Re-land "Shut down and restart the Dart VM as needed. (flutter#7832)"

This reverts commit 572fea3.

ci/licenses_golden/licenses_flutter

@@ -355,6 +355,10 @@ FILE: ../../../flutter/runtime/dart_snapshot_buffer.cc
 FILE: ../../../flutter/runtime/dart_snapshot_buffer.h
 FILE: ../../../flutter/runtime/dart_vm.cc
 FILE: ../../../flutter/runtime/dart_vm.h
+FILE: ../../../flutter/runtime/dart_vm_data.cc
+FILE: ../../../flutter/runtime/dart_vm_data.h
+FILE: ../../../flutter/runtime/dart_vm_lifecycle.cc
+FILE: ../../../flutter/runtime/dart_vm_lifecycle.h
 FILE: ../../../flutter/runtime/dart_vm_unittests.cc
 FILE: ../../../flutter/runtime/embedder_resources.cc
 FILE: ../../../flutter/runtime/embedder_resources.h

lib/ui/isolate_name_server/isolate_name_server_natives.cc

@@ -14,8 +14,10 @@ namespace blink {
 
 Dart_Handle IsolateNameServerNatives::LookupPortByName(
     const std::string& name) {
-  IsolateNameServer* name_server =
-      UIDartState::Current()->GetIsolateNameServer();
+  auto name_server = UIDartState::Current()->GetIsolateNameServer();
+  if (!name_server) {
+    return Dart_Null();
+  }
   Dart_Port port = name_server->LookupIsolatePortByName(name);
   if (port == ILLEGAL_PORT) {
     return Dart_Null();
@@ -26,8 +28,10 @@ Dart_Handle IsolateNameServerNatives::LookupPortByName(
 Dart_Handle IsolateNameServerNatives::RegisterPortWithName(
     Dart_Handle port_handle,
     const std::string& name) {
-  IsolateNameServer* name_server =
-      UIDartState::Current()->GetIsolateNameServer();
+  auto name_server = UIDartState::Current()->GetIsolateNameServer();
+  if (!name_server) {
+    return Dart_False();
+  }
   Dart_Port port = ILLEGAL_PORT;
   Dart_SendPortGetId(port_handle, &port);
   if (!name_server->RegisterIsolatePortWithName(port, name)) {
@@ -38,8 +42,10 @@ Dart_Handle IsolateNameServerNatives::RegisterPortWithName(
 
 Dart_Handle IsolateNameServerNatives::RemovePortNameMapping(
     const std::string& name) {
-  IsolateNameServer* name_server =
-      UIDartState::Current()->GetIsolateNameServer();
+  auto name_server = UIDartState::Current()->GetIsolateNameServer();
+  if (!name_server) {
+    return Dart_False();
+  }
   if (!name_server->RemoveIsolateNameMapping(name)) {
     return Dart_False();
   }

lib/ui/ui_dart_state.cc

@@ -23,7 +23,7 @@ UIDartState::UIDartState(
     std::string advisory_script_entrypoint,
     std::string logger_prefix,
     UnhandledExceptionCallback unhandled_exception_callback,
-    IsolateNameServer* isolate_name_server)
+    std::shared_ptr<IsolateNameServer> isolate_name_server)
     : task_runners_(std::move(task_runners)),
       add_callback_(std::move(add_callback)),
       remove_callback_(std::move(remove_callback)),
@@ -33,7 +33,7 @@ UIDartState::UIDartState(
       advisory_script_entrypoint_(std::move(advisory_script_entrypoint)),
       logger_prefix_(std::move(logger_prefix)),
       unhandled_exception_callback_(unhandled_exception_callback),
-      isolate_name_server_(isolate_name_server) {
+      isolate_name_server_(std::move(isolate_name_server)) {
   AddOrRemoveTaskObserver(true /* add */);
 }
 
@@ -124,7 +124,7 @@ fml::WeakPtr<GrContext> UIDartState::GetResourceContext() const {
   return io_manager_->GetResourceContext();
 }
 
