[WIP] Significant Refactor

[naftulikay]

Some of this is waiting on rust-lang/rustup#1658.

TODO

• Support a default toolchain.
• Support multiple toolchains.
• Support multiple components.
• Get rid of intermediate rustup.sh file.
• Generate rustup completions.
• Generate rustup man page.

[naftulikay]

CLI parsing is happening here in rustup and it's clap.

[naftulikay]

Some of the facts we'll need to determine:

rust_host_platform 👍 👎

rustup show will yield a first line like this:

Default host: x86_64-unknown-linux-gnu

In Jinja, we could grab this via something like

rustup_show.stdout_lines | 
    first | 
    regex_replace('(?<=^Default host\:\s)([^-]+)-([^-]+)-([^-]+)-([^-]+)', '\\1-\\2-\\3-\\4')

Or, in grep:

$ rustup show | grep -oP '(?<=^Default host\:\s)([^-]+)-([^-]+)-([^-]+)-([^-]+)'
x86_64-unknown-linux-gnu

A better way to do this would be to add a feature to rustup which just simply emits this host string directly, as changing the output of rustup would break the ability to detect this.

rustup_installed_components 🚫

Blocked on rust-lang/rustup#1659. Once this is merged and released, we can easily harvest installed components for selective installation.

rustup_installed_toolchains 👍

We can detect this now by using rustup toolchain list.

For searching within this list, we need rust_host_platform for extensions, as rustup toolchain list yields:

stable-x86_64-unknown-linux-gnu (default)
1.31.0-x86_64-unknown-linux-gnu

We want to support passing stable, nightly, 1.31.0, as well as the longer forms of stable-{{ rust_host_platform }}, etc. We can check if either {{ toolchain }} or {{ toolchain }}-{{ rust_host_platform }}.

[naftulikay]

Until rustup and cargo export JSON APIs, not worth the effort.