initial interpreter commit

src/interpreter/program.rs

@@ -0,0 +1,54 @@
+use std::sync::Arc;
+use std::collections::HashMap;
+use std::collections::hash_map::Entry;
+use parking_lot::RwLock;
+use elements::Module;
+use interpreter::Error;
+use interpreter::module::ModuleInstance;
+
+/// Program instance. Program is a set of instantiated modules.
+pub struct ProgramInstance {
+	/// Shared data reference.
+	essence: Arc<ProgramInstanceEssence>,
+}
+
+/// Program instance essence.
+pub struct ProgramInstanceEssence {
+	/// Loaded modules.
+	modules: RwLock<HashMap<String, Arc<ModuleInstance>>>,
+}
+
+impl ProgramInstance {
+	/// Create new program instance.
+	pub fn new() -> Self {
+		ProgramInstance {
+			essence: Arc::new(ProgramInstanceEssence::new()),
+		}
+	}
+
+	/// Instantiate module.
+	pub fn add_module(&self, name: &str, module: Module) -> Result<(), Error> {
+		let mut modules = self.essence.modules.write();
+		match modules.entry(name.into()) {
+			Entry::Occupied(_) => Err(Error::Program(format!("module {} already instantiated", name))),
+			Entry::Vacant(entry) => {
+				entry.insert(Arc::new(ModuleInstance::new(Arc::downgrade(&self.essence), module)?));
+				Ok(())
+			},
+		}
+	}
+}
+
+impl ProgramInstanceEssence {
+	/// Create new program essence.
+	pub fn new() -> Self {
+		ProgramInstanceEssence {
+			modules: RwLock::new(HashMap::new()),
+		}
+	}
+
+	/// Get module reference.
+	pub fn module(&self, name: &str) -> Option<Arc<ModuleInstance>> {
+		self.modules.read().get(name).cloned()
+	}
+}