Rust library for fetching the official Cap-n-Proto compiler (capnp) for a particular operating system, compiling files and aggregating them into a helper include file.
capnp_import builds a set of paths to files or folders using the capnp tool, which it downloads or builds if it is missing, and aggregates the resulting import files into a helper include file. Usage:
// Inside build.rs
capnp_import::process(&["schema"]).expect("Capnp generation failed!");
// Inside main.rs
use std::env;
include!(concat!(env!("OUT_DIR"), "/capnp_include.rs"));
A release archive for the given version for the current operating system will be downloaded and the binary will be extracted into the target directory. If a particular version was already downloaded and is present in the target directory, it will be reused. If no binary is available, a source release will be downloaded and a build will be attempted. If this isn't supported, the tool will try to use an existing capnp installation on the machine.