WorkerWrapper.cpp

#include "WorkerWrapper.h"

#include <android/looper.h>
#include <pthread.h>

#include <thread>

#include "ArgConverter.h"
#include "CallbackHandlers.h"
#include "CrashBreadcrumbs.h"
#include "JEnv.h"
#include "JniLocalRef.h"
#include "ModuleInternal.h"
#include "NativeScriptAssert.h"
#include "NativeScriptException.h"
#include "NativeScriptPlatform.h"
#include "Runtime.h"

#include <unistd.h>

#ifdef APPLICATION_IN_DEBUG
#include "JsV8InspectorClient.h"
#include "WorkerInspectorClient.h"
#endif

using namespace v8;

namespace tns {

namespace {

/*
 * Reports a worker entry that failed to evaluate, with the web's order: the
 * worker scope's own `onerror` gets first refusal (a truthy return consumes the
 * failure) and only an unconsumed one reaches the parent's Worker object.
 * Mirrors the worker branch of the unhandled-rejection path in
 * NativeScriptException.cpp, which this rejection no longer travels: attaching
 * a rejection handler to the entry's evaluation promise marks it handled.
 */
void ReportEntryRejection(Isolate* isolate, Local<Value> reason,
                          const std::shared_ptr<WorkerWrapper>& wrapper) {
    auto context = isolate->GetCurrentContext();

    std::string message = "Unhandled promise rejection: ";
    Local<String> detail;
    if (!reason.IsEmpty() && reason->ToDetailString(context).ToLocal(&detail)) {
        message += ArgConverter::ConvertToString(detail);
    }

    std::string stackTrace;
    if (!reason.IsEmpty()) {
        auto stack = Exception::GetStackTrace(reason);
        if (!stack.IsEmpty()) {
            stackTrace = NativeScriptException::GetErrorStackTrace(stack);
        }
    }

    Local<Value> onError;
    if (context->Global()
                ->Get(context, ArgConverter::ConvertToV8String(isolate, "onerror"))
                .ToLocal(&onError) &&
        onError->IsFunction()) {
        Local<Value> args[] = {ArgConverter::ConvertToV8String(isolate, message)};
        Local<Value> result;
        // A handler that throws has not consumed anything - the failure falls
        // through to the parent, as if no handler had been installed.
        TryCatch tc(isolate);
        if (onError.As<Function>()
                    ->Call(context, Undefined(isolate), 1, args)
                    .ToLocal(&result) &&
            !result.IsEmpty() && result->BooleanValue(isolate)) {
            return;
        }
    }

    wrapper->PassUncaughtExceptionFromWorkerToParent(message, "", stackTrace, 0);
}

}  // namespace

WorkerWrapper::WorkerWrapper(Isolate* parentIsolate, int workerId, std::string workerPath,
                             std::string callingDir, int priority, IsolateLimits limits,
                             Local<Object> workerObject)
        : parentIsolate_(parentIsolate),
          // runs on the parent's thread, where the parent runtime is alive
          parentTasks_(Runtime::GetRuntime(parentIsolate)->GetEventLoop()),
          workerIsolate_(nullptr),
          runtime_(nullptr),
          workerId_(workerId),
          workerPath_(std::move(workerPath)),
          callingDir_(std::move(callingDir)),
          // workerPath_ (not workerPath) - the parameter was just moved from
          threadName_("W" + std::to_string(workerId) + ": " + workerPath_),
          priority_(priority),
          limits_(std::move(limits)),
          // Runs on the parent's thread, so this is the parent's live vocabulary.
          inheritedVocabulary_(CaptureLoaderVocabulary(parentIsolate)),
          poWorker_(new Persistent<Object>(parentIsolate, workerObject)),
          isClosing_(false),
          isTerminating_(false),
          isDisposed_(false),
          messagesEnabled_(false),
          heapLimitExceeded_(false),
          javaLooperRef_(nullptr) {
    heapLimitMessage_ = "Worker JS heap out of memory";
    if (limits_.maxOldGenerationSizeBytes.has_value()) {
        heapLimitMessage_ += " (maxOldGenerationSizeMb: " +
                             std::to_string(*limits_.maxOldGenerationSizeBytes / (1024 * 1024)) +
                             ")";
    }
}

