[rcl_actions] More advanced binding generation

- Add "save-bindgen" feature to store generated bindings in source directory.
- Add "doc-only" to disable bindgen and linking, and use saved bindings
  in source directory.
- Generated bindings are cached to speed up bindgen process.

r2r_actions/Cargo.toml

@@ -17,3 +17,10 @@ r2r_msg_gen = { path = "../r2r_msg_gen", version = "0.3.3" }
 [build-dependencies]
 bindgen = "0.63.0"
 r2r_common = { path = "../r2r_common", version = "0.3.2" }
+
+[features]
+save-bindgen = ["r2r_rcl/save-bindgen", "r2r_msg_gen/save-bindgen"]
+doc-only = ["r2r_rcl/doc-only", "r2r_msg_gen/doc-only"]
+
+[package.metadata.docs.rs]
+features = ["doc-only"]

r2r_actions/build.rs

@@ -1,16 +1,67 @@
-use std::env;
-use std::path::PathBuf;
+use std::fs::OpenOptions;
+use std::path::{Path, PathBuf};
+use std::{env, fs};
+
+const BINDINGS_FILENAME: &str = "action_bindings.rs";
 
 fn main() {
     r2r_common::print_cargo_watches();
-    r2r_common::print_cargo_link_search();
 
-    let mut builder = r2r_common::setup_bindgen_builder();
-    builder = builder.header("src/action_wrapper.h");
+    run_bindgen();
+    run_dynlink();
+}
 
-    println!("cargo:rustc-link-lib=dylib=rcl_action");
+fn run_bindgen() {
+    let env_hash = r2r_common::get_env_hash();
+    let out_dir = PathBuf::from(env::var("OUT_DIR").unwrap());
+    let manifest_dir = Path::new(env!("CARGO_MANIFEST_DIR"));
+    let bindgen_dir = out_dir.join(env_hash);
+    let save_dir = manifest_dir.join("bindings");
+    let cache_file = bindgen_dir.join(BINDINGS_FILENAME);
+    let target_file = out_dir.join(BINDINGS_FILENAME);
+    let mark_file = bindgen_dir.join("done");
+    let saved_file = save_dir.join(BINDINGS_FILENAME);
 
-    let bindings = builder
+    if cfg!(feature = "doc-only") {
+        // If "doc-only" feature is present, copy from $crate/bindings/* to OUT_DIR
+        eprintln!(
+            "Copy from '{}' to '{}'",
+            saved_file.display(),
+            target_file.display()
+        );
+        fs::copy(&saved_file, &target_file).unwrap();
+    } else {
+        // If bindgen was done before, use cached files.
+        if !mark_file.exists() {
+            eprintln!("Generate bindings file '{}'", cache_file.display());
+            fs::create_dir_all(&bindgen_dir).unwrap();
+            generate_bindings(&cache_file);
+            touch(&mark_file);
+        } else {
+            eprintln!("Used cached file  '{}'", cache_file.display());
+        }
+
+        fs::copy(&cache_file, &target_file).unwrap();
+
+        #[cfg(feature = "save-bindgen")]
+        {
+            fs::create_dir_all(&save_dir).unwrap();
+            fs::copy(&cache_file, &saved_file).unwrap();
+        }
+    }
+}
+
+fn run_dynlink() {
+    #[cfg(not(feature = "doc-only"))]
+    {
+        r2r_common::print_cargo_link_search();
+        println!("cargo:rustc-link-lib=dylib=rcl_action");
+    }
+}
+
+fn generate_bindings(out_file: &Path) {
+    let bindings = r2r_common::setup_bindgen_builder()
+        .header("src/action_wrapper.h")
         .no_debug("_OSUnaligned.*")
         .derive_partialeq(true)
         .derive_copy(true)
@@ -44,8 +95,15 @@ fn main() {
         .generate()
         .expect("Unable to generate bindings");
 
-    let out_path = PathBuf::from(env::var("OUT_DIR").unwrap());
     bindings
-        .write_to_file(out_path.join("action_bindings.rs"))
+        .write_to_file(out_file)
         .expect("Couldn't write bindings!");
 }
+
+fn touch(path: &Path) {
+    OpenOptions::new()
+        .create(true)
+        .write(true)
+        .open(path)
+        .unwrap_or_else(|_| panic!("Unable to create file '{}'", path.display()));
+}