Implement call (#243)

.gitignore

@@ -22,6 +22,11 @@ luneDocs.json
 luneTypes.d.luau
 
 # Files generated by runtime or build scripts
+
 scripts/brick_color.rs
 scripts/font_enum_map.rs
 scripts/physical_properties_enum_map.rs
+
+# Files generated by tests
+
+/tests/ffi/**/*.so

crates/lune-std-ffi/src/c/c_arr.rs

@@ -5,13 +5,14 @@ use mlua::prelude::*;
 
 use super::{
     association_names::CARR_INNER,
-    c_helper::{get_conv, get_ensured_size, libffi_type_from_userdata, pretty_format_userdata},
+    c_helper::{get_conv, libffi_type_from_userdata, pretty_format_userdata},
     CPtr,
 };
 use crate::ffi::{
     ffi_association::{get_association, set_association},
     FfiBox, GetNativeData, NativeConvert, NativeData, NativeSize,
 };
+use crate::libffi_helper::get_ensured_size;
 
 // This is a series of some type.
 // It provides the final size and the offset of the index,

crates/lune-std-ffi/src/c/c_fn.rs

@@ -1,20 +1,17 @@
 use std::ptr;
 
-use libffi::low::ffi_cif;
 use libffi::middle::{Cif, Type};
 use mlua::prelude::*;
 
+use super::c_helper::{get_size, get_userdata};
 use super::{
     association_names::{CALLABLE_CFN, CALLABLE_REF, CFN_ARGS, CFN_RESULT},
-    c_helper::{
-        get_conv, get_conv_list_from_table, libffi_type_from_userdata, libffi_type_list_from_table,
-    },
+    c_helper::{get_conv, libffi_type_from_userdata, libffi_type_list_from_table},
 };
-use crate::ffi::bit_mask::u8_test_not;
 use crate::ffi::{
-    ffi_association::set_association, FfiClosure, NativeArgInfo, NativeConvert, NativeResultInfo,
+    bit_mask::u8_test_not, ffi_association::set_association, FfiCallable, FfiRef, FfiRefFlag,
+    NativeArgInfo, NativeData, NativeResultInfo,
 };
-use crate::ffi::{FfiCallable, FfiRef, FfiRefFlag, NativeData};
 
 // cfn is a type declaration for a function.
 // Basically, when calling an external function, this type declaration
@@ -33,7 +30,7 @@ use crate::ffi::{FfiCallable, FfiRef, FfiRefFlag, NativeData};
 // moved to a Lua function or vice versa.
 
 pub struct CFn {
-    cif: *mut ffi_cif,
+    cif: Cif,
     arg_info_list: Vec<NativeArgInfo>,
     result_info: NativeResultInfo,
 }
@@ -46,37 +43,44 @@ impl CFn {
         ret: Type,
         arg_info_list: Vec<NativeArgInfo>,
         result_info: NativeResultInfo,
-    ) -> Self {
-        Self {
-            cif: Cif::new(args.clone(), ret.clone()).as_raw_ptr(),
+    ) -> LuaResult<Self> {
+        // let cif = ;
+
+        Ok(Self {
+            cif: Cif::new(args.clone(), ret.clone()),
             arg_info_list,
             result_info,
-        }
+        })
     }
 
     pub fn new_from_lua_table<'lua>(
         lua: &'lua Lua,
-        args: LuaTable,
+        arg_table: LuaTable,
         ret: LuaAnyUserData,
     ) -> LuaResult<LuaAnyUserData<'lua>> {
-        let args_types = libffi_type_list_from_table(lua, &args)?;
+        let args_types = libffi_type_list_from_table(lua, &arg_table)?;
         let ret_type = libffi_type_from_userdata(lua, &ret)?;
 
-        let mut arg_info_list = Vec::<NativeArgInfo>::with_capacity(args.raw_len());
-        for conv in unsafe { get_conv_list_from_table(&args)? } {
-            arg_info_list.push(NativeArgInfo { conv })
+        let arg_len = arg_table.raw_len();
+        let mut arg_info_list = Vec::<NativeArgInfo>::with_capacity(arg_len);
+        for index in 0..arg_len {
+            let userdata = get_userdata(arg_table.raw_get(index + 1)?)?;
+            arg_info_list.push(NativeArgInfo {
+                conv: unsafe { get_conv(&userdata)? },
+                size: get_size(&userdata)?,
+            });
         }
-
         let result_info = NativeResultInfo {
             conv: unsafe { get_conv(&ret)? },
+            size: get_size(&ret)?,
         };
 
         let cfn =
-            lua.create_userdata(Self::new(args_types, ret_type, arg_info_list, result_info))?;
+            lua.create_userdata(Self::new(args_types, ret_type, arg_info_list, result_info)?)?;
 
