single threads; custom timer; letters

source/cell.c

@@ -9,6 +9,7 @@
 #include <limits.h>
 #include <errno.h>
 #include <sys/stat.h>
+#include <time.h>
 
 #include <SDL3/SDL_atomic.h>
 
@@ -61,6 +62,107 @@ static Uint32 queue_event;
 static SDL_AtomicInt engine_shutdown;
 static SDL_Thread **runners = NULL;
 
+// TIMERS
+struct timer_entry { uint64_t when_ns; cell_rt *actor; uint32_t id; };
+static struct timer_entry *timers = NULL;
+static uint32_t timer_counter = 1;
+static SDL_Mutex *timer_mutex = NULL; // protects access to timers
+
+static inline uint64_t now_ns()
+{
+  return SDL_GetTicksNS();
+}
+
+static void process_due_timers(void)
+{
+  uint64_t tnow = now_ns();
+  SDL_LockMutex(timer_mutex);
+  while (arrlen(timers) && timers[0].when_ns <= tnow) {
+    struct timer_entry te = timers[0];
+    arrdel(timers, 0);
+    SDL_UnlockMutex(timer_mutex);
+
+    /* Marshal callback into actor mailbox. */
+    SDL_LockMutex(te.actor->msg_mutex);
+    int idx = hmgeti(te.actor->timers, te.id);
+    if (idx != -1) {
+      JSValue cb = te.actor->timers[idx].value; /* already duped when stored */
+      hmdel(te.actor->timers, te.id);
+      
+      letter l;
+      l.type = LETTER_CALLBACK;
+      l.callback = cb;
+      arrput(te.actor->letters, l);
+    }
+    SDL_UnlockMutex(te.actor->msg_mutex);
+    set_actor_state(te.actor);
+
+    SDL_LockMutex(timer_mutex);
+  }
+  SDL_UnlockMutex(timer_mutex);
+}
+
+static uint64_t next_timeout_ns(void)
+{
+  SDL_LockMutex(timer_mutex);
+  uint64_t timeout = arrlen(timers) ? (timers[0].when_ns - now_ns()) : UINT64_MAX;
+  SDL_UnlockMutex(timer_mutex);
+  return timeout;
+}
+
+static void timer_insert(struct timer_entry te)
+{
+  SDL_LockMutex(timer_mutex);
+  size_t n = arrlen(timers);
+  arrput(timers, te);
+  for (size_t i = n; i > 0 && timers[i].when_ns < timers[i-1].when_ns; --i) {
+    struct timer_entry tmp = timers[i];
+    timers[i] = timers[i-1];
+    timers[i-1] = tmp;
+  }
+  SDL_UnlockMutex(timer_mutex);
+}
+
+/* Public API used by JS glue (replaces SDL_AddTimer). */
+uint32_t scheduler_add_timer(cell_rt *actor, double seconds, JSValue cb)
+{
+  uint32_t id = SDL_AtomicIncRef((SDL_AtomicInt*)&timer_counter);
+  uint64_t deadline = now_ns() + (uint64_t)(seconds * 1e9);
+
+  SDL_LockMutex(timer_mutex);
+  timer_insert((struct timer_entry){ deadline, actor, id });
+  SDL_UnlockMutex(timer_mutex);
+
+  /* Stash in actor map so removal/GC works. Duplicated to hold ref. */
+  SDL_LockMutex(actor->msg_mutex);
+  hmput(actor->timers, id, JS_DupValue(actor->context, cb));
+  SDL_UnlockMutex(actor->msg_mutex);
+
+  /* Wake a sleeper if this timer is sooner than the current next. */
+  SDL_SignalCondition(queue_cond);
+  return id;
+}
+
+void scheduler_remove_timer(cell_rt *actor, uint32_t id)
+{
+  SDL_LockMutex(timer_mutex);
+  for (int i = 0; i < arrlen(timers); ++i) {
+    if (timers[i].id == id) {
+      arrdel(timers, i);
+      break;
+    }
+  }
+  SDL_UnlockMutex(timer_mutex);
+
+  SDL_LockMutex(actor->msg_mutex);
+  int idx = hmgeti(actor->timers, id);
+  if (idx != -1) {
+    JS_FreeValue(actor->context, actor->timers[idx].value);
+    hmdel(actor->timers, id);
+  }
+  SDL_UnlockMutex(actor->msg_mutex);
+}
+
 static void exit_handler(void)
 {
   SDL_SetAtomicInt(&engine_shutdown, 1);
@@ -115,8 +217,17 @@ void actor_free(cell_rt *actor)
   for (int i = 0; i < arrlen(actor->js_swapchains); i++)
     JS_FreeValue(js, actor->js_swapchains[i]);
 
