env memory

src/interpreter/env.rs

@@ -1,6 +1,6 @@
 use std::sync::Arc;
 use builder::module;
-use elements::{Module, FunctionType};
+use elements::{Module, FunctionType, ExportEntry, Internal, MemoryType};
 use interpreter::Error;
 use interpreter::module::{ModuleInstanceInterface, ItemIndex, CallerContext};
 use interpreter::memory::MemoryInstance;
@@ -8,14 +8,18 @@ use interpreter::table::TableInstance;
 use interpreter::value::RuntimeValue;
 use interpreter::variable::VariableInstance;
 
+const MEMORY_LIMIT_MIN: u32 = 1;
+
 pub struct EnvModuleInstance {
 	module: Module,
+	memory: Arc<MemoryInstance>,
 }
 
 impl EnvModuleInstance {
 	pub fn new(module: Module) -> Result<Self, Error> {
 		Ok(EnvModuleInstance {
 			module: module,
+			memory: MemoryInstance::new(&MemoryType::new(MEMORY_LIMIT_MIN, None))?,
 		})
 	}
 }
@@ -37,8 +41,11 @@ impl ModuleInstanceInterface for EnvModuleInstance {
 		unimplemented!()
 	}
 
-	fn memory(&self, _index: ItemIndex) -> Result<Arc<MemoryInstance>, Error> {
-		unimplemented!()
+	fn memory(&self, index: ItemIndex) -> Result<Arc<MemoryInstance>, Error> {
+		match &index {
+			&ItemIndex::Internal(0) => Ok(self.memory.clone()),
+			_ => Err(Error::Env(format!("trying to get memory with index {:?}", index))),
+		}
 	}
 
 	fn global(&self, _index: ItemIndex) -> Result<Arc<VariableInstance>, Error> {
@@ -60,7 +67,10 @@ impl ModuleInstanceInterface for EnvModuleInstance {
 
 pub fn env_module() -> Result<EnvModuleInstance, Error> {
 	let module = module()
-		.memory().build() // TODO: limits
+		.memory()
+			.with_min(MEMORY_LIMIT_MIN)
+			.build()
+		.with_export(ExportEntry::new("memory".into(), Internal::Memory(0)))
 		.build();
 	EnvModuleInstance::new(module)
 }

src/interpreter/mod.rs

@@ -25,6 +25,8 @@ pub enum Error {
 	Value(String),
 	/// Interpreter (code) error.
 	Interpreter(String),
+	/// Env module error.
+	Env(String),
 	/// Trap.
 	Trap(String),
 }
@@ -43,6 +45,7 @@ impl Into<String> for Error {
 			Error::Stack(s) => s,
 			Error::Interpreter(s) => s,
 			Error::Value(s) => s,
+			Error::Env(s) => s,
 			Error::Trap(s) => format!("trap: {}", s),
 		}
 	}