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

src/kernel/thread_manager.rs

@@ -1,4 +1,4 @@
-use std::{rc::Rc, cell::{Cell, RefCell, RefMut, Ref}};
+use std::{rc::Rc, cell::{RefCell, RefMut, Ref}};
 
 use crate::{utility::list::List, simulator::{machine::{NUM_INT_REGS, NUM_FP_REGS}, interrupt::InterruptStatus}};
 
@@ -7,15 +7,15 @@ use super::{scheduler::Scheduler, thread::Thread, system::System, mgerror::Error
 pub const SIMULATORSTACKSIZE: usize = 32 * 1024;
 
 #[derive(PartialEq)]
-pub struct ThreadManager<'a> {
+pub struct ThreadManager {
     pub g_current_thread: Option<Rc<RefCell<Thread>>>,
     pub g_thread_to_be_destroyed: Option<Rc<RefCell<Thread>>>,
     pub g_alive: List<Rc<RefCell<Thread>>>,
     pub g_scheduler: Scheduler,
-    pub system: Cell<Option<&'a System<'a>>>
+    pub system: Option<Rc<RefCell<System>>>
 }
 
-impl<'a> ThreadManager<'a> {
+impl ThreadManager {
 
     pub fn new() -> Self {
         Self { 
@@ -23,10 +23,15 @@ impl<'a> ThreadManager<'a> {
             g_thread_to_be_destroyed: Option::None, 
             g_alive: List::new(),
             g_scheduler: Scheduler::new(), 
-            system: Cell::new(None)
+            system: Option::None
         }
     }
 
+    pub fn freeze(this: &Rc<RefCell<ThreadManager>>) {
+        let copy = Rc::clone(this);
+        this.borrow_mut().g_scheduler.thread_manager = Option::Some(copy);
+    }
+
     /// Start a thread, attaching it to a process
     pub fn start_thread(&mut self, thread: Rc<RefCell<Thread>>, owner: Process, func_pc: i64, argument: i64) -> Result<(), ErrorCode> {
         let mut thread_m = thread.borrow_mut();
@@ -38,7 +43,7 @@ impl<'a> ThreadManager<'a> {
         thread_m.init_simulator_context(base_stack_addr);
         thread_m.process.as_mut().unwrap().num_thread += 1;
         self.get_g_alive().push(Rc::clone(&thread));
-        self.g_scheduler().ready_to_run(Rc::clone(&thread));
+        self.g_scheduler.ready_to_run(Rc::clone(&thread));
         Result::Ok(())
     }
 
@@ -53,16 +58,17 @@ impl<'a> ThreadManager<'a> {
     /// 
     /// Cannot use yield as a function name -> reserved name in rust
     pub fn thread_yield(&mut self, thread: Rc<RefCell<Thread>>) {
-        if let Some(system) = self.system.get() {
-            let mut machine = system.get_g_machine().borrow_mut();
+        if let Some(system) = &self.system {
+            let sys = system.borrow_mut();
+            let mut machine = sys.get_g_machine().borrow_mut();
             let old_status = machine.interrupt.set_status(crate::simulator::interrupt::InterruptStatus::InterruptOff);
             
             assert_eq!(Option::Some(Rc::clone(&thread)), self.g_current_thread);
-            let next_thread = self.g_scheduler().find_next_to_run();
+            let next_thread = self.g_scheduler.find_next_to_run();
             if let Some(next_thread) = next_thread {
-                let scheduler = self.g_scheduler();
+                let scheduler = &mut self.g_scheduler;
                 scheduler.ready_to_run(thread);
-                scheduler.switch_to(system, next_thread);
+                scheduler.switch_to(next_thread);
             }
             machine.interrupt.set_status(old_status);
         }
@@ -72,16 +78,17 @@ impl<'a> ThreadManager<'a> {
     pub fn thread_sleep(&mut self, thread: Rc<RefCell<Thread>>) {
         
         assert_eq!(Option::Some(Rc::clone(&thread)), self.g_current_thread);
-        if let Some(system) = self.system.get() {
-            let mut machine = system.get_g_machine().borrow_mut();
+        if let Some(system) = &self.system {
+            let sys = system.borrow_mut();
+            let machine = sys.get_g_machine().borrow_mut();
             assert_eq!(machine.interrupt.get_status(), InterruptStatus::InterruptOff);
 
-            let mut next_thread = self.g_scheduler().find_next_to_run();
+            let mut next_thread = self.g_scheduler.find_next_to_run();
             while next_thread.is_none() {
                 machine.interrupt.idle();
-                next_thread = self.g_scheduler().find_next_to_run();
+                next_thread = self.g_scheduler.find_next_to_run();
             }
-            self.g_scheduler().switch_to(system, Rc::clone(&next_thread.unwrap()));
+            self.g_scheduler.switch_to(Rc::clone(&next_thread.unwrap()));
             
         }
     }
@@ -92,8 +99,9 @@ impl<'a> ThreadManager<'a> {
     }
 
     pub fn thread_save_processor_state(&mut self, thread: Rc<RefCell<Thread>>) {
-        if let Some(system) = self.system.get() {
+        if let Some(system) = &self.system {
             let mut t: RefMut<_> = thread.borrow_mut();
+            let system = system.borrow_mut();
             for i in 0..NUM_INT_REGS {
                 t.thread_context.int_registers[i] = system.get_g_machine().borrow().read_int_register(i);
             }
@@ -106,7 +114,8 @@ impl<'a> ThreadManager<'a> {
     }
 
     pub fn thread_restore_processor_state(&self, thread: Rc<RefCell<Thread>>) {
-        if let Some(system) = self.system.get() {
+        if let Some(system) = &self.system {
+            let system = system.borrow_mut();
             let t: Ref<_> = thread.borrow();
             for i in 0..NUM_INT_REGS {
                 let machine = system.get_g_machine();
@@ -135,11 +144,6 @@ impl<'a> ThreadManager<'a> {
         &mut self.g_alive
     }
 
-    /// Current scheduler
-    pub fn g_scheduler(&mut self) -> &mut Scheduler {
-        &mut self.g_scheduler
-    }
-
     /// Set currently running thread
     pub fn set_g_current_thread(&mut self, thread: Option<Rc<RefCell<Thread>>>) {
         self.g_current_thread = thread