rust-analyzer is an LSP server for the Rust language. It allows editors like vim, emacs, or VS Code to provide IDE-like features for Rust.
This program, rust-analyzer-chromiumos-wrapper, is a wrapper around rust-analyzer. It exists to translate paths between an instance of rust-analyzer running inside the chromiumos chroot and a client running outside the chroot.
It is of course possible to simply run rust-analyzer outside the chroot, but version mismatch issues may lead to a suboptimal experience.
It should run outside the chroot. If invoked in a chromiumos repo in a subdirectory of either chromiumos/src or chromiumos/chroot, it will attempt to invoke rust-analyzer inside the chroot and translate paths. Otherwise, it will attempt to invoke a rust-analyzer outside the chroot and will not translate paths.
It only supports a limited set of rust-analyzer‘s command line options, which aren’t necessary for acting as a LSP server anyway.
Outside the chroot, install the rust-analyzer-chromiumos-wrapper binary:
cargo install --path /path-to-a-chromiumos-checkout/src/third_party/toolchain-utils/rust-analyzer-chromiumos-wrapper
Make sure ~/.cargo/bin is in your PATH, or move/symlink ~/.cargo/bin/rust-analyzer-chromiumos-wrapper to a location in your PATH.
Configure your editor to use the binary rust-analyzer-chromiumos-wrapper as rust-analyzer. This configuration is specific to your editor, but see the Rust analyzer manual for more about several different editors.
The following sections explain how this can be done for various editors.
In Neovim, if you're using nvim-lspconfig, this can be done by putting the following in your init.lua:
require('lspconfig')['rust_analyzer'].setup {
cmd = {'rust-analyzer-chromiumos-wrapper'},
}
In VSCode the rust-analyzer extension handles interaction with the LSP. After installation, rust-analyzer is configured via settings.json. To use rust-analyzer-chromiumos-wrapper for chromiumos, edit the repositories .vscode/settings.json file. It should be present in any chromiumos checkout that you edited with VSCode.
Then add the following line:
"rust-analyzer.server.path": "/usr/local/google/home/bkersting/.cargo/bin/rust-analyzer-chromiumos-wrapper"
Due to having all chromiumos crates distributed in the workspace (and no global Cargo.toml defining the workspace), the crates you would like edit with rust-analyzer need to be declared in the rust-analyzer.linkedProjects setting. If you e.g. want to work on libchromeos-rs, put the following lines into settings.json:
"rust-analyzer.linkedProjects": [
"/path-to-chromiumos/src/platform2/libchromeos-rs/Cargo.toml",
]
Inside chroot we already have a rust-analyzer installation that is installed with the rust toolchain.
A wrapper isn't necessary for clangd, because clangd supports the option --path-mappings to translate paths. In principle a similar option could be added to rust-analyzer, obviating the need for this wrapper. See this issue on github.