void WorkerWrapper::Start() {
    auto self = shared_from_this();
    std::thread thread([self]() {
        self->BackgroundLooper(self);
    });
    thread.detach();
}

void WorkerWrapper::PostMessage(std::shared_ptr<worker::Message> message) {
    if (!isTerminating_ && !isClosing_) {
        queue_.Push(message);
    }
}

void WorkerWrapper::PostMessageToParent(std::shared_ptr<worker::Message> message) {
    if (isTerminating_) {
        return;
    }

    auto parentTasks = parentTasks_.lock();
    if (parentTasks == nullptr) {
        // the parent runtime is gone (e.g. a parent worker that shut down)
        return;
    }

    int workerId = workerId_;
    parentTasks->PostInternal([workerId, message]() {
        WorkerWrapper::FireMessageOnParentWorkerObject(workerId, message);
    });
}

void WorkerWrapper::Terminate() {
    if (isClosing_ || isDisposed_) {
        // The worker is already shutting down on its own; nothing to do.
        return;
    }

    bool wasTerminating = isTerminating_.exchange(true);
    if (wasTerminating) {
        return;
    }

    Isolate* isolate = workerIsolate_.load();
    if (isolate != nullptr) {
        // The only v8 call that is legal from another thread - interrupts any
        // JS currently running on the worker (e.g. a busy loop).
        isolate->TerminateExecution();
        // A pump parked with nothing queued runs no JS, so the interrupt
        // above never materializes for it - the loop's own flag ends it.
        auto loop = NativeScriptPlatform::Instance()->LookupEventLoop(isolate);
        if (loop != nullptr) {
            loop->NoteTerminationRequested();
        }
    }

#ifdef APPLICATION_IN_DEBUG
    {
        // A worker paused at a breakpoint sits in the inspector's nested pause
        // loop, not in Looper.loop() - kick it loose so TerminateExecution and
        // the looper quit below can take effect.
        std::lock_guard<std::mutex> lock(inspectorMutex_);
        if (inspector_ != nullptr) {
            inspector_->NotifyTerminating();
        }
    }
#endif

    QuitLooper();
}

size_t WorkerWrapper::OnNearHeapLimit(void* data, size_t currentHeapLimit,
                                      size_t initialHeapLimit) {
    auto* worker = static_cast<WorkerWrapper*>(data);

    // Node's allowance: raising the limit lets the in-progress GC finish
    // instead of aborting the process, and the isolate is being torn down
    // anyway. The same raised limit has to come back on every later
    // invocation, because returning a lower one is fatal to v8.
    constexpr size_t kHeapLimitAllowance = 16 * 1024 * 1024;
    size_t raisedLimit = currentHeapLimit + kHeapLimitAllowance;

    if (worker->heapLimitExceeded_.exchange(true, std::memory_order_acq_rel)) {
        return raisedLimit;
    }

    // Marshals strings onto the parent's loop and touches no v8 handle, which
    // is the only kind of reporting allowed from inside a GC.
    worker->PassUncaughtExceptionFromWorkerToParent(worker->heapLimitMessage_, worker->workerPath_,
                                                    "", 0);

    // Terminate() below only reaches workerIsolate_, which the bootstrap
    // publishes once the runtime is up - and a worker can exhaust its heap
    // before that. The isolate being collected is the one to interrupt.
    Isolate* isolate = Isolate::GetCurrent();
    if (isolate != nullptr) {
        isolate->TerminateExecution();
    }
    worker->Terminate();

    return raisedLimit;
}

void WorkerWrapper::Close() {
    bool wasClosing = isClosing_.exchange(true);
    if (wasClosing) {
        return;
    }

    // Once the current callback unwinds, Looper.loop() returns and the
    // thread proceeds to cleanup. Pending messages are dropped, matching the
    // previous front-of-queue TerminateAndCloseThread behavior.
    QuitLooper();
}

void WorkerWrapper::QuitLooper() {
    std::lock_guard<std::mutex> lock(looperMutex_);
    if (javaLooperRef_ != nullptr) {
        JEnv env;
        env.CallVoidMethod(javaLooperRef_, LOOPER_QUIT_METHOD_ID);
    }
}

int WorkerWrapper::DrainCallback(int fd, int events, void* data) {
    uint64_t value;
    read(fd, &value, sizeof(value));

    auto wrapper = static_cast<WorkerWrapper*>(data);
    wrapper->DrainPendingTasks();
    return 1;
}

int WorkerWrapper::DrainPendingTasks() {
    Isolate* isolate = workerIsolate_.load();
    if (isolate == nullptr || isTerminating_) {
        return 0;
    }

    v8::Locker locker(isolate);
    Isolate::Scope isolate_scope(isolate);
    HandleScope handle_scope(isolate);
    auto context = runtime_->GetContext();
    Context::Scope context_scope(context);
    auto globalObject = context->Global();

