Refactor host

examples/tictactoe.rs

@@ -4,8 +4,9 @@ use std::env;
 use std::fmt;
 use std::rc::Rc;
 use parity_wasm::elements::Module;
-use parity_wasm::interpreter::{Error as InterpreterError, HostModule, HostModuleBuilder,
+use parity_wasm::interpreter::{
-							   ModuleInstance, UserError};
+	Error as InterpreterError, HostModule, HostModuleBuilder,
+	ModuleInstance, UserError};
 
 #[derive(Debug)]
 pub enum Error {
@@ -157,16 +158,16 @@ fn env_host_module<'a>() -> HostModule<Runtime<'a>> {
 	let mut builder = HostModuleBuilder::<Runtime>::new();
 	builder.with_func1(
 		"set",
-		|state: &Runtime, idx: i32| -> Result<Option<()>, InterpreterError> {
+		|state: &Runtime, idx: i32| -> Result<(), InterpreterError> {
 			state.game.set(idx, state.player)?;
-			Ok(None)
+			Ok(())
 		},
 	);
 	builder.with_func1(
 		"get",
-		|state: &Runtime, idx: i32| -> Result<Option<i32>, InterpreterError> {
+		|state: &Runtime, idx: i32| -> Result<i32, InterpreterError> {
 			let val: i32 = tictactoe::Player::into_i32(state.game.get(idx).unwrap());
-			Ok(Some(val))
+			Ok(val)
 		},
 	);
 	builder.build()

src/interpreter/host.rs

@@ -7,7 +7,7 @@ use interpreter::func::FuncInstance;
 use interpreter::global::GlobalInstance;
 use interpreter::memory::MemoryInstance;
 use interpreter::table::TableInstance;
-use interpreter::value::RuntimeValue;
+use interpreter::value::{RuntimeValue, TryInto};
 use interpreter::Error;
 use interpreter::ImportResolver;
 
@@ -25,8 +25,8 @@ impl<St> HostModuleBuilder<St> {
 	}
 
 	pub fn with_func0<
-		Cl: Fn(&St) -> Result<Option<Ret>, Error> + 'static,
+		Cl: Fn(&St) -> Result<Ret, Error> + 'static,
-		Ret: AsReturnVal + 'static,
+		Ret: IntoReturnVal + 'static,
 		N: Into<String>,
 	>(
 		&mut self,
@@ -35,8 +35,8 @@ impl<St> HostModuleBuilder<St> {
 	) {
 		let func_type = FunctionType::new(vec![], Ret::value_type());
 		let host_func = Rc::new(move |state: &St, _args: &[RuntimeValue]| -> Result<Option<RuntimeValue>, Error> {
-			let result = f(state);
+			let result = f(state)?.into_return_val();
-			result.map(|r| r.and_then(|r| r.as_return_val()))
+			Ok(result)
 		});
 
 		let func = FuncInstance::alloc_host(Rc::new(func_type), host_func);
@@ -44,8 +44,8 @@ impl<St> HostModuleBuilder<St> {
 	}
 
 	pub fn with_func1<
-		Cl: Fn(&St, P1) -> Result<Option<Ret>, Error> + 'static,
+		Cl: Fn(&St, P1) -> Result<Ret, Error> + 'static,
-		Ret: AsReturnVal + 'static,
+		Ret: IntoReturnVal + 'static,
 		P1: FromArg + 'static,
 		N: Into<String>,
 	>(
@@ -56,8 +56,8 @@ impl<St> HostModuleBuilder<St> {
 		let func_type = FunctionType::new(vec![P1::value_type()], Ret::value_type());
 		let host_func = Rc::new(move |state: &St, args: &[RuntimeValue]| -> Result<Option<RuntimeValue>, Error> {
 			let arg0 = P1::from_arg(&args[0]);
-			let result = f(state, arg0);
+			let result = f(state, arg0)?.into_return_val();
-			result.map(|r| r.and_then(|r| r.as_return_val()))
+			Ok(result)
 		});
 
 		let func = FuncInstance::alloc_host(Rc::new(func_type), host_func);
@@ -65,8 +65,8 @@ impl<St> HostModuleBuilder<St> {
 	}
 
