This PR massively speeds up the case in which you need to install wheels
that already exist in the global cache.
The new strategy is as follows:
- Download the wheel into the content-addressed cache.
- Unzip the wheel into the cache, but ignore content-addressing. It
turns out that writing to `cacache` for every file in the zip added a
ton of overhead, and I don't see any actual advantages to doing so.
Instead, we just unzip the contents into a directory at, e.g.,
`~/.cache/puffin/django-4.1.5`.
- (The unzip itself is now parallelized with Rayon.)
- When installing the wheel, we now support unzipping from a directory
instead of a zip archive. This required duplicating and tweaking a few
functions.
- When installing the wheel, we now use reflinks (or copy-on-write
links). These have a few fantastic properties: (1) they're extremely
cheap to create (on macOS, they are allegedly faster than hard links);
(2) they minimize disk space, since we avoid copying files entirely in
the vast majority of cases; and (3) if the user then edits a file
locally, the cache doesn't get polluted. Orogene, Bun, and soon pnpm all
use reflinks.
Puffin is now ~15x faster than `pip` for the common case of installing
cached data into a fresh environment.
Closes https://github.com/astral-sh/puffin/issues/21.
Closes https://github.com/astral-sh/puffin/issues/39.
This PR modifies the `install-wheel-rs` (and a few other crates) to get
everything playing nicely. Specifically, CI should pass, and all these
crates now use workspace dependencies between one another.
As part of this change, I split out the wheel name parsing into its own
`wheel-filename` crate, and the compatibility tag parsing into its own
`platform-tags` crate.
This PR copies over the `install-wheel-rs` crate at commit
`10730ea1a84c58af6b35fb74c89ed0578ab042b6` with no modifications.
It won't pass CI, but modifications will intentionally be confined to
later PRs.
