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#include "node_messaging.h"
#include "async_wrap-inl.h"
#include "debug_utils-inl.h"
#include "memory_tracker-inl.h"
#include "node_contextify.h"
#include "node_buffer.h"
#include "node_errors.h"
#include "node_process-inl.h"
#include "util-inl.h"
using node::contextify::ContextifyContext;
using node::errors::TryCatchScope;
using v8::Array;
using v8::ArrayBuffer;
using v8::BackingStore;
using v8::CompiledWasmModule;
using v8::Context;
using v8::EscapableHandleScope;
using v8::Function;
using v8::FunctionCallbackInfo;
using v8::FunctionTemplate;
using v8::Global;
using v8::HandleScope;
using v8::Isolate;
using v8::Just;
using v8::Local;
using v8::Maybe;
using v8::MaybeLocal;
using v8::Nothing;
using v8::Object;
using v8::SharedArrayBuffer;
using v8::String;
using v8::Symbol;
using v8::Value;
using v8::ValueDeserializer;
using v8::ValueSerializer;
using v8::WasmModuleObject;
namespace node {
using BaseObjectList = std::vector<BaseObjectPtr<BaseObject>>;
BaseObject::TransferMode BaseObject::GetTransferMode() const {
return BaseObject::TransferMode::kUntransferable;
}
std::unique_ptr<worker::TransferData> BaseObject::TransferForMessaging() {
return CloneForMessaging();
}
std::unique_ptr<worker::TransferData> BaseObject::CloneForMessaging() const {
return {};
}
Maybe<BaseObjectList> BaseObject::NestedTransferables() const {
return Just(BaseObjectList {});
}
Maybe<bool> BaseObject::FinalizeTransferRead(
Local<Context> context, ValueDeserializer* deserializer) {
return Just(true);
}
namespace worker {
Maybe<bool> TransferData::FinalizeTransferWrite(
Local<Context> context, ValueSerializer* serializer) {
return Just(true);
}
Message::Message(MallocedBuffer<char>&& buffer)
: main_message_buf_(std::move(buffer)) {}
bool Message::IsCloseMessage() const {
return main_message_buf_.data == nullptr;
}
namespace {
// This is used to tell V8 how to read transferred host objects, like other
// `MessagePort`s and `SharedArrayBuffer`s, and make new JS objects out of them.
class DeserializerDelegate : public ValueDeserializer::Delegate {
public:
DeserializerDelegate(
Message* m,
Environment* env,
const std::vector<BaseObjectPtr<BaseObject>>& host_objects,
const std::vector<Local<SharedArrayBuffer>>& shared_array_buffers,
const std::vector<CompiledWasmModule>& wasm_modules)
: host_objects_(host_objects),
shared_array_buffers_(shared_array_buffers),
wasm_modules_(wasm_modules) {}
MaybeLocal<Object> ReadHostObject(Isolate* isolate) override {
// Identifying the index in the message's BaseObject array is sufficient.
uint32_t id;
if (!deserializer->ReadUint32(&id))
return MaybeLocal<Object>();
CHECK_LE(id, host_objects_.size());
return host_objects_[id]->object(isolate);
}
MaybeLocal<SharedArrayBuffer> GetSharedArrayBufferFromId(
Isolate* isolate, uint32_t clone_id) override {
CHECK_LE(clone_id, shared_array_buffers_.size());
return shared_array_buffers_[clone_id];
}
MaybeLocal<WasmModuleObject> GetWasmModuleFromId(
Isolate* isolate, uint32_t transfer_id) override {
CHECK_LE(transfer_id, wasm_modules_.size());
return WasmModuleObject::FromCompiledModule(
isolate, wasm_modules_[transfer_id]);
}
ValueDeserializer* deserializer = nullptr;
private:
const std::vector<BaseObjectPtr<BaseObject>>& host_objects_;
const std::vector<Local<SharedArrayBuffer>>& shared_array_buffers_;
const std::vector<CompiledWasmModule>& wasm_modules_;
};
} // anonymous namespace
MaybeLocal<Value> Message::Deserialize(Environment* env,
Local<Context> context) {
CHECK(!IsCloseMessage());
EscapableHandleScope handle_scope(env->isolate());
Context::Scope context_scope(context);
// Create all necessary objects for transferables, e.g. MessagePort handles.