-IsolateNameServer* UIDartState::GetIsolateNameServer() {
+std::shared_ptr<IsolateNameServer> UIDartState::GetIsolateNameServer() const {
   return isolate_name_server_;
 }
 

lib/ui/ui_dart_state.h

@@ -53,7 +53,7 @@ class UIDartState : public tonic::DartState {
 
   fml::WeakPtr<GrContext> GetResourceContext() const;
 
-  IsolateNameServer* GetIsolateNameServer();
+  std::shared_ptr<IsolateNameServer> GetIsolateNameServer() const;
 
   tonic::DartErrorHandleType GetLastError();
 
@@ -81,7 +81,7 @@ class UIDartState : public tonic::DartState {
               std::string advisory_script_entrypoint,
               std::string logger_prefix,
               UnhandledExceptionCallback unhandled_exception_callback,
-              IsolateNameServer* isolate_name_server);
+              std::shared_ptr<IsolateNameServer> isolate_name_server);
 
   ~UIDartState() override;
 
@@ -107,7 +107,7 @@ class UIDartState : public tonic::DartState {
   std::unique_ptr<Window> window_;
   tonic::DartMicrotaskQueue microtask_queue_;
   UnhandledExceptionCallback unhandled_exception_callback_;
-  IsolateNameServer* isolate_name_server_;
+  const std::shared_ptr<IsolateNameServer> isolate_name_server_;
 
   void AddOrRemoveTaskObserver(bool add);
 };

runtime/BUILD.gn

@@ -36,6 +36,10 @@ source_set("runtime") {
     "dart_snapshot_buffer.h",
     "dart_vm.cc",
     "dart_vm.h",
+    "dart_vm_data.cc",
+    "dart_vm_data.h",
+    "dart_vm_lifecycle.cc",
+    "dart_vm_lifecycle.h",
     "embedder_resources.cc",
     "embedder_resources.h",
     "runtime_controller.cc",
@@ -73,7 +77,9 @@ source_set("runtime") {
       flutter_runtime_mode != "dynamic_release" && !is_fuchsia) {
     # Only link in Observatory in non-release modes on non-Fuchsia. Fuchsia
     # instead puts Observatory into the runner's package.
-    deps += [ "//third_party/dart/runtime/observatory:embedded_observatory_archive" ]
+    deps += [
+      "//third_party/dart/runtime/observatory:embedded_observatory_archive",
+    ]
   }
 }
 
@@ -95,6 +101,7 @@ executable("runtime_unittests") {
     ":runtime_fixtures",
     "$flutter_root/fml",
     "$flutter_root/lib/snapshot",
+    "$flutter_root/shell/common",
     "$flutter_root/testing",
     "//third_party/dart/runtime:libdart_jit",
     "//third_party/skia",

runtime/dart_isolate.cc

@@ -14,6 +14,7 @@
 #include "flutter/lib/ui/dart_ui.h"
 #include "flutter/runtime/dart_service_isolate.h"
 #include "flutter/runtime/dart_vm.h"
+#include "flutter/runtime/dart_vm_lifecycle.h"
 #include "third_party/dart/runtime/include/dart_api.h"
 #include "third_party/dart/runtime/include/dart_tools_api.h"
 #include "third_party/tonic/converter/dart_converter.h"
@@ -29,9 +30,9 @@
 namespace blink {
 
 std::weak_ptr<DartIsolate> DartIsolate::CreateRootIsolate(
-    DartVM* vm,
-    fml::RefPtr<DartSnapshot> isolate_snapshot,
-    fml::RefPtr<DartSnapshot> shared_snapshot,
+    const Settings& settings,
+    fml::RefPtr<const DartSnapshot> isolate_snapshot,
+    fml::RefPtr<const DartSnapshot> shared_snapshot,
     TaskRunners task_runners,
     std::unique_ptr<Window> window,
     fml::WeakPtr<SnapshotDelegate> snapshot_delegate,
@@ -50,7 +51,7 @@ std::weak_ptr<DartIsolate> DartIsolate::CreateRootIsolate(
   // isolate lifecycle is entirely managed by the VM).
   auto root_embedder_data = std::make_unique<std::shared_ptr<DartIsolate>>(
       std::make_shared<DartIsolate>(
-          vm,                            // VM
+          settings,                      // settings
           std::move(isolate_snapshot),   // isolate snapshot
           std::move(shared_snapshot),    // shared snapshot
           task_runners,                  // task runners
@@ -93,46 +94,41 @@ std::weak_ptr<DartIsolate> DartIsolate::CreateRootIsolate(
   return embedder_isolate;
 }
 