    // WHATWG parity: the implicit port's message queue starts disabled and is
    // enabled once the entry script has finished evaluating (including after a
    // pending top-level await settles). Until then messages stay buffered here;
    // afterwards every message dispatches whether or not a handler exists — a
    // handler installed later misses earlier messages, exactly as on the web.
    if (!messagesEnabled_.load(std::memory_order_acquire)) {
        return 0;
    }

    auto messages = queue_.PopAll();
    if (messages.empty()) {
        return 0;
    }

    int dispatched = 0;
    for (auto& message : messages) {
        if (isTerminating_ || isClosing_) {
            break;
        }
        dispatched++;

        TryCatch tc(isolate);

        Local<Value> callback;
        if (!globalObject->Get(context, ArgConverter::ConvertToV8String(isolate, "onmessage"))
                     .ToLocal(&callback) ||
            !callback->IsFunction()) {
            DEBUG_WRITE(
                    "WORKER: couldn't fire a worker's `onmessage` callback because it isn't implemented!");
            continue;
        }

        Local<Value> data;
        if (message->Deserialize(isolate, context).ToLocal(&data)) {
            auto event = Object::New(isolate);
            event->DefineOwnProperty(context, ArgConverter::ConvertToV8String(isolate, "data"),
                                     data, PropertyAttribute::ReadOnly);
            Local<Value> args[] = {event};
            callback.As<Function>()->Call(context, Undefined(isolate), 1, args);
        }

        if (tc.HasCaught() && !isTerminating_) {
            CallbackHandlers::CallWorkerScopeOnErrorHandle(isolate, tc);
        }
    }
    return dispatched;
}

void WorkerWrapper::EnableMessageQueue() {
    messagesEnabled_.store(true, std::memory_order_release);
    queue_.Signal();
}

void WorkerWrapper::FireMessageOnParentWorkerObject(int workerId,
                                                  std::shared_ptr<worker::Message> message) {
    auto wrapper = WorkerWrapper::GetById(workerId);
    if (wrapper == nullptr) {
        DEBUG_WRITE("MAIN: no worker instance was found with workerId=%d.", workerId);
        return;
    }

    Isolate* isolate = wrapper->parentIsolate_;
    v8::Locker locker(isolate);
    Isolate::Scope isolate_scope(isolate);
    HandleScope handle_scope(isolate);

    if (wrapper->poWorker_ == nullptr || wrapper->poWorker_->IsEmpty()) {
        DEBUG_WRITE(
                "MAIN: couldn't fire a worker(id=%d) object's `onmessage` callback because the worker has been cleared.",
                workerId);
        return;
    }

    auto worker = Local<Object>::New(isolate, *wrapper->poWorker_);
    auto context = Runtime::GetRuntime(isolate)->GetContext();
    Context::Scope context_scope(context);

    try {
        Local<Value> callback;
        if (!worker->Get(context, ArgConverter::ConvertToV8String(isolate, "onmessage"))
                     .ToLocal(&callback) ||
            !callback->IsFunction()) {
            DEBUG_WRITE(
                    "MAIN: couldn't fire a worker(id=%d) object's `onmessage` callback because it isn't implemented.",
                    workerId);
            return;
        }

