Use shared ref to pass the State.

examples/tictactoe.rs

@@ -0,0 +1,235 @@
+extern crate parity_wasm;
+
+use std::env;
+use std::fmt;
+use std::rc::Rc;
+use parity_wasm::elements::Module;
+use parity_wasm::interpreter::{Error as InterpreterError, HostModule, HostModuleBuilder,
+							   ModuleInstance, UserError};
+
+#[derive(Debug)]
+pub enum Error {
+	OutOfRange,
+	AlreadyOccupied,
+	Interpreter(InterpreterError),
+}
+
+impl fmt::Display for Error {
+	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+		write!(f, "{:?}", self)
+	}
+}
+
+impl From<InterpreterError> for Error {
+	fn from(e: InterpreterError) -> Self {
+		Error::Interpreter(e)
+	}
+}
+
+impl UserError for Error {}
+
+mod tictactoe {
+	use std::cell::RefCell;
+	use super::Error;
+
+	#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+	pub enum Player {
+		X,
+		O,
+	}
+
+	#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+	pub enum GameResult {
+		Draw,
+		Won(Player),
+	}
+
+	impl Player {
+		pub fn into_i32(maybe_player: Option<Player>) -> i32 {
+			match maybe_player {
+				None => 0,
+				Some(Player::X) => 1,
+				Some(Player::O) => 2,
+			}
+		}
+	}
+
+	#[derive(Debug)]
+	pub struct Game {
+		board: RefCell<[Option<Player>; 9]>,
+	}
+
+	impl Game {
+		pub fn new() -> Game {
+			Game {
+				board: RefCell::new([None; 9]),
+			}
+		}
+
+		pub fn set(&self, idx: i32, player: Player) -> Result<(), Error> {
+			let mut board = self.board.borrow_mut();
+			if idx < 0 || idx > 9 {
+				return Err(Error::OutOfRange);
+			}
+			if board[idx as usize] != None {
+				return Err(Error::AlreadyOccupied);
+			}
+			board[idx as usize] = Some(player);
+			Ok(())
+		}
+
+		pub fn get(&self, idx: i32) -> Result<Option<Player>, Error> {
+			if idx < 0 || idx > 9 {
+				return Err(Error::OutOfRange);
+			}
+			Ok(self.board.borrow()[idx as usize])
+		}
+
+		pub fn game_result(&self) -> Option<GameResult> {
+			let board = self.board.borrow();
+
+			// 0, 1, 2
+			// 3, 4, 5
+			// 6, 7, 8
+			let patterns = &[
+				// Rows
+				(0, 1, 2),
+				(3, 4, 5),
+				(6, 7, 8),
+
+				// Columns
+				(0, 3, 6),
+				(1, 4, 7),
+				(2, 5, 8),
+
+				// Diagonals
+				(0, 4, 8),
+				(2, 4, 6),
+			];
+
+			// Returns Some(player) if all cells contain same Player.
+			let all_same = |i1: usize, i2: usize, i3: usize| -> Option<Player> {
+				if board[i1].is_none() {
+					return None;
+				}
+				if board[i1] == board[i2] && board[i2] == board[i3] {
+					return board[i1];
+				}
+				None
+			};
+
+			for &(i1, i2, i3) in patterns {
+				if let Some(player) = all_same(i1, i2, i3) {
+					return Some(GameResult::Won(player));
+				}