std::vector<BaseObjectPtr<BaseObject>> host_objects(transferables_.size());
auto cleanup = OnScopeLeave([&]() {
for (BaseObjectPtr<BaseObject> object : host_objects) {
if (!object) continue;
// If the function did not finish successfully, host_objects will contain
// a list of objects that will never be passed to JS. Therefore, we
// destroy them here.
object->Detach();
}
});
for (uint32_t i = 0; i < transferables_.size(); ++i) {
TransferData* data = transferables_[i].get();
host_objects[i] = data->Deserialize(
env, context, std::move(transferables_[i]));
if (!host_objects[i]) return {};
}
transferables_.clear();
std::vector<Local<SharedArrayBuffer>> shared_array_buffers;
// Attach all transferred SharedArrayBuffers to their new Isolate.
for (uint32_t i = 0; i < shared_array_buffers_.size(); ++i) {
Local<SharedArrayBuffer> sab =
SharedArrayBuffer::New(env->isolate(),
std::move(shared_array_buffers_[i]));
shared_array_buffers.push_back(sab);
}
shared_array_buffers_.clear();
DeserializerDelegate delegate(
this, env, host_objects, shared_array_buffers, wasm_modules_);
ValueDeserializer deserializer(
env->isolate(),
reinterpret_cast<const uint8_t*>(main_message_buf_.data),
main_message_buf_.size,
&delegate);
delegate.deserializer = &deserializer;
// Attach all transferred ArrayBuffers to their new Isolate.
for (uint32_t i = 0; i < array_buffers_.size(); ++i) {
Local<ArrayBuffer> ab =
ArrayBuffer::New(env->isolate(), std::move(array_buffers_[i]));
deserializer.TransferArrayBuffer(i, ab);
}
array_buffers_.clear();
if (deserializer.ReadHeader(context).IsNothing())
return {};
Local<Value> return_value;
if (!deserializer.ReadValue(context).ToLocal(&return_value))
return {};
for (BaseObjectPtr<BaseObject> base_object : host_objects) {
if (base_object->FinalizeTransferRead(context, &deserializer).IsNothing())
return {};
}
host_objects.clear();
return handle_scope.Escape(return_value);
}
void Message::AddSharedArrayBuffer(
std::shared_ptr<BackingStore> backing_store) {
shared_array_buffers_.emplace_back(std::move(backing_store));
}
void Message::AddTransferable(std::unique_ptr<TransferData>&& data) {
transferables_.emplace_back(std::move(data));
}
uint32_t Message::AddWASMModule(CompiledWasmModule&& mod) {
wasm_modules_.emplace_back(std::move(mod));
return wasm_modules_.size() - 1;
}
namespace {
MaybeLocal<Function> GetEmitMessageFunction(Local<Context> context) {
Isolate* isolate = context->GetIsolate();
Local<Object> per_context_bindings;
Local<Value> emit_message_val;
if (!GetPerContextExports(context).ToLocal(&per_context_bindings) ||
!per_context_bindings->Get(context,
FIXED_ONE_BYTE_STRING(isolate, "emitMessage"))
.ToLocal(&emit_message_val)) {
return MaybeLocal<Function>();
}
CHECK(emit_message_val->IsFunction());
return emit_message_val.As<Function>();
}
MaybeLocal<Function> GetDOMException(Local<Context> context) {
Isolate* isolate = context->GetIsolate();
Local<Object> per_context_bindings;
Local<Value> domexception_ctor_val;
if (!GetPerContextExports(context).ToLocal(&per_context_bindings) ||
!per_context_bindings->Get(context,
FIXED_ONE_BYTE_STRING(isolate, "DOMException"))
.ToLocal(&domexception_ctor_val)) {
return MaybeLocal<Function>();
}
CHECK(domexception_ctor_val->IsFunction());
Local<Function> domexception_ctor = domexception_ctor_val.As<Function>();
return domexception_ctor;
}
void ThrowDataCloneException(Local<Context> context, Local<String> message) {
Isolate* isolate = context->GetIsolate();
Local<Value> argv[] = {message,
FIXED_ONE_BYTE_STRING(isolate, "DataCloneError")};
Local<Value> exception;
Local<Function> domexception_ctor;
if (!GetDOMException(context).ToLocal(&domexception_ctor) ||
!domexception_ctor->NewInstance(context, arraysize(argv), argv)
.ToLocal(&exception)) {
return;
}
isolate->ThrowException(exception);
}
// This tells V8 how to serialize objects that it does not understand
// (e.g. C++ objects) into the output buffer, in a way that our own
// DeserializerDelegate understands how to unpack.