        Local<Value> data;
        if (message->Deserialize(isolate, context).ToLocal(&data)) {
            auto event = Object::New(isolate);
            event->DefineOwnProperty(context, ArgConverter::ConvertToV8String(isolate, "data"),
                                     data, PropertyAttribute::ReadOnly);
            Local<Value> args[] = {event};
            callback.As<Function>()->Call(context, Undefined(isolate), 1, args);
        }
    } catch (NativeScriptException& ex) {
        ex.ReThrowToV8();
    }
}

void WorkerWrapper::PassUncaughtExceptionFromWorkerToParent(const std::string& message,
                                                          const std::string& filename,
                                                          const std::string& stackTrace,
                                                          int lineno) {
    auto parentTasks = parentTasks_.lock();
    if (parentTasks == nullptr) {
        // the parent runtime is gone (e.g. a parent worker that shut down)
        return;
    }

    int workerId = workerId_;
    std::string threadName = threadName_;
    Isolate* parentIsolate = parentIsolate_;

    parentTasks->PostInternal([workerId, message, filename, stackTrace, lineno, threadName,
                       parentIsolate]() {
        v8::Locker locker(parentIsolate);
        Isolate::Scope isolate_scope(parentIsolate);
        HandleScope handle_scope(parentIsolate);
        auto context = Runtime::GetRuntime(parentIsolate)->GetContext();
        Context::Scope context_scope(context);

        WorkerWrapper::FireErrorOnParentWorkerObject(workerId, message, stackTrace, filename,
                                                     lineno, threadName);
    });
}

void WorkerWrapper::FireErrorOnParentWorkerObject(int workerId, const std::string& message,
                                                const std::string& stackTrace,
                                                const std::string& filename, int lineno,
                                                const std::string& threadName) {
    auto wrapper = WorkerWrapper::GetById(workerId);
    if (wrapper == nullptr) {
        DEBUG_WRITE("MAIN: no worker instance was found with workerId=%d.", workerId);
        return;
    }

    Isolate* isolate = wrapper->parentIsolate_;

    try {
        if (wrapper->poWorker_ == nullptr || wrapper->poWorker_->IsEmpty()) {
            DEBUG_WRITE(
                    "MAIN: couldn't fire a worker(id=%d) object's `onerror` callback because the worker has been cleared.",
                    workerId);
            return;
        }

        auto worker = Local<Object>::New(isolate, *wrapper->poWorker_);
        auto context = Runtime::GetRuntime(isolate)->GetContext();

        Local<Value> callback;
        bool hasOnError =
                worker->Get(context, ArgConverter::ConvertToV8String(isolate, "onerror"))
                        .ToLocal(&callback) &&
                callback->IsFunction();

        if (hasOnError) {
            auto errEvent = Object::New(isolate);
            errEvent->Set(context, ArgConverter::ConvertToV8String(isolate, "message"),
                          ArgConverter::ConvertToV8String(isolate, message));
            errEvent->Set(context, ArgConverter::ConvertToV8String(isolate, "stackTrace"),
                          ArgConverter::ConvertToV8String(isolate, stackTrace));
            errEvent->Set(context, ArgConverter::ConvertToV8String(isolate, "filename"),
                          ArgConverter::ConvertToV8String(isolate, filename));
            errEvent->Set(context, ArgConverter::ConvertToV8String(isolate, "lineno"),
                          Number::New(isolate, lineno));

            Local<Value> args[] = {errEvent};

            // If the handler returns a truthy value the exception is handled
            // and must not be raised to application level
            Local<Value> result;
            callback.As<Function>()->Call(context, Undefined(isolate), 1, args).ToLocal(&result);
            if (!result.IsEmpty() && result->BooleanValue(isolate)) {
                return;
            }
        }

        DEBUG_WRITE(
                "Unhandled exception in '%s' thread. file: %s, line %d, message: %s\nStackTrace: %s",
                threadName.c_str(), filename.c_str(), lineno, message.c_str(),
                stackTrace.c_str());
    } catch (NativeScriptException& ex) {
        ex.ReThrowToV8();
    }
}

void WorkerWrapper::BackgroundLooper(std::shared_ptr<WorkerWrapper> self) {
    JavaVM* jvm = Runtime::GetJVM();
    JNIEnv* jniEnv = nullptr;

    JavaVMAttachArgs attachArgs;
    attachArgs.version = JNI_VERSION_1_6;
    attachArgs.name = const_cast<char*>(threadName_.c_str());
    attachArgs.group = nullptr;
    jvm->AttachCurrentThread(&jniEnv, &attachArgs);

    // pthread names are limited to 15 chars
    pthread_setname_np(pthread_self(), threadName_.substr(0, 15).c_str());

    int runtimeId = -1;

    try {
        JEnv env;

