rust/bindings/build.rs

// Copyright 2024, Linaro Limited
// Author(s): Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
// SPDX-License-Identifier: GPL-2.0-or-later

#[cfg(unix)]
use std::os::unix::fs::symlink as symlink_file;
#[cfg(windows)]
use std::os::windows::fs::symlink_file;
use std::{env, fs::remove_file, io::Result, path::Path};

fn main() -> Result<()> {
    let manifest_dir = env!("CARGO_MANIFEST_DIR");
    let root = env::var("MESON_BUILD_ROOT").expect(concat!(
        "\n",
        "    MESON_BUILD_ROOT not found.  Maybe you wanted one of\n",
        "    `make clippy`, `make rustfmt`, `make rustdoc`?\n",
        "\n",
        "    For other uses of `cargo`, start a subshell with\n",
        "    `pyvenv/bin/meson devenv`, or point MESON_BUILD_ROOT to\n",
        "    the top of the build tree."
    ));

    let sub = get_rust_subdir(manifest_dir).unwrap();
    let file = format!("{root}/{sub}/bindings.inc.rs");
    let file = Path::new(&file);

    if !file.exists() {
        panic!(concat!(
            "\n",
            "    No generated C bindings found! Run `make` first; or maybe you\n",
            "    wanted one of `make clippy`, `make rustfmt`, `make rustdoc`?\n",
        ));
    }

    let out_dir = env::var("OUT_DIR").unwrap();
    let dest_path = format!("{out_dir}/bindings.inc.rs");
    let dest_path = Path::new(&dest_path);
    if dest_path.symlink_metadata().is_ok() {
        remove_file(dest_path)?;
    }
    symlink_file(file, dest_path)?;

    println!("cargo:rerun-if-changed=build.rs");
    Ok(())
}

fn get_rust_subdir(path: &str) -> Option<&str> {
    path.find("/rust").map(|index| &path[index + 1..])
}