1 files changed, 52 insertions, 0 deletions
diff --git a/src/rust/unit-wasm-sys/build.rs b/src/rust/unit-wasm-sys/build.rs
new file mode 100644
index 0000000..bd2ebd5
--- /dev/null
+++ b/src/rust/unit-wasm-sys/build.rs
@@ -0,0 +1,52 @@
+// buildscript for the unit-wasm-sys crate.
+
+use std::env;
+use std::path::{Path, PathBuf};
+
+fn main() {
+    // Tell rustc where to find the libunit-wasm library.
+    let libunit_wasm_dir = "libunit-wasm";
+
+    let dir = env::var("CARGO_MANIFEST_DIR").unwrap();
+
+    // Some generics
+    println!("cargo:rerun-if-changed=build.rs");
+    println!("cargo:rerun-if-changed=wrapper.h");
+
+    // The rustc-link-search tells Cargo to pass the `-L` flag to the
+    // compiler to add a directory to the library search plugin. The
+    // `native` keyword means "only looking for `native libraries` in
+    // this directory".
+    println!(
+        "cargo:rustc-link-search=native={}",
+        Path::new(&dir).join(libunit_wasm_dir).display()
+    );
+
+    // The rustc-link-lib tells Cargo to link the given library using
+    // the compiler's `-l` flag. This is needed to start building our
+    // FFIs.
+    println!("cargo:rustc-link-lib=static=unit-wasm");
+
+    generate_bindings();
+}
+
+fn generate_bindings() {
+    let wasi_sysroot = "--sysroot=".to_owned() + &env::var("WASI_SYSROOT").unwrap();
+    let bindings = bindgen::Builder::default()
+        // The input header file.
+        .header("libunit-wasm/include/unit/unit-wasm.h")
+        .allowlist_function("^luw_.*")
+        .allowlist_var("^luw_.*")
+        .allowlist_type("^luw_.*")
+        .clang_args(vec![wasi_sysroot]) // Needed for strings.h
+        .generate()
+        .expect("Unable to generate bindings");
+
+    let out_dir_env =
+        env::var("OUT_DIR").expect("The required environment variable OUT_DIR was not set");
+    let out_path = PathBuf::from(out_dir_env);
+
+    bindings
+        .write_to_file(out_path.join("bindings.rs"))
+        .expect("Couldn't write bindings!");
+}