        // Performs the cgroup/scheduling-policy move in addition to the nice
        // value, exactly like the previous Java-side
        // Process.setThreadPriority(THREAD_PRIORITY_BACKGROUND) call.
        env.CallStaticVoidMethod(PROCESS_CLASS, SET_THREAD_PRIORITY_METHOD_ID, priority_);

        if (!isTerminating_ && !isClosing_) {
            // Prepares the Java Looper for this thread and creates the
            // per-worker com.tns.Runtime (which creates the worker isolate on
            // this thread via initNativeScript -> PrepareV8Runtime).
            JniLocalRef callingDir(env.NewStringUTF(callingDir_.c_str()));
            // The isolate is created on this thread inside the call below,
            // which has no parameter to carry any of this; the thread-local
            // slot is the channel. The near-heap-limit callback is armed for
            // every worker, capped or not - without it an isolate that
            // exhausts its heap aborts the whole process instead of surfacing
            // on the parent's Worker object.
            Runtime::SetPendingIsolateSetup({limits_, WorkerWrapper::OnNearHeapLimit, this});
            runtimeId = env.CallStaticIntMethod(RUNTIME_CLASS, INIT_WORKER_RUNTIME_METHOD_ID,
                                                workerId_, (jstring) callingDir);
            runtime_ = Runtime::GetRuntime(runtimeId);
            CrashBreadcrumbs::SetWorkerScript(runtimeId, workerPath_.c_str());

            {
                std::lock_guard<std::mutex> lock(looperMutex_);
                JniLocalRef looper(env.CallStaticObjectMethod(LOOPER_CLASS, MY_LOOPER_METHOD_ID));
                javaLooperRef_ = env.NewGlobalRef(looper);
            }

            // Looper.prepare() ran above, so ALooper_forThread() returns the
            // native looper backing the Java one - fds added here are pumped
            // by Looper.loop().
            queue_.Initialize(ALooper_forThread(), WorkerWrapper::DrainCallback, this);
            // The inbox rides its own fd, which a pump never polls; the hook
            // lets a looper-equivalent pump drain it (the loop's Shutdown, on
            // this thread, unregisters it before `this` can die).
            auto pumpLoop = runtime_->GetEventLoop();
            if (pumpLoop != nullptr) {
                pumpLoop->SetPumpDrainHook([this]() { return DrainPendingTasks(); });
            }

            Isolate* isolate = runtime_->GetIsolate();

            {
                v8::Locker locker(isolate);
                Isolate::Scope isolate_scope(isolate);
                HandleScope handle_scope(isolate);
                isolate->SetData((uint32_t) Runtime::IsolateData::WORKER_WRAPPER, this);
                workerIsolate_.store(isolate);

                auto context = runtime_->GetContext();
                Context::Scope context_scope(context);

                // Before any module load runs in this isolate.
                InstallLoaderVocabulary(isolate, inheritedVocabulary_);

#ifdef APPLICATION_IN_DEBUG
                // Expose this worker to an attached Chrome DevTools frontend
                // as a child target, mirroring the iOS runtime. Created before
                // the script runs so the worker's scripts are visible to the
                // debugger from the start.
                CreateInspector(isolate);
#endif

                if (!isTerminating_) {
                    runtime_->RunWorker(workerPath_);