class SerializerDelegate : public ValueSerializer::Delegate {
public:
SerializerDelegate(Environment* env, Local<Context> context, Message* m)
: env_(env), context_(context), msg_(m) {}
void ThrowDataCloneError(Local<String> message) override {
ThrowDataCloneException(context_, message);
}
Maybe<bool> WriteHostObject(Isolate* isolate, Local<Object> object) override {
if (env_->base_object_ctor_template()->HasInstance(object)) {
return WriteHostObject(
BaseObjectPtr<BaseObject> { Unwrap<BaseObject>(object) });
}
ThrowDataCloneError(env_->clone_unsupported_type_str());
return Nothing<bool>();
}
Maybe<uint32_t> GetSharedArrayBufferId(
Isolate* isolate,
Local<SharedArrayBuffer> shared_array_buffer) override {
uint32_t i;
for (i = 0; i < seen_shared_array_buffers_.size(); ++i) {
if (PersistentToLocal::Strong(seen_shared_array_buffers_[i]) ==
shared_array_buffer) {
return Just(i);
}
}
seen_shared_array_buffers_.emplace_back(
Global<SharedArrayBuffer> { isolate, shared_array_buffer });
msg_->AddSharedArrayBuffer(shared_array_buffer->GetBackingStore());
return Just(i);
}
Maybe<uint32_t> GetWasmModuleTransferId(
Isolate* isolate, Local<WasmModuleObject> module) override {
return Just(msg_->AddWASMModule(module->GetCompiledModule()));
}
Maybe<bool> Finish(Local<Context> context) {
for (uint32_t i = 0; i < host_objects_.size(); i++) {
BaseObjectPtr<BaseObject> host_object = std::move(host_objects_[i]);
std::unique_ptr<TransferData> data;
if (i < first_cloned_object_index_)
data = host_object->TransferForMessaging();
if (!data)
data = host_object->CloneForMessaging();
if (!data) return Nothing<bool>();
if (data->FinalizeTransferWrite(context, serializer).IsNothing())
return Nothing<bool>();
msg_->AddTransferable(std::move(data));
}
return Just(true);
}
inline void AddHostObject(BaseObjectPtr<BaseObject> host_object) {
// Make sure we have not started serializing the value itself yet.
CHECK_EQ(first_cloned_object_index_, SIZE_MAX);
host_objects_.emplace_back(std::move(host_object));
}
// Some objects in the transfer list may register sub-objects that can be
// transferred. This could e.g. be a public JS wrapper object, such as a
// FileHandle, that is registering its C++ handle for transfer.
