Replace prebuild binary dll's with a version build at test time

This commit replaces the prebuild binary dlls with a version build as at
test time via an dev-dependency crate.

Author: weiznich

Cargo.toml

@@ -33,6 +33,7 @@ version = "1"
 [dev-dependencies]
 libc = "0.2"
 static_assertions = "1.1"
+windows_test_dll = { path = "windows_test_dll" }
 
 [package.metadata.docs.rs]
 all-features = true
@@ -43,3 +44,9 @@ unexpected_cfgs = { level = "warn", check-cfg = [
     'cfg(libloading_docs)',
     'cfg(target_os, values("cygwin"))',
 ] }
+
+[workspace]
+members = [
+    "windows_test_dll",
+    "."
+]

tests/nagisa32.dll

@@ -3,24 +3,29 @@ extern crate libloading;
 use libloading::os::windows::*;
 use std::ffi::CStr;
 use std::os::raw::c_void;
-// The ordinal DLL contains exactly one function (other than DllMain, that is) with ordinal number
-// 1. This function has the sugnature `fn() -> *const c_char` and returns a string "bunny\0" (in
-// reference to WindowsBunny).
-//
-// Both x86_64 and x86 versions of the .dll are functionally the same. Ideally we would compile the
-// dlls with well known ordinals from our own testing helpers library, but rustc does not allow
-// specifying a custom .def file (https://github.com/rust-lang/rust/issues/35089)
-//
-// The DLLs were kindly compiled by WindowsBunny (aka. @retep998).
 
-#[cfg(target_arch = "x86")]
+#[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
 fn load_ordinal_lib() -> Library {
-    unsafe { Library::new("tests/nagisa32.dll").expect("nagisa32.dll") }
-}
+    use std::path::PathBuf;
 
-#[cfg(target_arch = "x86_64")]
-fn load_ordinal_lib() -> Library {
-    unsafe { Library::new("tests/nagisa64.dll").expect("nagisa64.dll") }
+    const TEST_DLL: &'static str = "windows_test_dll.dll";
+
+    let library_path = std::env::var("LD_LIBRARY_PATH").unwrap();
+    let path = std::env::var("PATH").unwrap();
+    println!("{library_path}");
+    println!("{path}");
+    let library_path = library_path.split(":").find(|s| s.ends_with("deps"));
+    let path = path.split(":").find(|s| s.ends_with("deps"));
+    let path = match (path, library_path) {
+        (Some(p), _) if PathBuf::from(p).join(TEST_DLL).exists() => PathBuf::from(p).join(TEST_DLL),
+        (_, Some(p)) if PathBuf::from(p).join(TEST_DLL).exists() => PathBuf::from(p).join(TEST_DLL),
+        _ => panic!("No test DLL found"),
+    };
+    let path = path.display().to_string();
+
+    println!("Windows test dll path: {path}");
+
+    unsafe { Library::new(format!("{path}")).expect("Windows test dll not found") }
 }
 
 #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]

tests/nagisa64.dll

@@ -0,0 +1,9 @@
+[package]
+name = "windows_test_dll"
+version = "0.1.0"
+edition = "2024"
+
+[lib]
+crate-type = ["cdylib"]
+
+[dependencies]

tests/windows.rs

@@ -0,0 +1,7 @@
+#![crate_type = "cdylib"]
+use std::ffi::c_char;
+
+#[unsafe(no_mangle)]
+pub extern "C" fn test() -> *const c_char {
+    "bunny\0".as_ptr().cast()
+}