build.rs

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

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let hdf5_include_dir = env::var("HDF5_INCLUDE_DIR")
        .expect("Please set the `HDF5_INCLUDE_DIR` environment variable");
    let hdf5_lib_dir =
        env::var("HDF5_LIB_DIR").expect("Please set the `HDF5_LIB_DIR` environment variable");
    let hdf5_bin_dir =
        env::var("HDF5_BIN_DIR").expect("Please set the `HDF5_BIN_DIR` environment variable");

    println!("cargo:rerun-if-changed=c_pycode/pycode_h5.c");
    println!("cargo:rerun-if-changed=c_pycode/pycode_h5.h");
    println!("cargo:rerun-if-changed=c_pycode/CMakeLists.txt");

    let mut build = cmake::Config::new("./c_pycode");
    let c_pycode_location = build.profile("Release").build();

    let bindings = bindgen::Builder::default()
        .header("c_pycode/pycode_h5.h")
        .clang_arg(format!("-I{}", hdf5_include_dir))
        .parse_callbacks(Box::new(bindgen::CargoCallbacks::new()))
        .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");

    println!(
        "cargo:rustc-link-search=native={}",
        format!("{}/lib", c_pycode_location.display())
    );
    println!("cargo:rustc-link-lib=static={}", "pycode_h5");
    println!(
        "cargo:rustc-link-search=native={}",
        format!("{hdf5_lib_dir}")
    );
    println!("cargo:rustc-link-lib=dylib={}", "hdf5");

    let hdf5_bin_dir = PathBuf::from(hdf5_bin_dir);
    let out_dir = env::var("OUT_DIR").unwrap();
    let mut target_dir = PathBuf::from(out_dir);

    // Traverse up the directory tree to reach the `target` directory
    target_dir.pop(); // remove "out_dir"
    target_dir.pop(); // remove "build"
    target_dir.pop(); // remove <project-name>
    target_dir.pop(); // remove "debug" or "release"
    target_dir.pop(); // remove "target"

    #[cfg(target_os = "windows")]
    {
        std::fs::copy(
            hdf5_bin_dir.join("hdf5.dll"),
            target_dir.join("pycode.libs/hdf5.dll"),
        )
        .expect("failed to copy hdf5.dll");
    }
    #[cfg(target_os = "linux")]
    {
        std::fs::copy(
            hdf5_bin_dir.join("libhdf5.so"),
            target_dir.join("pycode.libs/libhdf5.so"),
        )
        .expect("failed to copy libhdf5.so");
    }
    Ok(())
}