Rollup merge of #78590 - DeveloperC286:issue_60302, r=varkor

refactor: removing alloc::collections::vec_deque ignore-tidy-filelength

This PR removes the need for ignore-tidy-filelength for alloc::collections::vec_deque which is part of the issue #60302

It is probably easiest to review this PR by looking at it commit by commit rather than looking at the overall diff.

library/alloc/src/collections/vec_deque/into_iter.rs

@@ -0,0 +1,57 @@
+use core::fmt;
+use core::iter::FusedIterator;
+
+use super::VecDeque;
+
+/// An owning iterator over the elements of a `VecDeque`.
+///
+/// This `struct` is created by the [`into_iter`] method on [`VecDeque`]
+/// (provided by the `IntoIterator` trait). See its documentation for more.
+///
+/// [`into_iter`]: VecDeque::into_iter
+#[derive(Clone)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct IntoIter<T> {
+    pub(crate) inner: VecDeque<T>,
+}
+
+#[stable(feature = "collection_debug", since = "1.17.0")]
+impl<T: fmt::Debug> fmt::Debug for IntoIter<T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_tuple("IntoIter").field(&self.inner).finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> Iterator for IntoIter<T> {
+    type Item = T;
+
+    #[inline]
+    fn next(&mut self) -> Option<T> {
+        self.inner.pop_front()
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let len = self.inner.len();
+        (len, Some(len))
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> DoubleEndedIterator for IntoIter<T> {
+    #[inline]
+    fn next_back(&mut self) -> Option<T> {
+        self.inner.pop_back()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> ExactSizeIterator for IntoIter<T> {
+    fn is_empty(&self) -> bool {
+        self.inner.is_empty()
+    }
+}
+
+#[stable(feature = "fused", since = "1.26.0")]
+impl<T> FusedIterator for IntoIter<T> {}

