Merge pull request #514 from madsmtm/msg-send-refactor

Refactor message sending

Author: madsmtm

LAYERED_SAFETY.md

@@ -52,14 +52,14 @@ Doing the Rust equivalent of Objective-C's `NSUInteger hash_code = [obj hash];`.
 
 ```rust
 let obj: *const c_void = ...;
-let sel = unsafe { sel_registerName(b"hash\0".as_ptr() as *const c_char) };
-let fnptr = unsafe {
+let sel = unsafe { ffi::sel_registerName(b"hash\0".as_ptr() as *const c_char) };
+let msg_send_fn = unsafe {
     mem::transmute::<
-        extern "C" fn(*const c_void, SEL) -> NSUInteger,
-        extern "C" fn(),
-    >(objc_msgSend)
+        unsafe extern "C" fn(),
+        unsafe extern "C" fn(*const c_void, SEL) -> NSUInteger,
+    >(ffi::objc_msgSend)
 };
-let hash_code = unsafe { fnptr(obj, sel) };
+let hash_code = unsafe { msg_send_fn(obj, sel) };
 ```
 
 
@@ -68,8 +68,7 @@ let hash_code = unsafe { fnptr(obj, sel) };
 We can improve on this using [`MessageReceiver::send_message`], which
 abstracts away the calling convention details, as well as adding an `Encode`
 bound on all the involved types. This ensures that we don't accidentally try
-to pass e.g. a `Vec<T>`, which does not have a stable memory layout. It also
-handles details surrounding Objective-C's `BOOL` type.
+to pass e.g. a `Vec<T>`, which does not have a stable memory layout.
 
 Additionally, when `debug_assertions` are enabled, the types involved in the
 message send are compared to the types exposed in the Objective-C runtime.
@@ -97,7 +96,8 @@ let hash_code: NSUInteger = unsafe {
 
 Introducing macros: [`msg_send!`] can abstract away the tediousness of writing
 the selector expression, as well as ensuring that the number of arguments to
-the method is correct.
+the method is correct. It also handles details surrounding Objective-C's
+`BOOL` type.
 
 [`msg_send!`]: https://docs.rs/objc2/0.3.0-beta.4/objc2/macro.msg_send.html
 

crates/icrate/tests/array.rs

@@ -1,9 +1,11 @@
 #![cfg(feature = "Foundation_NSArray")]
 #![cfg(feature = "Foundation_NSNumber")]
+use core::ptr;
+
 use icrate::Foundation::{NSArray, NSNumber, NSObject};
 use objc2::mutability::IsRetainable;
 use objc2::rc::{Id, __RcTestObject, __ThreadTestData};
-use objc2::runtime::ProtocolObject;
+use objc2::runtime::{AnyObject, ProtocolObject};
 use objc2::{extern_protocol, ProtocolType};
 
 fn sample_array(len: usize) -> Id<NSArray<NSObject>> {
@@ -283,3 +285,15 @@ fn test_trait_retainable() {
     let _ = NSArray::from_id_slice(&[obj.clone(), obj.clone()]);
     let _ = NSArray::from_vec(vec![obj.clone(), obj.clone()]);
 }
+
+#[test]
+fn test_access_anyobject() {
+    let obj: Id<AnyObject> = Id::into_super(NSObject::new());
+    let array = NSArray::from_id_slice(&[obj.clone(), obj.clone()]);
+    assert!(ptr::eq(&array[0], &*obj));
+    assert!(ptr::eq(array.get(0).unwrap(), &*obj));
+    assert!(ptr::eq(&*array.get_retained(0).unwrap(), &*obj));
+    for _ in array.iter() {}
+    for _ in array.iter_retained() {}
+    for _ in array {}
+}

crates/objc2/CHANGELOG.md

@@ -10,6 +10,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 * Added the following traits to the `mutability` module (see the documentation
   for motivation and usage info):
   - `HasStableHash`.
+  - `IsAllowedMutable`.
   - `IsMainThreadOnly`.
   - `CounterpartOrSelf`.
 * Added new `encode` traits `EncodeReturn`, `EncodeArgument` and
@@ -25,6 +26,27 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
   This effectively means you can now `copy` a `ProtocolObject<dyn NSCopying>`.
 * **BREAKING**: Allow implementing `DefaultId` for any type, not just those
   who are `IsAllocableAnyThread`.
+* **BREAKING**: Moved the `MethodImplementation` trait from the `declare`
+  module to the `runtime` module.
+* **BREAKING**: Moved the `MessageReceiver` trait to the `runtime` module.
+* **BREAKING**: Make the `MessageReceiver` trait no longer implemented for
+  references to `Id`. Dereference the `Id` yourself.
+
+  Note: Passing `&Id` in `msg_send!` is still supported.
+* **BREAKING**: `MessageReceiver::send_message` and
+  `MessageReceiver::send_super_message` now take `EncodeArguments` and return
+  `EncodeReturn`, instead of internal traits.
+
+  This is done to make `MessageReceiver` more straightforward to understand,
+  although it now also has slightly less functionality than `msg_send!`.
+
+  In particular automatic conversion of `bool` is not supported in
+  `MessageReceiver`.
+* Relaxed the requirements for receivers in `MethodImplementation`; now,
+  anything that implements `MessageReceiver` can be used as the receiver of
+  a method.
+* **BREAKING**: Renamed the associated types `Ret` and `Args` on
+  `MethodImplementation` to `Return` and `Arguments`.
 
