Unfortunately, we still need to have a representation of ns{Fixed,}{C,}StringRepr in tree, as some FFI structs need to control and run their destructors independently. Not providing a drop-implementation-free version of these types means that they are unusable in those situations, such as in the style bindings. This may be avoidable when `union` is stabilized in rust, as that will allow for structs which contain a value of a type to control whether or not that type's destructor gets run. (https://github.com/rust-lang/rust/issues/32836) This patch will pretty-much be a backout of bug 1316696.

MozReview-Commit-ID: 3VUWFA5tX1L

Comment on attachment 8836901 [details] [diff] [review] Re-introduce the ns[C]StringRepr type for use in bindings with custom destructor logic Review of attachment 8836901 [details] [diff] [review]: ----------------------------------------------------------------- rs=me on the presumption that this is a revert of the backout.

Comment on attachment 8836901 [details] [diff] [review] Re-introduce the ns[C]StringRepr type for use in bindings with custom destructor logic This isn't exactly just a backout, as I still wanted ns[C]String to be `#[repr(C)]` which was also added in that patch, and I wanted to verify that both the ns[C]StringRepr and ns[C]String had the correct layout. I'd appreciate it if you could look over the changes a bit more closely :).

Comment on attachment 8836901 [details] [diff] [review] Re-introduce the ns[C]StringRepr type for use in bindings with custom destructor logic Review of attachment 8836901 [details] [diff] [review]: ----------------------------------------------------------------- ::: xpcom/rust/nsstring/src/lib.rs @@ +843,5 @@ > + align: *mut usize, > + offset: *mut usize) { > + unsafe { > + // Create a temporary value of type T to get offsets, sizes > + // and aligns off of I think "...and alignments from" reads better, WDYT?

Pushed by michael@thelayzells.com: https://hg.mozilla.org/integration/mozilla-inbound/rev/7ecbacf4e84c Re-introduce the ns[C]StringRepr type for use in bindings with custom destructor logic, r=froydnj

Pushed by michael@thelayzells.com: https://hg.mozilla.org/integration/mozilla-inbound/rev/7045bd028af0 Comment wording fixup, r=me

https://hg.mozilla.org/mozilla-central/rev/7ecbacf4e84c https://hg.mozilla.org/mozilla-central/rev/7045bd028af0