Rollup merge of #70910 - rakshith-ravi:master, r=cuviper
Hides default fns inside Fuse impl to avoid exposing it to any crate Fixes #70796 @cuviper I've added some default, private traits to do the job for us. If required, I can expose them to a specific visibility if you want to call these functions for #70332 r? @cuviper
This commit is contained in:
Dylan DPC
GitHub
commit
d19458784f
1 changed files with 244 additions and 63 deletions
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@ -44,6 +44,19 @@ macro_rules! fuse {
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};
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}
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// NOTE: for `I: FusedIterator`, we assume that the iterator is always `Some`.
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// Implementing this as a directly-expanded macro helps codegen performance.
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macro_rules! unchecked {
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($self:ident) => {
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match $self {
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Fuse { iter: Some(iter) } => iter,
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// SAFETY: the specialized iterator never sets `None`
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Fuse { iter: None } => unsafe { intrinsics::unreachable() },
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}
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};
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}
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// Any implementation here is made internal to avoid exposing default fns outside this trait
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#[stable(feature = "rust1", since = "1.0.0")]
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impl<I> Iterator for Fuse<I>
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where
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@ -51,6 +64,193 @@ where
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{
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type Item = <I as Iterator>::Item;
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#[inline]
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fn next(&mut self) -> Option<Self::Item> {
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FuseImpl::next(self)
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}
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#[inline]
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fn nth(&mut self, n: usize) -> Option<I::Item> {
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FuseImpl::nth(self, n)
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}
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#[inline]
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fn last(self) -> Option<Self::Item> {
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FuseImpl::last(self)
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}
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#[inline]
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fn count(self) -> usize {
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FuseImpl::count(self)
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}
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#[inline]
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fn size_hint(&self) -> (usize, Option<usize>) {
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FuseImpl::size_hint(self)
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}
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#[inline]
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fn try_fold<Acc, Fold, R>(&mut self, acc: Acc, fold: Fold) -> R
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where
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Self: Sized,
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Fold: FnMut(Acc, Self::Item) -> R,
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R: Try<Ok = Acc>,
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{
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FuseImpl::try_fold(self, acc, fold)
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}
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#[inline]
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fn fold<Acc, Fold>(self, acc: Acc, fold: Fold) -> Acc
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where
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Fold: FnMut(Acc, Self::Item) -> Acc,
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{
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FuseImpl::fold(self, acc, fold)
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}
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#[inline]
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fn find<P>(&mut self, predicate: P) -> Option<Self::Item>
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where
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P: FnMut(&Self::Item) -> bool,
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{
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FuseImpl::find(self, predicate)
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}
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}
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#[stable(feature = "rust1", since = "1.0.0")]
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impl<I> DoubleEndedIterator for Fuse<I>
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where
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I: DoubleEndedIterator,
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{
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#[inline]
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fn next_back(&mut self) -> Option<<I as Iterator>::Item> {
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FuseImpl::next_back(self)
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}
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#[inline]
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fn nth_back(&mut self, n: usize) -> Option<<I as Iterator>::Item> {
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FuseImpl::nth_back(self, n)
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}
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#[inline]
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fn try_rfold<Acc, Fold, R>(&mut self, acc: Acc, fold: Fold) -> R
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where
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Self: Sized,
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Fold: FnMut(Acc, Self::Item) -> R,
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R: Try<Ok = Acc>,
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{
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FuseImpl::try_rfold(self, acc, fold)
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}
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#[inline]
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fn rfold<Acc, Fold>(self, acc: Acc, fold: Fold) -> Acc
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where
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Fold: FnMut(Acc, Self::Item) -> Acc,
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{
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FuseImpl::rfold(self, acc, fold)
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}
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#[inline]
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fn rfind<P>(&mut self, predicate: P) -> Option<Self::Item>
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where
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P: FnMut(&Self::Item) -> bool,
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{
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FuseImpl::rfind(self, predicate)
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}
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}
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#[stable(feature = "rust1", since = "1.0.0")]
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impl<I> ExactSizeIterator for Fuse<I>
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where
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I: ExactSizeIterator,
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{
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fn len(&self) -> usize {
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FuseImpl::len(self)
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}
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fn is_empty(&self) -> bool {
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FuseImpl::is_empty(self)
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}
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}
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unsafe impl<I> TrustedRandomAccess for Fuse<I>
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where
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I: TrustedRandomAccess,
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{
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unsafe fn get_unchecked(&mut self, i: usize) -> I::Item {
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match self.iter {
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Some(ref mut iter) => iter.get_unchecked(i),
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// SAFETY: the caller asserts there is an item at `i`, so we're not exhausted.