 ### Deprecated
 * Soft deprecated using `msg_send!` without a comma between arguments (i.e.
@@ -52,10 +74,14 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ### Fixed
 * Fixed the name of the protocol that `NSObjectProtocol` references.
+* Allow cloning `Id<AnyObject>`.
+* **BREAKING**: Restrict message sending to `&mut` references to things that
+  implement `IsAllowedMutable`.
 
 ### Removed
 * **BREAKING**: Removed `ProtocolType` implementation for `NSObject`.
   Use the more precise `NSObjectProtocol` trait instead!
+* **BREAKING**: Removed the `MessageArguments` trait.
 
 
 ## 0.4.1 - 2023-07-31

crates/objc2/src/__macro_helpers/convert.rs

@@ -1,4 +1,4 @@
-use crate::encode::{EncodeArgument, EncodeReturn};
+use crate::encode::{EncodeArgument, EncodeArguments, EncodeReturn};
 use crate::rc::Id;
 use crate::runtime::Bool;
 use crate::Message;
@@ -31,6 +31,7 @@ pub trait ConvertArgument: argument_private::Sealed {
     fn __into_argument(self) -> (Self::__Inner, Self::__StoredBeforeMessage);
 
     #[doc(hidden)]
+    #[inline]
     unsafe fn __process_after_message_send(_stored: Self::__StoredBeforeMessage) {}
 }
 
@@ -121,6 +122,167 @@ impl ConvertReturn for bool {
     }
 }
 
+pub trait ConvertArguments {
+    #[doc(hidden)]
+    type __Inner: EncodeArguments;
+
+    #[doc(hidden)]
+    type __StoredBeforeMessage: Sized;
+
+    #[doc(hidden)]
+    fn __into_arguments(self) -> (Self::__Inner, Self::__StoredBeforeMessage);
+
+    #[doc(hidden)]
+    unsafe fn __process_after_message_send(_stored: Self::__StoredBeforeMessage);
+}
+
+pub trait TupleExtender<T> {
+    #[doc(hidden)]
+    type PlusOneArgument;
+    #[doc(hidden)]
+    fn add_argument(self, arg: T) -> Self::PlusOneArgument;
+}
+
+macro_rules! args_impl {
+    ($($a:ident: $t:ident),*) => (
+        impl<$($t: ConvertArgument),*> ConvertArguments for ($($t,)*) {
+            type __Inner = ($($t::__Inner,)*);
+
+            type __StoredBeforeMessage = ($($t::__StoredBeforeMessage,)*);
+
+            #[inline]
+            fn __into_arguments(self) -> (Self::__Inner, Self::__StoredBeforeMessage) {
+                let ($($a,)*) = self;
+                $(let $a = ConvertArgument::__into_argument($a);)*
+
+                (($($a.0,)*), ($($a.1,)*))
+            }
+
+            #[inline]
+            unsafe fn __process_after_message_send(($($a,)*): Self::__StoredBeforeMessage) {
+                $(
+                    unsafe { <$t as ConvertArgument>::__process_after_message_send($a) };
+                )*
+            }
+        }
+
+        impl<$($t,)* T> TupleExtender<T> for ($($t,)*) {
+            type PlusOneArgument = ($($t,)* T,);
+
+            #[inline]
+            fn add_argument(self, arg: T) -> Self::PlusOneArgument {
+                let ($($a,)*) = self;
+                ($($a,)* arg,)
+            }
+        }
+    );
+}
+
+args_impl!();
+args_impl!(a: A);
+args_impl!(a: A, b: B);
+args_impl!(a: A, b: B, c: C);
+args_impl!(a: A, b: B, c: C, d: D);
+args_impl!(a: A, b: B, c: C, d: D, e: E);
+args_impl!(a: A, b: B, c: C, d: D, e: E, f: F);
+args_impl!(a: A, b: B, c: C, d: D, e: E, f: F, g: G);
+args_impl!(a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H);
+args_impl!(a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I);
+args_impl!(a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J);
+args_impl!(
+    a: A,
+    b: B,
+    c: C,
+    d: D,
+    e: E,
+    f: F,
+    g: G,
+    h: H,
+    i: I,
+    j: J,
+    k: K
+);
+args_impl!(
+    a: A,
+    b: B,
+    c: C,
+    d: D,
+    e: E,
+    f: F,
+    g: G,
+    h: H,
+    i: I,
+    j: J,
+    k: K,
+    l: L
+);
+args_impl!(
+    a: A,
+    b: B,
+    c: C,
+    d: D,
+    e: E,
+    f: F,
+    g: G,
+    h: H,
+    i: I,
+    j: J,
+    k: K,
+    l: L,
+    m: M
+);
+args_impl!(
+    a: A,
+    b: B,
+    c: C,
+    d: D,
+    e: E,
+    f: F,
+    g: G,
+    h: H,
+    i: I,
+    j: J,
+    k: K,
+    l: L,
+    m: M,
+    n: N
+);
+args_impl!(
+    a: A,
+    b: B,
+    c: C,
+    d: D,
+    e: E,
+    f: F,
+    g: G,
+    h: H,
+    i: I,
+    j: J,
+    k: K,
+    l: L,
+    m: M,
+    n: N,
+    o: O
+);
+args_impl!(
+    a: A,
+    b: B,
+    c: C,
+    d: D,
+    e: E,
+    f: F,
+    g: G,
+    h: H,
+    i: I,
+    j: J,
+    k: K,
+    l: L,
+    m: M,
+    n: N,
+    o: O,
+    p: P
+);
+
 #[cfg(test)]
 mod tests {
     use super::*;