+			}
+
+			// Ok, there is no winner. Check if it's draw.
+			let all_occupied = board.iter().all(|&cell| cell.is_some());
+			if all_occupied {
+				Some(GameResult::Draw)
+			} else {
+				// Nah, there are still empty cells left.
+				None
+			}
+		}
+	}
+}
+
+struct Runtime<'a> {
+	player: tictactoe::Player,
+	game: &'a tictactoe::Game,
+}
+
+fn instantiate<'a, 'b>(
+	module: &Module,
+	env: &HostModule<Runtime<'a>>,
+	runtime: &'b Runtime<'a>,
+) -> Result<Rc<ModuleInstance<Runtime<'a>>>, Error> {
+	let instance = ModuleInstance::instantiate(module)
+		.with_import("env", &*env)
+		.run_start(runtime)?;
+
+	Ok(instance)
+}
+
+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.game.set(idx, state.player)?;
+			Ok(None)
+		},
+	);
+	builder.with_func1(
+		"get",
+		|state: &Runtime, idx: i32| -> Result<Option<i32>, InterpreterError> {
+			let val: i32 = tictactoe::Player::into_i32(state.game.get(idx).unwrap());
+			Ok(Some(val))
+		},
+	);
+	builder.build()
+}
+
+fn play<'a>(
+	x_module: &Module,
+	o_module: &Module,
+	host_module: &HostModule<Runtime<'a>>,
+	game: &'a tictactoe::Game,
+) -> Result<tictactoe::GameResult, Error> {
+	// Instantiate modules of X and O players.
+	let x_instance = {
+		let mut runtime = Runtime {
+			player: tictactoe::Player::X,
+			game: game,
+		};
+		instantiate(x_module, host_module, &runtime)?
+	};
+	let o_instance = {
+		let mut runtime = Runtime {
+			player: tictactoe::Player::O,
+			game: game,
+		};
+		instantiate(o_module, host_module, &runtime)?
+	};
+
+	let mut turn_of = tictactoe::Player::X;
+	let game_result = loop {
+		let (instance, next_turn_of) = match turn_of {
+			tictactoe::Player::X => (&x_instance, tictactoe::Player::O),
+			tictactoe::Player::O => (&o_instance, tictactoe::Player::X),
+		};
+
+		let mut runtime = Runtime {
+			player: turn_of,
+			game: game,
+		};
+		let _ = instance.invoke_export("mk_turn", vec![], &runtime)?;
+
+		match game.game_result() {
+			Some(game_result) => break game_result,
+			None => {}
+		}
+
+		turn_of = next_turn_of;
+	};
+
+	Ok(game_result)
+}
+
+fn main() {
+	let game = tictactoe::Game::new();
+	let env_host_module = env_host_module();
+
+	let args: Vec<_> = env::args().collect();
+	if args.len() < 3 {
+		println!("Usage: {} <x player module> <y player module>", args[0]);
+		return;
+	}
+	let x_module = parity_wasm::deserialize_file(&args[1]).expect("X player module to load");
+	let o_module = parity_wasm::deserialize_file(&args[2]).expect("Y player module to load");
+
+	let result = play(&x_module, &o_module, &env_host_module, &game);
+	println!("result = {:?}, game = {:#?}", result, game);
+}