 	pub fn with_func2<
-		Cl: Fn(&St, P1, P2) -> Result<Option<Ret>, Error> + 'static,
+		Cl: Fn(&St, P1, P2) -> Result<Ret, Error> + 'static,
-		Ret: AsReturnVal + 'static,
+		Ret: IntoReturnVal + 'static,
 		P1: FromArg + 'static,
 		P2: FromArg + 'static,
 		N: Into<String>,
@@ -79,8 +79,8 @@ impl<St> HostModuleBuilder<St> {
 		let host_func = Rc::new(move |state: &St, args: &[RuntimeValue]| -> Result<Option<RuntimeValue>, Error> {
 			let p1 = P1::from_arg(&args[0]);
 			let p2 = P2::from_arg(&args[1]);
-			let result = f(state, p1, p2);
+			let result = f(state, p1, p2)?.into_return_val();
-			result.map(|r| r.and_then(|r| r.as_return_val()))
+			Ok(result)
 		});
 
 		let func = FuncInstance::alloc_host(Rc::new(func_type), host_func);
@@ -177,49 +177,66 @@ impl<St> ImportResolver<St> for HostModule<St> {
 	}
 }
 
-pub trait AnyFunc<St> {
+pub trait FromArg where Self: Sized {
-	fn call_as_any(
-		&self,
-		state: &St,
-		args: &[RuntimeValue],
-	) -> Result<Option<RuntimeValue>, Error>;
-}
-
-pub trait FromArg {
 	fn from_arg(arg: &RuntimeValue) -> Self;
 	fn value_type() -> ValueType;
 }
 
-impl FromArg for i32 {
+macro_rules! impl_from_arg {
-	fn from_arg(arg: &RuntimeValue) -> Self {
+	($ty: ident, $val_ty: ident) => {
-		match arg {
+		impl FromArg for $ty {
-			&RuntimeValue::I32(v) => v,
+			fn from_arg(arg: &RuntimeValue) -> Self {
-			unexpected => panic!("Expected I32, got {:?}", unexpected),
+				arg
-		}
+					.try_into()
-	}
+					.expect(
+						concat!("Due to validation, arg expected to be ", stringify!($val_ty))
+					)
+			}
 
-	fn value_type() -> ValueType {
+			fn value_type() -> ValueType {
-		ValueType::I32
+				use self::ValueType::*;
+				$val_ty
+			}
+		}
 	}
 }
 
-pub trait AsReturnVal {
+impl_from_arg!(i32, I32);
-	fn as_return_val(self) -> Option<RuntimeValue>;
+impl_from_arg!(u32, I32);
+impl_from_arg!(i64, I64);
+impl_from_arg!(u64, I64);
+impl_from_arg!(f32, F32);
+impl_from_arg!(f64, F64);
+
+pub trait IntoReturnVal {
+	fn into_return_val(self) -> Option<RuntimeValue>;
 	fn value_type() -> Option<ValueType>;
 }
 
-impl AsReturnVal for i32 {
+macro_rules! impl_into_return_val {
-	fn as_return_val(self) -> Option<RuntimeValue> {
+	($ty: ident, $val_ty: ident) => {
-		Some(self.into())
+		impl IntoReturnVal for $ty {
-	}
+			fn into_return_val(self) -> Option<RuntimeValue> {
+				Some(self.into())
+			}
 
-	fn value_type() -> Option<ValueType> {
+			fn value_type() -> Option<ValueType> {
-		Some(ValueType::I32)
+				use self::ValueType::*;
+				Some($val_ty)
+			}
+		}
 	}
 }
 
-impl AsReturnVal for () {
+impl_into_return_val!(i32, I32);
-	fn as_return_val(self) -> Option<RuntimeValue> {
+impl_into_return_val!(u32, I32);
+impl_into_return_val!(i64, I64);
+impl_into_return_val!(u64, I64);
+impl_into_return_val!(f32, F32);
+impl_into_return_val!(f64, F64);
+
+impl IntoReturnVal for () {
+	fn into_return_val(self) -> Option<RuntimeValue> {
 		None
 	}
 
