Refactor VZV code to center on (and Deref to) VarZeroSlice; make VZVB…

…orrowed private (#1418)

components/plurals/src/rules/runtime/ast.rs

@@ -456,7 +456,7 @@ mod serde {
                 let string: String = self.to_string();
                 serializer.serialize_str(&string)
             } else {
-                serializer.serialize_bytes(self.0.as_encoded_bytes())
+                serializer.serialize_bytes(self.0.as_bytes())
             }
         }
     }
@@ -634,7 +634,7 @@ mod test {
         let relations = alloc::vec![relation];
         let vzv = VarZeroVec::from(relations.as_slice());
         assert_eq!(
-            vzv.as_encoded_bytes(),
+            vzv.as_bytes(),
             &[1, 0, 0, 0, 0, 0, 0, 0, 192, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0]
         );
     }

utils/zerovec/benches/vzv.rs

@@ -45,7 +45,7 @@ fn overview_bench(c: &mut Criterion) {
     // Same as vzv/char_count/vzv but with different inputs
     let seed = 42;
     let (string_vec, _) = random_alphanums(2..=10, 100, seed);
-    let bytes: Vec<u8> = VarZeroVec::<str>::from(&string_vec).into_encoded_bytes();
+    let bytes: Vec<u8> = VarZeroVec::<str>::from(&string_vec).into_bytes();
     let vzv = VarZeroVec::<str>::parse_byte_slice(black_box(bytes.as_slice())).unwrap();
 
     c.bench_function("vzv/overview", |b| {
@@ -73,7 +73,7 @@ fn overview_bench(c: &mut Criterion) {
 fn char_count_benches(c: &mut Criterion) {
     let seed = 2021;
     let (string_vec, _) = random_alphanums(2..=20, 100, seed);
-    let bytes: Vec<u8> = VarZeroVec::<str>::from(&string_vec).into_encoded_bytes();
+    let bytes: Vec<u8> = VarZeroVec::<str>::from(&string_vec).into_bytes();
     let vzv = VarZeroVec::<str>::parse_byte_slice(black_box(bytes.as_slice())).unwrap();
 
     // *** Count chars in vec of 100 strings ***
@@ -100,7 +100,7 @@ fn binary_search_benches(c: &mut Criterion) {
     let seed = 2021;
     let (string_vec, seed) = random_alphanums(2..=20, 500, seed);
     let (needles, _) = random_alphanums(2..=20, 10, seed);
-    let bytes: Vec<u8> = VarZeroVec::<str>::from(&string_vec).into_encoded_bytes();
+    let bytes: Vec<u8> = VarZeroVec::<str>::from(&string_vec).into_bytes();
     let vzv = VarZeroVec::<str>::parse_byte_slice(black_box(bytes.as_slice())).unwrap();
     let single_needle = "lmnop".to_string();
 
@@ -165,9 +165,9 @@ fn vzv_precompute_bench(c: &mut Criterion) {
     let seed = 2021;
     let (string_vec, seed) = random_alphanums(2..=20, 500, seed);
     let (needles, _) = random_alphanums(2..=20, 10, seed);
-    let bytes: Vec<u8> = VarZeroVec::<str>::from(&string_vec).into_encoded_bytes();
+    let bytes: Vec<u8> = VarZeroVec::<str>::from(&string_vec).into_bytes();
     let vzv = VarZeroVec::<str>::parse_byte_slice(black_box(bytes.as_slice())).unwrap();
-    let borrowed = vzv.as_borrowed();
+    let borrowed = vzv.as_components();
     let slice = vzv.as_slice();
     let single_needle = "lmnop".to_string();
 

utils/zerovec/src/map/vecs.rs

@@ -4,8 +4,7 @@
 
 use crate::ule::*;
 use crate::varzerovec::owned::VarZeroVecOwned;
-use crate::varzerovec::VarZeroVecBorrowed;
-use crate::VarZeroVec;
+use crate::{VarZeroSlice, VarZeroVec};
 use crate::{ZeroSlice, ZeroVec};
 use alloc::boxed::Box;
 use alloc::vec::Vec;
@@ -283,25 +282,24 @@ where
     }
 }
 
