Require async

src/dusk/script/module/CMakeLists.txt

@@ -10,4 +10,5 @@ target_sources(${DUSK_LIBRARY_TARGET_NAME}
 )
 
 # Subdirs
+add_subdirectory(event)
 add_subdirectory(require)

src/dusk/script/module/event/CMakeLists.txt

@@ -0,0 +1,9 @@
+# Copyright (c) 2026 Dominic Masters
+#
+# This software is released under the MIT License.
+# https://opensource.org/licenses/MIT
+
+target_sources(${DUSK_LIBRARY_TARGET_NAME}
+  PUBLIC
+    moduleevent.c
+)

src/dusk/script/module/event/moduleevent.c

@@ -0,0 +1,112 @@
+/**
+ * Copyright (c) 2026 Dominic Masters
+ *
+ * This software is released under the MIT License.
+ * https://opensource.org/licenses/MIT
+ */
+
+#include "moduleevent.h"
+#include "util/memory.h"
+#include "assert/assert.h"
+
+#define MODULE_EVENT_PENDING_MAX 32
+
+typedef struct {
+  event_t *event;
+  jerry_value_t promise;
+} moduleeventpending_t;
+
+scriptproto_t MODULE_EVENT_PROTO;
+
+static moduleeventpending_t MODULE_EVENT_PENDING[MODULE_EVENT_PENDING_MAX];
+static uint32_t MODULE_EVENT_PENDING_COUNT = 0;
+
+/**
+ * Single shared C callback subscribed to any event that has JS awaits.
+ * Resolves all pending promises for the fired event, then unsubscribes.
+ * The user pointer is the event_t * so we can look up and unsubscribe.
+ */
+static void moduleEventFireCallback(void *params, void *user) {
+  (void)params;
+  event_t *event = (event_t *)user;
+
+  uint32_t i = 0;
+  while(i < MODULE_EVENT_PENDING_COUNT) {
+    if(MODULE_EVENT_PENDING[i].event != event) { i++; continue; }
+    jerry_value_t ret = jerry_promise_resolve(
+      MODULE_EVENT_PENDING[i].promise, jerry_undefined()
+    );
+    jerry_value_free(ret);
+    jerry_value_free(MODULE_EVENT_PENDING[i].promise);
+    MODULE_EVENT_PENDING_COUNT--;
+    if(i < MODULE_EVENT_PENDING_COUNT) {
+      MODULE_EVENT_PENDING[i] = MODULE_EVENT_PENDING[MODULE_EVENT_PENDING_COUNT];
+    }
+  }
+
+  eventUnsubscribe(event, moduleEventFireCallback);
+}
+
+static jerry_value_t moduleEventWait(
+  const jerry_call_info_t *callInfo,
+  const jerry_value_t args[],
+  const jerry_length_t argc
+) {
+  (void)args; (void)argc;
+
+  jsevent_t *ev = scriptProtoGetValue(&MODULE_EVENT_PROTO, callInfo->this_value);
+  if(!ev) return moduleBaseThrow("Event.wait: invalid this");
+
+  if(MODULE_EVENT_PENDING_COUNT >= MODULE_EVENT_PENDING_MAX) {
+    return moduleBaseThrow("Event.wait: too many pending awaits");
+  }
+
+  // Only subscribe once per event — check if we already have a pending await
+  bool_t subscribed = false;
+  for(uint32_t i = 0; i < MODULE_EVENT_PENDING_COUNT; i++) {
+    if(MODULE_EVENT_PENDING[i].event == ev->event) { subscribed = true; break; }
+  }
+
+  if(!subscribed) {
+    if(ev->event->count >= ev->event->size) {
+      return moduleBaseThrow("Event.wait: event subscriber capacity exceeded");
+    }
+    eventSubscribe(ev->event, moduleEventFireCallback, (void *)ev->event);
+  }
+
+  jerry_value_t promise = jerry_promise();
+  MODULE_EVENT_PENDING[MODULE_EVENT_PENDING_COUNT].event = ev->event;
+  MODULE_EVENT_PENDING[MODULE_EVENT_PENDING_COUNT].promise = jerry_value_copy(promise);
+  MODULE_EVENT_PENDING_COUNT++;
+  return promise;
+}
+
+jerry_value_t moduleEventCreate(event_t *event) {
+  assertNotNull(event, "moduleEventCreate: event must not be NULL");
+  jsevent_t ev = { .event = event };
+  return scriptProtoCreateValue(&MODULE_EVENT_PROTO, &ev);
+}
+
+void moduleEventInit(void) {
+  MODULE_EVENT_PENDING_COUNT = 0;
+  scriptProtoInit(&MODULE_EVENT_PROTO, NULL, sizeof(jsevent_t), NULL);
+  scriptProtoDefineFunc(&MODULE_EVENT_PROTO, "wait", moduleEventWait);
+}
+
+void moduleEventDispose(void) {
+  // Unsubscribe from each distinct event still in the pending list
+  for(uint32_t i = 0; i < MODULE_EVENT_PENDING_COUNT; i++) {
+    bool_t alreadyUnsub = false;
+    for(uint32_t j = 0; j < i; j++) {
+      if(MODULE_EVENT_PENDING[j].event == MODULE_EVENT_PENDING[i].event) {
+        alreadyUnsub = true; break;
+      }
+    }
+    if(!alreadyUnsub) {
+      eventUnsubscribe(MODULE_EVENT_PENDING[i].event, moduleEventFireCallback);
+    }
+    jerry_value_free(MODULE_EVENT_PENDING[i].promise);
+  }
+  MODULE_EVENT_PENDING_COUNT = 0;
+  scriptProtoDispose(&MODULE_EVENT_PROTO);
+}