+  /* Remove all timers for this actor from the global timer queue */
+  SDL_LockMutex(timer_mutex);
+  for (int i = arrlen(timers) - 1; i >= 0; i--) {
+    if (timers[i].actor == actor) {
+      arrdel(timers, i);
+    }
+  }
+  SDL_UnlockMutex(timer_mutex);
+
+  /* Free timer callbacks stored in actor */
   for (int i = 0; i < hmlen(actor->timers); i++) {
-    SDL_RemoveTimer(actor->timers[i].key);
     JS_FreeValue(js, actor->timers[i].value);
   }
   
@@ -124,16 +235,16 @@ void actor_free(cell_rt *actor)
   arrfree(actor->js_swapchains);
   arrfree(actor->module_registry);
   
-  for (int i = 0; i < arrlen(actor->messages); i++)
-    free(actor->messages[i]);
-    
-  arrfree(actor->messages);
-
-  /* If still present, free each JSValue. */
-  for (int i = 0; i < arrlen(actor->events); i++)
-    JS_FreeValue(js, actor->events[i]);
-
-  arrfree(actor->events);
+  /* Free all letters in the queue */
+  for (int i = 0; i < arrlen(actor->letters); i++) {
+    if (actor->letters[i].type == LETTER_WOTA) {
+      free(actor->letters[i].wota_data);
+    } else if (actor->letters[i].type == LETTER_CALLBACK) {
+      JS_FreeValue(js, actor->letters[i].callback);
+    }
+  }
+  
+  arrfree(actor->letters);
   
   JSRuntime *rt = JS_GetRuntime(js);
   JS_SetInterruptHandler(rt, NULL, NULL);  
@@ -331,8 +442,7 @@ cell_rt *create_actor(void *wota)
   actor->unneeded = JS_UNDEFINED;
   actor->on_exception = JS_UNDEFINED;
 
-  arrsetcap(actor->messages, 5);
-  arrsetcap(actor->events,   5);
+  arrsetcap(actor->letters, 5);
 
   actor->mutex = SDL_CreateMutex();      /* Protects JSContext + state */
   actor->msg_mutex = SDL_CreateMutex();  /* Mailbox queue lock */
@@ -384,8 +494,12 @@ const char *send_message(const char *id, void *msg)
     return "Could not get actor from id.";
   }
   
+  letter l;
+  l.type = LETTER_WOTA;
+  l.wota_data = msg;
+  
   SDL_LockMutex(target->msg_mutex);
-  arrput(target->messages, msg);
+  arrput(target->letters, l);
   if (target->ar) {
     SDL_RemoveTimer(target->ar);
     target->ar = 0;
@@ -397,7 +511,7 @@ const char *send_message(const char *id, void *msg)
   return NULL;
 }
 
-/* set_actor_state should check if either messages or events are pending. */
+/* set_actor_state should check if any letters are pending. */
 void set_actor_state(cell_rt *actor)
 {
   SDL_LockMutex(actor->msg_mutex);
@@ -408,8 +522,7 @@ void set_actor_state(cell_rt *actor)
     return;
   }
     
