Remove INSObject::new

Some classes (NSValue is the current example of this, but it's probably not the only case) don't want to handle cases where the users didn't supply a value, and implement `init` with throwing an exception or returning `nil`.

We could panic in those cases (though we can't currently catch GNUStep exceptions), but instead we should just simply not provide a way to construct these invalid instances.

objc2_foundation/examples/basic_usage.rs

@@ -1,7 +1,6 @@
 use objc2::rc::autoreleasepool;
 use objc2_foundation::{
-    INSArray, INSCopying, INSDictionary, INSObject, INSString, NSArray, NSDictionary, NSObject,
-    NSString,
+    INSArray, INSCopying, INSDictionary, INSString, NSArray, NSDictionary, NSObject, NSString,
 };
 
 fn main() {

objc2_foundation/examples/class_with_lifetime.rs

@@ -24,7 +24,7 @@ unsafe impl RefEncode for MyObject<'_> {
 unsafe impl Message for MyObject<'_> {}
 
 impl<'a> MyObject<'a> {
-    fn new_with_ptr(number_ptr: &'a mut u8) -> Id<Self, Owned> {
+    fn new(number_ptr: &'a mut u8) -> Id<Self, Owned> {
         unsafe {
             let obj: *mut Self = msg_send![Self::class(), alloc];
             let obj: *mut Self = msg_send![obj, initWithPtr: number_ptr];
@@ -83,7 +83,7 @@ unsafe impl INSObject for MyObject<'_> {
 
 fn main() {
     let mut number = 54;
-    let mut obj = MyObject::new_with_ptr(&mut number);
+    let mut obj = MyObject::new(&mut number);
 
     println!("Number: {}", obj.get().unwrap());
 

objc2_foundation/examples/custom_class.rs

@@ -1,7 +1,8 @@
+use std::ptr::NonNull;
 use std::sync::Once;
 
 use objc2::declare::ClassDecl;
-use objc2::rc::Owned;
+use objc2::rc::{Id, Owned};
 use objc2::runtime::{Class, Object, Sel};
 use objc2::{msg_send, sel};
 use objc2::{Encoding, Message, RefEncode};
@@ -22,6 +23,11 @@ unsafe impl RefEncode for MYObject {
 }
 
 impl MYObject {
+    fn new() -> Id<Self, <Self as INSObject>::Ownership> {
+        let cls = Self::class();
+        unsafe { Id::new(NonNull::new_unchecked(msg_send![cls, new])) }
+    }
+
     fn number(&self) -> u32 {
         unsafe {
             let obj = &*(self as *const _ as *const Object);

objc2_foundation/src/array.rs

@@ -29,6 +29,8 @@ pub unsafe trait INSArray: INSObject {
     type Item: INSObject;
     type ItemOwnership: Ownership;
 
+    unsafe_def_fn!(fn new);
+
     #[doc(alias = "count")]
     fn len(&self) -> usize {
         unsafe { msg_send![self, count] }
@@ -387,7 +389,7 @@ mod tests {
         assert_eq!(array.first(), array.get(0));
         assert_eq!(array.last(), array.get(3));
 
-        let empty_array: Id<NSArray<NSObject, Owned>, _> = INSObject::new();
+        let empty_array = <NSArray<NSObject, Owned>>::new();
         assert!(empty_array.first().is_none());
         assert!(empty_array.last().is_none());
     }

objc2_foundation/src/data.rs

@@ -9,6 +9,8 @@ use objc2::msg_send;
 use objc2::rc::{Id, Owned, Shared};
 
 pub unsafe trait INSData: INSObject {
+    unsafe_def_fn!(fn new);
+
     fn len(&self) -> usize {
         unsafe { msg_send![self, length] }
     }
@@ -179,7 +181,6 @@ impl DerefMut for NSMutableData {
 #[cfg(test)]
 mod tests {
     use super::{INSData, INSMutableData, NSData, NSMutableData};
-    use crate::INSObject;
     #[cfg(feature = "block")]
     use alloc::vec;
 

objc2_foundation/src/dictionary.rs

@@ -32,6 +32,8 @@ pub unsafe trait INSDictionary: INSObject {
     type Value: INSObject;
     type ValueOwnership: Ownership;
 