         // Create association to hold argument and result type
-        set_association(lua, CFN_ARGS, &cfn, args)?;
-        set_association(lua, CFN_ARGS, &cfn, ret)?;
+        set_association(lua, CFN_ARGS, &cfn, arg_table)?;
+        set_association(lua, CFN_RESULT, &cfn, ret)?;
 
         Ok(cfn)
     }
@@ -88,22 +92,22 @@ impl LuaUserData for CFn {
         //     lua.create_userdata(FfiClosure::new(this.cif, userdata))
         // })
         methods.add_function(
-            "func",
+            "caller",
             |lua, (cfn, function_ref): (LuaAnyUserData, LuaAnyUserData)| {
                 let this = cfn.borrow::<CFn>()?;
 
                 if !function_ref.is::<FfiRef>() {
-                    return Err(LuaError::external(""));
+                    return Err(LuaError::external("argument 0 must be ffiref"));
                 }
 
                 let ffi_ref = function_ref.borrow::<FfiRef>()?;
                 if u8_test_not(ffi_ref.flags, FfiRefFlag::Function.value()) {
-                    return Err(LuaError::external(""));
+                    return Err(LuaError::external("not a function ref"));
                 }
 
                 let callable = lua.create_userdata(unsafe {
                     FfiCallable::new(
-                        this.cif,
+                        this.cif.as_raw_ptr(),
                         ptr::from_ref(&this.arg_info_list),
                         ptr::from_ref(&this.result_info),
                         ffi_ref.get_pointer(0),

crates/lune-std-ffi/src/c/c_helper.rs

@@ -1,17 +1,26 @@
 #![allow(clippy::inline_always)]
 
-use std::ptr::{self, null_mut};
-
-use libffi::{low, middle::Type, raw};
+use libffi::middle::Type;
 use lune_utils::fmt::{pretty_format_value, ValueFormatConfig};
 use mlua::prelude::*;
 
 use super::{
-    association_names::CTYPE_STATIC, types::get_ctype_conv, CArr, CPtr, CStruct, CTypeStatic,
-};
-use crate::ffi::{
-    ffi_association::get_association, NativeConvert, NativeSignedness, NativeSize, FFI_STATUS_NAMES,
+    association_names::CTYPE_STATIC,
+    types::{get_ctype_conv, get_ctype_size},
+    CArr, CPtr, CStruct, CTypeStatic,
 };
+use crate::ffi::{ffi_association::get_association, NativeConvert, NativeSize};
+
+pub fn get_userdata(value: LuaValue) -> LuaResult<LuaAnyUserData> {
+    if let LuaValue::UserData(field_type) = value {
+        Ok(field_type)
+    } else {
+        Err(LuaError::external(format!(
+            "Unexpected field. CStruct, CType or CArr is required for element but got {}",
+            pretty_format_value(&value, &ValueFormatConfig::new())
+        )))
+    }
+}
 
 // Get the NativeConvert handle from the type UserData
 // this is intended to avoid lookup userdata and lua table every time. (eg: struct)
@@ -33,30 +42,21 @@ pub unsafe fn get_conv_list_from_table(
 
     for i in 0..len {
         let value: LuaValue = table.raw_get(i + 1)?;
-
-        if let LuaValue::UserData(field_type) = value {
-            conv_list.push(get_conv(&field_type)?);
-        } else {
-            return Err(LuaError::external(format!(
-                "Unexpected field. CStruct, CType or CArr is required for element but got {}",
-                pretty_format_value(&value, &ValueFormatConfig::new())
-            )));
-        }
+        conv_list.push(get_conv(&get_userdata(value)?)?);
     }
 
     Ok(conv_list)
 }
 
-// #[inline(always)]
-// pub fn type_size_from_userdata(this: &LuaAnyUserData) -> LuaResult<usize> {
-//     if this.is::<CStruct>() {
-//         Ok(this.borrow::<CStruct>()?.get_size())
-//     } else if this.is::<CArr>() {
-//         Ok(this.borrow::<CArr>()?.get_size())
-//     } else {
-//         ctype_size_from_userdata(this)
-//     }
-// }
+pub fn get_size(this: &LuaAnyUserData) -> LuaResult<usize> {
+    if this.is::<CStruct>() {
+        Ok(this.borrow::<CStruct>()?.get_size())
+    } else if this.is::<CArr>() {
+        Ok(this.borrow::<CArr>()?.get_size())
+    } else {
+        get_ctype_size(this)
+    }
+}
 
