cleaup platform-switching Rust platform

examples/platform-switching/rust-platform/build.rs

@@ -1,3 +1,5 @@
+use std::path::{Path, PathBuf};
+
 fn main() {
     #[cfg(not(windows))]
     println!("cargo:rustc-link-lib=dylib=app");
@@ -5,5 +7,34 @@ fn main() {
     #[cfg(windows)]
     println!("cargo:rustc-link-lib=dylib=libapp");
 
-    println!("cargo:rustc-link-search=.");
+    #[cfg(target_os = "macos")]
+    let dylib_file_name = "libapp.dylib";
+
+    #[cfg(target_os = "linux")]
+    let dylib_file_name = "libapp.so";
+
+    #[cfg(target_os = "windows")]
+    let dylib_file_name = "libapp.dll";
+
+    // Get the build cache directory (OUT_DIR)
+    let out_dir = std::env::var("OUT_DIR").unwrap();
+
+    let lib_app = workspace_root()
+        .join("examples")
+        .join("platform-switching")
+        .join("rust-platform")
+        .join(dylib_file_name);
+
+    let out_path = Path::new(&out_dir).join(dylib_file_name);
+
+    // copy the dylib to the output build cache
+    std::fs::copy(lib_app, out_path).unwrap();
+
+    // Search for static libraries in the cache directory
+    println!("cargo:rustc-link-search=native={out_dir}");
+}
+
+pub fn workspace_root() -> PathBuf {
+    let root = std::env::var("ROC_WORKSPACE_DIR").expect("Can't find the ROC_WORKSPACE_DIR variable expected to be set in .cargo/config.toml. Are you running tests outside of cargo?");
+    PathBuf::from(root)
 }

examples/platform-switching/rust-platform/src/lib.rs

@@ -2,20 +2,24 @@
 
 use core::ffi::c_void;
 use roc_std::RocStr;
-use std::ffi::CStr;
 use std::io::Write;
-use std::os::raw::c_char;
 
 extern "C" {
     #[link_name = "roc__mainForHost_1_exposed_generic"]
     fn roc_main(_: &mut RocStr);
 }
 
+/// # Safety
+///
+/// TODO
 #[no_mangle]
 pub unsafe extern "C" fn roc_alloc(size: usize, _alignment: u32) -> *mut c_void {
-    return libc::malloc(size);
+    libc::malloc(size)
 }
 
+/// # Safety
+///
+/// TODO
 #[no_mangle]
 pub unsafe extern "C" fn roc_realloc(
     c_ptr: *mut c_void,
@@ -23,14 +27,20 @@ pub unsafe extern "C" fn roc_realloc(
     _old_size: usize,
     _alignment: u32,
 ) -> *mut c_void {
-    return libc::realloc(c_ptr, new_size);
+    libc::realloc(c_ptr, new_size)
 }
 
+/// # Safety
+///
+/// TODO
 #[no_mangle]
 pub unsafe extern "C" fn roc_dealloc(c_ptr: *mut c_void, _alignment: u32) {
-    return libc::free(c_ptr);
+    libc::free(c_ptr);
 }
 
+/// # Safety
+///
+/// TODO
 #[no_mangle]
 pub unsafe extern "C" fn roc_panic(msg: *mut RocStr, tag_id: u32) {
     match tag_id {
@@ -45,22 +55,34 @@ pub unsafe extern "C" fn roc_panic(msg: *mut RocStr, tag_id: u32) {
     std::process::exit(1);
 }
 
+/// # Safety
+///
+/// TODO
 #[no_mangle]
 pub unsafe extern "C" fn roc_dbg(loc: *mut RocStr, msg: *mut RocStr, src: *mut RocStr) {
     eprintln!("[{}] {} = {}", &*loc, &*src, &*msg);
 }
 
+/// # Safety
+///
+/// TODO
 #[no_mangle]
 pub unsafe extern "C" fn roc_memset(dst: *mut c_void, c: i32, n: usize) -> *mut c_void {
     libc::memset(dst, c, n)
 }
 
+/// # Safety
+///
+/// TODO
 #[cfg(unix)]
 #[no_mangle]
 pub unsafe extern "C" fn roc_getppid() -> libc::pid_t {
     libc::getppid()
 }
 
+/// # Safety
+///
+/// TODO
 #[cfg(unix)]
 #[no_mangle]
 pub unsafe extern "C" fn roc_mmap(
@@ -74,6 +96,9 @@ pub unsafe extern "C" fn roc_mmap(
     libc::mmap(addr, len, prot, flags, fd, offset)
 }
 
+/// # Safety
+///
+/// TODO
 #[cfg(unix)]
 #[no_mangle]
 pub unsafe extern "C" fn roc_shm_open(
@@ -84,6 +109,9 @@ pub unsafe extern "C" fn roc_shm_open(
     libc::shm_open(name, oflag, mode as libc::c_uint)
 }
 
+/// # Safety
+///
+/// TODO
 #[no_mangle]
 pub extern "C" fn rust_main() -> i32 {
     let mut roc_str = RocStr::default();