-  int has_messages = arrlen(actor->messages);
-  int has_events = arrlen(actor->events);
+  int has_letters = arrlen(actor->letters);
   int has_upcoming = hmlen(actor->timers);
   
   if (actor->state == ACTOR_RUNNING)
@@ -417,7 +530,7 @@ void set_actor_state(cell_rt *actor)
 
   switch(actor->state) {
     case ACTOR_IDLE:
-      if (has_messages || has_events) {
+      if (has_letters) {
         actor->state = ACTOR_READY;
         SDL_LockMutex(queue_mutex);
         if (actor->main_thread_only) {
@@ -435,7 +548,7 @@ void set_actor_state(cell_rt *actor)
       break;
     
     case ACTOR_READY:
-      if (!has_messages && !has_events) {
+      if (!has_letters) {
         actor->state = ACTOR_IDLE;
         goto END;
       }
@@ -460,45 +573,48 @@ void actor_turn(cell_rt *actor, int greedy)
   SDL_LockMutex(actor->msg_mutex);
   actor->state = ACTOR_RUNNING;
   
-  int msgs = 0;
-  int events = 0;
+  int letters_count = 0;
   int need_stop = 0;
   JSValue result;
   
-  msgs = arrlen(actor->messages);
-  events = arrlen(actor->events);
+  letters_count = arrlen(actor->letters);
   need_stop = actor->need_stop;
   SDL_UnlockMutex(actor->msg_mutex);
   
   if (need_stop) goto KILL;
-  if (!msgs && !events) goto END;
-  if (!msgs) goto EVENT;
+  if (!letters_count) goto END;
   
-  MESSAGE:
+  PROCESS_LETTER:
   SDL_LockMutex(actor->msg_mutex);
-  void *msg = actor->messages[0];
-  arrdel(actor->messages,0);
+  letter l = actor->letters[0];
+  arrdel(actor->letters, 0);
   SDL_UnlockMutex(actor->msg_mutex);
   
   SDL_LockMutex(actor->mutex);
-  JSValue arg = wota2value(actor->context, msg);
-  free(msg);
-  result = JS_Call(actor->context, actor->message_handle, JS_UNDEFINED, 1, &arg);
-  uncaught_exception(actor->context, result);
-  JS_FreeValue(actor->context,arg);
+  
+  if (l.type == LETTER_WOTA) {
+    JSValue arg = wota2value(actor->context, l.wota_data);
+    free(l.wota_data);
+    result = JS_Call(actor->context, actor->message_handle, JS_UNDEFINED, 1, &arg);
+    uncaught_exception(actor->context, result);
+    JS_FreeValue(actor->context, arg);
+  } else if (l.type == LETTER_CALLBACK) {
+    result = JS_Call(actor->context, l.callback, JS_UNDEFINED, 0, NULL);
+    uncaught_exception(actor->context, result);
+    JS_FreeValue(actor->context, l.callback);
+  }
+  
   SDL_UnlockMutex(actor->mutex);
 
   if (!greedy) goto END;
   
   SDL_LockMutex(actor->msg_mutex);
   need_stop = actor->need_stop;
-  msgs = arrlen(actor->messages);
-  events = arrlen(actor->events);
+  letters_count = arrlen(actor->letters);
   SDL_UnlockMutex(actor->msg_mutex);
   
   if (need_stop) goto KILL;
-  
-  if (!msgs && !events) goto END;
+  if (!letters_count) goto END;
   
   SDL_LockMutex(queue_mutex);
   int queuen = arrlen(ready_queue);
@@ -507,39 +623,7 @@ void actor_turn(cell_rt *actor, int greedy)
   if (queuen != 0)
     goto END;
     