 // get Vec<libffi_type> from table(array) of c-type userdata
 pub fn libffi_type_list_from_table(lua: &Lua, table: &LuaTable) -> LuaResult<Vec<Type>> {
@@ -162,26 +162,3 @@ pub fn pretty_format_userdata(lua: &Lua, userdata: &LuaAnyUserData) -> LuaResult
         ))
     }
 }
-
-// Ensure sizeof c-type (raw::libffi_type)
-// See: http://www.chiark.greenend.org.uk/doc/libffi-dev/html/Size-and-Alignment.html
-pub fn get_ensured_size(ffi_type: *mut raw::ffi_type) -> LuaResult<usize> {
-    let mut cif = low::ffi_cif::default();
-    let result = unsafe {
-        raw::ffi_prep_cif(
-            ptr::from_mut(&mut cif),
-            raw::ffi_abi_FFI_DEFAULT_ABI,
-            0,
-            ffi_type,
-            null_mut(),
-        )
-    };
-
-    if result != raw::ffi_status_FFI_OK {
-        return Err(LuaError::external(format!(
-            "ffi_get_struct_offsets failed. expected result {}, got {}",
-            FFI_STATUS_NAMES[0], FFI_STATUS_NAMES[result as usize]
-        )));
-    }
-    unsafe { Ok((*ffi_type).size) }
-}

crates/lune-std-ffi/src/c/c_string.rs

@@ -4,3 +4,5 @@
 // but separated it for clarity.
 // This also allows operations such as ffi.string:intoBox().
 // (Write a string to an already existing box)
+
+// FIXME: use buffer instead?

crates/lune-std-ffi/src/c/c_type.rs

@@ -7,11 +7,12 @@ use lune_utils::fmt::{pretty_format_value, ValueFormatConfig};
 use mlua::prelude::*;
 use num::cast::AsPrimitive;
 
-use super::{association_names::CTYPE_STATIC, c_helper::get_ensured_size, CArr, CPtr};
+use super::{association_names::CTYPE_STATIC, CArr, CPtr};
 use crate::ffi::{
     ffi_association::set_association, native_num_cast, FfiBox, GetNativeData, NativeConvert,
     NativeData, NativeSignedness, NativeSize,
 };
+use crate::libffi_helper::get_ensured_size;
 
 // We can't get a CType<T> through mlua, something like
 // .is::<CType<dyn Any>> will fail.
@@ -106,11 +107,9 @@ where
         libffi_type: Type,
         name: Option<&'static str>,
     ) -> LuaResult<LuaAnyUserData<'lua>> {
-        // let libffi_cfi = Cif::new(vec![libffi_type.clone()], Type::void());
         let size = get_ensured_size(libffi_type.as_raw_ptr())?;
 
         let ctype = Self {
-            // libffi_cif: libffi_cfi,
             libffi_type,
             size,
             name,

crates/lune-std-ffi/src/c/types/mod.rs

@@ -8,7 +8,7 @@ use mlua::prelude::*;
 use num::cast::AsPrimitive;
 
 use super::{CType, CTypeCast};
-use crate::ffi::{NativeConvert, NativeData};
+use crate::ffi::{NativeConvert, NativeData, NativeSize};
 
 pub mod f32;
 pub mod f64;
@@ -145,3 +145,18 @@ macro_rules! define_get_ctype_conv {
 pub unsafe fn get_ctype_conv(userdata: &LuaAnyUserData) -> LuaResult<*const dyn NativeConvert> {
     define_get_ctype_conv!(userdata, u8, u16, u32, u64, u128, i8, i16, i32, i64, i128, f32, f64)
 }
+
+macro_rules! define_get_ctype_size {
+    ($userdata:ident, $f:ty, $( $c:ty ),*) => {
+        if $userdata.is::<CType<$f>>() {
+            Ok($userdata.borrow::<CType<$f>>()?.get_size())
+        }$( else if $userdata.is::<CType<$c>>() {
+            Ok($userdata.borrow::<CType<$c>>()?.get_size())
+        })* else {
+            Err(LuaError::external("Unexpected type"))
+        }
+    };
+}
+pub fn get_ctype_size(userdata: &LuaAnyUserData) -> LuaResult<usize> {
+    define_get_ctype_size!(userdata, u8, u16, u32, u64, u128, i8, i16, i32, i64, i128, f32, f64)
+}

