1 files changed, 50 insertions, 0 deletions
diff --git a/components/script/dom/bindings/function.rs b/components/script/dom/bindings/function.rs
new file mode 100644
index 00000000000..86f4903b07d
--- /dev/null
+++ b/components/script/dom/bindings/function.rs
@@ -0,0 +1,50 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/// Defines a macro `native_fn!` to create a JavaScript function from a Rust function pointer.
+/// # Example
+/// ```
+/// let js_function: Rc<Function> = native_fn!(my_rust_function, c"myFunction", 2, 0);
+/// ```
+#[macro_export]
+macro_rules! native_fn {
+    ($call:expr, $name:expr, $nargs:expr, $flags:expr) => {{
+        let cx = $crate::dom::types::GlobalScope::get_cx();
+        let fun_obj = $crate::native_raw_obj_fn!(cx, $call, $name, $nargs, $flags);
+        #[allow(unsafe_code)]
+        unsafe {
+            Function::new(cx, fun_obj)
+        }
+    }};
+}
+
+/// Defines a macro `native_raw_obj_fn!` to create a raw JavaScript function object.
+/// # Example
+/// ```
+/// let raw_function_obj: *mut JSObject = native_raw_obj_fn!(cx, my_rust_function, c"myFunction", 2, 0);
+/// ```
+#[macro_export]
+macro_rules! native_raw_obj_fn {
+    ($cx:expr, $call:expr, $name:expr, $nargs:expr, $flags:expr) => {{
+        #[allow(unsafe_code)]
+        #[allow(clippy::macro_metavars_in_unsafe)]
+        unsafe extern "C" fn wrapper(cx: *mut JSContext, argc: u32, vp: *mut JSVal) -> bool {
+            $call(cx, argc, vp)
+        }
+        #[allow(unsafe_code)]
+        #[allow(clippy::macro_metavars_in_unsafe)]
+        unsafe {
+            let name: &std::ffi::CStr = $name;
+            let raw_fun = $crate::dom::bindings::import::module::jsapi::JS_NewFunction(
+                *$cx,
+                Some(wrapper),
+                $nargs,
+                $flags,
+                name.as_ptr() as *const std::ffi::c_char,
+            );
+            assert!(!raw_fun.is_null());
+            $crate::dom::bindings::import::module::jsapi::JS_GetFunctionObject(raw_fun)
+        }
+    }};
+}