-  if (msgs)
-    goto MESSAGE;
-
-  EVENT:
-  SDL_LockMutex(actor->msg_mutex);
-  JSValue event = actor->events[0];
-  arrdel(actor->events, 0);
-  SDL_UnlockMutex(actor->msg_mutex);
-  
-  SDL_LockMutex(actor->mutex);
-  result = JS_Call(actor->context, event, JS_UNDEFINED, 0, NULL);
-  uncaught_exception(actor->context, result);
-  JS_FreeValue(actor->context, event);
-  SDL_UnlockMutex(actor->mutex);
-
-  if (!greedy) goto END;
-  
-  SDL_LockMutex(actor->msg_mutex);
-  events = arrlen(actor->events);
-  need_stop = actor->need_stop;
-  SDL_UnlockMutex(actor->msg_mutex);
-  
-  if (need_stop) goto KILL;
-  if (!events) goto END;
-  
-  SDL_LockMutex(queue_mutex);
-  int n = arrlen(ready_queue);
-  SDL_UnlockMutex(queue_mutex);
-  
-  if (n != 0)
-    goto END;
-  
-  goto EVENT;
+  goto PROCESS_LETTER;
 
   END:
 #ifdef TRACY_ENABLE
@@ -559,22 +643,6 @@ void actor_turn(cell_rt *actor, int greedy)
   actor_free(actor);
 }
 
-/* Timer callback adds an event to the queue under evt_mutex. */
-Uint32 actor_timer_cb(cell_rt *actor, SDL_TimerID id, Uint32 interval)
-{
-  SDL_LockMutex(actor->msg_mutex);
-  int idx = hmgeti(actor->timers, id);
-  if (idx == -1) goto END;
-
-  JSValue cb = actor->timers[idx].value;
-  hmdel(actor->timers, id);
-  arrput(actor->events, cb);
-  set_actor_state(actor);
-
-  END:
-  SDL_UnlockMutex(actor->msg_mutex);  
-  return 0;
-}
 
 /* JS function that schedules a timer. */
 JSValue js_actor_delay(JSContext *js, JSValue self, int argc, JSValue *argv)
@@ -587,18 +655,16 @@ JSValue js_actor_delay(JSContext *js, JSValue self, int argc, JSValue *argv)
   JS_ToFloat64(js, &seconds, argv[1]);
   if (seconds <= 0) {
     SDL_LockMutex(actor->msg_mutex);
-    JSValue cb = JS_DupValue(js, argv[0]);
-    arrput(actor->events, cb);
+    letter l;
+    l.type = LETTER_CALLBACK;
+    l.callback = JS_DupValue(js, argv[0]);
+    arrput(actor->letters, l);
     SDL_UnlockMutex(actor->msg_mutex);
     return JS_NewInt32(js, -1);
   }
-  Uint64 ns = seconds * SDL_NS_PER_SECOND;
-  
-  Uint32 id = SDL_AddTimerNS(ns, actor_timer_cb, actor);
+  uint32_t id = scheduler_add_timer(actor, seconds, argv[0]);
   
   SDL_LockMutex(actor->msg_mutex);
-  JSValue cb = JS_DupValue(js, argv[0]);
-  hmput(actor->timers, id, cb);
   if (actor->ar) {
     SDL_RemoveTimer(actor->ar);
     actor->ar = 0;
@@ -611,23 +677,11 @@ JSValue js_actor_delay(JSContext *js, JSValue self, int argc, JSValue *argv)
 JSValue js_actor_removetimer(JSContext *js, JSValue self, int argc, JSValue *argv)
 {
   cell_rt *actor = JS_GetContextOpaque(js);
-  Uint32 timer_id;
+  uint32_t timer_id;
   JS_ToUint32(js, &timer_id, argv[0]);
-  if (timer_id == -1) return JS_UNDEFINED;
+  if (timer_id == (uint32_t)-1) return JS_UNDEFINED;
   
-  SDL_RemoveTimer(timer_id);
-
-  JSValue cb = JS_UNDEFINED;
-  
-  SDL_LockMutex(actor->msg_mutex);
-  int id = hmgeti(actor->timers, timer_id);
-  if (id != -1) {
-    cb = actor->timers[id].value;
-    hmdel(actor->timers, timer_id);
-  }
-  SDL_UnlockMutex(actor->msg_mutex);
-  
-  JS_FreeValue(js,cb);
+  scheduler_remove_timer(actor, timer_id);
 
   return JS_UNDEFINED;
 }
@@ -1567,6 +1621,7 @@ int main(int argc, char **argv)
   queue_cond = SDL_CreateCondition();
   actors_mutex = SDL_CreateMutex();
   event_watchers_mutex = SDL_CreateMutex();
+  timer_mutex = SDL_CreateMutex();
 
