn from_included() {
         included::GetVersion();
     }
 }
+
+#[test]
+fn prepend() {
+    use b_prepend::*;
+    let mut dates = [
+        DateTime { UniversalTime: 123 },
+        DateTime { UniversalTime: 42 },
+    ];
+    dates.sort();
+    assert_eq!(
+        &dates,
+        &[
+            DateTime { UniversalTime: 42 },
+            DateTime { UniversalTime: 123 }
+        ]
+    );
+}

crates/tests/win32/tests/win32.rs

@@ -182,7 +182,7 @@ fn com_inheritance() {
         assert!(factory.IsCurrent().as_bool());
 
         // IDXGIFactory2
-        factory.IsWindowedStereoEnabled();
+        _ = factory.IsWindowedStereoEnabled();
 
         // IDXGIFactory3
         assert!(factory.GetCreationFlags() == 0);
@@ -202,7 +202,7 @@ fn com_inheritance() {
 #[test]
 fn onecore_imports() -> windows::core::Result<()> {
     unsafe {
-        HasExpandedResources()?;
+        _ = HasExpandedResources()?;
 
         let uri = CreateUri(w!("http://kennykerr.ca"), URI_CREATE_FLAGS::default(), 0)?;
 

crates/tools/windows/bindings.txt

@@ -1,6 +1,10 @@
 --in crates/libs/bindgen/default
 --out crates/libs/windows/src/lib.rs
 --config package
+--config prepend:Windows.Win32.Foundation.WIN32_ERROR=#[must_use]
+--config prepend:Windows.Win32.Foundation.BOOL=#[must_use]
+--config prepend:Windows.Win32.Foundation.NTSTATUS=#[must_use]
+--config prepend:Windows.Win32.System.Rpc.RPC_STATUS=#[must_use]
 
 --filter
     Windows