1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140

use std::sync::Arc;
use std::collections::HashMap;
use parking_lot::RwLock;
use elements::{FunctionType, Internal, ValueType};
use interpreter::Error;
use interpreter::module::{ModuleInstanceInterface, ExecutionParams, ItemIndex,
	CallerContext, ExportEntryType};
use interpreter::memory::MemoryInstance;
use interpreter::table::TableInstance;
use interpreter::value::RuntimeValue;
use interpreter::variable::{VariableInstance, VariableType};

/// Min index of native function.
pub const NATIVE_INDEX_FUNC_MIN: u32 = 10001;

/// User function closure type.
// pub type UserFunctionClosure<'a> = &'a mut FnMut(context: CallerContext) -> Result<Option<RuntimeValue>, Error>;

/// User functions executor.
pub trait UserFunctionExecutor {
	/// Execute function with given name.
	fn execute(&mut self, name: &str, context: CallerContext) -> Result<Option<RuntimeValue>, Error>;
}

/// User function type.
pub struct UserFunction {
	/// User function name.
	pub name: String,
	/// User function parameters (for signature matching).
	pub params: Vec<ValueType>,
	/// User function return type (for signature matching).
	pub result: Option<ValueType>,
}

/// Set of user-defined functions
pub struct UserFunctions<'a> {
	/// Functions list.
	pub functions: Vec<UserFunction>,
	/// Functions executor.
	pub executor: &'a mut UserFunctionExecutor,
}

/// Native module instance.
pub struct NativeModuleInstance<'a> {
	/// Underllying module reference.
	env: Arc<ModuleInstanceInterface>,
	/// User function executor.
	executor: RwLock<&'a mut UserFunctionExecutor>,
	/// By-name functions index.
	by_name: HashMap<String, u32>,
	/// User functions list.
	functions: Vec<UserFunction>,
}

impl<'a> NativeModuleInstance<'a> {
	/// Create new native module
	pub fn new(env: Arc<ModuleInstanceInterface>, functions: UserFunctions<'a>) -> Result<Self, Error> {
		Ok(NativeModuleInstance {
			env: env,
			executor: RwLock::new(functions.executor),
			by_name: functions.functions.iter().enumerate().map(|(i, f)| (f.name.clone(), i as u32)).collect(),
			functions: functions.functions,
		})
	}
}

impl<'a> ModuleInstanceInterface for NativeModuleInstance<'a> {
	fn instantiate<'b>(&self, is_user_module: bool, externals: Option<&'b HashMap<String, Arc<ModuleInstanceInterface + 'b>>>) -> Result<(), Error> {
		self.env.instantiate(is_user_module, externals)
	}

	fn execute_index(&self, index: u32, params: ExecutionParams) -> Result<Option<RuntimeValue>, Error> {
		self.env.execute_index(index, params)
	}

	fn execute_export(&self, name: &str, params: ExecutionParams) -> Result<Option<RuntimeValue>, Error> {
		self.env.execute_export(name, params)
	}

	fn export_entry<'b>(&self, name: &str, externals: Option<&'b HashMap<String, Arc<ModuleInstanceInterface + 'b>>>, required_type: &ExportEntryType) -> Result<Internal, Error> {
		if let Some(index) = self.by_name.get(name) {
			return Ok(Internal::Function(NATIVE_INDEX_FUNC_MIN + *index));
		}

		self.env.export_entry(name, externals, required_type)
	}

	fn function_type<'b>(&self, function_index: ItemIndex, externals: Option<&'b HashMap<String, Arc<ModuleInstanceInterface + 'b>>>) -> Result<FunctionType, Error> {
		let index = match function_index {
			ItemIndex::IndexSpace(index) | ItemIndex::Internal(index) => index,
			ItemIndex::External(_) => unreachable!("trying to call function, exported by native env module"),
		};

		if index < NATIVE_INDEX_FUNC_MIN {
			return self.env.function_type(function_index, externals);
		}

		self.functions
			.get((index - NATIVE_INDEX_FUNC_MIN) as usize)
			.ok_or(Error::Native(format!("missing native env function with index {}", index)))
			.map(|f| FunctionType::new(f.params.clone(), f.result.clone()))
	}

	fn table(&self, index: ItemIndex) -> Result<Arc<TableInstance>, Error> {
		self.env.table(index)
	}

	fn memory(&self, index: ItemIndex) -> Result<Arc<MemoryInstance>, Error> {
		self.env.memory(index)
	}

	fn global(&self, index: ItemIndex, variable_type: Option<VariableType>) -> Result<Arc<VariableInstance>, Error> {
		self.env.global(index, variable_type)
	}

	fn call_function(&self, outer: CallerContext, index: ItemIndex, function_type: Option<&FunctionType>) -> Result<Option<RuntimeValue>, Error> {
		self.env.call_function(outer, index, function_type)
	}

	fn call_function_indirect(&self, outer: CallerContext, table_index: ItemIndex, type_index: u32, func_index: u32) -> Result<Option<RuntimeValue>, Error> {
		self.env.call_function_indirect(outer, table_index, type_index, func_index)
	}

	fn call_internal_function(&self, outer: CallerContext, index: u32, function_type: Option<&FunctionType>) -> Result<Option<RuntimeValue>, Error> {
		if index < NATIVE_INDEX_FUNC_MIN {
			return self.env.call_internal_function(outer, index, function_type);
		}

		// TODO: check type
		self.functions
			.get((index - NATIVE_INDEX_FUNC_MIN) as usize)
			.ok_or(Error::Native(format!("trying to call native function with index {}", index)))
			.and_then(|f| self.executor.write().execute(&f.name, outer))
	}
}

/// Create wrapper for env module with given native user functions.
pub fn env_native_module(env: Arc<ModuleInstanceInterface>, user_functions: UserFunctions) -> Result<NativeModuleInstance, Error> {
	NativeModuleInstance::new(env, user_functions)
}