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None => intrinsics::unreachable(),
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}
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}
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fn may_have_side_effect() -> bool {
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I::may_have_side_effect()
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}
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}
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// Fuse specialization trait
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#[doc(hidden)]
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trait FuseImpl<I> {
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type Item;
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// Functions specific to any normal Iterators
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fn next(&mut self) -> Option<Self::Item>;
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fn nth(&mut self, n: usize) -> Option<Self::Item>;
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fn last(self) -> Option<Self::Item>;
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fn count(self) -> usize;
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fn size_hint(&self) -> (usize, Option<usize>);
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fn try_fold<Acc, Fold, R>(&mut self, acc: Acc, fold: Fold) -> R
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where
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Self: Sized,
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Fold: FnMut(Acc, Self::Item) -> R,
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R: Try<Ok = Acc>;
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fn fold<Acc, Fold>(self, acc: Acc, fold: Fold) -> Acc
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where
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Fold: FnMut(Acc, Self::Item) -> Acc;
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fn find<P>(&mut self, predicate: P) -> Option<Self::Item>
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where
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P: FnMut(&Self::Item) -> bool;
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// Functions specific to DoubleEndedIterators
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fn next_back(&mut self) -> Option<Self::Item>
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where
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I: DoubleEndedIterator;
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fn nth_back(&mut self, n: usize) -> Option<Self::Item>
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where
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I: DoubleEndedIterator;
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fn try_rfold<Acc, Fold, R>(&mut self, acc: Acc, fold: Fold) -> R
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where
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Self: Sized,
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Fold: FnMut(Acc, Self::Item) -> R,
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R: Try<Ok = Acc>,
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I: DoubleEndedIterator;
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fn rfold<Acc, Fold>(self, acc: Acc, fold: Fold) -> Acc
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where
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Fold: FnMut(Acc, Self::Item) -> Acc,
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I: DoubleEndedIterator;
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fn rfind<P>(&mut self, predicate: P) -> Option<Self::Item>
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where
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P: FnMut(&Self::Item) -> bool,
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I: DoubleEndedIterator;
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// Functions specific to ExactSizeIterator
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fn len(&self) -> usize
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where
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I: ExactSizeIterator;
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fn is_empty(&self) -> bool
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where
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I: ExactSizeIterator;
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}
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// General Fuse impl
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#[doc(hidden)]
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impl<I> FuseImpl<I> for Fuse<I>
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where
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I: Iterator,
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{
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type Item = <I as Iterator>::Item;
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#[inline]
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default fn next(&mut self) -> Option<<I as Iterator>::Item> {
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fuse!(self.iter.next())
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@ -117,20 +317,20 @@ where
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{
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fuse!(self.iter.find(predicate))
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}
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}
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#[stable(feature = "rust1", since = "1.0.0")]
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impl<I> DoubleEndedIterator for Fuse<I>
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where
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I: DoubleEndedIterator,
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{
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#[inline]
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default fn next_back(&mut self) -> Option<<I as Iterator>::Item> {
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default fn next_back(&mut self) -> Option<<I as Iterator>::Item>
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where
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I: DoubleEndedIterator,
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{
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fuse!(self.iter.next_back())
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}
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#[inline]
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default fn nth_back(&mut self, n: usize) -> Option<<I as Iterator>::Item> {
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default fn nth_back(&mut self, n: usize) -> Option<<I as Iterator>::Item>
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where
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I: DoubleEndedIterator,
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{
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fuse!(self.iter.nth_back(n))
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}
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@ -140,6 +340,7 @@ where
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Self: Sized,
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Fold: FnMut(Acc, Self::Item) -> R,
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R: Try<Ok = Acc>,
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I: DoubleEndedIterator,
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{
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if let Some(ref mut iter) = self.iter {
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acc = iter.try_rfold(acc, fold)?;
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@ -152,6 +353,7 @@ where
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default fn rfold<Acc, Fold>(self, mut acc: Acc, fold: Fold) -> Acc
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where
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Fold: FnMut(Acc, Self::Item) -> Acc,
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I: DoubleEndedIterator,
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{
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if let Some(iter) = self.iter {
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acc = iter.rfold(acc, fold);
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@ -163,24 +365,27 @@ where
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default fn rfind<P>(&mut self, predicate: P) -> Option<Self::Item>
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where
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P: FnMut(&Self::Item) -> bool,
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I: DoubleEndedIterator,
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{
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fuse!(self.iter.rfind(predicate))
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}
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}
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#[stable(feature = "rust1", since = "1.0.0")]
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impl<I> ExactSizeIterator for Fuse<I>
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where
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I: ExactSizeIterator,
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{
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default fn len(&self) -> usize {
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#[inline]
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default fn len(&self) -> usize
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where
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I: ExactSizeIterator,
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{
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match self.iter {
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Some(ref iter) => iter.len(),
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None => 0,
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}
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}
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default fn is_empty(&self) -> bool {
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#[inline]
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default fn is_empty(&self) -> bool
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where
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I: ExactSizeIterator,
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{
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match self.iter {
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Some(ref iter) => iter.is_empty(),
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None => true,
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@ -188,20 +393,8 @@ where
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}
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}
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// NOTE: for `I: FusedIterator`, we assume that the iterator is always `Some`.
