Fix scheduler switch_to by making a lot of change(use smart pointers in place of lifetime reference)

src/kernel/system.rs

@@ -1,4 +1,4 @@
-use std::cell::RefCell;
+use std::{cell::RefCell, rc::Rc};
 
 use crate::simulator::machine::Machine;
 
@@ -15,24 +15,27 @@ use super::thread_manager::ThreadManager;
 /// - The thread to be destroyed next
 /// - The scheduler which acts upon these threads
 #[derive(PartialEq)]
-pub struct System<'a> {
+pub struct System {
     g_machine: RefCell<Machine>,
-    thread_manager: ThreadManager<'a>
+    thread_manager: Rc<RefCell<ThreadManager>>
 }
 
-impl<'a> System<'a> {
+impl System {
 
     /// System constructor
-    pub fn new(machine: Machine) -> System<'a> {
+    pub fn new(machine: Machine) -> System {
         Self {
             g_machine: RefCell::new(machine),
-            thread_manager: ThreadManager::new()
+            thread_manager: Rc::new(RefCell::new(ThreadManager::new()))
         }
     }
 
     /// use thread_manager setter to send it system instance
-    pub fn freeze(&'a mut self) {
-        self.thread_manager.system.set(Option::Some(self));
+    pub fn freeze(this: Rc<RefCell<System>>) {
+        let copy = Rc::clone(&this);
+        let tm = &this.borrow_mut().thread_manager;
+        tm.borrow_mut().system = Option::Some(copy);
+        ThreadManager::freeze(tm);
     }
 
     // GETTERS