src/interpreter/func.rs

@@ -84,7 +84,7 @@ impl<St> FuncInstance<St> {
 	pub fn invoke(
 		func: Rc<FuncInstance<St>>,
 		args: Vec<RuntimeValue>,
-		state: &mut St,
+		state: &St,
 	) -> Result<Option<RuntimeValue>, Error> {
 		enum InvokeKind<St> {
 			Internal(FunctionContext<St>),

src/interpreter/host.rs

@@ -11,7 +11,7 @@ use interpreter::value::RuntimeValue;
 use interpreter::Error;
 use interpreter::ImportResolver;
 
-pub type HostFunc<St> = Fn(&mut St, &[RuntimeValue]) -> Result<Option<RuntimeValue>, Error>;
+pub type HostFunc<St> = Fn(&St, &[RuntimeValue]) -> Result<Option<RuntimeValue>, Error>;
 
 pub struct HostModuleBuilder<St> {
 	exports: HashMap<String, ExternVal<St>>,
@@ -25,7 +25,7 @@ impl<St> HostModuleBuilder<St> {
 	}
 
 	pub fn with_func0<
-		Cl: Fn(&mut St) -> Result<Option<Ret>, Error> + 'static,
+		Cl: Fn(&St) -> Result<Option<Ret>, Error> + 'static,
 		Ret: AsReturnVal + 'static,
 		N: Into<String>,
 	>(
@@ -34,7 +34,7 @@ impl<St> HostModuleBuilder<St> {
 		f: Cl,
 	) {
 		let func_type = FunctionType::new(vec![], Ret::value_type());
-		let host_func = Rc::new(move |state: &mut St, _args: &[RuntimeValue]| -> Result<Option<RuntimeValue>, Error> {
+		let host_func = Rc::new(move |state: &St, _args: &[RuntimeValue]| -> Result<Option<RuntimeValue>, Error> {
 			let result = f(state);
 			result.map(|r| r.and_then(|r| r.as_return_val()))
 		});
@@ -44,7 +44,7 @@ impl<St> HostModuleBuilder<St> {
 	}
 
 	pub fn with_func1<
-		Cl: Fn(&mut St, P1) -> Result<Option<Ret>, Error> + 'static,
+		Cl: Fn(&St, P1) -> Result<Option<Ret>, Error> + 'static,
 		Ret: AsReturnVal + 'static,
 		P1: FromArg + 'static,
 		N: Into<String>,
@@ -54,7 +54,7 @@ impl<St> HostModuleBuilder<St> {
 		f: Cl,
 	) {
 		let func_type = FunctionType::new(vec![P1::value_type()], Ret::value_type());
-		let host_func = Rc::new(move |state: &mut St, args: &[RuntimeValue]| -> Result<Option<RuntimeValue>, Error> {
+		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);
 			result.map(|r| r.and_then(|r| r.as_return_val()))
@@ -65,7 +65,7 @@ impl<St> HostModuleBuilder<St> {
 	}
 
 	pub fn with_func2<
-		Cl: Fn(&mut St, P1, P2) -> Result<Option<Ret>, Error> + 'static,
+		Cl: Fn(&St, P1, P2) -> Result<Option<Ret>, Error> + 'static,
 		Ret: AsReturnVal + 'static,
 		P1: FromArg + 'static,
 		P2: FromArg + 'static,
@@ -76,7 +76,7 @@ impl<St> HostModuleBuilder<St> {
 		f: Cl,
 	) {
 		let func_type = FunctionType::new(vec![P1::value_type(), P2::value_type()], Ret::value_type());
-		let host_func = Rc::new(move |state: &mut St, args: &[RuntimeValue]| -> Result<Option<RuntimeValue>, Error> {
+		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);
@@ -180,7 +180,7 @@ impl<St> ImportResolver<St> for HostModule<St> {
 pub trait AnyFunc<St> {
 	fn call_as_any(
 		&self,
-		state: &mut St,
+		state: &St,
 		args: &[RuntimeValue],
 	) -> Result<Option<RuntimeValue>, Error>;
 }
@@ -228,10 +228,10 @@ impl AsReturnVal for () {
 	}
 }
 
-impl<St, Ret: AsReturnVal> AnyFunc<St> for Fn(&mut St) -> Result<Option<Ret>, Error> {
+impl<St, Ret: AsReturnVal> AnyFunc<St> for Fn(&St) -> Result<Option<Ret>, Error> {
 	fn call_as_any(
 		&self,
-		state: &mut St,
+		state: &St,
 		_args: &[RuntimeValue],
 	) -> Result<Option<RuntimeValue>, Error> {
 		let result = self(state);
@@ -239,10 +239,10 @@ impl<St, Ret: AsReturnVal> AnyFunc<St> for Fn(&mut St) -> Result<Option<Ret>, Er
 	}
 }
 
-impl<St, Ret: AsReturnVal, P1: FromArg, P2: FromArg> AnyFunc<St> for Fn(&mut St, P1, P2) -> Result<Option<Ret>, Error> {
+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: &mut St,
+		state: &St,
 		args: &[RuntimeValue],
 	) -> Result<Option<RuntimeValue>, Error> {
 		let p1 = P1::from_arg(&args[0]);

src/interpreter/module.rs

@@ -401,7 +401,7 @@ impl<St> ModuleInstance<St> {
 		&self,
 		func_idx: u32,
 		args: Vec<RuntimeValue>,
-		state: &mut St,
+		state: &St,
 	) -> Result<Option<RuntimeValue>, Error> {
 		let func_instance = self.func_by_index(func_idx).ok_or_else(|| {
 			Error::Program(format!(
@@ -416,7 +416,7 @@ impl<St> ModuleInstance<St> {
 		&self,
 		func_name: &str,
 		args: Vec<RuntimeValue>,
-		state: &mut St,
+		state: &St,
 	) -> Result<Option<RuntimeValue>, Error> {
 		let extern_val = self.export_by_name(func_name).ok_or_else(|| {
 			Error::Program(format!("Module doesn't have export {}", func_name))
@@ -466,7 +466,7 @@ impl<'a, St: 'a> InstantiationWizard<'a, St> {
 		self
 	}
 
