Change protocol implementation syntax

This allows using types in the inheritance chain again

Author: madsmtm

objc2-foundation/examples/declaration.rs

@@ -14,11 +14,6 @@ extern_class! {
 }
 
 declare_class! {
-    // For some reason, `NSApplicationDelegate` is not a "real" protocol we
-    // can retrieve using `objc_getProtocol` - it seems it is created by
-    // `clang` only when used in Objective-C...
-    //
-    // TODO: Investigate this!
     unsafe struct CustomAppDelegate: NSResponder, NSObject {
         pub ivar: u8,
         another_ivar: Bool,
@@ -57,6 +52,12 @@ declare_class! {
             println!("A class method!");
         }
     }
+
+    // For some reason, `NSApplicationDelegate` is not a "real" protocol we
+    // can retrieve using `objc_getProtocol` - it seems it is created by
+    // `clang` only when used in Objective-C...
+    //
+    // TODO: Investigate this!
 }
 
 impl CustomAppDelegate {

objc2-foundation/src/macros.rs

@@ -752,15 +752,15 @@ macro_rules! __inner_declare_class {
 ///
 /// # Examples
 ///
-/// Declare a class `MyCustomObject` with a few instance variables and
-/// methods.
+/// Declare a class `MyCustomObject` that inherits `NSObject`, has a few
+/// instance variables and methods, and implements the `NSCopying` protocol.
 ///
 /// ```
 /// use std::os::raw::c_int;
 /// use objc2::{msg_send, msg_send_bool, msg_send_id};
 /// use objc2::rc::{Id, Owned};
 /// use objc2::runtime::Bool;
-/// use objc2_foundation::{declare_class, NSObject};
+/// use objc2_foundation::{declare_class, NSCopying, NSObject, NSZone};
 /// #
 /// # #[cfg(feature = "gnustep-1-7")]
 /// # unsafe { objc2::__gnustep_hack::get_class_to_force_linkage() };
@@ -797,6 +797,15 @@ macro_rules! __inner_declare_class {
 ///             Bool::YES
 ///         }
 ///     }
+///
+///     unsafe impl protocol NSCopying {
+///         @sel(copyWithZone:)
+///         fn copy_with_zone(&self, _zone: *const NSZone) -> *mut Self {
+///             let mut obj = Self::new(*self.foo);
+///             *obj.bar = *self.bar;
+///             obj.autorelease_return()
+///         }
+///     }
 /// }
 ///
 /// impl MyCustomObject {
@@ -814,11 +823,19 @@ macro_rules! __inner_declare_class {
 ///     }
 /// }
 ///
+/// unsafe impl NSCopying for MyCustomObject {
+///     type Ownership = Owned;
+///     type Output = Self;
+/// }
+///
 /// fn main() {
 ///     let obj = MyCustomObject::new(3);
 ///     assert_eq!(*obj.foo, 3);
 ///     assert_eq!(*obj.bar, 42);
+///
+///     let obj = obj.copy();
 ///     assert_eq!(obj.get_foo(), 3);
+///
 ///     assert!(MyCustomObject::my_class_method());
 /// }
 /// ```
@@ -828,7 +845,7 @@ macro_rules! __inner_declare_class {
 /// ```text
 /// #import <Foundation/Foundation.h>
 ///
-/// @interface MyCustomObject: NSObject {
+/// @interface MyCustomObject: NSObject <NSCopying> {
 ///     int bar;
 /// }
 ///
@@ -861,20 +878,33 @@ macro_rules! __inner_declare_class {
 ///     return YES;
 /// }
 ///
+/// - (id)copyWithZone:(NSZone *)_zone {
+///     MyCustomObject* obj = [[MyCustomObject alloc] initWithFoo: self->foo];
+///     obj->bar = self->bar;
+///     return obj;
+/// }
+///
 /// @end
 /// ```
 #[macro_export]
 macro_rules! declare_class {
     {
         $(#[$m:meta])*
-        unsafe $v:vis struct $name:ident: $inherits:ident $(, $inheritance_rest:ident)* $(<$($protocols:ident),+ $(,)?>)? {
+        unsafe $v:vis struct $name:ident: $inherits:ty $(, $inheritance_rest:ty)* {
             $($ivar_v:vis $ivar:ident: $ivar_ty:ty,)*
         }
 
         $(#[$impl_m:meta])*
         unsafe impl {
             $($methods:tt)*
         }
+
+        $(
+            $(#[$impl_protocol_m:meta])*
+            unsafe impl protocol $protocols:ident {
+                $($protocol_methods:tt)*
+            }
+        ),*
     } => {
         $(
             #[allow(non_camel_case_types)]
@@ -916,13 +946,6 @@ macro_rules! declare_class {
                     let superclass = <$inherits>::class();
                     let mut builder = ClassBuilder::new(stringify!($name), superclass).unwrap();
 
-                    // Implement protocols
-                    $(
-                        $(
-                            builder.add_protocol(Protocol::get(stringify!($protocols)).unwrap());
-                        )+
-                    )?
-
                     $(
                         builder.add_ivar::<<$ivar as $crate::objc2::declare::IvarType>::Type>(
                             <$ivar as $crate::objc2::declare::IvarType>::NAME
@@ -940,6 +963,22 @@ macro_rules! declare_class {
                         }
                     }
 
+                    // Implement protocols
+                    $(
+                        builder.add_protocol(Protocol::get(stringify!($protocols)).unwrap());
+
+                        // SAFETY: Upheld by caller
+                        unsafe {
+                            $crate::__inner_declare_class! {
+                                @rewrite_methods
+                                @register_out
+                                @builder
+
+                                $($protocol_methods)*
+                            }
+                        }
+                    )*
+
                     let _cls = builder.register();
                 });
 
@@ -958,6 +997,20 @@ macro_rules! declare_class {
                 $($methods)*
             }
         }
+
+        // Protocol methods
+        $(
+            $(#[$impl_protocol_m])*
+            impl $name {
+                $crate::__inner_declare_class! {
+                    @rewrite_methods
+                    @method_out
+                    @__builder
+
+                    $($protocol_methods)*
+                }
+            }
+        )*
     };
 }
 

objc2-foundation/src/zone.rs

@@ -5,7 +5,8 @@ use objc2::{Encoding, RefEncode};
 /// A type used to identify and manage memory zones.
 ///
 /// Zones are ignored on all newer platforms, you should very rarely need to
-/// use this.
+/// use this, but may be useful if you need to implement `copyWithZone:` or
+/// `allocWithZone:`.
 ///
 /// See [Apple's documentation](https://developer.apple.com/documentation/foundation/nszone?language=objc).
 #[derive(Debug)]