From fe48f0d61b370c2d85d727ba37f218b0190e4e93 Mon Sep 17 00:00:00 2001
From: Alessandre Laguierce <alessandre.laguierce@enseirb-matmeca.fr>
Date: Fri, 28 Mar 2025 09:36:08 +0100
Subject: [PATCH] feat: correct few things to converge to Faverge's happiness

---
 src/thread/thread.c | 21 ++++++---------------
 1 file changed, 6 insertions(+), 15 deletions(-)

diff --git a/src/thread/thread.c b/src/thread/thread.c
index d4ead2f..2812288 100644
--- a/src/thread/thread.c
+++ b/src/thread/thread.c
@@ -17,9 +17,7 @@
 #define WAS_ALLOCATED(entry) (entry->status & ALLOCATED)
 #define WAITING 0x4
 #define IS_WAITING(entry) (entry->status & WAITING)
-#define GET_WAITED_THREAD(entry) ((struct context_entry*)entry->waiting)
 #define GET_LAST_WAITED_THREAD(entry) (entry->last_waited ? entry->last_waited->last_thread : NULL)
-#define IS_WAITED_THREAD_FINISHED(entry) (GET_WAITED_THREAD(entry)->status & FINISHED)
 #define WAITED 0x8
 #define IS_WAITED(entry) (entry->status & WAITED)
 
@@ -27,7 +25,7 @@
 #define STACK_SIZE 4096
 #endif
 
-// Variables used to clean up everything at the end of the processus
+// Variables used to clean up everything at the end of the processes
 static char stack_for_freeing[STACK_SIZE] = {0};
 static int stack_valgrind_id = 0;
 static ucontext_t context_for_freeing;
@@ -39,8 +37,6 @@ struct context_entry {
     TAILQ_ENTRY(context_entry)
     link; // Use to navigate inside the list
     ucontext_t context;
-    thread_t id;
-    void *waiting; // the thread that the entry is waiting for
     void *retvalue; // return value or if the thread is waited, the id of the thread that wait for it
     struct last_thread_t *last_waited;
     int valgrind_id;
@@ -75,11 +71,8 @@ int thread_yield(void)
      * check if the thread is not the running one.
      */
     struct context_entry* first = TAILQ_FIRST(&head);
-    if (!first) {
-        return -1;
-    }
     TAILQ_REMOVE(&head, first, link);
-    if (!IS_FINISHED(running) && !(IS_WAITING(running) && !IS_WAITED_THREAD_FINISHED(running))) {
+    if (!IS_FINISHED(running) && !IS_WAITING(running)) {
         TAILQ_INSERT_TAIL(&head, running, link);
     }
     TRACE("PICKING %p (previous was %p)", first->id, running->id);
@@ -96,7 +89,7 @@ thread_t thread_self(void)
     if (running == NULL) {
         return 0;
     }
-    return running->id;
+    return running;
 }
 
 /**
@@ -133,8 +126,6 @@ int thread_create(thread_t* newthread, void* (*func)(void*), void* funcarg)
         new_entry->valgrind_id = VALGRIND_STACK_REGISTER(
             new_entry->context.uc_stack.ss_sp,
             new_entry->context.uc_stack.ss_sp + new_entry->context.uc_stack.ss_size);
-
-        new_entry->id = new_entry;
     }
 
     getcontext(&new_entry->context);
@@ -145,7 +136,7 @@ int thread_create(thread_t* newthread, void* (*func)(void*), void* funcarg)
     new_entry->retvalue = NULL;
     new_entry->last_waited = NULL;
 
-    *newthread = new_entry->id;
+    *newthread = new_entry;
 
     makecontext(&new_entry->context, (void (*)(void))thread_function_wrapper, 2, func, funcarg);
 
@@ -175,7 +166,6 @@ int thread_join(thread_t thread, void** retval)
     if (!IS_FINISHED(entry)) {
         // Use status to be in waiting state
         running->status |= WAITING;
-        running->waiting = entry;
         // Mark the waited thread as waited to not be waited by any other thread.
         entry->status |= WAITED;
         // Use retvalue to share which thread is currently waiting for this thread
@@ -212,6 +202,8 @@ int thread_join(thread_t thread, void** retval)
   
 
         DBG("%p is waiting for %p", running, entry);
+        TAILQ_REMOVE(&head, GET_LAST_WAITED_THREAD(running), link);
+        TAILQ_INSERT_HEAD(&head, GET_LAST_WAITED_THREAD(running), link);
         do {
             thread_yield();
         } while (!IS_FINISHED(entry));
@@ -300,7 +292,6 @@ void __attribute__((constructor)) setup_main_thread()
     struct context_entry* main = malloc(sizeof(*main));
     // memset(main, 0, sizeof(*main));
     getcontext(&main->context);
-    main->id = main;
     main->status = 0;
     main->retvalue = NULL;
     main->last_waited = NULL;