+    unsafe_def_fn!(fn new);
+
     #[doc(alias = "count")]
     fn len(&self) -> usize {
         unsafe { msg_send![self, count] }
@@ -169,7 +171,7 @@ mod tests {
     use objc2::rc::{autoreleasepool, Id, Shared};
 
     use super::{INSDictionary, NSDictionary};
-    use crate::{INSArray, INSObject, INSString, NSObject, NSString};
+    use crate::{INSArray, INSString, NSObject, NSString};
 
     fn sample_dict(key: &str) -> Id<NSDictionary<NSString, NSObject>, Shared> {
         let string = NSString::from_str(key);

objc2_foundation/src/enumerator.rs

@@ -173,29 +173,25 @@ mod tests {
 
     #[test]
     fn test_enumerator() {
-        let vec = (0u32..4).map(NSValue::from_value).collect();
+        let vec = (0u32..4).map(NSValue::new).collect();
         let array = NSArray::from_vec(vec);
 
         let enumerator = array.object_enumerator();
         assert!(enumerator.count() == 4);
 
         let enumerator = array.object_enumerator();
-        assert!(enumerator
-            .enumerate()
-            .all(|(i, obj)| obj.get() == Some(i as u32)));
+        assert!(enumerator.enumerate().all(|(i, obj)| obj.get() == i as u32));
     }
 
     #[test]
     fn test_fast_enumerator() {
-        let vec = (0u32..4).map(NSValue::from_value).collect();
+        let vec = (0u32..4).map(NSValue::new).collect();
         let array = NSArray::from_vec(vec);
 
         let enumerator = array.enumerator();
         assert!(enumerator.count() == 4);
 
         let enumerator = array.enumerator();
-        assert!(enumerator
-            .enumerate()
-            .all(|(i, obj)| obj.get() == Some(i as u32)));
+        assert!(enumerator.enumerate().all(|(i, obj)| obj.get() == i as u32));
     }
 }

objc2_foundation/src/macros.rs

@@ -75,3 +75,12 @@ macro_rules! object_impl {
         }
     );
 }
+
+macro_rules! unsafe_def_fn {
+    ($v:vis fn new) => {
+        $v fn new() -> Id<Self, <Self as INSObject>::Ownership> {
+            let cls = <Self as INSObject>::class();
+            unsafe { Id::new(NonNull::new_unchecked(msg_send![cls, new])) }
+        }
+    };
+}

objc2_foundation/src/object.rs

@@ -47,15 +47,14 @@ pub unsafe trait INSObject: Sized + Message {
         let result: Bool = unsafe { msg_send![self, isKindOfClass: cls] };
         result.is_true()
     }
-
-    fn new() -> Id<Self, Self::Ownership> {
-        let cls = Self::class();
-        unsafe { Id::new(msg_send![cls, new]) }
-    }
 }
 
 object_struct!(unsafe NSObject, Owned);
 
+impl NSObject {
+    unsafe_def_fn!(pub fn new);
+}
+
 #[cfg(test)]
 mod tests {
     use super::{INSObject, NSObject};

objc2_foundation/src/string.rs

@@ -17,6 +17,8 @@ const UTF8_ENCODING: usize = 4;
 const UTF8_ENCODING: i32 = 4;
 
 pub unsafe trait INSString: INSObject {
+    unsafe_def_fn!(fn new);
+
     fn len(&self) -> usize {
         unsafe { msg_send![self, lengthOfBytesUsingEncoding: UTF8_ENCODING] }
     }

objc2_foundation/src/value.rs

@@ -17,18 +17,23 @@ use super::{INSCopying, INSObject};
 pub unsafe trait INSValue: INSObject {
     type Value: 'static + Copy + Encode;
 
