feat: Allow resetting of engine at runtime

builtins/web/timers.cpp

@@ -229,4 +229,12 @@ bool install(api::Engine *engine) {
   return JS_DefineFunctions(engine->cx(), engine->global(), methods);
 }
 
+void reset() {
+  for (auto &[id, timer] : TIMERS_MAP->timers_) {
+    timer->cancel(ENGINE);
+  }
+  TIMERS_MAP->timers_.clear();
+  TIMERS_MAP->next_timer_id = 1;
+}
+
 } // namespace builtins::web::timers

builtins/web/timers.h

@@ -14,6 +14,7 @@ bool set_interval(JSContext *cx, HandleObject handler, JS::HandleValueVector arg
 void clear_timeout_or_interval(int32_t timer_id);
 
 bool install(api::Engine *engine);
+void reset();
 
 } // namespace builtins::web::timers
 

include/extension-api.h

@@ -172,6 +172,7 @@ class Engine {
   void report_unhandled_promise_rejections();
   static void clear_unhandled_promise_rejections();
 
+  void reset();
   void abort(const char *reason);
 
   static bool debug_logging_enabled();

runtime/engine.cpp

@@ -3,6 +3,7 @@
 #include "debugger.h"
 #include "encode.h"
 #include "event_loop.h"
+#include "../builtins/web/timers.h"
 #include "script_loader.h"
 
 #include "js/CompilationAndEvaluation.h"
@@ -708,3 +709,11 @@ void Engine::report_unhandled_promise_rejections() {
 void Engine::clear_unhandled_promise_rejections() {
   JS::SetClear(CONTEXT, unhandledRejectedPromises);
 }
+void Engine::reset() {
+  clear_unhandled_promise_rejections();
+  core::EventLoop::reset(this);
+  builtins::web::timers::reset();
+  core::EventLoop::reset(this);
+  JS::PrepareForFullGC(cx());
+  JS::NonIncrementalGC(cx(), JS::GCOptions::Normal, JS::GCReason::API);
+}

runtime/event_loop.cpp

@@ -99,4 +99,13 @@ bool EventLoop::run_event_loop(api::Engine *engine, double total_compute) {
 
 void EventLoop::init(JSContext *cx) { queue.init(cx); }
 
+void EventLoop::reset(api::Engine *engine) {
+  auto &q = queue.get();
+  for (const auto& task : q.tasks) {
+    task->cancel(engine);
+  }
+  q.tasks.clear();
+  q.interest_cnt = 0;
+}
+
 } // namespace core

runtime/event_loop.h

@@ -41,6 +41,11 @@ class EventLoop {
    * Remove a queued async task.
    */
   static bool cancel_async_task(api::Engine *engine, const RefPtr<api::AsyncTask>& task);
+
+  /**
+   * Reset the event loop state, cancelling all pending tasks and clearing interest count.
+   */
+  static void reset(api::Engine *engine);
 };
 
 } // namespace core