vzense-rust 0.2.1

High-level library for Vzense cameras
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use std::path::Path;
use std::{fs, io};

// prevent running main() for docs.rs
#[cfg(not(feature = "docsrs"))]
fn main() {
    /*
    Shared libraries need to be within the target dir, see
    https://doc.rust-lang.org/cargo/reference/environment-variables.html#dynamic-library-paths

    Therefore, libraries are first extracted from `vzense-lib.tar.xz`` to `targst/vzense_lib/` and then symlinked from there to target/<buildType>/deps/.
    */

    let lib_src = std::env::current_dir().unwrap().join("target/vzense-lib");

    // check if libraries have been extracted already
    if !lib_src.exists() {
        std::fs::copy("vzense-lib.tar.xz", "target/vzense-lib.tar.xz")
            .expect("could not copy vzense-lib");

        // decompress the vzense-lib directory
        std::process::Command::new("unxz")
            .current_dir("target/")
            .arg("vzense-lib.tar.xz")
            .output()
            .expect("could not unxz vzense-lib");

        // untar
        std::process::Command::new("tar")
            .current_dir("target/")
            .arg("-xf")
            .arg("vzense-lib.tar")
            .output()
            .expect("could not untar vzense-lib");

        // rm tar
        std::process::Command::new("rm")
            .current_dir("target/")
            .arg("vzense-lib.tar")
            .output()
            .unwrap();
    }

    let mut deps_path = std::env::current_exe().unwrap();
    for _ in 0..3 {
        deps_path.pop(); // 3 x cd ..
    }
    deps_path.push("deps"); // cd deps

    // create symlinks
    symlink_dir_all(lib_src, deps_path.clone()).expect("failed to create symlinks to libraries");

    // tell cargo to look for shared libraries in the specified directory
    println!("cargo:rustc-link-search={}", deps_path.to_str().unwrap());

    // necessary for runtime to find shared libraries
    println!(
        "cargo:rustc-link-arg=-Wl,-rpath,{}",
        deps_path.to_str().unwrap()
    );

    // tell rustc to link the shared libraries
    println!("cargo:rustc-link-lib=vzense_api");
    println!("cargo:rustc-link-lib=Scepter_api");
}

/// create symlinks recursively to whole directory
fn symlink_dir_all(src: impl AsRef<Path>, dst: impl AsRef<Path>) -> io::Result<()> {
    fs::create_dir_all(&dst)?;
    for entry in fs::read_dir(src)? {
        let entry = entry?;
        let file = dst.as_ref().join(entry.file_name());
        let ty = entry.file_type()?;
        if ty.is_dir() {
            symlink_dir_all(entry.path(), file)?;
        } else {
            // fs::copy(entry.path(), file)?;
            if !file.exists() {
                std::os::unix::fs::symlink(entry.path(), file)?;
            }
        }
    }
    Ok(())
}