+    // Default / empty new is not provided because `-init` returns `nil` on
+    // Apple and GNUStep throws an exception on all other messages to this
+    // invalid instance.
+
     /// TODO.
     ///
-    /// If the value was created using [`INSObject::new`], the value may not
-    /// be initialized. In that case, this will return [`None`].
-    fn get(&self) -> Option<Self::Value> {
-        // If encoding is `None`, this was created using INSObject::new
+    /// Note that this is broken on GNUStep for some types, see
+    /// [gnustep/libs-base#216].
+    ///
+    /// [gnustep/libs-base#216]: https://github.com/gnustep/libs-base/pull/216
+    fn get(&self) -> Self::Value {
         if let Some(encoding) = self.encoding() {
             // TODO: This can be a debug assertion (?)
-            assert!(&Self::Value::ENCODING == encoding);
-            Some(unsafe { self.get_unchecked() })
+            assert!(&Self::Value::ENCODING == encoding, "Wrong encoding");
+            unsafe { self.get_unchecked() }
         } else {
-            None
+            panic!("Missing NSValue encoding");
         }
     }
 
@@ -44,7 +49,7 @@ pub unsafe trait INSValue: INSObject {
         result.map(|s| unsafe { CStr::from_ptr(s.as_ptr()) }.to_str().unwrap())
     }
 
-    fn from_value(value: Self::Value) -> Id<Self, Self::Ownership> {
+    fn new(value: Self::Value) -> Id<Self, Self::Ownership> {
         let cls = Self::class();
         let bytes = &value as *const Self::Value as *const c_void;
         let encoding = CString::new(Self::Value::ENCODING.to_string()).unwrap();
@@ -70,31 +75,7 @@ unsafe impl<T: 'static> INSObject for NSValue<T> {
     type Ownership = Shared;
 
     fn class() -> &'static Class {
-        #[cfg(not(gnustep))]
-        return class!(NSValue);
-
-        #[cfg(gnustep)]
-        // We can't use NSValue directly, because its `new` method throws an
-        // exception (instead of just becoming an invalid NSValue). Luckily,
-        // the `GSValue` subclass has the desired behaviour, so we can just
-        // use that. Unfortunately, this is less efficient for the following:
-        // ```
-        // match T::ENCODING {
-        //     Encoding::Object => ...,
-        //     Encoding::Struct("_NSPoint", _) => ...,
-        //     Encoding::Pointer(&Encoding::Void) => ...,
-        //     Encoding::Struct("_NSRange", _) => ...,
-        //     Encoding::Struct("_NSRect", _) => ...,
-        //     Encoding::Struct("_NSSize", _) => ...,
-        // }
-        // ```
-        //
-        // See GNUStep's `NSValue +valueClassWithObjCType` and
-        // `GSConcreteValueTemplate.m` for more, though we can't use the
-        // classes in there either, because their `new` methods return valid
-        // objects (and so `<NSValue<NSRange>>::new()` would work differently
-        // on GNUStep).
-        return class!(GSValue);
+        class!(NSValue)
     }
 }
 
@@ -108,31 +89,24 @@ unsafe impl<T: 'static> INSCopying for NSValue<T> {
 
 #[cfg(test)]
 mod tests {
-    use crate::{INSObject, INSValue, NSRange, NSValue};
+    use crate::{INSValue, NSRange, NSValue};
     use objc2::Encode;
 
     #[test]
     fn test_value() {
-        let val = NSValue::from_value(13u32);
-        assert_eq!(val.get().unwrap(), 13);
+        let val = NSValue::new(13u32);
+        assert_eq!(val.get(), 13);
         assert!(&u32::ENCODING == val.encoding().unwrap());
     }
 
-    #[test]
-    fn test_value_new() {
-        let val = <NSValue<u8>>::new();
-        assert!(val.encoding().is_none());
-        assert!(val.get().is_none());
-    }
-
     #[test]
     fn test_value_nsrange() {
-        let val = NSValue::from_value(NSRange::from(1..2));
+        let val = NSValue::new(NSRange::from(1..2));
         assert!(&NSRange::ENCODING == val.encoding().unwrap());
-        assert_eq!(val.get().unwrap(), NSRange::from(1..2));
-
-        let val = <NSValue<NSRange>>::new();
-        assert!(val.encoding().is_none());
-        assert!(val.get().is_none());
+        let range: NSRange = unsafe { objc2::msg_send![val, rangeValue] };
+        assert_eq!(range, NSRange::from(1..2));
+        // NSValue -getValue is broken on GNUStep for some types
+        #[cfg(not(gnustep))]
+        assert_eq!(val.get(), NSRange::from(1..2));
     }
 }