crates/lune-std-ffi/src/ffi/ffi_box/mod.rs

@@ -128,7 +128,7 @@ impl NativeData for FfiBox {
         if offset < 0 {
             return false;
         }
-        self.size() > ((offset as usize) + size)
+        self.size() - (offset as usize) >= size
     }
     unsafe fn get_pointer(&self, offset: isize) -> *mut () {
         self.data

crates/lune-std-ffi/src/ffi/ffi_callable.rs

@@ -1,12 +1,9 @@
 use core::ffi::c_void;
 use std::cell::Ref;
-// use std::ptr;
 
 use libffi::{
-    // low::{closure_alloc, ffi_cif, CodePtr, RawCallback},
     low::{ffi_cif, CodePtr},
-    // middle::Cif,
-    // raw::ffi_prep_closure_loc,
+    raw::ffi_call,
 };
 use mlua::prelude::*;
 
@@ -14,37 +11,64 @@ use super::{GetNativeData, NativeArgInfo, NativeData, NativeResultInfo};
 
 pub struct FfiCallable {
     cif: *mut ffi_cif,
-    arg_info: *const Vec<NativeArgInfo>,
+    arg_info_list: *const Vec<NativeArgInfo>,
     result_info: *const NativeResultInfo,
     code: CodePtr,
-
-    // Caching for better performance
-    result_size: usize,
 }
 
 impl FfiCallable {
     pub unsafe fn new(
         cif: *mut ffi_cif,
-        arg_info: *const Vec<NativeArgInfo>,
+        arg_info_list: *const Vec<NativeArgInfo>,
         result_info: *const NativeResultInfo,
         function_pointer: *const (),
     ) -> Self {
-        let result_size = (*(*result_info).conv).get_size();
         Self {
             cif,
-            arg_info,
+            arg_info_list,
             result_info,
             code: CodePtr::from_ptr(function_pointer.cast::<c_void>()),
-
-            result_size,
         }
     }
 
     pub unsafe fn call(&self, result: &Ref<dyn NativeData>, args: LuaMultiValue) -> LuaResult<()> {
         result
-            .check_boundary(0, self.result_size)
+            .check_boundary(0, self.result_info.as_ref().unwrap().size)
             .then_some(())
-            .ok_or_else(|| LuaError::external("result boundary check failed"))
+            .ok_or_else(|| LuaError::external("result boundary check failed"))?;
+
+        // cache Vec => unable to create async call but no allocation
+        let arg_info_list = self.arg_info_list.as_ref().unwrap();
+        let mut arg_list = Vec::<*mut c_void>::with_capacity(arg_info_list.len());
+
+        for index in 0..arg_info_list.len() {
+            let arg_info = arg_info_list.get(index).unwrap();
+            let arg = args
+                .get(index)
+                .ok_or_else(|| LuaError::external(format!("argument {index} required")))?;
+            let arg_pointer = if let LuaValue::UserData(userdata) = arg {
+                let data_handle = userdata.get_data_handle()?;
+                data_handle
+                    .check_boundary(0, arg_info.size)
+                    .then_some(())
+                    .ok_or_else(|| {
+                        LuaError::external(format!("argument {index} boundary check failed"))
+                    })?;
+                data_handle.get_pointer(0)
+            } else {
+                return Err(LuaError::external("unimpl"));
+            };
+            arg_list.push(arg_pointer.cast::<c_void>());
+        }
+
+        ffi_call(
+            self.cif,
+            Some(*self.code.as_safe_fun()),
+            result.get_pointer(0).cast::<c_void>(),
+            arg_list.as_mut_ptr(),
+        );
+
+        Ok(())
     }
 }
 
@@ -63,5 +87,6 @@ impl LuaUserData for FfiCallable {
                 unsafe { this.call(&result.clone().get_data_handle()?, args) }
             },
         );
+        // ref, leak ..?
     }
 }

crates/lune-std-ffi/src/ffi/ffi_lib.rs

@@ -1,6 +1,6 @@
 use core::ffi::c_void;
 
-use dlopen2::symbor::Library;
+use dlopen2::raw::Library;
 use mlua::prelude::*;
 
 use super::{
@@ -41,12 +41,17 @@ impl FfiLib {
         let lib = this.borrow::<FfiLib>()?;
         let sym = unsafe {
             lib.0
-                .symbol::<*mut c_void>(name.as_str())
+                .symbol::<*const c_void>(name.as_str())
                 .map_err(|err| LuaError::external(format!("{err}")))?
         };
+        let ptr = sym.cast::<()>().cast_mut();
 
