root actor runs only on main thread; restrict ffi main thread functions to it

source/jsffi.c

@@ -2457,6 +2457,9 @@ JS_FreeValue(js,v); \
 } \
 
 JSC_CCALL(os_engine_start,
+  if (SDL_GetCurrentThreadID() != main_thread)
+    return JS_ThrowInternalError(js, "This can only be called from the root actor.");
+    
   if (global_window)
     return JS_ThrowReferenceError(js, "The engine was already started.");
     
@@ -6298,6 +6301,9 @@ JSC_CCALL(os_make_surface,
 )
 
 JSC_CCALL(os_make_cursor,
+  if (SDL_GetCurrentThreadID() != main_thread)
+    return JS_ThrowInternalError(js, "This can only be called from the root actor.");
+
   SDL_Surface *s = js2SDL_Surface(js,argv[0]);
   HMM_Vec2 hot = js2vec2(js,argv[1]);
   SDL_Cursor *c = SDL_CreateColorCursor(s, hot.x, hot.y);

source/prosperon.c

@@ -41,6 +41,7 @@
 #define ENGINE "scripts/core/engine.js"
 
 static prosperon_rt **ready_queue = NULL;
+static prosperon_rt **main_ready_queue = NULL;
 static SDL_Mutex *queue_mutex = NULL;
 static SDL_Condition *queue_cond = NULL;
 static SDL_Mutex *actors_mutex = NULL;
@@ -48,6 +49,8 @@ static struct { char *key; prosperon_rt *value; } *actors = NULL;
 static unsigned char *zip_buffer_global = NULL;
 static char *prosperon = NULL;
 
+static Uint32 queue_event;
+
 static SDL_AtomicInt shutdown;
 static SDL_Thread **runners = NULL;
 
@@ -226,6 +229,8 @@ prosperon_rt *get_actor(char *id)
 char *register_actor(char *id, prosperon_rt *actor)
 {
   if (shgeti(actors, id) != -1) return "Actor with given ID already exists.";
+  if (shlen(actors) == 0)
+    actor->main_thread_only = 1;
   actor->id = strdup(id);
   SDL_LockMutex(actors_mutex);
   shput(actors, id, actor);
@@ -262,6 +267,7 @@ static void set_actor_state(prosperon_rt *actor)
     
   int has_messages = arrlen(actor->messages);
   int has_events = arrlen(actor->events);
+  int has_upcoming = hmlen(actor->timers);
   
   if (actor->state == ACTOR_RUNNING)
     actor->state = ACTOR_IDLE;
@@ -271,8 +277,15 @@ static void set_actor_state(prosperon_rt *actor)
       if (has_messages || has_events) {
         actor->state = ACTOR_READY;
         SDL_LockMutex(queue_mutex);
-        arrput(ready_queue, actor);
+        if (actor->main_thread_only) {
+          arrput(main_ready_queue, actor);
+          SDL_Event event;
+          event.type = queue_event;
+          SDL_PushEvent(&event);
+        } else {
           SDL_SignalCondition(queue_cond);        
+          arrput(ready_queue, actor);
+        }
         SDL_UnlockMutex(queue_mutex);
         goto END;
       }
@@ -287,12 +300,12 @@ static void set_actor_state(prosperon_rt *actor)
   }
 
   END:
-  if (actor->state == ACTOR_IDLE && !actor->ar)
+  if (actor->state == ACTOR_IDLE && !actor->ar && !has_upcoming)
     actor->ar = SDL_AddTimerNS(SDL_SECONDS_TO_NS(1), actor_remove_cb, actor);
   SDL_UnlockMutex(actor->msg_mutex);
 }
 
-void actor_turn(prosperon_rt *actor)
+void actor_turn(prosperon_rt *actor, int greedy)
 {
   SDL_LockMutex(actor->msg_mutex);
   actor->state = ACTOR_RUNNING;
@@ -327,6 +340,8 @@ void actor_turn(prosperon_rt *actor)
   JS_FreeValue(actor->context,arg);
   SDL_UnlockMutex(actor->mutex);
 
+  if (!greedy) goto END;
+  
   SDL_LockMutex(actor->msg_mutex);
   need_stop = actor->need_stop;
   msgs = arrlen(actor->messages);
@@ -359,6 +374,8 @@ void actor_turn(prosperon_rt *actor)
   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;
@@ -486,6 +503,10 @@ JSValue js_actor_delay(JSContext *js, JSValue self, int argc, JSValue *argv)
   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;
+  }
   SDL_UnlockMutex(actor->msg_mutex);
 
   return JS_UNDEFINED;
@@ -627,7 +648,7 @@ static int crank_actor(void *data)
     }
     SDL_UnlockMutex(queue_mutex);
 
-    if (actor) actor_turn(actor);
+    if (actor) actor_turn(actor, 1);
   }
   return 0;
 }
@@ -1279,17 +1300,18 @@ static WotaBuffer event2wota(const SDL_Event *event) {
     return wb;
 }
 
-
-
 int main(int argc, char **argv)
 {
   SDL_Init(SDL_INIT_EVENTS | SDL_INIT_VIDEO);
+  queue_event = SDL_RegisterEvents(1);
+
   int cores = SDL_GetNumLogicalCPUCores();
   if (cores == 1) {
     printf("Platform has only one core!\n");
     return 1;
   }
   main_thread = SDL_GetCurrentThreadID();
+  printf("main is %u\n", main_thread);
   if (!main_thread) {
     printf("Platform does not support threads!\n");
     return 1;
@@ -1331,6 +1353,9 @@ int main(int argc, char **argv)
 
   SDL_Event event;
   while (SDL_WaitEvent(&event)) {
+    if (event.type == queue_event)
+      goto QUEUE;
+
     WotaBuffer wb = event2wota(&event);
 
     // Broadcast this event to all actors
@@ -1345,6 +1370,20 @@ int main(int argc, char **argv)
     SDL_UnlockMutex(actors_mutex);
 
     wota_buffer_free(&wb);  // free WotaBuffer
+
+    QUEUE:
+    SDL_LockMutex(queue_mutex);
+    if (arrlen(main_ready_queue) == 0) {
+      SDL_UnlockMutex(queue_mutex);
+      continue;
+    }
+    prosperon_rt *actor = main_ready_queue[0];
+    arrdel(main_ready_queue, 0);
+    SDL_UnlockMutex(queue_mutex);
+
+    actor_turn(actor, 0);
+
+    END:
   }
   return 0;
 }

source/prosperon.h

@@ -62,6 +62,7 @@ typedef struct prosperon_rt {
   int state;
   Uint32 ar;
   int need_stop;
+  int main_thread_only;
 } prosperon_rt;
 
 extern SDL_ThreadID main_thread;

tests/window.js

@@ -0,0 +1,27 @@
+prosperon.win = prosperon.engine_start({
+  title:`Prosperon [${prosperon.version}-${prosperon.revision}]`,
+  width: 1280,
+  height: 720,
+  high_dpi:0,
+  alpha:1,
+  fullscreen:0,
+  sample_count:1,
+  enable_clipboard:true,
+  enable_dragndrop: true,
+  max_dropped_files: 1,
+  swap_interval: 1,
+  name: "Prosperon",
+  version:prosperon.version + "-" + prosperon.revision,
+  identifier: "world.pockle.prosperon",
+  creator: "Pockle World LLC",
+  copyright: "Copyright Pockle World 2025",
+  type: "game",
+  url: "https://prosperon.dev"
+})
+
+function loop() {
+  $_.delay(loop, 1/60)
+}
+loop()
+
+$_.delay($_.stop, 3)