src/dusk/script/module/event/moduleevent.h

@@ -0,0 +1,36 @@
+/**
+ * Copyright (c) 2026 Dominic Masters
+ *
+ * This software is released under the MIT License.
+ * https://opensource.org/licenses/MIT
+ */
+
+#pragma once
+#include "script/module/modulebase.h"
+#include "script/scriptproto.h"
+#include "event/event.h"
+
+/** C struct wrapped by every Event JS instance. */
+typedef struct {
+  event_t *event;
+} jsevent_t;
+
+extern scriptproto_t MODULE_EVENT_PROTO;
+
+/**
+ * Wraps a C event_t pointer in a JS Event object.
+ *
+ * @param event The event to wrap. Must outlive the returned JS value.
+ * @return A new JS Event instance.
+ */
+jerry_value_t moduleEventCreate(event_t *event);
+
+/**
+ * Initializes the Event module and registers the global Event prototype.
+ */
+void moduleEventInit(void);
+
+/**
+ * Disposes the Event module, rejecting any pending awaits and cleaning up.
+ */
+void moduleEventDispose(void);

src/dusk/script/module/modulelist.c

@@ -12,6 +12,7 @@
 #include "script/module/display/modulescreen.h"
 #include "script/module/engine/moduleengine.h"
 #include "script/module/engine/moduleframe.h"
+#include "script/module/event/moduleevent.h"
 #include "script/module/engine/moduletimeout.h"
 #include "script/module/entity/component/modulecomponentlist.h"
 #include "script/module/entity/modulecomponent.h"
@@ -24,6 +25,7 @@
 
 
 void moduleListInit(void) {
+  moduleEventInit();
   moduleTextureInit();
   moduleColorInit();
   moduleAssetInit();
@@ -64,4 +66,5 @@ void moduleListDispose(void) {
   moduleAssetDispose();
   moduleColorDispose();
   moduleTextureDispose();
+  moduleEventDispose();
 }