-        let luasym =
-            lua.create_userdata(FfiRef::new((*sym).cast(), LIB_REF_FLAGS, UNSIZED_BOUNDS))?;
+        // unsafe {
+        //     let f = transmute::<*mut (), unsafe extern "C" fn(i32, i32) -> i32>(ptr);
+        //     dbg!(f(1, 2));
+        // }
+
+        let luasym = lua.create_userdata(FfiRef::new(ptr, LIB_REF_FLAGS, UNSIZED_BOUNDS))?;
 
         set_association(lua, SYM_INNER, &luasym, &this)?;
 
@@ -57,8 +62,7 @@ impl FfiLib {
 impl LuaUserData for FfiLib {
     fn add_methods<'lua, M: LuaUserDataMethods<'lua, Self>>(methods: &mut M) {
         methods.add_function("find", |lua, (this, name): (LuaAnyUserData, String)| {
-            let luasym = FfiLib::get_sym(lua, this, name)?;
-            Ok(luasym)
+            FfiLib::get_sym(lua, this, name)
         });
     }
 }

crates/lune-std-ffi/src/ffi/ffi_native/arg.rs

@@ -11,5 +11,6 @@ pub enum NativeArgType {
 
 pub struct NativeArgInfo {
     pub conv: *const dyn NativeConvert,
+    pub size: usize,
     // pub kind: NativeArgType,
 }

crates/lune-std-ffi/src/ffi/ffi_native/convert.rs

@@ -4,13 +4,10 @@ use std::cell::Ref;
 
 use mlua::prelude::*;
 
-use super::{NativeData, NativeSize};
+use super::NativeData;
 
 // Handle native data, provide type conversion between luavalue and native types
-pub trait NativeConvert
-where
-    Self: NativeSize,
-{
+pub trait NativeConvert {
     // Convert luavalue into data, then write into ptr
     unsafe fn luavalue_into<'lua>(
         &self,

crates/lune-std-ffi/src/ffi/ffi_native/mod.rs

@@ -15,9 +15,7 @@ pub trait NativeSignedness {
 }
 
 pub use self::{
-    arg::FfiArgRefOption,
     arg::NativeArgInfo,
-    arg::NativeArgType,
     cast::native_num_cast,
     convert::NativeConvert,
     data::GetNativeData,

crates/lune-std-ffi/src/ffi/ffi_native/result.rs

@@ -7,5 +7,6 @@ use super::NativeConvert;
 
 pub struct NativeResultInfo {
     pub conv: *const dyn NativeConvert,
+    pub size: usize,
     // kind: NativeResultType,
 }

crates/lune-std-ffi/src/ffi/ffi_ref/bounds.rs

@@ -1,5 +1,3 @@
-use std::clone;
-
 // Memory range for ref or box data. For boundary checking
 pub struct FfiRefBounds {
     // Indicates how much data is above the pointer

crates/lune-std-ffi/src/ffi/mod.rs

@@ -15,10 +15,9 @@ pub use self::{
     ffi_closure::FfiClosure,
     ffi_lib::FfiLib,
     ffi_native::{
-        native_num_cast, FfiArgRefOption, GetNativeData, NativeArgInfo, NativeArgType,
-        NativeConvert, NativeData, NativeResultInfo, NativeSignedness, NativeSize,
+        native_num_cast, GetNativeData, NativeArgInfo, NativeConvert, NativeData, NativeResultInfo,
+        NativeSignedness, NativeSize,
     },
-    ffi_raw::FfiRaw,
     ffi_ref::{create_nullptr, FfiRef, FfiRefFlag},
 };
 

crates/lune-std-ffi/src/lib.rs

@@ -6,6 +6,7 @@ use mlua::prelude::*;
 
 mod c;
 mod ffi;
+mod libffi_helper;
 
