Merge pull request #143 from madsmtm/foundation-asref-asmut

Impl `AsRef` and `AsMut` for objects, to convert them to their superclasses

Author: madsmtm

objc2-foundation/src/array.rs

@@ -43,7 +43,7 @@ unsafe impl<T: Send> Send for NSArray<T, Owned> {}
 object! {
     // TODO: Ensure that this deref to NSArray is safe!
     // This "inherits" NSArray, and has the same `Send`/`Sync` impls as that.
-    unsafe pub struct NSMutableArray<T, O: Ownership>: NSArray<T, O> {}
+    unsafe pub struct NSMutableArray<T, O: Ownership>: NSArray<T, O>, NSObject {}
 }
 
 unsafe fn from_refs<T: Message + ?Sized>(cls: &Class, refs: &[&T]) -> *mut Object {

objc2-foundation/src/data.rs

@@ -32,7 +32,7 @@ object! {
     /// See [Apple's documentation](https://developer.apple.com/documentation/foundation/nsmutabledata?language=objc).
     ///
     /// [`Vec`]: std::vec::Vec
-    unsafe pub struct NSMutableData: NSData;
+    unsafe pub struct NSMutableData: NSData, NSObject;
 }
 
 // TODO: SAFETY

objc2-foundation/src/macros.rs

@@ -1,3 +1,24 @@
+macro_rules! __impl_as_ref_as_mut {
+    ($name:ident<$($t:ident $(: $b:ident)?),*>,) => {};
+    ($name:ident<$($t:ident $(: $b:ident)?),*>, $item:ty, $($tail:ty,)*) => {
+        impl<$($t $(: $b)?),*> AsRef<$item> for $name<$($t),*> {
+            #[inline]
+            fn as_ref(&self) -> &$item {
+                &**self
+            }
+        }
+
+        impl<$($t $(: $b)?),*> AsMut<$item> for $name<$($t),*> {
+            #[inline]
+            fn as_mut(&mut self) -> &mut $item {
+                &mut **self
+            }
+        }
+
+        __impl_as_ref_as_mut!($name<$($t $(: $b)?),*>, $($tail,)*);
+    };
+}
+
 /// TODO
 ///
 /// # Safety
@@ -9,13 +30,32 @@
 macro_rules! object {
     (
         $(#[$m:meta])*
-        unsafe $v:vis struct $name:ident: $inherits:ty $(;)?
+        unsafe $v:vis struct $name:ident: $($inheritance_chain:ty),+ $(;)?
     ) => {
-        object!($(#[$m])* unsafe $v struct $name<>: $inherits {});
+        object! {
+            @__inner
+            $(#[$m])*
+            unsafe $v struct $name<>: $($inheritance_chain,)+ ::objc2::runtime::Object {}
+        }
     };
     (
         $(#[$m:meta])*
-        unsafe $v:vis struct $name:ident<$($t:ident $(: $b:ident)?),*>: $inherits:ty {
+        unsafe $v:vis struct $name:ident<$($t:ident $(: $b:ident)?),*>: $($inheritance_chain:ty),+ {
+            $($p:ident: $pty:ty,)*
+        }
+    ) => {
+        object! {
+            @__inner
+            $(#[$m])*
+            unsafe $v struct $name<$($t $(: $b)?),*>: $($inheritance_chain,)+ ::objc2::runtime::Object {
+                $($p: $pty,)*
+            }
+        }
+    };
+    (
+        @__inner
+        $(#[$m:meta])*
+        unsafe $v:vis struct $name:ident<$($t:ident $(: $b:ident)?),*>: $inherits:ty $(, $inheritance_rest:ty)* {
             $($p:ident: $pty:ty,)*
         }
     ) => {
@@ -85,7 +125,7 @@ macro_rules! object {
             }
         }
 
-        // TODO: AsRef and AsMut
+        __impl_as_ref_as_mut!($name<$($t $(: $b)?),*>, $inherits, $($inheritance_rest,)*);
 
         // Objective-C equality has approximately the same semantics as Rust
         // equality (although less aptly specified).
@@ -100,13 +140,7 @@ macro_rules! object {
         impl<$($t: ::core::cmp::PartialEq $(+ $b)?),*> ::core::cmp::PartialEq for $name<$($t),*> {
             #[inline]
             fn eq(&self, other: &Self) -> bool {
-                use ::objc2::MessageReceiver;
-                use $crate::NSObject;
-                // "downgrading" to  NSObject to work around generic
-                // downgrading not having been set up yet.
-                // TODO: Fix this.
-                let other: &NSObject = unsafe { &*other.as_raw_receiver().cast() };
-                self.is_equal(other)
+                self.is_equal(&*other)
             }
         }
 

objc2-foundation/src/mutable_attributed_string.rs

@@ -1,13 +1,13 @@
 use objc2::msg_send;
 use objc2::rc::{DefaultId, Id, Owned, Shared};
 
-use crate::{NSAttributedString, NSCopying, NSMutableCopying, NSString};
+use crate::{NSAttributedString, NSCopying, NSMutableCopying, NSObject, NSString};
 
 object! {
     /// A mutable string that has associated attributes.
     ///
     /// See [Apple's documentation](https://developer.apple.com/documentation/foundation/nsmutableattributedstring?language=objc).
-    unsafe pub struct NSMutableAttributedString: NSAttributedString;
+    unsafe pub struct NSMutableAttributedString: NSAttributedString, NSObject;
 }
 
 // TODO: SAFETY

objc2-foundation/src/mutable_string.rs

@@ -6,13 +6,13 @@ use core::str;
 use objc2::msg_send;
 use objc2::rc::{DefaultId, Id, Owned, Shared};
 
-use crate::{NSCopying, NSMutableCopying, NSString};
+use crate::{NSCopying, NSMutableCopying, NSObject, NSString};
 
 object! {
     /// A dynamic plain-text Unicode string object.
     ///
     /// See [Apple's documentation](https://developer.apple.com/documentation/foundation/nsmutablestring?language=objc).
-    unsafe pub struct NSMutableString: NSString;
+    unsafe pub struct NSMutableString: NSString, NSObject;
 }
 
 // TODO: SAFETY

objc2-foundation/src/object.rs

@@ -5,7 +5,8 @@ use objc2::runtime::{Bool, Class, Object};
 use super::NSString;
 
 object! {
-    unsafe pub struct NSObject: Object;
+    @__inner
+    unsafe pub struct NSObject<>: Object {}
 }
 
 impl NSObject {