                    // The near-heap-limit callback has already reported to
                    // the parent and asked v8 to terminate this isolate;
                    // everything below would run JS on it.
                    if (!HeapLimitExceeded()) {
                        // WHATWG parity: enable the implicit port's message queue
                        // once the entry has finished evaluating. RunWorker returns
                        // settled for classic scripts and pumped HTTP entries; a
                        // local top-level-await entry that outlived its settle
                        // window enables when its evaluation promise settles —
                        // rejected included, since a broken worker still drains its
                        // inbox into a listenerless global, as on the web.
                        Local<Promise> pendingEntry;
                        if (!ModuleInternal::PendingEntryEvaluation(isolate, workerPath_)
                                     .ToLocal(&pendingEntry)) {
                            EnableMessageQueue();
                        } else {
                            // Neither handler may capture anything: they resolve the
                            // wrapper by id because the worker may be gone by the
                            // time the entry settles. Both run on this thread, in
                            // this isolate.
                            auto onFulfilled = [](const v8::FunctionCallbackInfo<Value>& info) {
                                auto wrapper = WorkerWrapper::GetById(
                                        info.Data().As<v8::Int32>()->Value());
                                if (wrapper != nullptr) {
                                    wrapper->EnableMessageQueue();
                                }
                            };
                            // A rejection needs its own handler: sharing the fulfill
                            // one would mark the entry's evaluation promise handled
                            // and drop the failure on the floor.
                            auto onRejected = [](const v8::FunctionCallbackInfo<Value>& info) {
                                auto wrapper = WorkerWrapper::GetById(
                                        info.Data().As<v8::Int32>()->Value());
                                if (wrapper == nullptr) {
                                    return;
                                }
                                wrapper->EnableMessageQueue();
                                if (wrapper->IsTerminating() || wrapper->IsDisposed()) {
                                    return;
                                }
                                auto isolate = info.GetIsolate();
                                ReportEntryRejection(isolate,
                                                     info.Length() > 0
                                                             ? info[0]
                                                             : Undefined(isolate).As<Value>(),
                                                     wrapper);
                            };
                            auto workerIdData = v8::Integer::New(isolate, workerId_);
                            Local<Function> enableFn;
                            Local<Function> reportFn;
                            if (Function::New(context, onFulfilled, workerIdData)
                                        .ToLocal(&enableFn) &&
                                Function::New(context, onRejected, workerIdData)
                                        .ToLocal(&reportFn)) {
                                pendingEntry->Then(context, enableFn, reportFn)
                                        .FromMaybe(Local<Promise>());
                            } else {
                                EnableMessageQueue();
                            }
                        }
                    }
                }
            }

            // Deliver messages that were posted before the worker was ready
            // (replaces the old Java Handshake + pendingWorkerMessages).
            DrainPendingTasks();

            if (!isTerminating_ && !isClosing_) {
                // Blocks, pumping Java Handler messages (cross-thread Java->JS
                // calls), timers and the worker inbox until quit() is called.
                env.CallStaticVoidMethod(RUNTIME_CLASS, RUN_WORKER_LOOP_METHOD_ID);
            }
        }
    } catch (NativeScriptException& ex) {
        if (jniEnv->ExceptionCheck()) {
            jniEnv->ExceptionClear();
        }
        if (!isTerminating_) {
            PassUncaughtExceptionFromWorkerToParent(ex.GetErrorMessage(), workerPath_, "", 0);
        }
    } catch (std::exception& ex) {
        DEBUG_WRITE_FORCE("Worker(id=%d) error: c++ exception: %s", workerId_, ex.what());
    } catch (...) {
        DEBUG_WRITE_FORCE("Worker(id=%d) error: unknown c++ exception!", workerId_);
    }

    // ----- Shutdown (close, terminate or bootstrap failure) -----

    isTerminating_ = true;

    // Terminate any workers this worker created (nested workers). Their
    // Worker object persistents live in this isolate, so they must be
    // released before the isolate is disposed below. Each child cascades to
    // its own children during its shutdown.
    {
        Isolate* isolate = workerIsolate_.load();
        if (isolate != nullptr) {
            TerminateChildren(isolate);
        }
    }

#ifdef APPLICATION_IN_DEBUG
    // The inspector must be gone before the Runtime (and with it the isolate)
    // is deleted below; unregistering also tells DevTools the target is gone.
    DestroyInspector();
#endif

    // On this thread: safe to unregister the inbox fd from the looper.
    queue_.Terminate();

    if (runtime_ != nullptr) {
        try {
            // Java-side detach (GcListener.unsubscribe + runtimeCache.remove)
            // must happen before the isolate is disposed, preserving the old
            // WorkerThreadHandler -> TerminateWorkerCallback ordering.
            JEnv env;
            env.CallStaticVoidMethod(RUNTIME_CLASS, DETACH_WORKER_RUNTIME_METHOD_ID, runtimeId);
        } catch (NativeScriptException& ex) {
            if (jniEnv->ExceptionCheck()) {
                jniEnv->ExceptionClear();
            }
            DEBUG_WRITE_FORCE("Worker(id=%d) error while detaching Java runtime: %s", workerId_,
                              ex.GetErrorMessage().c_str());
        }