-impl<'a, T> ZeroVecLike<'a, T> for VarZeroVecBorrowed<'a, T>
+impl<'a, T> ZeroVecLike<'a, T> for &'a VarZeroSlice<T>
 where
     T: VarULE,
     T: Ord,
     T: ?Sized,
 {
     type GetType = T;
     fn zvl_new() -> Self {
-        Self::new()
+        VarZeroSlice::new_empty()
     }
     fn zvl_binary_search(&self, k: &T) -> Result<usize, usize> {
-        Self::binary_search(self, k)
+        self.binary_search(k)
     }
     fn zvl_get(&self, index: usize) -> Option<&T> {
-        // using UFCS to avoid accidental recursion
-        Self::get(*self, index)
+        self.get(index)
     }
     fn zvl_len(&self) -> usize {
-        Self::len(*self)
+        self.len()
     }
     fn zvl_is_ascending(&self) -> bool {
         if !self.is_empty() {
@@ -326,15 +324,14 @@ where
     }
 }
 
-impl<'a, T> BorrowedZeroVecLike<'a, T> for VarZeroVecBorrowed<'a, T>
+impl<'a, T> BorrowedZeroVecLike<'a, T> for &'a VarZeroSlice<T>
 where
     T: VarULE,
     T: Ord,
     T: ?Sized,
 {
     fn zvl_get_borrowed(&self, index: usize) -> Option<&'a T> {
-        // using UFCS to avoid accidental recursion
-        Self::get(*self, index)
+        self.get(index)
     }
 }
 
@@ -345,7 +342,7 @@ where
     T: ?Sized,
 {
     type OwnedType = Box<T>;
-    type BorrowedVariant = VarZeroVecBorrowed<'a, T>;
+    type BorrowedVariant = &'a VarZeroSlice<T>;
     fn zvl_insert(&mut self, index: usize, value: &T) {
         self.make_mut().insert(index, value)
     }
@@ -374,18 +371,18 @@ where
     fn zvl_reserve(&mut self, addl: usize) {
         self.make_mut().reserve(addl)
     }
-    fn zvl_as_borrowed(&'a self) -> VarZeroVecBorrowed<'a, T> {
-        self.as_borrowed()
+    fn zvl_as_borrowed(&'a self) -> &'a VarZeroSlice<T> {
+        self.as_slice()
     }
-    fn zvl_as_borrowed_inner(&self) -> Option<VarZeroVecBorrowed<'a, T>> {
+    fn zvl_as_borrowed_inner(&self) -> Option<&'a VarZeroSlice<T>> {
         if let VarZeroVec::Borrowed(b) = *self {
             Some(b)
         } else {
             None
         }
     }
-    fn zvl_from_borrowed(b: VarZeroVecBorrowed<'a, T>) -> Self {
-        VarZeroVec::Borrowed(b)
+    fn zvl_from_borrowed(b: &'a VarZeroSlice<T>) -> Self {
+        b.as_varzerovec()
     }
 
     fn owned_as_t(o: &Self::OwnedType) -> &T {

utils/zerovec/src/ule/custom/encode.rs

@@ -188,11 +188,11 @@ where
 
     fn encode_var_ule_len(&self) -> usize {
         // TODO(#1410): Rethink length errors in VZV.
-        crate::varzerovec::borrowed::compute_serializable_len(self).unwrap() as usize
+        crate::varzerovec::components::compute_serializable_len(self).unwrap() as usize
     }
 
     fn encode_var_ule_write(&self, dst: &mut [u8]) {
-        crate::varzerovec::borrowed::write_serializable_bytes(self, dst)
+        crate::varzerovec::components::write_serializable_bytes(self, dst)
     }
 }
 
@@ -228,13 +228,13 @@ where
 
     #[inline]
     fn encode_var_ule_len(&self) -> usize {
-        self.as_encoded_bytes().len()
+        self.as_bytes().len()
     }
 
     #[inline]
     fn encode_var_ule_write(&self, dst: &mut [u8]) {
-        debug_assert_eq!(self.as_encoded_bytes().len(), dst.len());
-        dst.copy_from_slice(self.as_encoded_bytes());
+        debug_assert_eq!(self.as_bytes().len(), dst.len());
+        dst.copy_from_slice(self.as_bytes());
     }
 }
 

utils/zerovec/src/varzerovec/borrowed.rs → utils/zerovec/src/varzerovec/components.rs

@@ -15,17 +15,16 @@ fn usizeify(x: RawBytesULE<4>) -> usize {
     u32::from_unaligned(x) as usize
 }
 
