Introduce ruff_index crate (#4597)

crates/ruff_index/src/vec.rs

@@ -0,0 +1,170 @@
+use crate::slice::IndexSlice;
+use crate::Idx;
+use std::borrow::{Borrow, BorrowMut};
+use std::fmt::{Debug, Formatter};
+use std::marker::PhantomData;
+use std::ops::{Deref, DerefMut, RangeBounds};
+
+/// An owned sequence of `T` indexed by `I`
+#[derive(Clone, PartialEq, Eq, Hash)]
+#[repr(transparent)]
+pub struct IndexVec<I, T> {
+    pub raw: Vec<T>,
+    index: PhantomData<I>,
+}
+
+impl<I: Idx, T> IndexVec<I, T> {
+    #[inline]
+    pub fn new() -> Self {
+        Self {
+            raw: Vec::new(),
+            index: PhantomData,
+        }
+    }
+
+    #[inline]
+    pub fn with_capacity(capacity: usize) -> Self {
+        Self {
+            raw: Vec::with_capacity(capacity),
+            index: PhantomData,
+        }
+    }
+
+    #[inline]
+    pub fn from_raw(raw: Vec<T>) -> Self {
+        Self {
+            raw,
+            index: PhantomData,
+        }
+    }
+
+    #[inline]
+    pub fn drain<R: RangeBounds<usize>>(&mut self, range: R) -> impl Iterator<Item = T> + '_ {
+        self.raw.drain(range)
+    }
+
+    #[inline]
+    pub fn truncate(&mut self, a: usize) {
+        self.raw.truncate(a);
+    }
+
+    #[inline]
+    pub fn as_slice(&self) -> &IndexSlice<I, T> {
+        IndexSlice::from_raw(&self.raw)
+    }
+
+    #[inline]
+    pub fn as_mut_slice(&mut self) -> &mut IndexSlice<I, T> {
+        IndexSlice::from_raw_mut(&mut self.raw)
+    }
+
+    #[inline]
+    pub fn push(&mut self, data: T) -> I {
+        let index = self.next_index();
+        self.raw.push(data);
+        index
+    }
+
+    #[inline]
+    pub fn next_index(&self) -> I {
+        I::new(self.raw.len())
+    }
+}
+
+impl<I, T> Debug for IndexVec<I, T>
+where
+    T: Debug,
+{
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        std::fmt::Debug::fmt(&self.raw, f)
+    }
+}
+
+impl<I: Idx, T> Deref for IndexVec<I, T> {
+    type Target = IndexSlice<I, T>;
+
+    fn deref(&self) -> &Self::Target {
+        self.as_slice()
+    }
+}
+
+impl<I: Idx, T> DerefMut for IndexVec<I, T> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        self.as_mut_slice()
+    }
+}
+
+impl<I: Idx, T> Borrow<IndexSlice<I, T>> for IndexVec<I, T> {
+    fn borrow(&self) -> &IndexSlice<I, T> {
+        self
+    }
+}
+
+impl<I: Idx, T> BorrowMut<IndexSlice<I, T>> for IndexVec<I, T> {
+    fn borrow_mut(&mut self) -> &mut IndexSlice<I, T> {
+        self
+    }
+}
+
+impl<I, T> Extend<T> for IndexVec<I, T> {
+    #[inline]
+    fn extend<Iter: IntoIterator<Item = T>>(&mut self, iter: Iter) {
+        self.raw.extend(iter);
+    }
+}
+
+impl<I: Idx, T> FromIterator<T> for IndexVec<I, T> {
+    #[inline]
+    fn from_iter<Iter: IntoIterator<Item = T>>(iter: Iter) -> Self {
+        Self::from_raw(Vec::from_iter(iter))
+    }
+}
+
+impl<I: Idx, T> IntoIterator for IndexVec<I, T> {
+    type Item = T;
+    type IntoIter = std::vec::IntoIter<T>;
+
+    #[inline]
+    fn into_iter(self) -> std::vec::IntoIter<T> {
+        self.raw.into_iter()
+    }
+}
+
+impl<'a, I: Idx, T> IntoIterator for &'a IndexVec<I, T> {
+    type Item = &'a T;
+    type IntoIter = std::slice::Iter<'a, T>;
+
+    #[inline]
+    fn into_iter(self) -> std::slice::Iter<'a, T> {
+        self.iter()
+    }
+}
+
+impl<'a, I: Idx, T> IntoIterator for &'a mut IndexVec<I, T> {
+    type Item = &'a mut T;
+    type IntoIter = std::slice::IterMut<'a, T>;
+
+    #[inline]
+    fn into_iter(self) -> std::slice::IterMut<'a, T> {
+        self.iter_mut()
+    }
+}
+
+impl<I: Idx, T> Default for IndexVec<I, T> {
+    #[inline]
+    fn default() -> Self {
+        IndexVec::new()
+    }
+}
+
+impl<I: Idx, T, const N: usize> From<[T; N]> for IndexVec<I, T> {
+    #[inline]
+    fn from(array: [T; N]) -> Self {
+        IndexVec::from_raw(array.into())
+    }
+}
+
+// Whether `IndexVec` is `Send` depends only on the data,
+// not the phantom data.
+#[allow(unsafe_code)]
+unsafe impl<I: Idx, T> Send for IndexVec<I, T> where T: Send {}