        // Take the isolate from the runtime, not from workerIsolate_: if the
        // bootstrap failed between initWorkerRuntime and the workerIsolate_
        // publish (e.g. a JNI error while resolving the looper), the atomic is
        // still null while the isolate very much needs disposing.
        workerIsolate_.store(nullptr);
        Isolate* isolate = runtime_->GetIsolate();
        {
            v8::Locker locker(isolate);
            Isolate::Scope isolate_scope(isolate);
            HandleScope handle_scope(isolate);
            // v8 keeps the registration until the isolate is disposed, and a
            // final GC during disposal would find `this` mid-teardown.
            isolate->RemoveNearHeapLimitCallback(WorkerWrapper::OnNearHeapLimit, 0);
            runtime_->DestroyRuntime();
        }
        CallbackHandlers::WaitForMainThreadCallbacks(isolate);
        isolate->Dispose();
        // Dispose freed the isolate's memory, so its address can be reused by
        // a concurrent Isolate::New - drop the platform's loop entry now, not
        // in ~Runtime (which still runs JNI calls first). The matched erase
        // means the late ~Runtime backstop can't evict a new tenant.
        NativeScriptPlatform::Instance()->IsolateDisposed(isolate,
                                                          runtime_->GetEventLoop());

        // The Runtime destructor still makes JNI calls - it must run before
        // DetachCurrentThread below.
        delete runtime_;
        runtime_ = nullptr;
    }

    {
        std::lock_guard<std::mutex> lock(looperMutex_);
        if (javaLooperRef_ != nullptr) {
            jniEnv->DeleteGlobalRef(javaLooperRef_);
            javaLooperRef_ = nullptr;
        }
    }

    isDisposed_ = true;

    // Notify the parent thread so the Worker object's persistent handle and
    // the registry entry are released (no-op if terminate() or the parent's
    // own shutdown already cleared them).
    if (auto parentTasks = parentTasks_.lock()) {
        int workerId = workerId_;
        parentTasks->PostInternal([workerId]() {
            WorkerWrapper::ClearWorkerOnParent(workerId);
        });
    }

    // ART aborts if a native thread exits while still attached. This must be
    // the very last JNI-touching action on this thread.
    jvm->DetachCurrentThread();
}

int WorkerWrapper::NextWorkerId() {
    return nextWorkerId_.fetch_add(1, std::memory_order_relaxed) + 1;
}

std::shared_ptr<WorkerWrapper> WorkerWrapper::GetById(int workerId) {
    std::lock_guard<std::mutex> lock(registryMutex_);
    auto it = registry_.find(workerId);
    return it != registry_.end() ? it->second : nullptr;
}

void WorkerWrapper::Insert(int workerId, std::shared_ptr<WorkerWrapper> wrapper) {
    std::lock_guard<std::mutex> lock(registryMutex_);
    registry_.emplace(workerId, std::move(wrapper));
}

void WorkerWrapper::ClearWorkerOnParent(int workerId) {
    std::shared_ptr<WorkerWrapper> wrapper;
    {
        std::lock_guard<std::mutex> lock(registryMutex_);
        auto it = registry_.find(workerId);
        if (it == registry_.end()) {
            return;
        }
        wrapper = it->second;
        registry_.erase(it);
    }

    if (wrapper->poWorker_ != nullptr) {
        v8::Locker locker(wrapper->parentIsolate_);
        wrapper->poWorker_->Reset();
        delete wrapper->poWorker_;
        wrapper->poWorker_ = nullptr;
    }
}

void WorkerWrapper::TerminateChildren(Isolate* parentIsolate) {
    std::vector<std::shared_ptr<WorkerWrapper>> children;
    {
        std::lock_guard<std::mutex> lock(registryMutex_);
        for (auto& entry : registry_) {
            if (entry.second->parentIsolate_ == parentIsolate) {
                children.push_back(entry.second);
            }
        }
    }

    for (auto& child : children) {
        DEBUG_WRITE(
                "Terminating nested worker(id=%d) because its parent is shutting down",
                child->workerId_);
        child->Terminate();
        ClearWorkerOnParent(child->workerId_);
    }
}

WorkerWrapper* WorkerWrapper::FromIsolate(Isolate* isolate) {
    return static_cast<WorkerWrapper*>(
            isolate->GetData((uint32_t) Runtime::IsolateData::WORKER_WRAPPER));
}

void WorkerWrapper::EnsureJniCached() {
    if (RUNTIME_CLASS != nullptr) {
        return;
    }

    JEnv env;

