Add feature to generate bindings during build

This patch adds the bindgen feature to the crate that allows users to
re-generate the bindings, including layout tests, during the build
instead of using the pre-generated bindings.  Per default, this feature
is disabled.

1 files changed, 32 insertions, 0 deletions

diff --git a/build.rs b/build.rs
index a6ae9fc..d097021 100644
--- a/build.rs
+++ b/build.rs
@@ -54,6 +54,35 @@ fn prepare_version_source(
     Ok(out)
 }
 
+#[cfg(feature = "bindgen")]
+fn generate_bindings(library_path: &path::Path, out_path: &path::Path) {
+    let header_path = library_path.join("NK_C_API.h");
+    let header_str = header_path
+        .to_str()
+        .expect("Header path contains invalid UTF-8");
+
+    let include_path = library_path.join("libnitrokey");
+    let include_str = include_path
+        .to_str()
+        .expect("Include path contains invalid UTF-8");
+
+    println!("cargo:rerun-if-changed={}", header_str);
+
+    // always keep options in sync with Makefile
+    let bindings = bindgen::Builder::default()
+        .header(header_str)
+        .whitelist_function("NK_.*")
+        .whitelist_var("NK_.*")
+        .whitelist_var("MAXIMUM_STR_REPLY_LENGTH")
+        .derive_default(true)
+        .clang_arg(&format!("-I{}", include_str))
+        .generate()
+        .expect("Unable to generate bindings");
+    bindings
+        .write_to_file(out_path.join("bindings.rs"))
+        .expect("Could not write bindings");
+}
+
 fn main() {
     if env::var("USE_SYSTEM_LIBNITROKEY").is_ok() {
         println!("cargo:rustc-link-lib=nitrokey");
@@ -78,6 +107,9 @@ fn main() {
     let version_source = prepare_version_source(LIBNITROKEY_VERSION, &out_path, &library_path)
         .expect("Could not prepare the version source file");
 
+    #[cfg(feature = "bindgen")]
+    generate_bindings(library_path, &out_path);
+
     cc::Build::new()
         .cpp(true)
         .flag("-std=c++14")