Merge pull request #486 from Dirbaio/vecview-dedup

vec: remove code duplication due to VecView.

Author: Dirbaio

src/defmt.rs

@@ -1,9 +1,9 @@
 //! Defmt implementations for heapless types
 
-use crate::Vec;
+use crate::{storage::Storage, vec::VecInner};
 use defmt::Formatter;
 
-impl<T, const N: usize> defmt::Format for Vec<T, N>
+impl<T, S: Storage> defmt::Format for VecInner<T, S>
 where
     T: defmt::Format,
 {

src/lib.rs

@@ -96,13 +96,6 @@ pub use indexmap::{
 pub use indexset::{FnvIndexSet, IndexSet, Iter as IndexSetIter};
 pub use linear_map::LinearMap;
 pub use string::String;
-
-// Workaround https://github.com/rust-lang/rust/issues/119015. This is required so that the methods on `VecView` and `Vec` are properly documented.
-// cfg(doc) prevents `VecInner` being part of the public API.
-// doc(hidden) prevents the `pub use vec::VecInner` from being visible in the documentation.
-#[cfg(doc)]
-#[doc(hidden)]
-pub use vec::VecInner as _;
 pub use vec::{Vec, VecView};
 
 #[macro_use]
@@ -114,8 +107,9 @@ mod histbuf;
 mod indexmap;
 mod indexset;
 mod linear_map;
+pub mod storage;
 pub mod string;
-mod vec;
+pub mod vec;
 
 #[cfg(feature = "serde")]
 mod de;

src/ser.rs

@@ -1,8 +1,8 @@
 use core::hash::{BuildHasher, Hash};
 
 use crate::{
-    binary_heap::Kind as BinaryHeapKind, BinaryHeap, Deque, IndexMap, IndexSet, LinearMap, String,
-    Vec,
+    binary_heap::Kind as BinaryHeapKind, storage::Storage, vec::VecInner, BinaryHeap, Deque,
+    IndexMap, IndexSet, LinearMap, String,
 };
 use serde::ser::{Serialize, SerializeMap, SerializeSeq, Serializer};
 
@@ -42,7 +42,7 @@ where
     }
 }
 
-impl<T, const N: usize> Serialize for Vec<T, N>
+impl<T, St: Storage> Serialize for VecInner<T, St>
 where
     T: Serialize,
 {

src/storage.rs

@@ -0,0 +1,43 @@
+//! `Storage` trait defining how data is stored in a container.
+
+use core::borrow::{Borrow, BorrowMut};
+
+pub(crate) trait SealedStorage {
+    type Buffer<T>: ?Sized + Borrow<[T]> + BorrowMut<[T]>;
+}
+
+/// Trait defining how data for a container is stored.
+///
+/// There's two implementations available:
+///
+/// - [`OwnedStorage`]: stores the data in an array `[T; N]` whose size is known at compile time.
+/// - [`ViewStorage`]: stores the data in an unsized `[T]`.
+///
+/// This allows containers to be generic over either sized or unsized storage. For example,
+/// the [`vec`](crate::vec) module contains a [`VecInner`](crate::vec::VecInner) struct
+/// that's generic on [`Storage`], and two type aliases for convenience:
+///
+/// - [`Vec<T, N>`](crate::vec::Vec) = `VecInner<T, OwnedStorage<N>>`
+/// - [`VecView<T>`](crate::vec::VecView) = `VecInner<T, ViewStorage>`
+///
+/// `Vec` can be unsized into `VecView`, either by unsizing coercions such as `&mut Vec -> &mut VecView` or
+/// `Box<Vec> -> Box<VecView>`, or explicitly with [`.as_view()`](crate::vec::Vec::as_view) or [`.as_mut_view()`](crate::vec::Vec::as_mut_view).
+///
+/// This trait is sealed, so you cannot implement it for your own types. You can only use
+/// the implementations provided by this crate.
+#[allow(private_bounds)]
+pub trait Storage: SealedStorage {}
+
+/// Implementation of [`Storage`] that stores the data in an array `[T; N]` whose size is known at compile time.
+pub enum OwnedStorage<const N: usize> {}
+impl<const N: usize> Storage for OwnedStorage<N> {}
+impl<const N: usize> SealedStorage for OwnedStorage<N> {
+    type Buffer<T> = [T; N];
+}
+
+/// Implementation of [`Storage`] that stores the data in an unsized `[T]`.
+pub enum ViewStorage {}
+impl Storage for ViewStorage {}
+impl SealedStorage for ViewStorage {
+    type Buffer<T> = [T];
+}

src/ufmt.rs

@@ -1,4 +1,4 @@
-use crate::{string::String, vec::Vec};
+use crate::{storage::Storage, string::String, vec::VecInner};
 use ufmt_write::uWrite;
 
 impl<const N: usize> uWrite for String<N> {
@@ -8,7 +8,7 @@ impl<const N: usize> uWrite for String<N> {
     }
 }
 
-impl<const N: usize> uWrite for Vec<u8, N> {
+impl<S: Storage> uWrite for VecInner<u8, S> {
     type Error = ();
     fn write_str(&mut self, s: &str) -> Result<(), Self::Error> {
         self.extend_from_slice(s.as_bytes())
@@ -17,7 +17,7 @@ impl<const N: usize> uWrite for Vec<u8, N> {
 
 #[cfg(test)]
 mod tests {
-    use super::*;
+    use crate::{String, Vec};
 
     use ufmt::{derive::uDebug, uwrite};