src/dusk/script/module/require/modulerequire.c

@@ -10,7 +10,75 @@
 #include "util/memory.h"
 #include "util/string.h"
 #include "assert/assert.h"
-#include "console/console.h"
+
+#define MODULE_REQUIRE_ASYNC_MAX 16
+
+typedef struct {
+  assetentry_t *entry;
+  jerry_value_t promise;
+} modulerequireasyncpending_t;
+
+static modulerequireasyncpending_t MODULE_REQUIRE_ASYNC_PENDING[MODULE_REQUIRE_ASYNC_MAX];
+static uint32_t MODULE_REQUIRE_ASYNC_PENDING_COUNT = 0;
+
+/* Resolves or rejects every promise associated with entry, then unsubscribes. */
+static void moduleRequireAsyncOnError(void *params, void *user);
+
+static void moduleRequireAsyncOnLoaded(void *params, void *user) {
+  assetentry_t *entry = (assetentry_t *)params;
+  (void)user;
+
+  eventUnsubscribe(&entry->onLoaded, moduleRequireAsyncOnLoaded);
+  eventUnsubscribe(&entry->onError, moduleRequireAsyncOnError);
+
+  jerry_value_t exports = jerry_value_is_undefined(entry->data.script.exports)
+    ? jerry_undefined()
+    : jerry_value_copy(entry->data.script.exports);
+
+  uint32_t i = 0;
+  while(i < MODULE_REQUIRE_ASYNC_PENDING_COUNT) {
+    if(MODULE_REQUIRE_ASYNC_PENDING[i].entry != entry) { i++; continue; }
+    assetUnlockEntry(entry);
+    jerry_value_t copy = jerry_value_copy(exports);
+    jerry_value_t ret = jerry_promise_resolve(MODULE_REQUIRE_ASYNC_PENDING[i].promise, copy);
+    jerry_value_free(ret);
+    jerry_value_free(copy);
+    jerry_value_free(MODULE_REQUIRE_ASYNC_PENDING[i].promise);
+    MODULE_REQUIRE_ASYNC_PENDING_COUNT--;
+    if(i < MODULE_REQUIRE_ASYNC_PENDING_COUNT) {
+      MODULE_REQUIRE_ASYNC_PENDING[i] = MODULE_REQUIRE_ASYNC_PENDING[MODULE_REQUIRE_ASYNC_PENDING_COUNT];
+    }
+  }
+
+  jerry_value_free(exports);
+}
+
+static void moduleRequireAsyncOnError(void *params, void *user) {
+  assetentry_t *entry = (assetentry_t *)params;
+  (void)user;
+
+  eventUnsubscribe(&entry->onLoaded, moduleRequireAsyncOnLoaded);
+  eventUnsubscribe(&entry->onError, moduleRequireAsyncOnError);
+
+  jerry_value_t errStr = jerry_string_sz("Module load failed");
+
+  uint32_t i = 0;
+  while(i < MODULE_REQUIRE_ASYNC_PENDING_COUNT) {
+    if(MODULE_REQUIRE_ASYNC_PENDING[i].entry != entry) { i++; continue; }
+    assetUnlockEntry(entry);
+    jerry_value_t copy = jerry_value_copy(errStr);
+    jerry_value_t ret = jerry_promise_reject(MODULE_REQUIRE_ASYNC_PENDING[i].promise, copy);
+    jerry_value_free(ret);
+    jerry_value_free(copy);
+    jerry_value_free(MODULE_REQUIRE_ASYNC_PENDING[i].promise);
+    MODULE_REQUIRE_ASYNC_PENDING_COUNT--;
+    if(i < MODULE_REQUIRE_ASYNC_PENDING_COUNT) {
+      MODULE_REQUIRE_ASYNC_PENDING[i] = MODULE_REQUIRE_ASYNC_PENDING[MODULE_REQUIRE_ASYNC_PENDING_COUNT];
+    }
+  }
+
+  jerry_value_free(errStr);
+}
 
 jerry_value_t moduleRequireFunc(
   const jerry_call_info_t *callInfo,
@@ -23,45 +91,30 @@ jerry_value_t moduleRequireFunc(
   if(argc < 1 || !jerry_value_is_string(args[0])) {
     return moduleBaseThrow("Expected a string argument for module name.");
   }
-  
-  // Is filename too long?
-  if(
-    jerry_string_size(args[0], JERRY_ENCODING_UTF8) >= ASSET_FILE_NAME_MAX
-  ) {
+  if(jerry_string_size(args[0], JERRY_ENCODING_UTF8) >= ASSET_FILE_NAME_MAX) {
     return moduleBaseThrow("Module name too long.");
   }
 
-  // Get C string
   char_t moduleName[ASSET_FILE_NAME_MAX];
   moduleBaseToString(args[0], moduleName, sizeof(moduleName));
 
-  // Lock and load the asset.
   assetloaderinput_t input;
   input.script.nothing = NULL;
-
-  assetentry_t *entry = assetLock(
-    moduleName,
-    ASSET_LOADER_TYPE_SCRIPT,
-    &input
-  );
+  assetentry_t *entry = assetLock(moduleName, ASSET_LOADER_TYPE_SCRIPT, &input);
 
   errorret_t err = assetRequireLoaded(entry);
-
   if(errorIsNotOk(err)) {
     assetUnlockEntry(entry);
     return moduleBaseThrowError(err);
   }
 
-  // Now the module is loaded, copy it before unlocking.
   if(jerry_value_is_undefined(entry->data.script.exports)) {
     assetUnlockEntry(entry);
     return jerry_undefined();
   }
 
-  jerry_value_t exportsCopy = jerry_value_copy(
-    entry->data.script.exports
-  );
-  assetUnlockEntry(entry);// Frees entry->data.script.exports
+  jerry_value_t exportsCopy = jerry_value_copy(entry->data.script.exports);
+  assetUnlockEntry(entry);
   return exportsCopy;
 }
 
@@ -73,47 +126,92 @@ jerry_value_t moduleRequireAsyncFunc(
   assertNotNull(callInfo, "callInfo must not be null.");
   assertNotNull(args, "args must not be null.");
 
-  // Filename, required
   if(argc < 1 || !jerry_value_is_string(args[0])) {
-    return moduleBaseThrow(
-      "requireAsync expects filename."
-    );
+    return moduleBaseThrow("requireAsync expects a filename string.");
   }
-
-  // Callback, optional.
-  if(argc >= 2 && !jerry_value_is_function(args[1])) {
-    return moduleBaseThrow(
-      "requireAsync callback must be a function."
-    );
-  }
-
-  // Is filename too long?
-  if(
-    jerry_string_size(args[0], JERRY_ENCODING_UTF8) >= ASSET_FILE_NAME_MAX
-  ) {
+  if(jerry_string_size(args[0], JERRY_ENCODING_UTF8) >= ASSET_FILE_NAME_MAX) {
     return moduleBaseThrow("Module name too long.");
   }
+  if(MODULE_REQUIRE_ASYNC_PENDING_COUNT >= MODULE_REQUIRE_ASYNC_MAX) {
+    return moduleBaseThrow("Too many pending requireAsync calls.");
+  }
 
