Support `u128`/`i128` in runtime interface (#4703)

* Support `u128`/`i128` in runtime interface

This implements support for `u128`/`i128` as parameters/return value in
runtime interfaces. As we can not pass them as identity, as for the
other primitives types, we pass them as an pointer to an `[u8; 16]` array.

* Remove some unsafe code usage

substrate/primitives/runtime-interface/src/impls.rs

@@ -471,3 +471,55 @@ impl<T: sp_wasm_interface::PointerType> IntoFFIValue for Pointer<T> {
 		Ok(self.into())
 	}
 }
+
+/// Implement the traits for `u128`/`i128`
+macro_rules! for_u128_i128 {
+	($type:ty) => {
+		/// `u128`/`i128` is passed as `u32`.
+		///
+		/// The `u32` is a pointer to an `[u8; 16]` array.
+		impl RIType for $type {
+			type FFIType = u32;
+		}
+
+		#[cfg(not(feature = "std"))]
+		impl IntoFFIValue for $type {
+			type Owned = ();
+
+			fn into_ffi_value(&self) -> WrappedFFIValue<u32> {
+				unsafe { (mem::transmute::<&Self, *const u8>(self) as u32).into() }
+			}
+		}
+
+		#[cfg(not(feature = "std"))]
+		impl FromFFIValue for $type {
+			fn from_ffi_value(arg: u32) -> $type {
+				<$type>::from_le_bytes(<[u8; mem::size_of::<$type>()]>::from_ffi_value(arg))
+			}
+		}
+
+		#[cfg(feature = "std")]
+		impl FromFFIValue for $type {
+			type SelfInstance = $type;
+
+			fn from_ffi_value(context: &mut dyn FunctionContext, arg: u32) -> Result<$type> {
+				let data = context.read_memory(Pointer::new(arg), mem::size_of::<$type>() as u32)?;
+				let mut res = [0u8; mem::size_of::<$type>()];
+				res.copy_from_slice(&data);
+				Ok(<$type>::from_le_bytes(res))
+			}
+		}
+
+		#[cfg(feature = "std")]
+		impl IntoFFIValue for $type {
+			fn into_ffi_value(self, context: &mut dyn FunctionContext) -> Result<u32> {
+				let addr = context.allocate_memory(mem::size_of::<$type>() as u32)?;
+				context.write_memory(addr, &self.to_le_bytes())?;
+				Ok(addr.into())
+			}
+		}
+	}
+}
+
+for_u128_i128!(u128);
+for_u128_i128!(i128);

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

@@ -81,10 +81,12 @@
 //! | `u16` | `u16` | `Identity` |
 //! | `u32` | `u32` | `Identity` |
 //! | `u64` | `u64` | `Identity` |
+//! | `i128` | `u32` | `v.as_ptr()` (pointer to a 16 byte array) |
 //! | `i8` | `i8` | `Identity` |
 //! | `i16` | `i16` | `Identity` |
 //! | `i32` | `i32` | `Identity` |
 //! | `i64` | `i64` | `Identity` |
+//! | `u128` | `u32` | `v.as_ptr()` (pointer to a 16 byte array) |
 //! | `bool` | `u8` | `if v { 1 } else { 0 }` |
 //! | `&str` | `u64` | <code>v.len() 32bit << 32 &#124; v.as_ptr() 32bit</code> |
 //! | `&[u8]` | `u64` | <code>v.len() 32bit << 32 &#124; v.as_ptr() 32bit</code> |
@@ -93,6 +95,7 @@
 //! | `&[T] where T: Encode` | `u64` | `let e = v.encode();`<br><br><code>e.len() 32bit << 32 &#124; e.as_ptr() 32bit</code> |
 //! | `[u8; N]` | `u32` | `v.as_ptr()` |
 //! | `*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> |
 //!

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

@@ -82,6 +82,16 @@ pub trait TestApi {
 	fn overwrite_native_function_implementation() -> bool {
 		false
 	}
+
+	/// Gets an `u128` and returns this value
+	fn get_and_return_u128(val: u128) -> u128 {
+		val
+	}
+
+	/// Gets an `i128` and returns this value
+	fn get_and_return_i128(val: i128) -> i128 {
+		val
+	}
 }
 
 /// Two random external functions from the old runtime interface.
@@ -191,4 +201,14 @@ wasm_export_functions! {
 
 		assert!(test_api::overwrite_native_function_implementation());
 	}
+
+	fn test_u128_i128_as_parameter_and_return_value() {
+		for val in &[u128::max_value(), 1u128, 5000u128, u64::max_value() as u128] {
+			assert_eq!(*val, test_api::get_and_return_u128(*val));
+		}
+
+		for val in &[i128::max_value(), i128::min_value(), 1i128, 5000i128, u64::max_value() as i128] {
+			assert_eq!(*val, test_api::get_and_return_i128(*val));
+		}
+	}
 }

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

@@ -108,3 +108,8 @@ fn test_invalid_utf8_data_should_return_an_error() {
 fn test_overwrite_native_function_implementation() {
 	call_wasm_method::<HostFunctions>("test_overwrite_native_function_implementation");
 }
+
+#[test]
+fn test_u128_i128_as_parameter_and_return_value() {
+	call_wasm_method::<HostFunctions>("test_u128_i128_as_parameter_and_return_value");
+}