build.rs

use std::env;

fn main() {
  // Note(Lokathor): I was told by thomcc@github to put this in because it makes
  // the build faster if this crate is used within a workspace.
  //
  // The build script only uses the bundled C source to build the lib, so unless
  // we actually replace the C source, we don't need to re-run the build script.
  // This won't affect our ability to develop the Rust level bindings.
  println!("cargo:rerun-if-changed=build.rs");

  let target = env::var("TARGET").expect("Could not read `TARGET`!");
  println!("target:{}", target);

  let out_dir = env::var("OUT_DIR").expect("Could not read `OUT_DIR`!");
  println!("out_dir:{}", out_dir);

  let cargo_manifest_dir = env::var("CARGO_MANIFEST_DIR")
    .expect("Could not read `CARGO_MANIFEST_DIR`!");
  println!("cargo_manifest_dir:{}", cargo_manifest_dir);

  let dll_from = std::path::Path::new(&cargo_manifest_dir).join("SDL2.dll");
  println!("dll_from:{}", dll_from.display());

  let dll_to = std::path::Path::new(&out_dir).join("SDL2.dll");
  println!("dll_to:{}", dll_to.display());

  std::fs::copy(dll_from, dll_to).unwrap();

  if cfg!(feature = "experimental_fast_build")
    && target == "x86_64-pc-windows-msvc"
  {
    let manifest_dir = std::path::PathBuf::from(
      env::var("CARGO_MANIFEST_DIR")
        .expect("Could not read `CARGO_MANIFEST_DIR`!"),
    );
    // declare search path
    println!(
      "cargo:rustc-link-search={}",
      manifest_dir
        .join("SDL2-2.0.16-devel")
        .join("x86_64-pc-windows-msvc")
        .display()
    );
    // declare linking (the bundled files only work with dynamic linking)
    assert!(cfg!(feature = "dynamic_link"));
    println!("cargo:rustc-link-lib=SDL2");
  } else if cfg!(not(feature = "cargo_check")) {
    let manifest_dir = std::path::PathBuf::from(
      env::var("CARGO_MANIFEST_DIR")
        .expect("Could not read `CARGO_MANIFEST_DIR`!"),
    );

    let mut cm = cmake::Config::new(manifest_dir.join("SDL2-2.0.16"));
    cm.static_crt(true);
    cm.target(&env::var("TARGET").expect("Couldn't read `TARGET`"));
    cm.define("SDL_SHARED", "ON");
    cm.define("SDL_STATIC", "ON");
    cm.define("HIDAPI", "ON");
    cm.profile("Release");
    let build_output_path = cm.build();
    println!("build_output_path: {}", build_output_path.display());

    println!(
      "cargo:rustc-link-search={}",
      build_output_path.join("lib").display()
    );

    if cfg!(windows) {
      if cfg!(feature = "dynamic_link") {
        println!("cargo:rustc-link-lib=SDL2");
      } else {
        println!("cargo:rustc-link-lib=static=SDL2-static");
        println!("cargo:rustc-link-lib=user32");
        println!("cargo:rustc-link-lib=gdi32");
        println!("cargo:rustc-link-lib=winmm");
        println!("cargo:rustc-link-lib=imm32");
        println!("cargo:rustc-link-lib=ole32");
        println!("cargo:rustc-link-lib=oleaut32");
        println!("cargo:rustc-link-lib=version");
        println!("cargo:rustc-link-lib=uuid");
        println!("cargo:rustc-link-lib=advapi32");
        println!("cargo:rustc-link-lib=setupapi");
        println!("cargo:rustc-link-lib=shell32");
      }
    } else if cfg!(unix) {
      let sdl2_cfg_cmd = format!(
        "{}",
        build_output_path.join("bin").join("sdl2-config").display()
      );
      // Call sdl2-config and do what it says to do.
      let link_style_arg: &str =
        if cfg!(feature = "dynamic_link") { "--libs" } else { "--static-libs" };
      let sd2_config_linking = std::process::Command::new(sdl2_cfg_cmd)
        .arg(link_style_arg)
        .output()
        .unwrap_or_else(|_| {
          panic!("Couldn't run `sdl2-config {}`.", link_style_arg)
        });
      assert!(sd2_config_linking.status.success());

      let sd2_config_linking_stdout: String =
        String::from_utf8_lossy(&sd2_config_linking.stdout).into_owned();
      println!("sd2_config_linking_stdout: {}", sd2_config_linking_stdout);
      assert!(sd2_config_linking_stdout.len() > 0);

      for term in sd2_config_linking_stdout.split_whitespace() {
        if term.starts_with("-L") {
          println!("cargo:rustc-link-search=native={}", &term[2..]);
        } else if term.starts_with("-lSDL2") {
          if cfg!(feature = "dynamic_link") {
            println!("cargo:rustc-link-lib=SDL2")
          } else {
            println!("cargo:rustc-link-lib=static=SDL2")
          };
        } else if term.starts_with("-l") {
          // normal link
          if term.ends_with(".framework") {
            // macOS framework link, weirdly through -l
            let name_framework = term.rsplit("/").next().unwrap();
            let name = name_framework.split(".").next().unwrap();
            println!("cargo:rustc-link-lib=framework={}", name);
          } else {
            println!("cargo:rustc-link-lib={}", &term[2..]);
          }
        } else if term.starts_with("-Wl,-framework,") {
          // macOS framework link
          println!("cargo:rustc-link-lib=framework={}", &term[15..]);
        } else if term.starts_with("-Wl,-weak_framework,") {
          // rust doesn't seem to have "weak" framework linking so we just
          // declare a normal framework link.
          println!("cargo:rustc-link-lib=framework={}", &term[20..]);
        } else if term.starts_with("-Wl,-rpath,") {
          // I don't know why this works, but it does seem to?
          println!("cargo:rustc-env=DYLD_LIBRARY_PATH={}", &term[11..]);
        } else if term.starts_with("-Wl,--enable-new-dtags") {
          // Do we do anything here?
        } else if term.starts_with("-Wl,--no-undefined") {
          // Do we do anything here?
        } else if term.starts_with("-pthread") {
          // Nothing special on the Rust side, I'm told.
        } else if term.starts_with("-Wl,-current_version,") {
          // I don't think rust passes along a current version number?
        } else if term.starts_with("-Wl,-compatibility_version,") {
          // I don't think rust passes along a compatibility version number?
        } else if term.starts_with("-Wl,-undefined,error") {
          // This asks the linker to error on undefined symbols(?), which it
          // already will do.
        } else {
          panic!("Unknown term: >>{}<<", term);
        }
      }
    } else {
      panic!("Sorry, I only know how to build/link SDL2 on windows and unix.");
    }
  }
}