    RUNTIME_CLASS = env.FindClass("com/tns/Runtime");
    NS_CHECK(RUNTIME_CLASS != nullptr);
    INIT_WORKER_RUNTIME_METHOD_ID =
            env.GetStaticMethodID(RUNTIME_CLASS, "initWorkerRuntime", "(ILjava/lang/String;)I");
    RUN_WORKER_LOOP_METHOD_ID = env.GetStaticMethodID(RUNTIME_CLASS, "runWorkerLoop", "()V");
    DETACH_WORKER_RUNTIME_METHOD_ID =
            env.GetStaticMethodID(RUNTIME_CLASS, "detachWorkerRuntime", "(I)V");

    LOOPER_CLASS = env.FindClass("android/os/Looper");
    NS_CHECK(LOOPER_CLASS != nullptr);
    MY_LOOPER_METHOD_ID =
            env.GetStaticMethodID(LOOPER_CLASS, "myLooper", "()Landroid/os/Looper;");
    LOOPER_QUIT_METHOD_ID = env.GetMethodID(LOOPER_CLASS, "quit", "()V");

    PROCESS_CLASS = env.FindClass("android/os/Process");
    NS_CHECK(PROCESS_CLASS != nullptr);
    SET_THREAD_PRIORITY_METHOD_ID =
            env.GetStaticMethodID(PROCESS_CLASS, "setThreadPriority", "(I)V");
}

#ifdef APPLICATION_IN_DEBUG
void WorkerWrapper::CreateInspector(Isolate* isolate) {
    // Only when the root inspector client exists (debuggable app, created on
    // the main thread during runtime init) - never construct it from here.
    JsV8InspectorClient* root = JsV8InspectorClient::GetInstanceIfCreated();
    if (root == nullptr) {
        return;
    }

    // Same url the module loader reports in Debugger.scriptParsed: an http(s)
    // entry already IS that url, only a filesystem path needs the scheme.
    std::string url = ModuleInternal::IsHttpModulePath(workerPath_)
                              ? workerPath_
                              : "file://" + workerPath_;

    auto* client = new WorkerInspectorClient(workerId_, isolate, ALooper_forThread(), url);
    {
        std::lock_guard<std::mutex> lock(inspectorMutex_);
        inspector_ = client;
    }

    // Register only once fully constructed: registration makes the client
    // reachable from the socket thread.
    root->RegisterWorkerTarget(workerId_, client);
}

void WorkerWrapper::DestroyInspector() {
    WorkerInspectorClient* client = nullptr;
    {
        std::lock_guard<std::mutex> lock(inspectorMutex_);
        client = inspector_;
        inspector_ = nullptr;
    }

    if (client == nullptr) {
        return;
    }

    // Unregister first: after this returns no other thread can reach the
    // client through the root's registry.
    JsV8InspectorClient* root = JsV8InspectorClient::GetInstanceIfCreated();
    if (root != nullptr) {
        root->UnregisterWorkerTarget(workerId_);
    }

    delete client;
}

void WorkerWrapper::ConsoleLog(v8_inspector::ConsoleAPIType method,
                               const std::vector<Local<Value>>& args) {
    std::lock_guard<std::mutex> lock(inspectorMutex_);
    if (inspector_ != nullptr) {
        inspector_->consoleLog(method, args);
    }
}
#endif

std::mutex WorkerWrapper::registryMutex_;
std::map<int, std::shared_ptr<WorkerWrapper>> WorkerWrapper::registry_;
std::atomic_int WorkerWrapper::nextWorkerId_(0);

jclass WorkerWrapper::RUNTIME_CLASS = nullptr;
jclass WorkerWrapper::LOOPER_CLASS = nullptr;
jclass WorkerWrapper::PROCESS_CLASS = nullptr;
jmethodID WorkerWrapper::INIT_WORKER_RUNTIME_METHOD_ID = nullptr;
jmethodID WorkerWrapper::RUN_WORKER_LOOP_METHOD_ID = nullptr;
jmethodID WorkerWrapper::DETACH_WORKER_RUNTIME_METHOD_ID = nullptr;
jmethodID WorkerWrapper::MY_LOOPER_METHOD_ID = nullptr;
jmethodID WorkerWrapper::LOOPER_QUIT_METHOD_ID = nullptr;
jmethodID WorkerWrapper::SET_THREAD_PRIORITY_METHOD_ID = nullptr;

}  // namespace tns