 use crate::{
     c::{create_all_c_types, create_all_types, CFn, CStruct},

crates/lune-std-ffi/src/libffi_helper.rs

@@ -0,0 +1,29 @@
+use std::ptr::{self, null_mut};
+
+use libffi::{low, raw};
+use mlua::prelude::*;
+
+use crate::ffi::FFI_STATUS_NAMES;
+
+// Ensure sizeof c-type (raw::libffi_type)
+// See: http://www.chiark.greenend.org.uk/doc/libffi-dev/html/Size-and-Alignment.html
+pub fn get_ensured_size(ffi_type: *mut raw::ffi_type) -> LuaResult<usize> {
+    let mut cif = low::ffi_cif::default();
+    let result = unsafe {
+        raw::ffi_prep_cif(
+            ptr::from_mut(&mut cif),
+            raw::ffi_abi_FFI_DEFAULT_ABI,
+            0,
+            ffi_type,
+            null_mut(),
+        )
+    };
+
+    if result != raw::ffi_status_FFI_OK {
+        return Err(LuaError::external(format!(
+            "ffi_prep_cif failed. expected result {}, got {}",
+            FFI_STATUS_NAMES[0], FFI_STATUS_NAMES[result as usize]
+        )));
+    }
+    unsafe { Ok((*ffi_type).size) }
+}

tests/ffi/external_math/init.luau

@@ -0,0 +1,42 @@
+local ffi = require("@lune/ffi")
+
+local testdir = "./tests/ffi/external_math"
+
+local compile = require("../utility/compile")
+compile(`{testdir}/lib.c`, `{testdir}/lib.so`)
+
+local lib = ffi.open(`{testdir}/lib.so`)
+
+local function test_add_int()
+	local add_int = ffi.fn({ ffi.int, ffi.int }, ffi.int)
+
+	local add_int_caller = add_int:caller(lib:find("add_int"))
+
+	local resultBox = ffi.box(ffi.int.size)
+	local arg1 = ffi.int:box(100)
+	local arg2 = ffi.int:box(200)
+
+	add_int_caller:call(resultBox, arg1, arg2)
+	local result = ffi.int:from(resultBox)
+
+	assert(result == 300, `add_int failed. result expected 300, got {result}`)
+end
+
+test_add_int()
+
+local function test_mul_int()
+	local mul_int = ffi.fn({ ffi.int, ffi.int }, ffi.int)
+
+	local mul_int_caller = mul_int:caller(lib:find("mul_int"))
+
+	local resultBox = ffi.box(ffi.int.size)
+	local arg1 = ffi.int:box(100)
+	local arg2 = ffi.int:box(200)
+
+	mul_int_caller:call(resultBox, arg1, arg2)
+	local result = ffi.int:from(resultBox)
+
+	assert(result == 20000, `mul_int failed. result expected 20000, got {result}`)
+end
+
+test_mul_int()

tests/ffi/external_math/lib.c

@@ -0,0 +1,7 @@
+int add_int(int a, int b) {
+    return a + b;
+}
+
+int mul_int(int a, int b) {
+    return a * b;
+}

tests/ffi/external_struct/init.luau

@@ -0,0 +1,30 @@
+local ffi = require("@lune/ffi")
+
+local testdir = "./tests/ffi/external_struct"
+
+local compile = require("../utility/compile")
+compile(`{testdir}/lib.c`, `{testdir}/lib.so`)
+
+local lib = ffi.open(`{testdir}/lib.so`)
+
+local function test_AB()
+	local ArgStruct = ffi.struct({ ffi.int, ffi.int:ptr() })
+	local ResultStruct = ffi.struct({ ffi.int, ffi.int })
+
+	local AB = ffi.fn({ ArgStruct }, ResultStruct)
+
+	local AB_caller = AB:caller(lib:find("AB"))
+
+	local resultBox = ffi.box(ffi.int.size)
+	local a = ffi.int:box(100)
+	local b = ffi.int:box(200)
+	local arg = ArgStruct:box({ a, b:leak() })
+
+	AB_caller:call(resultBox, arg)
+	local result = ResultStruct:from(resultBox)
+
+	assert(result[0] == 300, `AB failed. result expected 300, got {result}`)
+	assert(result[1] == 20000, `AB failed. result expected 300, got {result}`)
+end
+
+test_AB()

tests/ffi/external_struct/lib.c

@@ -0,0 +1,14 @@
+typedef struct {
+    int a;
+    int* b;
+} ArgStruct;
+
+typedef struct {
+    int sum;
+    int mul;
+} ResultStruct;
+
+ResultStruct AB(ArgStruct t) {
+    ResultStruct result = { t.a+*t.b, t.a**t.b };
+    return result;
+}

tests/ffi/utility/compile.luau

@@ -0,0 +1,9 @@
+local process = require("@lune/process")
+local function compile(file, out)
+	local gcc = process.spawn("gcc", { "-shared", "-o", out, "-fPIC", file })
+	if not gcc.ok then
+		error("Failed to execute gcc command\n" .. gcc.stdout .. gcc.stderr)
+	end
+end
+
+return compile