@@ -227,27 +244,3 @@ impl AsReturnVal for () {
 		None
 	}
 }
-
-impl<St, Ret: AsReturnVal> AnyFunc<St> for Fn(&St) -> Result<Option<Ret>, Error> {
-	fn call_as_any(
-		&self,
-		state: &St,
-		_args: &[RuntimeValue],
-	) -> Result<Option<RuntimeValue>, Error> {
-		let result = self(state);
-		result.map(|r| r.and_then(|r| r.as_return_val()))
-	}
-}
-
-impl<St, Ret: AsReturnVal, P1: FromArg, P2: FromArg> AnyFunc<St> for Fn(&St, P1, P2) -> Result<Option<Ret>, Error> {
-	fn call_as_any(
-		&self,
-		state: &St,
-		args: &[RuntimeValue],
-	) -> Result<Option<RuntimeValue>, Error> {
-		let p1 = P1::from_arg(&args[0]);
-		let p2 = P2::from_arg(&args[1]);
-		let result = self(state, p1, p2);
-		result.map(|r| r.and_then(|r| r.as_return_val()))
-	}
-}

src/interpreter/mod.rs

@@ -151,7 +151,7 @@ pub use self::memory::MemoryInstance;
 pub use self::table::TableInstance;
 pub use self::program::ProgramInstance;
 pub use self::value::RuntimeValue;
-pub use self::host::{HostModule, HostModuleBuilder, HostFunc, AsReturnVal, FromArg};
+pub use self::host::{HostModule, HostModuleBuilder, HostFunc, IntoReturnVal, FromArg};
 pub use self::imports::{ImportResolver, Imports};
 pub use self::module::ModuleInstance;
 pub use self::global::GlobalInstance;

src/interpreter/tests/basics.rs

@@ -133,7 +133,7 @@ fn build_env_module() -> HostModule<TestState> {
 		let sum = memory_value + fn_argument;
 		state.memory.set(0, &vec![sum]).unwrap();
 		state.values.borrow_mut().push(sum as i32);
-		Ok(Some(sum as i32))
+		Ok(sum as i32)
 	});
 	builder.with_func2("sub", |state: &TestState, arg: i32, unused: i32| {
 		let memory_value = state.memory.get(0, 1).unwrap()[0];
@@ -144,9 +144,9 @@ fn build_env_module() -> HostModule<TestState> {
 		let diff = memory_value - fn_argument;
 		state.memory.set(0, &vec![diff]).unwrap();
 		state.values.borrow_mut().push(diff as i32);
-		Ok(Some(diff as i32))
+		Ok(diff as i32)
 	});
-	builder.with_func2("err", |_: &TestState, _unused1: i32, _unused2: i32| -> Result<Option<i32>, Error> {
+	builder.with_func2("err", |_: &TestState, _unused1: i32, _unused2: i32| -> Result<i32, Error> {
 		Err(Error::User(Box::new(UserErrorWithCode { error_code: 777 })))
 	});
 	builder.insert_memory("memory", Rc::new(MemoryInstance::new(&MemoryType::new(256, None)).unwrap()));
@@ -323,14 +323,14 @@ fn native_ref_state() {
 			let mut host_module_builder = HostModuleBuilder::<HostState>::new();
 			host_module_builder.with_func1(
 				"inc",
-				|state: &HostState, val: i32| -> Result<Option<()>, Error> {
+				|state: &HostState, val: i32| -> Result<(), Error> {
 					let mut ext_state = state.ext_state.borrow_mut();
 					// TODO: fix this
 					fn inc(acc: &mut i32, val: i32) {
 						*acc += val;
 					}
 					inc(&mut *ext_state, val);
-					Ok(None)
+					Ok(())
 				},
 			);
 			host_module_builder.build()

src/interpreter/value.rs

@@ -153,6 +153,18 @@ impl From<i64> for RuntimeValue {
 	}
 }
 
+impl From<u32> for RuntimeValue {
+	fn from(val: u32) -> Self {
+		RuntimeValue::I32(val as i32)
+	}
+}
+
+impl From<u64> for RuntimeValue {
+	fn from(val: u64) -> Self {
+		RuntimeValue::I64(val as i64)
+	}
+}
+
 impl From<f32> for RuntimeValue {
 	fn from(val: f32) -> Self {
 		RuntimeValue::F32(val)