-	pub fn run_start(mut self, state: &mut St) -> Result<Rc<ModuleInstance<St>>, Error> {
+	pub fn run_start(mut self, state: &St) -> Result<Rc<ModuleInstance<St>>, Error> {
 		let imports = self.imports.get_or_insert_with(|| Imports::default());
 		let instance = ModuleInstance::instantiate_with_imports(self.module, imports)?;
 

src/interpreter/program.rs

@@ -28,7 +28,7 @@ impl<St> ProgramInstance<St> {
 		&mut self,
 		name: &str,
 		module: Module,
-		state: &mut St,
+		state: &St,
 	) -> Result<Rc<ModuleInstance<St>>, Error> {
 		let module_instance = {
 			let mut imports = Imports::new();
@@ -72,7 +72,7 @@ impl<St> ProgramInstance<St> {
 		module_name: &str,
 		func_name: &str,
 		args: Vec<RuntimeValue>,
-		state: &mut St,
+		state: &St,
 	) -> Result<Option<RuntimeValue>, Error> {
 		let module_instance = self.modules.get(module_name).ok_or_else(|| {
 			Error::Program(format!("Module {} not found", module_name))
@@ -85,7 +85,7 @@ impl<St> ProgramInstance<St> {
 		module_name: &str,
 		func_idx: u32,
 		args: Vec<RuntimeValue>,
-		state: &mut St,
+		state: &St,
 	) -> Result<Option<RuntimeValue>, Error> {
 		let module_instance = self.modules.get(module_name).cloned().ok_or_else(|| {
 			Error::Program(format!("Module {} not found", module_name))
@@ -97,7 +97,7 @@ impl<St> ProgramInstance<St> {
 		&mut self,
 		func_instance: Rc<FuncInstance<St>>,
 		args: Vec<RuntimeValue>,
-		state: &mut St,
+		state: &St,
 	) -> Result<Option<RuntimeValue>, Error> {
 		FuncInstance::invoke(Rc::clone(&func_instance), args, state)
 	}

src/interpreter/runner.rs

@@ -18,7 +18,7 @@ use common::stack::StackWithLimit;
 
 /// Function interpreter.
 pub struct Interpreter<'a, St: 'a> {
-	state: &'a mut St,
+	state: &'a St,
 }
 
 /// Function execution context.
@@ -64,7 +64,7 @@ enum RunResult<St> {
 }
 
 impl<'a, St: 'a> Interpreter<'a, St> {
-	pub fn new(state: &'a mut St) -> Interpreter<'a, St> {
+	pub fn new(state: &'a St) -> Interpreter<'a, St> {
 		Interpreter {
 			state
 		}

src/interpreter/tests/basics.rs

@@ -1,6 +1,7 @@
 ///! Basic tests for instructions/constructions, missing in wabt tests
 
 use std::rc::Rc;
+use std::cell::RefCell;
 use builder::module;
 use elements::{ExportEntry, Internal, ImportEntry, External, GlobalEntry, GlobalType,
 	InitExpr, ValueType, Opcodes, Opcode, TableType, MemoryType};
@@ -118,12 +119,12 @@ impl UserError for UserErrorWithCode {}
 
 struct TestState {
 	pub memory: Rc<MemoryInstance>,
-	pub values: Vec<i32>,
+	pub values: RefCell<Vec<i32>>,
 }
 
