JSRuntime lifetime managed by WebFPage lifetime (#629)

Prior to WebF 0.16.0 "[Add Dedicated Threading
support.](#512)", the JSRuntime
lifecycle was managed by the DartIsolateContext lifecycle.


![ui_thread](https://github.com/user-attachments/assets/8e211366-eecd-4326-87e9-98ced7a34938)

But in Dedicated threads, the JSRuntime life cycle must be managed by
the WebFPage life cycle, and the `runtime_` redundancy created in
DartIsolateContext.

Therefore, JSRuntime lifetime managed by WebFPage lifetime in UI thread
mode is more uniform



![page_lifetime](https://github.com/user-attachments/assets/d5ea64e6-feca-40b5-9504-68fb1e245633)

Author: andycall

bridge/core/dart_isolate_context.cc

@@ -85,8 +85,10 @@ void DartIsolateContext::InitializeJSRuntime() {
 }
 
 void DartIsolateContext::FinalizeJSRuntime() {
-  if (running_dart_isolates > 0)
+  if (running_dart_isolates > 0 ||
+      runtime_ == nullptr) {
     return;
+  }
 
   // Prebuilt strings stored in JSRuntime. Only needs to dispose when runtime disposed.
   names_installer::Dispose();
@@ -107,10 +109,10 @@ DartIsolateContext::DartIsolateContext(const uint64_t* dart_methods, int32_t dar
       dart_method_ptr_(std::make_unique<DartMethodPointer>(this, dart_methods, dart_methods_length)) {
   is_valid_ = true;
   running_dart_isolates++;
-  InitializeJSRuntime();
 }
 
 JSRuntime* DartIsolateContext::runtime() {
+  assert_m(runtime_ != nullptr, "nullptr is unsafe");
   return runtime_;
 }
 
@@ -187,10 +189,19 @@ void* DartIsolateContext::AddNewPage(double thread_identity,
   return nullptr;
 }
 
+std::unique_ptr<WebFPage> DartIsolateContext::InitializeNewPageSync(DartIsolateContext* dart_isolate_context,
+                                                                    size_t sync_buffer_size,
+                                                                    double page_context_id) {
+  dart_isolate_context->profiler()->StartTrackInitialize();
+  DartIsolateContext::InitializeJSRuntime();
+  auto page = std::make_unique<WebFPage>(dart_isolate_context, false, sync_buffer_size, page_context_id, nullptr);
+  dart_isolate_context->profiler()->FinishTrackInitialize();
+
+  return page;
+}
+
 void* DartIsolateContext::AddNewPageSync(double thread_identity) {
-  profiler()->StartTrackSteps("WebFPage::Initialize");
-  auto page = std::make_unique<WebFPage>(this, false, 0, thread_identity, nullptr);
-  profiler()->FinishTrackSteps();
+  auto page = InitializeNewPageSync(this, 0, thread_identity);
 
   void* p = page.get();
   pages_in_ui_thread_.emplace(std::move(page));
@@ -252,6 +263,10 @@ void DartIsolateContext::RemovePageSync(double thread_identity, WebFPage* page)
       break;
     }
   }
+
+  if (pages_in_ui_thread_.empty()) {
+    FinalizeJSRuntime();
+  }
 }
 
 }  // namespace webf

bridge/core/dart_isolate_context.h

@@ -74,6 +74,9 @@ class DartIsolateContext {
  private:
   static void InitializeJSRuntime();
   static void FinalizeJSRuntime();
+  static std::unique_ptr<WebFPage> InitializeNewPageSync(DartIsolateContext* dart_isolate_context,
+                                                         size_t sync_buffer_size,
+                                                         double page_context_id);
   static void InitializeNewPageInJSThread(PageGroup* page_group,
                                           DartIsolateContext* dart_isolate_context,
                                           double page_context_id,

bridge/include/webf_bridge.h

@@ -147,6 +147,6 @@ WEBF_EXPORT_C void executeNativeCallback(DartWork* work_ptr);
 WEBF_EXPORT_C
 void init_dart_dynamic_linking(void* data);
 WEBF_EXPORT_C
-void register_dart_context_finalizer(Dart_Handle dart_handle, void* dart_isolate_context);
+void on_dart_context_finalized(void* dart_isolate_context);
 
 #endif  // WEBF_BRIDGE_EXPORT_H

bridge/webf_bridge.cc

@@ -67,15 +67,11 @@ void* allocateNewPageSync(double thread_identity, void* ptr) {
   auto* dart_isolate_context = (webf::DartIsolateContext*)ptr;
   assert(dart_isolate_context != nullptr);
 
