chore: ffi prelude to avoid dupe types, makefile entries for bindings

.gitignore

@@ -1 +1,4 @@
 /target
+expanded.rs
+stealth_address_kit.h
+stealth_address_kit.nim

Makefile

@@ -1,6 +1,7 @@
 .PHONY: deps clean example
 deps:
 	@cargo install cross --git https://github.com/cross-rs/cross.git --rev 1511a28
+	@cargo install cbindgen
 
 clean:
 	@cargo clean
@@ -11,3 +12,11 @@ example:
 bench:
 	@cargo bench --all-features
 	cp -r target/criterion/** benchmarks/
+
+generate_c_bindings:
+	@cargo expand --all-features -p stealth_address_kit > expanded.rs
+	@cbindgen --output stealth_address_kit.h --lang c expanded.rs
+
+generate_nim_bindings:
+	@cargo expand --all-features -p stealth_address_kit > expanded.rs
+	@nbindgen --output stealth_address_kit.nim expanded.rs

sdk/src/ffi.rs

@@ -5,35 +5,8 @@ macro_rules! define_curve_ffi {
         use ark_serialize::{CanonicalDeserialize, CanonicalSerialize, SerializationError};
         use num_traits::Zero;
         use std::ops::Add;
+        use crate::ffi_prelude::{CReturn, CErrorCode};
 
-        #[repr(C)]
-        #[derive(Debug, PartialOrd, PartialEq)]
-        pub enum CErrorCode {
-            NoError = 0,
-            SerializationErrorNotEnoughSpace = 1,
-            SerializationErrorInvalidData = 2,
-            SerializationErrorUnexpectedFlags = 3,
-            SerializationErrorIoError = 4,
-            InvalidKeys = 5,
-        }
-
-        impl From<SerializationError> for CErrorCode {
-            fn from(value: SerializationError) -> Self {
-                match value {
-                    SerializationError::NotEnoughSpace => CErrorCode::SerializationErrorNotEnoughSpace,
-                    SerializationError::InvalidData => CErrorCode::SerializationErrorInvalidData,
-                    SerializationError::UnexpectedFlags => CErrorCode::SerializationErrorUnexpectedFlags,
-                    SerializationError::IoError(_) => CErrorCode::SerializationErrorIoError,
-                }
-            }
-        }
-
-        #[repr(C)]
-        #[derive(Debug)]
-        pub struct CReturn<T> {
-            value: T,
-            err_code: CErrorCode,
-        }
         paste! {
             #[repr(C)]
             #[derive(Debug)]

sdk/src/ffi_prelude.rs

@@ -0,0 +1,30 @@
+use ark_serialize::SerializationError;
+
+#[repr(C)]
+#[derive(Debug, PartialOrd, PartialEq)]
+pub enum CErrorCode {
+    NoError = 0,
+    SerializationErrorNotEnoughSpace = 1,
+    SerializationErrorInvalidData = 2,
+    SerializationErrorUnexpectedFlags = 3,
+    SerializationErrorIoError = 4,
+    InvalidKeys = 5,
+}
+
+impl From<SerializationError> for CErrorCode {
+    fn from(value: SerializationError) -> Self {
+        match value {
+            SerializationError::NotEnoughSpace => CErrorCode::SerializationErrorNotEnoughSpace,
+            SerializationError::InvalidData => CErrorCode::SerializationErrorInvalidData,
+            SerializationError::UnexpectedFlags => CErrorCode::SerializationErrorUnexpectedFlags,
+            SerializationError::IoError(_) => CErrorCode::SerializationErrorIoError,
+        }
+    }
+}
+
+#[repr(C)]
+#[derive(Debug)]
+pub struct CReturn<T> {
+    pub(crate) value: T,
+    pub(crate) err_code: CErrorCode,
+}

sdk/src/lib.rs

@@ -34,6 +34,9 @@ mod vesta_impl;
 #[cfg(feature = "ffi")]
 #[cfg_attr(docsrs, doc(cfg(feature = "ffi")))]
 mod ffi;
+#[cfg(feature = "ffi")]
+#[cfg_attr(docsrs, doc(cfg(feature = "ffi")))]
+mod ffi_prelude;
 
 #[cfg(feature = "baby_jub_jub")]
 #[cfg_attr(docsrs, doc(cfg(feature = "baby_jub_jub")))]