Make CowArray an owned storage array, require Clone bound for into_shared

src/arraytraits.rs

@@ -10,18 +10,22 @@
 use alloc::boxed::Box;
 #[cfg(not(feature = "std"))]
 use alloc::vec::Vec;
+use std::hash;
 use std::mem;
+use std::mem::size_of;
 use std::ops::{Index, IndexMut};
-use std::{hash, mem::size_of};
 use std::{iter::FromIterator, slice};
 
 use crate::imp_prelude::*;
+use crate::Arc;
+
 use crate::{
     dimension,
     iter::{Iter, IterMut},
     numeric_util,
     FoldWhile,
     NdIndex,
+    OwnedArcRepr,
     Zip,
 };
 
@@ -457,7 +461,9 @@ where D: Dimension
 {
     fn from(arr: Array<A, D>) -> ArcArray<A, D>
     {
-        arr.into_shared()
+        let data = OwnedArcRepr(Arc::new(arr.data));
+        // safe because: equivalent unmoved data, ptr and dims remain valid
+        unsafe { ArrayBase::from_data_ptr(data, arr.ptr).with_strides_dim(arr.strides, arr.dim) }
     }
 }
 

src/data_traits.rs

@@ -534,7 +534,7 @@ unsafe impl<'a, A> DataMut for ViewRepr<&'a mut A> {}
 
 /// Array representation trait.
 ///
-/// A representation that is a unique or shared owner of its data.
+/// A representation which can be the owner of its data.
 ///
 /// ***Internal trait, see `Data`.***
 // The owned storage represents the ownership and allocation of the array's elements.
@@ -553,9 +553,13 @@ pub unsafe trait DataOwned: Data
     fn new(elements: Vec<Self::Elem>) -> Self;
 
     /// Converts the data representation to a shared (copy on write)
-    /// representation, without any copying.
+    /// representation, cloning the array elements if necessary.
     #[doc(hidden)]
-    fn into_shared(self) -> OwnedArcRepr<Self::Elem>;
+    #[allow(clippy::wrong_self_convention)]
+    fn into_shared<D>(self_: ArrayBase<Self, D>) -> ArcArray<Self::Elem, D>
+    where
+        Self::Elem: Clone,
+        D: Dimension;
 }
 
 /// Array representation trait.
@@ -578,9 +582,12 @@ unsafe impl<A> DataOwned for OwnedRepr<A>
         OwnedRepr::from(elements)
     }
 
-    fn into_shared(self) -> OwnedArcRepr<A>
+    fn into_shared<D>(self_: ArrayBase<Self, D>) -> ArcArray<A, D>
+    where
+        A: Clone,
+        D: Dimension,
     {
-        OwnedArcRepr(Arc::new(self))
+        ArcArray::from(self_)
     }
 }
 
@@ -593,9 +600,12 @@ unsafe impl<A> DataOwned for OwnedArcRepr<A>
         OwnedArcRepr(Arc::new(OwnedRepr::from(elements)))
     }
 
-    fn into_shared(self) -> OwnedArcRepr<A>
+    fn into_shared<D>(self_: ArrayBase<Self, D>) -> ArcArray<A, D>
+    where
+        A: Clone,
+        D: Dimension,
     {
-        self
+        self_
     }
 }
 
@@ -720,6 +730,24 @@ unsafe impl<'a, A> Data for CowRepr<'a, A>
 
 unsafe impl<'a, A> DataMut for CowRepr<'a, A> where A: Clone {}
 
+unsafe impl<'a, A> DataOwned for CowRepr<'a, A>
+{
+    type MaybeUninit = CowRepr<'a, MaybeUninit<A>>;
+
+    fn new(elements: Vec<A>) -> Self
+    {
+        CowRepr::Owned(OwnedRepr::new(elements))
+    }
+
+    fn into_shared<D>(self_: ArrayBase<Self, D>) -> ArcArray<A, D>
+    where
+        A: Clone,
+        D: Dimension,
+    {
+        self_.into_owned().into_shared()
+    }
+}
+
 /// Array representation trait.
 ///
 /// The RawDataSubst trait maps the element type of array storage, while

src/impl_methods.rs

@@ -292,13 +292,17 @@ where
     }
 
     /// Turn the array into a shared ownership (copy on write) array,
-    /// without any copying.
+    /// cloning the array elements if necessary.
+    ///
+    /// If you want to generalize over `Array` and `ArcArray` inputs but avoid
+    /// an `A: Clone` bound, use `Into::<ArcArray<A, D>>::into` instead of this
+    /// method.
     pub fn into_shared(self) -> ArcArray<A, D>
-    where S: DataOwned
+    where
+        A: Clone,
+        S: DataOwned,
     {
-        let data = self.data.into_shared();
-        // safe because: equivalent unmoved data, ptr and dims remain valid
-        unsafe { ArrayBase::from_data_ptr(data, self.ptr).with_strides_dim(self.strides, self.dim) }
+        S::into_shared(self)
     }
 
     /// Returns a reference to the first element of the array, or `None` if it