-/// A fully-borrowed [`VarZeroVec`]. This type has the same internal buffer representation
-/// of [`VarZeroVec`], making it cheaply convertible to [`VarZeroVec`] and [`VarZeroVecOwned`];
-/// however, unlike those two, it cannot be mutated.
+/// A more parsed version of `VarZeroSlice`. This type is where most of the VarZeroVec
+/// internal representation code lies.
 ///
 /// This is *basically* an `&'a [u8]` to a zero copy buffer, but split out into
 /// the buffer components. Logically this is capable of behaving as
 /// a `&'a [T::VarULE]`, but since `T::VarULE` is unsized that type does not actually
 /// exist.
 ///
-/// See [`VarZeroVecBorrowed::parse_byte_slice()`] for information on the internal invariants involved
-pub struct VarZeroVecBorrowed<'a, T: ?Sized> {
+/// See [`VarZeroVecComponents::parse_byte_slice()`] for information on the internal invariants involved
+pub struct VarZeroVecComponents<'a, T: ?Sized> {
     /// The list of indices into the `things` slice
     indices: &'a [RawBytesULE<4>],
     /// The contiguous list of `T::VarULE`s
@@ -37,10 +36,10 @@ pub struct VarZeroVecBorrowed<'a, T: ?Sized> {
 
 // #[derive()] won't work here since we do not want it to be
 // bound on T: Copy
-impl<'a, T: ?Sized> Copy for VarZeroVecBorrowed<'a, T> {}
-impl<'a, T: ?Sized> Clone for VarZeroVecBorrowed<'a, T> {
+impl<'a, T: ?Sized> Copy for VarZeroVecComponents<'a, T> {}
+impl<'a, T: ?Sized> Clone for VarZeroVecComponents<'a, T> {
     fn clone(&self) -> Self {
-        VarZeroVecBorrowed {
+        VarZeroVecComponents {
             indices: self.indices,
             things: self.things,
             entire_slice: self.entire_slice,
@@ -49,27 +48,14 @@ impl<'a, T: ?Sized> Clone for VarZeroVecBorrowed<'a, T> {
     }
 }
 
-impl<'a, T: VarULE + ?Sized> Default for VarZeroVecBorrowed<'a, T> {
+impl<'a, T: VarULE + ?Sized> Default for VarZeroVecComponents<'a, T> {
     #[inline]
     fn default() -> Self {
         Self::new()
     }
 }
 
-impl<'a, T: VarULE + ?Sized> VarZeroVecBorrowed<'a, T> {
-    /// Creates a new, empty `VarZeroVecBorrowed<T>`.
-    ///
-    /// Note: Since [`VarZeroVecBorrowed`] is not mutable, the return value will be a stub unless
-    /// wrapped in [`VarZeroVec::Borrowed`].
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// use zerovec::varzerovec::VarZeroVecBorrowed;
-    ///
-    /// let vzv: VarZeroVecBorrowed<str> = VarZeroVecBorrowed::new();
-    /// assert!(vzv.is_empty());
-    /// ```
+impl<'a, T: VarULE + ?Sized> VarZeroVecComponents<'a, T> {
     #[inline]
     pub fn new() -> Self {
         Self {
@@ -80,7 +66,7 @@ impl<'a, T: VarULE + ?Sized> VarZeroVecBorrowed<'a, T> {
         }
     }
 
-    /// Construct a new VarZeroVecBorrowed, checking invariants about the overall buffer size:
+    /// Construct a new VarZeroVecComponents, checking invariants about the overall buffer size:
     ///
     /// - There must be either zero or at least four bytes (if four, this is the "length" parsed as a usize)
     /// - There must be at least `4*length + 4` bytes total, to form the the array `indices` of indices
@@ -91,7 +77,7 @@ impl<'a, T: VarULE + ?Sized> VarZeroVecBorrowed<'a, T> {
     #[inline]
     pub fn parse_byte_slice(slice: &'a [u8]) -> Result<Self, ZeroVecError> {
         if slice.is_empty() {
-            return Ok(VarZeroVecBorrowed {
+            return Ok(VarZeroVecComponents {
                 indices: &[],
                 things: &[],
                 entire_slice: slice,
@@ -113,7 +99,7 @@ impl<'a, T: VarULE + ?Sized> VarZeroVecBorrowed<'a, T> {
             .get(4 * len + 4..)
             .ok_or(ZeroVecError::VarZeroVecFormatError)?;
 
-        let borrowed = VarZeroVecBorrowed {
+        let borrowed = VarZeroVecComponents {
             indices,
             things,
             entire_slice: slice,
@@ -127,17 +113,17 @@ impl<'a, T: VarULE + ?Sized> VarZeroVecBorrowed<'a, T> {
         Ok(borrowed)
     }
 
