Adds support for tuples in runtime-interface

primitives/runtime-interface/Cargo.toml

@@ -23,6 +23,7 @@ codec = { package = "parity-scale-codec", version = "1.3.1", default-features =
 static_assertions = "1.0.0"
 primitive-types = { version = "0.7.0", default-features = false }
 sp-storage = { version = "2.0.0", default-features = false, path = "../storage" }
+impl-trait-for-tuples = "0.1.3"
 
 [dev-dependencies]
 sp-runtime-interface-test-wasm = { version = "2.0.0", path = "test-wasm" }

primitives/runtime-interface/src/impls.rs

@@ -365,7 +365,9 @@ impl<T: codec::Codec> PassBy for Option<T> {
 	type PassBy = Codec<Self>;
 }
 
-impl PassBy for (u32, u32, u32, u32) {
+#[impl_trait_for_tuples::impl_for_tuples(30)]
+#[tuple_types_no_default_trait_bound]
+impl PassBy for Tuple where Self: codec::Codec {
 	type PassBy = Codec<Self>;
 }
 

primitives/runtime-interface/src/lib.rs

@@ -99,7 +99,7 @@
 //! | `*const T` | `u32` | `Identity` |
 //! | `Option<T>` | `u64` | `let e = v.encode();`<br><br><code>e.len() 32bit << 32 &#124; e.as_ptr() 32bit</code> |
 //! | [`T where T: PassBy<PassBy=Inner>`](./pass_by#Inner) | Depends on inner | Depends on inner |
-//! | [`T where T:PassBy<PassBy=Codec>`](./pass_by#Codec)|`u64`|<code>v.len() 32bit << 32 &#124;v.as_ptr() 32bit</code>|
+//! | [`T where T: PassBy<PassBy=Codec>`](./pass_by#Codec)|`u64`|<code>v.len() 32bit << 32 &#124;v.as_ptr() 32bit</code>|
 //!
 //! `Identity` means that the value is converted directly into the corresponding FFI type.
 

primitives/runtime-interface/test-wasm/src/lib.rs

@@ -120,6 +120,16 @@ pub trait TestApi {
 	fn test_versionning(&self, data: u32) -> bool {
 		data == 42
 	}
+
+	/// Returns the input values as tuple.
+	fn return_input_as_tuple(
+		a: Vec<u8>,
+		b: u32,
+		c: Option<Vec<u32>>,
+		d: u8,
+	) -> (Vec<u8>, u32, Option<Vec<u32>>, u8) {
+		(a, b, c, d)
+	}
 }
 
 /// This function is not used, but we require it for the compiler to include `sp-io`.
@@ -258,4 +268,18 @@ wasm_export_functions! {
 		assert!(!test_api::test_versionning(50));
 		assert!(!test_api::test_versionning(102));
 	}
+
+	fn test_return_input_as_tuple() {
+		let a = vec![1, 3, 4, 5];
+		let b = 10000;
+		let c = Some(vec![2, 3]);
+		let d = 5;
+
+		let res = test_api::return_input_as_tuple(a.clone(), b, c.clone(), d);
+
+		assert_eq!(a, res.0);
+		assert_eq!(b, res.1);
+		assert_eq!(c, res.2);
+		assert_eq!(d, res.3);
+	}
 }

primitives/runtime-interface/test/src/lib.rs

@@ -208,4 +208,9 @@ fn test_tracing() {
 
 	let inner = subscriber.0.lock().unwrap();
 	assert!(inner.spans.contains("return_input_version_1"));
-}
+}
+
+#[test]
+fn test_return_input_as_tuple() {
+	call_wasm_method::<HostFunctions>(&wasm_binary_unwrap()[..], "test_return_input_as_tuple");
+}