library/alloc/src/collections/vec_deque/iter.rs

@@ -0,0 +1,159 @@
+use core::fmt;
+use core::iter::FusedIterator;
+use core::ops::Try;
+
+use super::{count, wrap_index, RingSlices};
+
+/// An iterator over the elements of a `VecDeque`.
+///
+/// This `struct` is created by the [`iter`] method on [`super::VecDeque`]. See its
+/// documentation for more.
+///
+/// [`iter`]: super::VecDeque::iter
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Iter<'a, T: 'a> {
+    pub(crate) ring: &'a [T],
+    pub(crate) tail: usize,
+    pub(crate) head: usize,
+}
+
+#[stable(feature = "collection_debug", since = "1.17.0")]
+impl<T: fmt::Debug> fmt::Debug for Iter<'_, T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let (front, back) = RingSlices::ring_slices(self.ring, self.head, self.tail);
+        f.debug_tuple("Iter").field(&front).field(&back).finish()
+    }
+}
+
+// FIXME(#26925) Remove in favor of `#[derive(Clone)]`
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> Clone for Iter<'_, T> {
+    fn clone(&self) -> Self {
+        Iter { ring: self.ring, tail: self.tail, head: self.head }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, T> Iterator for Iter<'a, T> {
+    type Item = &'a T;
+
+    #[inline]
+    fn next(&mut self) -> Option<&'a T> {
+        if self.tail == self.head {
+            return None;
+        }
+        let tail = self.tail;
+        self.tail = wrap_index(self.tail.wrapping_add(1), self.ring.len());
+        unsafe { Some(self.ring.get_unchecked(tail)) }
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let len = count(self.tail, self.head, self.ring.len());
+        (len, Some(len))
+    }
+
+    fn fold<Acc, F>(self, mut accum: Acc, mut f: F) -> Acc
+    where
+        F: FnMut(Acc, Self::Item) -> Acc,
+    {
+        let (front, back) = RingSlices::ring_slices(self.ring, self.head, self.tail);
+        accum = front.iter().fold(accum, &mut f);
+        back.iter().fold(accum, &mut f)
+    }
+
+    fn try_fold<B, F, R>(&mut self, init: B, mut f: F) -> R
+    where
+        Self: Sized,
+        F: FnMut(B, Self::Item) -> R,
+        R: Try<Ok = B>,
+    {
+        let (mut iter, final_res);
+        if self.tail <= self.head {
+            // single slice self.ring[self.tail..self.head]
+            iter = self.ring[self.tail..self.head].iter();
+            final_res = iter.try_fold(init, &mut f);
+        } else {
+            // two slices: self.ring[self.tail..], self.ring[..self.head]
+            let (front, back) = self.ring.split_at(self.tail);
+            let mut back_iter = back.iter();
+            let res = back_iter.try_fold(init, &mut f);
+            let len = self.ring.len();
+            self.tail = (self.ring.len() - back_iter.len()) & (len - 1);
+            iter = front[..self.head].iter();
+            final_res = iter.try_fold(res?, &mut f);
+        }
+        self.tail = self.head - iter.len();
+        final_res
+    }
+
+    fn nth(&mut self, n: usize) -> Option<Self::Item> {
+        if n >= count(self.tail, self.head, self.ring.len()) {
+            self.tail = self.head;
+            None
+        } else {
+            self.tail = wrap_index(self.tail.wrapping_add(n), self.ring.len());
+            self.next()
+        }
+    }
+
+    #[inline]
+    fn last(mut self) -> Option<&'a T> {
+        self.next_back()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, T> DoubleEndedIterator for Iter<'a, T> {
+    #[inline]
+    fn next_back(&mut self) -> Option<&'a T> {
+        if self.tail == self.head {
+            return None;
+        }
+        self.head = wrap_index(self.head.wrapping_sub(1), self.ring.len());
+        unsafe { Some(self.ring.get_unchecked(self.head)) }
+    }
+
+    fn rfold<Acc, F>(self, mut accum: Acc, mut f: F) -> Acc
+    where
+        F: FnMut(Acc, Self::Item) -> Acc,
+    {
+        let (front, back) = RingSlices::ring_slices(self.ring, self.head, self.tail);
+        accum = back.iter().rfold(accum, &mut f);
+        front.iter().rfold(accum, &mut f)
+    }
+
+    fn try_rfold<B, F, R>(&mut self, init: B, mut f: F) -> R
+    where
+        Self: Sized,
+        F: FnMut(B, Self::Item) -> R,
+        R: Try<Ok = B>,
+    {
+        let (mut iter, final_res);
+        if self.tail <= self.head {
+            // single slice self.ring[self.tail..self.head]
+            iter = self.ring[self.tail..self.head].iter();
+            final_res = iter.try_rfold(init, &mut f);
+        } else {
+            // two slices: self.ring[self.tail..], self.ring[..self.head]
+            let (front, back) = self.ring.split_at(self.tail);
+            let mut front_iter = front[..self.head].iter();
+            let res = front_iter.try_rfold(init, &mut f);
+            self.head = front_iter.len();
+            iter = back.iter();
+            final_res = iter.try_rfold(res?, &mut f);
+        }
+        self.head = self.tail + iter.len();
+        final_res
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> ExactSizeIterator for Iter<'_, T> {
+    fn is_empty(&self) -> bool {
+        self.head == self.tail
+    }
+}
+
+#[stable(feature = "fused", since = "1.26.0")]
+impl<T> FusedIterator for Iter<'_, T> {}

