[libcxx-commits] [PATCH] D102037: [libcxx][views] Add drop_view.

[Tim Song via Phabricator via libcxx-commits]

tcanens added inline comments.


================
Comment at: libcxx/include/__ranges/drop_view.h:44
+    range_difference_t<_View> __count = 0;
+    iterator_t<_View> __cached_begin = ranges::begin(__base);
+
----------------
cjdb wrote:
> tcanens wrote:
> > tcanens wrote:
> > > There's no requirement that `ranges::begin` on a default-constructed view is even well-defined (see: `ref_view`).
> > > 
> > > Additionally, when a `drop_view` is copied, the cache must be invalidated in the copy.
> > ...and when a `drop_view` is moved-from, the cache must be invalidated in the original.
> @tcanens is this a non-propagating cache?
Yep. This is the original use case of //`non-propagating-cache`// in range-v3.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D102037/new/

https://reviews.llvm.org/D102037