-  dart_isolate_context->profiler()->StartTrackInitialize();
-
   void* result = static_cast<webf::DartIsolateContext*>(dart_isolate_context)->AddNewPageSync(thread_identity);
 #if ENABLE_LOG
   WEBF_LOG(INFO) << "[Dispatcher]: allocateNewPageSync Call END";
 #endif
 
-  dart_isolate_context->profiler()->FinishTrackInitialize();
-
   return result;
 }
 
@@ -289,7 +285,7 @@ void clearUICommandItems(void* page_) {
 }
 
 // Callbacks when dart context object was finalized by Dart GC.
-static void finalize_dart_context(void* isolate_callback_data, void* peer) {
+static void finalize_dart_context(void* peer) {
   WEBF_LOG(VERBOSE) << "[Dispatcher]: BEGIN FINALIZE DART CONTEXT: ";
   auto* dart_isolate_context = (webf::DartIsolateContext*)peer;
   dart_isolate_context->Dispose([dart_isolate_context]() {
@@ -306,9 +302,8 @@ void init_dart_dynamic_linking(void* data) {
   }
 }
 
-void register_dart_context_finalizer(Dart_Handle dart_handle, void* dart_isolate_context) {
-  Dart_NewFinalizableHandle_DL(dart_handle, reinterpret_cast<void*>(dart_isolate_context),
-                               sizeof(webf::DartIsolateContext), finalize_dart_context);
+void on_dart_context_finalized(void* dart_isolate_context) {
+  finalize_dart_context(dart_isolate_context);
 }
 
 int8_t isJSThreadBlocked(void* dart_isolate_context_, double context_id) {

webf/lib/src/bridge/bridge.dart

@@ -7,15 +7,24 @@ import 'dart:async';
 import 'dart:ffi';
 import 'package:webf/launcher.dart';
 
+import 'dynamic_library.dart';
 import 'binding.dart';
 import 'from_native.dart';
 import 'to_native.dart';
 import 'multiple_thread.dart';
 
-class DartContext {
+typedef NativeOnDartContextFinalized = Void Function(Pointer<Void> data);
+typedef DartOnDartContextFinalized = void Function(Pointer<Void> data);
+
+final _initDartDynamicLinking = WebFDynamicLibrary.ref
+    .lookup<NativeFunction<NativeOnDartContextFinalized>>('on_dart_context_finalized');
+
+class DartContext implements Finalizable {
+  static final _finalizer = NativeFinalizer(_initDartDynamicLinking);
+
   DartContext() : pointer = initDartIsolateContext(makeDartMethodsData()) {
     initDartDynamicLinking();
-    registerDartContextFinalizer(this);
+    _finalizer.attach(this, pointer);
   }
   final Pointer<Void> pointer;
 }
@@ -28,11 +37,11 @@ bool isJSRunningInDedicatedThread(double contextId) {
 
 /// Init bridge
 FutureOr<double> initBridge(WebFViewController view, WebFThread runningThread) async {
-  dartContext ??= DartContext();
-
   // Setup binding bridge.
   BindingBridge.setup();
 
+  dartContext ??= DartContext();
+
   double newContextId = runningThread.identity();
   await allocateNewPage(runningThread is FlutterUIThread, newContextId, runningThread.syncBufferSize());
 

webf/lib/src/bridge/to_native.dart

@@ -625,17 +625,6 @@ void initDartDynamicLinking() {
   _initDartDynamicLinking(NativeApi.initializeApiDLData);
 }
 
-typedef NativeRegisterDartContextFinalizer = Void Function(Handle object, Pointer<Void> dart_context);
-typedef DartRegisterDartContextFinalizer = void Function(Object object, Pointer<Void> dart_context);
-
-final DartRegisterDartContextFinalizer _registerDartContextFinalizer = WebFDynamicLibrary.ref
-    .lookup<NativeFunction<NativeRegisterDartContextFinalizer>>('register_dart_context_finalizer')
-    .asFunction();
-
-void registerDartContextFinalizer(DartContext dartContext) {
-  _registerDartContextFinalizer(dartContext, dartContext.pointer);
-}
-
 typedef NativeRegisterPluginByteCode = Void Function(Pointer<Uint8> bytes, Int32 length, Pointer<Utf8> pluginName);
 typedef DartRegisterPluginByteCode = void Function(Pointer<Uint8> bytes, int length, Pointer<Utf8> pluginName);
 

webf/lib/src/launcher/controller.dart

@@ -191,7 +191,7 @@ class WebFViewController implements WidgetsBindingObserver {
       debugDefaultTargetPlatformOverride = TargetPlatform.fuchsia;
       debugPaintSizeEnabled = true;
     }
-    BindingBridge.setup();
+
     _contextId = await initBridge(this, runningThread);
 
     _setupObserver();