-  // Get C string
   char_t moduleName[ASSET_FILE_NAME_MAX];
   moduleBaseToString(args[0], moduleName, sizeof(moduleName));
 
-  // Lock asset
   assetloaderinput_t input;
   input.script.nothing = NULL;
+  assetentry_t *entry = assetLock(moduleName, ASSET_LOADER_TYPE_SCRIPT, &input);
 
-  assetentry_t *entry = assetLock(
-    moduleName,
-    ASSET_LOADER_TYPE_SCRIPT,
-    &input
-  );
+  jerry_value_t promise = jerry_promise();
 
+  // Already loaded — resolve immediately.
+  if(entry->state == ASSET_ENTRY_STATE_LOADED) {
+    jerry_value_t exports = jerry_value_is_undefined(entry->data.script.exports)
+      ? jerry_undefined()
+      : jerry_value_copy(entry->data.script.exports);
+    assetUnlockEntry(entry);
+    jerry_value_t ret = jerry_promise_resolve(promise, exports);
+    jerry_value_free(ret);
+    jerry_value_free(exports);
+    return promise;
+  }
+
+  // Already errored — reject immediately.
+  if(entry->state == ASSET_ENTRY_STATE_ERROR) {
+    assetUnlockEntry(entry);
+    jerry_value_t errStr = jerry_string_sz("Module load failed");
+    jerry_value_t ret = jerry_promise_reject(promise, errStr);
+    jerry_value_free(ret);
+    jerry_value_free(errStr);
+    return promise;
+  }
+
+  // Subscribe to entry events only if this is the first pending await for it.
+  bool_t subscribed = false;
+  for(uint32_t i = 0; i < MODULE_REQUIRE_ASYNC_PENDING_COUNT; i++) {
+    if(MODULE_REQUIRE_ASYNC_PENDING[i].entry == entry) { subscribed = true; break; }
+  }
+  if(!subscribed) {
+    if(entry->onLoaded.count >= entry->onLoaded.size) {
+      assetUnlockEntry(entry);
+      jerry_value_free(promise);
+      return moduleBaseThrow("requireAsync: onLoaded event capacity exceeded.");
+    }
+    if(entry->onError.count >= entry->onError.size) {
+      assetUnlockEntry(entry);
+      jerry_value_free(promise);
+      return moduleBaseThrow("requireAsync: onError event capacity exceeded.");
+    }
+    eventSubscribe(&entry->onLoaded, moduleRequireAsyncOnLoaded, NULL);
+    eventSubscribe(&entry->onError, moduleRequireAsyncOnError, NULL);
+  }
+
+  MODULE_REQUIRE_ASYNC_PENDING[MODULE_REQUIRE_ASYNC_PENDING_COUNT].entry = entry;
+  MODULE_REQUIRE_ASYNC_PENDING[MODULE_REQUIRE_ASYNC_PENDING_COUNT].promise = jerry_value_copy(promise);
+  MODULE_REQUIRE_ASYNC_PENDING_COUNT++;
+  return promise;
 }
 
 void moduleRequireInit(void) {
+  MODULE_REQUIRE_ASYNC_PENDING_COUNT = 0;
   moduleBaseDefineGlobalMethod("require", moduleRequireFunc);
   moduleBaseDefineGlobalMethod("requireAsync", moduleRequireAsyncFunc);
 }
 
 void moduleRequireDispose(void) {
+  for(uint32_t i = 0; i < MODULE_REQUIRE_ASYNC_PENDING_COUNT; i++) {
+    assetentry_t *entry = MODULE_REQUIRE_ASYNC_PENDING[i].entry;
+    bool_t alreadyUnsub = false;
+    for(uint32_t j = 0; j < i; j++) {
+      if(MODULE_REQUIRE_ASYNC_PENDING[j].entry == entry) { alreadyUnsub = true; break; }
+    }
+    if(!alreadyUnsub) {
+      eventUnsubscribe(&entry->onLoaded, moduleRequireAsyncOnLoaded);
+      eventUnsubscribe(&entry->onError, moduleRequireAsyncOnError);
+    }
+    assetUnlockEntry(entry);
+    jerry_value_free(MODULE_REQUIRE_ASYNC_PENDING[i].promise);
+  }
+  MODULE_REQUIRE_ASYNC_PENDING_COUNT = 0;
 }