library/alloc/src/collections/vec_deque/iter_mut.rs

@@ -0,0 +1,128 @@
+use core::fmt;
+use core::iter::FusedIterator;
+use core::marker::PhantomData;
+
+use super::{count, wrap_index, RingSlices};
+
+/// A mutable iterator over the elements of a `VecDeque`.
+///
+/// This `struct` is created by the [`iter_mut`] method on [`super::VecDeque`]. See its
+/// documentation for more.
+///
+/// [`iter_mut`]: super::VecDeque::iter_mut
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct IterMut<'a, T: 'a> {
+    // Internal safety invariant: the entire slice is dereferencable.
+    pub(crate) ring: *mut [T],
+    pub(crate) tail: usize,
+    pub(crate) head: usize,
+    pub(crate) phantom: PhantomData<&'a mut [T]>,
+}
+
+// SAFETY: we do nothing thread-local and there is no interior mutability,
+// so the usual structural `Send`/`Sync` apply.
+#[stable(feature = "rust1", since = "1.0.0")]
+unsafe impl<T: Send> Send for IterMut<'_, T> {}
+#[stable(feature = "rust1", since = "1.0.0")]
+unsafe impl<T: Sync> Sync for IterMut<'_, T> {}
+
+#[stable(feature = "collection_debug", since = "1.17.0")]
+impl<T: fmt::Debug> fmt::Debug for IterMut<'_, T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let (front, back) = RingSlices::ring_slices(self.ring, self.head, self.tail);
+        // SAFETY: these are the elements we have not handed out yet, so aliasing is fine.
+        // The `IterMut` invariant also ensures everything is dereferencable.
+        let (front, back) = unsafe { (&*front, &*back) };
+        f.debug_tuple("IterMut").field(&front).field(&back).finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, T> Iterator for IterMut<'a, T> {
+    type Item = &'a mut T;
+
+    #[inline]
+    fn next(&mut self) -> Option<&'a mut T> {
+        if self.tail == self.head {
+            return None;
+        }
+        let tail = self.tail;
+        self.tail = wrap_index(self.tail.wrapping_add(1), self.ring.len());
+
+        unsafe {
+            let elem = self.ring.get_unchecked_mut(tail);
+            Some(&mut *elem)
+        }
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let len = count(self.tail, self.head, self.ring.len());
+        (len, Some(len))
+    }
+
+    fn fold<Acc, F>(self, mut accum: Acc, mut f: F) -> Acc
+    where
+        F: FnMut(Acc, Self::Item) -> Acc,
+    {
+        let (front, back) = RingSlices::ring_slices(self.ring, self.head, self.tail);
+        // SAFETY: these are the elements we have not handed out yet, so aliasing is fine.
+        // The `IterMut` invariant also ensures everything is dereferencable.
+        let (front, back) = unsafe { (&mut *front, &mut *back) };
+        accum = front.iter_mut().fold(accum, &mut f);
+        back.iter_mut().fold(accum, &mut f)
+    }
+
+    fn nth(&mut self, n: usize) -> Option<Self::Item> {
+        if n >= count(self.tail, self.head, self.ring.len()) {
+            self.tail = self.head;
+            None
+        } else {
+            self.tail = wrap_index(self.tail.wrapping_add(n), self.ring.len());
+            self.next()
+        }
+    }
+
+    #[inline]
+    fn last(mut self) -> Option<&'a mut T> {
+        self.next_back()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, T> DoubleEndedIterator for IterMut<'a, T> {
+    #[inline]
+    fn next_back(&mut self) -> Option<&'a mut T> {
+        if self.tail == self.head {
+            return None;
+        }
+        self.head = wrap_index(self.head.wrapping_sub(1), self.ring.len());
+
+        unsafe {
+            let elem = self.ring.get_unchecked_mut(self.head);
+            Some(&mut *elem)
+        }
+    }
+
+    fn rfold<Acc, F>(self, mut accum: Acc, mut f: F) -> Acc
+    where
+        F: FnMut(Acc, Self::Item) -> Acc,
+    {
+        let (front, back) = RingSlices::ring_slices(self.ring, self.head, self.tail);
+        // SAFETY: these are the elements we have not handed out yet, so aliasing is fine.
+        // The `IterMut` invariant also ensures everything is dereferencable.
+        let (front, back) = unsafe { (&mut *front, &mut *back) };
+        accum = back.iter_mut().rfold(accum, &mut f);
+        front.iter_mut().rfold(accum, &mut f)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> ExactSizeIterator for IterMut<'_, T> {
+    fn is_empty(&self) -> bool {
+        self.head == self.tail
+    }
+}
+
+#[stable(feature = "fused", since = "1.26.0")]
+impl<T> FusedIterator for IterMut<'_, T> {}

library/alloc/src/collections/vec_deque/macros.rs

@@ -0,0 +1,19 @@
+macro_rules! __impl_slice_eq1 {
+    ([$($vars:tt)*] $lhs:ty, $rhs:ty, $($constraints:tt)*) => {
+        #[stable(feature = "vec_deque_partial_eq_slice", since = "1.17.0")]
+        impl<A, B, $($vars)*> PartialEq<$rhs> for $lhs
+        where
+            A: PartialEq<B>,
+            $($constraints)*
+        {
+            fn eq(&self, other: &$rhs) -> bool {
+                if self.len() != other.len() {
+                    return false;
+                }
+                let (sa, sb) = self.as_slices();
+                let (oa, ob) = other[..].split_at(sa.len());
+                sa == oa && sb == ob
+            }
+        }
+    }
+}