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// Implementing this as a directly-expanded macro helps codegen performance.
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macro_rules! unchecked {
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($self:ident) => {
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match $self {
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Fuse { iter: Some(iter) } => iter,
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// SAFETY: the specialized iterator never sets `None`
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Fuse { iter: None } => unsafe { intrinsics::unreachable() },
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}
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};
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}
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#[stable(feature = "fused", since = "1.26.0")]
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impl<I> Iterator for Fuse<I>
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#[doc(hidden)]
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impl<I> FuseImpl<I> for Fuse<I>
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where
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I: FusedIterator,
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{
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@ -255,20 +448,20 @@ where
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{
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unchecked!(self).find(predicate)
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}
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}
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#[stable(feature = "fused", since = "1.26.0")]
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impl<I> DoubleEndedIterator for Fuse<I>
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where
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I: DoubleEndedIterator + FusedIterator,
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{
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#[inline]
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fn next_back(&mut self) -> Option<<I as Iterator>::Item> {
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fn next_back(&mut self) -> Option<<I as Iterator>::Item>
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where
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I: DoubleEndedIterator,
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{
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unchecked!(self).next_back()
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}
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#[inline]
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fn nth_back(&mut self, n: usize) -> Option<<I as Iterator>::Item> {
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fn nth_back(&mut self, n: usize) -> Option<<I as Iterator>::Item>
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where
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I: DoubleEndedIterator,
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{
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unchecked!(self).nth_back(n)
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}
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@ -278,6 +471,7 @@ where
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Self: Sized,
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Fold: FnMut(Acc, Self::Item) -> R,
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R: Try<Ok = Acc>,
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I: DoubleEndedIterator,
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{
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unchecked!(self).try_rfold(init, fold)
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}
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@ -286,6 +480,7 @@ where
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fn rfold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc
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where
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Fold: FnMut(Acc, Self::Item) -> Acc,
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I: DoubleEndedIterator,
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{
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unchecked!(self).rfold(init, fold)
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}
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@ -294,38 +489,24 @@ where
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fn rfind<P>(&mut self, predicate: P) -> Option<Self::Item>
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where
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P: FnMut(&Self::Item) -> bool,
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I: DoubleEndedIterator,
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{
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unchecked!(self).rfind(predicate)
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}
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}
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#[stable(feature = "rust1", since = "1.0.0")]
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impl<I> ExactSizeIterator for Fuse<I>
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where
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I: ExactSizeIterator + FusedIterator,
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{
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fn len(&self) -> usize {
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#[inline]
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fn len(&self) -> usize
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where
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I: ExactSizeIterator,
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{
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unchecked!(self).len()
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}
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fn is_empty(&self) -> bool {
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#[inline]
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fn is_empty(&self) -> bool
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where
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I: ExactSizeIterator,
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{
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unchecked!(self).is_empty()
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}
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}
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unsafe impl<I> TrustedRandomAccess for Fuse<I>
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where
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I: TrustedRandomAccess,
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{
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unsafe fn get_unchecked(&mut self, i: usize) -> I::Item {
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match self.iter {
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Some(ref mut iter) => iter.get_unchecked(i),
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// SAFETY: the caller asserts there is an item at `i`, so we're not exhausted.
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None => intrinsics::unreachable(),
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}
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}
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fn may_have_side_effect() -> bool {
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I::may_have_side_effect()
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}
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}
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