-DartIsolate::DartIsolate(DartVM* vm,
-                         fml::RefPtr<DartSnapshot> isolate_snapshot,
-                         fml::RefPtr<DartSnapshot> shared_snapshot,
+DartIsolate::DartIsolate(const Settings& settings,
+                         fml::RefPtr<const DartSnapshot> isolate_snapshot,
+                         fml::RefPtr<const DartSnapshot> shared_snapshot,
                          TaskRunners task_runners,
                          fml::WeakPtr<SnapshotDelegate> snapshot_delegate,
                          fml::WeakPtr<IOManager> io_manager,
                          std::string advisory_script_uri,
                          std::string advisory_script_entrypoint,
                          ChildIsolatePreparer child_isolate_preparer)
     : UIDartState(std::move(task_runners),
-                  vm->GetSettings().task_observer_add,
-                  vm->GetSettings().task_observer_remove,
+                  settings.task_observer_add,
+                  settings.task_observer_remove,
                   std::move(snapshot_delegate),
                   std::move(io_manager),
                   advisory_script_uri,
                   advisory_script_entrypoint,
-                  vm->GetSettings().log_tag,
-                  vm->GetSettings().unhandled_exception_callback,
-                  vm->GetIsolateNameServer()),
-      vm_(vm),
+                  settings.log_tag,
+                  settings.unhandled_exception_callback,
+                  DartVMRef::GetIsolateNameServer()),
+      settings_(settings),
       isolate_snapshot_(std::move(isolate_snapshot)),
       shared_snapshot_(std::move(shared_snapshot)),
       child_isolate_preparer_(std::move(child_isolate_preparer)) {
   FML_DCHECK(isolate_snapshot_) << "Must contain a valid isolate snapshot.";
-
-  if (vm_ == nullptr) {
-    return;
-  }
-
   phase_ = Phase::Uninitialized;
 }
 
 DartIsolate::~DartIsolate() = default;
 
-DartIsolate::Phase DartIsolate::GetPhase() const {
-  return phase_;
+const Settings& DartIsolate::GetSettings() const {
+  return settings_;
 }
 
-DartVM* DartIsolate::GetDartVM() const {
-  return vm_;
+DartIsolate::Phase DartIsolate::GetPhase() const {
+  return phase_;
 }
 
 bool DartIsolate::Initialize(Dart_Isolate dart_isolate, bool is_root_isolate) {
@@ -493,16 +489,16 @@ Dart_Isolate DartIsolate::DartCreateAndStartServiceIsolate(
     const char* package_config,
     Dart_IsolateFlags* flags,
     char** error) {
-  auto vm = DartVM::ForProcessIfInitialized();
+  auto vm_data = DartVMRef::GetVMData();
 
-  if (!vm) {
+  if (!vm_data) {
     *error = strdup(
-        "Could not resolve the VM when attempting to create the service "
-        "isolate.");
+        "Could not access VM data to initialize isolates. This may be because "
+        "the VM has initialized shutdown on another thread already.");
     return nullptr;
   }
 
-  const auto& settings = vm->GetSettings();
+  const auto& settings = vm_data->GetSettings();
 
   if (!settings.enable_observatory) {
     FML_DLOG(INFO) << "Observatory is disabled.";
@@ -515,21 +511,26 @@ Dart_Isolate DartIsolate::DartCreateAndStartServiceIsolate(
 
   flags->load_vmservice_library = true;
 
