identifier_str might look a bit overengineered, but we want to reuse
this bit of code and it needs a reference to the token from which to
pick the identifier.
The problem with this is that the token would be owned by self, but
the function needs to mutate (the interner), so this implementation is
the most straightforward way of acquiring and working with an
immutable reference to the token before interning the identifier.
Change-Id: I618ce8f789cb59b3a9c5b79a13111ea6d00b2424
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2592
Reviewed-by: tazjin <mail@tazj.in>
Tested-by: BuildkiteCI
This is based on this matklad post:
https://matklad.github.io/2020/03/22/fast-simple-rust-interner.html
It's modified slightly to provide a safer interface and slightly more
readable implementation:
* interned string IDs are wrapped in a newtype that is not publicly
constructible
* unsafe block is reduced to only the small scope in which it is
needed
* lookup lifetime is pinned explicitly to make the intent clearer when
reading this code
Change-Id: Ia3dae988f33f8e5e7d8dc0c1a9216914a945b036
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2578
Tested-by: BuildkiteCI
Reviewed-by: tazjin <mail@tazj.in>