   /* Create the initial actor from the command line */
   int actor_argc = argc - script_start;
@@ -1597,25 +1652,43 @@ int main(int argc, char **argv)
   signal(SIGSEGV, signal_handler);
   signal(SIGABRT, signal_handler);
   atexit(exit_handler);
-
-  SDL_AddEventWatch(event_watch, NULL);
-
+  
   /* Main loop: pump ready actors */
   SDL_Event event;
-  while (SDL_WaitEvent(&event)) {
-    if (event.type != queue_event) continue;
-
-  QUEUE:
-    SDL_LockMutex(queue_mutex);
-    if (arrlen(main_ready_queue) == 0) {
-      SDL_UnlockMutex(queue_mutex);
+  const uint64_t fallback_sleep = 1000000ULL; /* 1 ms */
+  
+  while (!SDL_GetAtomicInt(&engine_shutdown)) {
+    process_due_timers(); // Process any due timers first
+    
+    /* Check for SDL events with timeout */
+    uint64_t to_ns = next_timeout_ns();
+    if (to_ns == UINT64_MAX || to_ns > fallback_sleep) to_ns = fallback_sleep;
+    
+    /* Convert nanoseconds to milliseconds for SDL_WaitEventTimeout */
+    int timeout_ms = (int)(to_ns / 1000000ULL);
+    if (timeout_ms < 1) timeout_ms = 1;
+    
+    if (SDL_WaitEventTimeout(&event, timeout_ms)) {
+      if (event.type == queue_event) {
+        goto QUEUE;
+      }
+      /* Process other SDL events as needed */
       continue;
     }
-    cell_rt *actor = main_ready_queue[0];
-    arrdel(main_ready_queue, 0);
+    
+    /* Timeout occurred - check queues anyway */
+    QUEUE:
+    SDL_LockMutex(queue_mutex);
+    cell_rt *actor = NULL;
+    if (arrlen(main_ready_queue) > 0) {
+      actor = main_ready_queue[0];
+      arrdel(main_ready_queue, 0);
+    }
     SDL_UnlockMutex(queue_mutex);
-
-    actor_turn(actor, 0);
+    
+    if (actor) {
+      actor_turn(actor, 0);
+    }
   }
 
   return 0;

source/cell.h

@@ -7,6 +7,20 @@
 #include "qjs_blob.h"
 #include "blob.h"
 
+/* Letter type for unified message queue */
+typedef enum {
+  LETTER_WOTA,     /* Raw wota message */
+  LETTER_CALLBACK  /* JSValue callback function */
+} letter_type;
+
+typedef struct letter {
+  letter_type type;
+  union {
+    void *wota_data;   /* For LETTER_WOTA */
+    JSValue callback;  /* For LETTER_CALLBACK */
+  };
+} letter;
+
 #define STATE_VECTOR_LENGTH 624
 #define STATE_VECTOR_M      397
 
@@ -44,18 +58,17 @@ typedef struct cell_rt {
   
   /* Protects JSContext usage */
   SDL_Mutex *mutex;
-  
   SDL_Mutex *turn;
-
+  SDL_Mutex *msg_mutex; /* For messages queue only */
+  
   char *id;
   MTRand mrand;
 
   int idx_count;
 
   /* The “mailbox” for incoming messages + a dedicated lock for it: */
-  void **messages;
-  JSValue *events;
-  SDL_Mutex *msg_mutex; /* For messages queue only */
+  struct letter *letters;
+
 
   /* CHANGED FOR EVENTS: a separate lock for the actor->events queue */
   struct { Uint32 key; JSValue value; } *timers;