Add ClassType::NAME

Author: madsmtm

objc2/CHANGELOG.md

@@ -13,11 +13,14 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 * Added `IvarDrop<T>` to allow storing complex `Drop` values in ivars
   (currently `rc::Id<T, O>`, `Box<T>`, `Option<rc::Id<T, O>>` or
   `Option<Box<T>>`).
+* **BREAKING**: Added required `ClassType::NAME` constant for statically
+  determining the name of a specific class.
 
 ### Removed
 * **BREAKING**: `MaybeUninit` no longer implements `IvarType` directly; use
   `Ivar::write` instead.
 
+
 ## 0.3.0-beta.2 - 2022-08-28
 
 ### Added

objc2/examples/class_with_lifetime.rs

@@ -78,14 +78,15 @@ impl<'a> MyObject<'a> {
 
 unsafe impl<'a> ClassType for MyObject<'a> {
     type Super = NSObject;
+    const NAME: &'static str = "MyObject";
 
     fn class() -> &'static Class {
         // TODO: Use std::lazy::LazyCell
         static REGISTER_CLASS: Once = Once::new();
 
         REGISTER_CLASS.call_once(|| {
             let superclass = NSObject::class();
-            let mut builder = ClassBuilder::new("MyObject", superclass).unwrap();
+            let mut builder = ClassBuilder::new(Self::NAME, superclass).unwrap();
 
             builder.add_static_ivar::<NumberIvar<'a>>();
 

objc2/src/class_type.rs

@@ -18,11 +18,12 @@ use crate::Message;
 ///
 /// The class returned by [`Self::class`] must be a subclass of the class that
 /// [`Self::Super`] represents, and `as_super`/`as_super_mut` must be
-/// implemented correctly.
+/// implemented correctly. Finally [`Self::NAME`] must be correct.
 ///
 /// In pseudocode:
 /// ```ignore
 /// Self::class().superclass() == <Self::Super as ClassType>::class()
+/// Self::class().name() == Self::NAME
 /// ```
 ///
 ///
@@ -68,6 +69,9 @@ pub unsafe trait ClassType: Message {
     /// [`runtime::Object`]: crate::runtime::Object
     type Super: Message;
 
+    /// The name of the Objective-C class that this type represents.
+    const NAME: &'static str;
+
     /// Get a reference to the Objective-C class that this type represents.
     ///
     /// May register the class with the runtime if it wasn't already.

objc2/src/foundation/object.rs

@@ -17,6 +17,7 @@ __inner_extern_class! {
 
 unsafe impl ClassType for NSObject {
     type Super = Object;
+    const NAME: &'static str = "NSObject";
 
     #[inline]
     fn class() -> &'static Class {

objc2/src/macros/declare_class.rs

@@ -612,6 +612,7 @@ macro_rules! declare_class {
         // Creation
         unsafe impl ClassType for $for {
             type Super = $superclass;
+            const NAME: &'static str = stringify!($name);
 
             fn class() -> &'static $crate::runtime::Class {
                 // TODO: Use `core::cell::LazyCell`
@@ -626,7 +627,7 @@ macro_rules! declare_class {
                         stringify!($name),
                         ". Perhaps a class with that name already exists?",
                     );
-                    let mut builder = $crate::declare::ClassBuilder::new(stringify!($name), superclass).expect(err_str);
+                    let mut builder = $crate::declare::ClassBuilder::new(Self::NAME, superclass).expect(err_str);
 
                     // Ivars
                     $(

objc2/src/macros/extern_class.rs

@@ -254,6 +254,7 @@ macro_rules! __inner_extern_class {
 
         unsafe impl<$($t_for $(: $b_for)?),*> ClassType for $for {
             type Super = $superclass;
+            const NAME: &'static str = stringify!($name);
 
             #[inline]
             fn class() -> &'static $crate::runtime::Class {

objc2/src/rc/test_object.rs

@@ -162,3 +162,13 @@ impl RcTestObject {
         unsafe { Id::new(msg_send![Self::class(), new]) }.unwrap()
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn ensure_declared_name() {
+        assert_eq!(RcTestObject::class().name(), RcTestObject::NAME);
+    }
+}

tests/src/test_object.rs

@@ -22,6 +22,7 @@ unsafe impl RefEncode for MyTestObject {
 
 unsafe impl ClassType for MyTestObject {
     type Super = NSObject;
+    const NAME: &'static str = "MyTestObject";
 
     fn class() -> &'static Class {
         class!(MyTestObject)