[feature request] Add a feature to generate bindings at build-time

[derekdreery]

Using bindgen, the build.rs would look something like

extern crate bindgen;
extern crate pkg_config;

use std::env;
use std::path::PathBuf;

fn main() {
    if let Err(e) = pkg_config::probe_library("alsa") {
        match e {
            pkg_config::Error::Failure { .. } => panic! (
                "Pkg-config failed - usually this is because alsa development headers are not installed.\n\n\
                For Fedora users:\n# dnf install alsa-lib-devel\n\n\
                For Debian/Ubuntu users:\n# apt-get install libasound2-dev\n\n\
                pkg_config details:\n{}",
                e
            ),
            _ => panic!("{}", e)
        }
    }
    if env::var_os("CARGO_FEATURE_USE_BINDGEN").is_some() {
        let bindings = bindgen::Builder::default()
            .header("wrapper.h")
            .prepend_enum_name(false)
            .generate()
            .expect("Unable to generate bindings");

        let out_path = PathBuf::from(env::var("OUT_DIR").unwrap());
        bindings
            .write_to_file(out_path.join("bindings.rs"))
            .expect("Couldn't write bindings!");
    }
}

I'm happy to knock up a PR if you accept this feature.

[diwic]

Hi!

This sounds like a good idea, but I have one question before you start. Is it possible to avoid the build dependency of bindgen (and thus the 20 other crates that comes with it), if the bindgen feature is disabled?

Thanks!

[diwic]

It looks like it should be possible to have optional build-dependencies using a strategy similar to what's described here: https://docs.rs/ispc/1.0.6/ispc/

[diwic]

Closing due to inactivity.

[derekdreery]

yeah sorry for never getting round to this

[cyberia-ng]

I've done a patch that does this, but I have a couple of open questions. I'll do a PR and we can discuss it there?