+  if (advisory_script_uri == nullptr) {
+    advisory_script_uri = "";
+  }
+
+  if (advisory_script_entrypoint == nullptr) {
+    advisory_script_entrypoint = "";
+  }
+
   std::weak_ptr<DartIsolate> weak_service_isolate =
       DartIsolate::CreateRootIsolate(
-          vm.get(),                  // vm
-          vm->GetIsolateSnapshot(),  // isolate snapshot
-          vm->GetSharedSnapshot(),   // shared snapshot
-          null_task_runners,         // task runners
-          nullptr,                   // window
-          {},                        // snapshot delegate
-          {},                        // IO Manager
-          advisory_script_uri == nullptr ? ""
-                                         : advisory_script_uri,  // script uri
-          advisory_script_entrypoint == nullptr
-              ? ""
-              : advisory_script_entrypoint,  // script entrypoint
-          flags                              // flags
+          vm_data->GetSettings(),         // settings
+          vm_data->GetIsolateSnapshot(),  // service isolate snapshot
+          vm_data->GetSharedSnapshot(),   // shared snapshot
+          null_task_runners,              // service isolate task runners
+          nullptr,                        // window
+          {},                             // snapshot delegate
+          {},                             // IO Manager
+          advisory_script_uri,            // script uri
+          advisory_script_entrypoint,     // script entrypoint
+          flags                           // flags
       );
 
   std::shared_ptr<DartIsolate> service_isolate = weak_service_isolate.lock();
@@ -552,7 +553,13 @@ Dart_Isolate DartIsolate::DartCreateAndStartServiceIsolate(
     return nullptr;
   }
 
-  vm->GetServiceProtocol().ToggleHooks(true);
+  if (auto service_protocol = DartVMRef::GetServiceProtocol()) {
+    service_protocol->ToggleHooks(true);
+  } else {
+    FML_DLOG(ERROR)
+        << "Could not acquire the service protocol handlers. This might be "
+           "because the VM has already begun teardown on another thread.";
+  }
 
   return service_isolate->isolate();
 }
@@ -610,16 +617,13 @@ DartIsolate::CreateDartVMAndEmbedderObjectPair(
   std::unique_ptr<std::shared_ptr<DartIsolate>> embedder_isolate(
       p_parent_embedder_isolate);
 
-  if (embedder_isolate == nullptr ||
-      (*embedder_isolate)->GetDartVM() == nullptr) {
+  if (embedder_isolate == nullptr) {
     *error =
         strdup("Parent isolate did not have embedder specific callback data.");
     FML_DLOG(ERROR) << *error;
     return {nullptr, {}};
   }
 
-  DartVM* const vm = (*embedder_isolate)->GetDartVM();
-
   if (!is_root_isolate) {
     auto* raw_embedder_isolate = embedder_isolate.release();
 
@@ -628,7 +632,7 @@ DartIsolate::CreateDartVMAndEmbedderObjectPair(
 
     embedder_isolate = std::make_unique<std::shared_ptr<DartIsolate>>(
         std::make_shared<DartIsolate>(
-            vm,                                             // vm
+            (*raw_embedder_isolate)->GetSettings(),         // settings
             (*raw_embedder_isolate)->GetIsolateSnapshot(),  // isolate_snapshot
             (*raw_embedder_isolate)->GetSharedSnapshot(),   // shared_snapshot
             null_task_runners,                              // task_runners
@@ -701,11 +705,11 @@ void DartIsolate::DartIsolateCleanupCallback(
   delete embedder_isolate;
 }
 
-fml::RefPtr<DartSnapshot> DartIsolate::GetIsolateSnapshot() const {
+fml::RefPtr<const DartSnapshot> DartIsolate::GetIsolateSnapshot() const {
   return isolate_snapshot_;
 }
 
-fml::RefPtr<DartSnapshot> DartIsolate::GetSharedSnapshot() const {
+fml::RefPtr<const DartSnapshot> DartIsolate::GetSharedSnapshot() const {
   return shared_snapshot_;
 }