-    /// Construct a [`VarZeroVecBorrowed`] from a byte slice that has previously
-    /// successfully returned a [`VarZeroVecBorrowed`] when passed to
-    /// [`VarZeroVecBorrowed::parse_byte_slice()`]. Will return the same
-    /// object as one would get from calling [`VarZeroVecBorrowed::parse_byte_slice()`].
+    /// Construct a [`VarZeroVecComponents`] from a byte slice that has previously
+    /// successfully returned a [`VarZeroVecComponents`] when passed to
+    /// [`VarZeroVecComponents::parse_byte_slice()`]. Will return the same
+    /// object as one would get from calling [`VarZeroVecComponents::parse_byte_slice()`].
     ///
     /// # Safety
     /// The bytes must have previously successfully run through
-    /// [`VarZeroVecBorrowed::parse_byte_slice()`]
+    /// [`VarZeroVecComponents::parse_byte_slice()`]
     pub unsafe fn from_bytes_unchecked(slice: &'a [u8]) -> Self {
         if slice.is_empty() {
-            return VarZeroVecBorrowed {
+            return VarZeroVecComponents {
                 indices: &[],
                 things: &[],
                 entire_slice: slice,
@@ -152,7 +138,7 @@ impl<'a, T: VarULE + ?Sized> VarZeroVecBorrowed<'a, T> {
         let indices = RawBytesULE::<4>::from_byte_slice_unchecked(indices_bytes);
         let things = slice.get_unchecked(4 * len + 4..);
 
-        VarZeroVecBorrowed {
+        VarZeroVecComponents {
             indices,
             things,
             entire_slice: slice,
@@ -172,12 +158,6 @@ impl<'a, T: VarULE + ?Sized> VarZeroVecBorrowed<'a, T> {
         self.indices.is_empty()
     }
 
-    /// Get a reference to the entire backing buffer of this vector
-    #[inline]
-    pub fn as_encoded_bytes(self) -> &'a [u8] {
-        self.entire_slice
-    }
-
     /// Get the idx'th element out of this slice. Returns `None` if out of bounds.
     #[inline]
     pub fn get(self, idx: usize) -> Option<&'a T> {
@@ -204,15 +184,15 @@ impl<'a, T: VarULE + ?Sized> VarZeroVecBorrowed<'a, T> {
         T::from_byte_slice_unchecked(things_slice)
     }
 
-    /// Create an iterator over the Ts contained in VarZeroVecBorrowed, checking internal invariants:
+    /// Create an iterator over the Ts contained in VarZeroVecComponents, checking internal invariants:
     ///
     /// - `indices[i]..indices[i+1]` must index into a valid section of
     ///   `things`, such that it parses to a `T::VarULE`
     /// - `indices[len - 1]..things.len()` must index into a valid section of
     ///   `things`, such that it parses to a `T::VarULE`
     /// - `indices` is monotonically increasing
     ///
-    /// This method is NOT allowed to call any other methods on VarZeroVecBorrowed since all other methods
+    /// This method is NOT allowed to call any other methods on VarZeroVecComponents since all other methods
     /// assume that the slice has been passed through iter_checked
     #[inline]
     fn iter_checked(self) -> impl Iterator<Item = Result<&'a T, ZeroVecError>> {
@@ -244,7 +224,7 @@ impl<'a, T: VarULE + ?Sized> VarZeroVecBorrowed<'a, T> {
             .map(|s| s.and_then(|s| T::parse_byte_slice(s)))
     }
 
-    /// Create an iterator over the Ts contained in VarZeroVecBorrowed
+    /// Create an iterator over the Ts contained in VarZeroVecComponents
     #[inline]
     pub fn iter(self) -> impl Iterator<Item = &'a T> {
         let last = iter::from_fn(move || {
@@ -281,17 +261,17 @@ impl<'a, T: VarULE + ?Sized> VarZeroVecBorrowed<'a, T> {
             .copied()
             .map(u32::from_unaligned)
             .collect::<Vec<_>>();
-        format!("VarZeroVecBorrowed {{ indices: {:?} }}", indices)
+        format!("VarZeroVecComponents {{ indices: {:?} }}", indices)
     }
 }
 
-impl<'a, T> VarZeroVecBorrowed<'a, T>
+impl<'a, T> VarZeroVecComponents<'a, T>
 where
     T: VarULE,
     T: ?Sized,
     T: Ord,
 {
-    /// Binary searches a sorted `VarZeroVecBorrowed<T>` for the given element. For more information, see
+    /// Binary searches a sorted `VarZeroVecComponents<T>` for the given element. For more information, see
     /// the primitive function [`binary_search`](slice::binary_search).
     pub fn binary_search(&self, needle: &T) -> Result<usize, usize> {
         // This code is an absolute atrocity. This code is not a place of honor. This