 fn build_env_module() -> HostModule<TestState> {
 	let mut builder = HostModuleBuilder::<TestState>::new();
-	builder.with_func2("add", |state: &mut TestState, arg: i32, unused: i32| {
+	builder.with_func2("add", |state: &TestState, arg: i32, unused: i32| {
 		let memory_value = state.memory.get(0, 1).unwrap()[0];
 		let fn_argument_unused = unused as u8;
 		let fn_argument = arg as u8;
@@ -131,10 +132,10 @@ fn build_env_module() -> HostModule<TestState> {
 
 		let sum = memory_value + fn_argument;
 		state.memory.set(0, &vec![sum]).unwrap();
-		state.values.push(sum as i32);
+		state.values.borrow_mut().push(sum as i32);
 		Ok(Some(sum as i32))
 	});
-	builder.with_func2("sub", |state: &mut TestState, arg: i32, unused: i32| {
+	builder.with_func2("sub", |state: &TestState, arg: i32, unused: i32| {
 		let memory_value = state.memory.get(0, 1).unwrap()[0];
 		let fn_argument_unused = unused as u8;
 		let fn_argument = arg as u8;
@@ -142,10 +143,10 @@ fn build_env_module() -> HostModule<TestState> {
 
 		let diff = memory_value - fn_argument;
 		state.memory.set(0, &vec![diff]).unwrap();
-		state.values.push(diff as i32);
+		state.values.borrow_mut().push(diff as i32);
 		Ok(Some(diff as i32))
 	});
-	builder.with_func2("err", |_: &mut TestState, _unused1: i32, _unused2: i32| -> Result<Option<i32>, Error> {
+	builder.with_func2("err", |_: &TestState, _unused1: i32, _unused2: i32| -> Result<Option<i32>, Error> {
 		Err(Error::User(Box::new(UserErrorWithCode { error_code: 777 })))
 	});
 	builder.insert_memory("memory", Rc::new(MemoryInstance::new(&MemoryType::new(256, None)).unwrap()));
@@ -161,7 +162,7 @@ fn native_env_function() {
 
 	let mut state = TestState {
 		memory: env_memory,
-		values: Vec::new(),
+		values: RefCell::new(Vec::new()),
 	};
 	{
 		let module = module()
@@ -212,7 +213,7 @@ fn native_env_function() {
 	}
 
 	assert_eq!(state.memory.get(0, 1).unwrap()[0], 42);
-	assert_eq!(state.values, vec![7, 57, 42]);
+	assert_eq!(&*state.values.borrow(), &[7, 57, 42]);
 }
 
 #[test]
@@ -233,8 +234,8 @@ fn native_env_global() {
 				])).build()
 				.build()
 			.build();
-		program.add_module("main", module, &mut State)?;
+		program.add_module("main", module, &State)?;
-		program.invoke_index("main", 0, vec![], &mut State)
+		program.invoke_index("main", 0, vec![], &State)
 	};
 
 	// try to add module, exporting non-existant env' variable => error
@@ -260,7 +261,7 @@ fn native_custom_error() {
 
 	let mut state = TestState {
 		memory: env_memory,
-		values: Vec::new(),
+		values: RefCell::new(Vec::new()),
 	};
 
 	let module = module()
@@ -297,7 +298,7 @@ fn native_ref_state() {
 
 	// This structure holds state for our host module.
 	struct HostState<'a> {
-		ext_state: &'a mut ExtState,
+		ext_state: RefCell<&'a mut ExtState>,
 	}
 
 	let main_module = module()
@@ -322,8 +323,13 @@ fn native_ref_state() {
 			let mut host_module_builder = HostModuleBuilder::<HostState>::new();
 			host_module_builder.with_func1(
 				"inc",
-				|state: &mut HostState, val: i32| -> Result<Option<()>, Error> {
+				|state: &HostState, val: i32| -> Result<Option<()>, Error> {
-					*state.ext_state += val;
+					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)
 				},
 			);
@@ -331,7 +337,7 @@ fn native_ref_state() {
 		};
 
 		let mut host_state = HostState {
-			ext_state: &mut ext_state,
+			ext_state: RefCell::new(&mut ext_state),
 		};
 
 		let instance = ModuleInstance::instantiate(&main_module)