inline Maybe<bool> AddNestedHostObjects() {
for (size_t i = 0; i < host_objects_.size(); i++) {
std::vector<BaseObjectPtr<BaseObject>> nested_transferables;
if (!host_objects_[i]->NestedTransferables().To(&nested_transferables))
return Nothing<bool>();
for (auto nested_transferable : nested_transferables) {
if (std::find(host_objects_.begin(),
host_objects_.end(),
nested_transferable) == host_objects_.end()) {
AddHostObject(nested_transferable);
}
}
}
return Just(true);
}
ValueSerializer* serializer = nullptr;
private:
Maybe<bool> WriteHostObject(BaseObjectPtr<BaseObject> host_object) {
BaseObject::TransferMode mode = host_object->GetTransferMode();
if (mode == BaseObject::TransferMode::kUntransferable) {
ThrowDataCloneError(env_->clone_unsupported_type_str());
return Nothing<bool>();
}
for (uint32_t i = 0; i < host_objects_.size(); i++) {
if (host_objects_[i] == host_object) {
serializer->WriteUint32(i);
return Just(true);
}
}
if (mode == BaseObject::TransferMode::kTransferable) {
// TODO(addaleax): This message code is too specific. Fix that in a
// semver-major follow-up.
THROW_ERR_MISSING_MESSAGE_PORT_IN_TRANSFER_LIST(env_);
return Nothing<bool>();
}
CHECK_EQ(mode, BaseObject::TransferMode::kCloneable);
uint32_t index = host_objects_.size();
if (first_cloned_object_index_ == SIZE_MAX)
first_cloned_object_index_ = index;
serializer->WriteUint32(index);
host_objects_.push_back(host_object);
return Just(true);
}
Environment* env_;
Local<Context> context_;
Message* msg_;
std::vector<Global<SharedArrayBuffer>> seen_shared_array_buffers_;
std::vector<BaseObjectPtr<BaseObject>> host_objects_;
size_t first_cloned_object_index_ = SIZE_MAX;
friend class worker::Message;
};
} // anonymous namespace
Maybe<bool> Message::Serialize(Environment* env,
Local<Context> context,
Local<Value> input,
const TransferList& transfer_list_v,
Local<Object> source_port) {
HandleScope handle_scope(env->isolate());
Context::Scope context_scope(context);
// Verify that we're not silently overwriting an existing message.
CHECK(main_message_buf_.is_empty());
SerializerDelegate delegate(env, context, this);
ValueSerializer serializer(env->isolate(), &delegate);
delegate.serializer = &serializer;
std::vector<Local<ArrayBuffer>> array_buffers;
for (uint32_t i = 0; i < transfer_list_v.length(); ++i) {
Local<Value> entry = transfer_list_v[i];
if (entry->IsObject()) {
// See https://github.com/nodejs/node/pull/30339#issuecomment-552225353
// for details.
bool untransferable;
if (!entry.As<Object>()->HasPrivate(
context,
env->untransferable_object_private_symbol())
.To(&untransferable)) {
return Nothing<bool>();
}
if (untransferable) continue;
}
// Currently, we support ArrayBuffers and BaseObjects for which
// GetTransferMode() does not return kUntransferable.
if (entry->IsArrayBuffer()) {
Local<ArrayBuffer> ab = entry.As<ArrayBuffer>();
// If we cannot render the ArrayBuffer unusable in this Isolate,
// copying the buffer will have to do.
// Note that we can currently transfer ArrayBuffers even if they were
// not allocated by Node’s ArrayBufferAllocator in the first place,
// because we pass the underlying v8::BackingStore around rather than
// raw data *and* an Isolate with a non-default ArrayBuffer allocator
// is always going to outlive any Workers it creates, and so will its
// allocator along with it.
if (!ab->IsDetachable()) continue;
if (std::find(array_buffers.begin(), array_buffers.end(), ab) !=
array_buffers.end()) {
ThrowDataCloneException(
context,
FIXED_ONE_BYTE_STRING(
env->isolate(),
"Transfer list contains duplicate ArrayBuffer"));
return Nothing<bool>();
}
// We simply use the array index in the `array_buffers` list as the
// ID that we write into the serialized buffer.
uint32_t id = array_buffers.size();
array_buffers.push_back(ab);
serializer.TransferArrayBuffer(id, ab);
continue;
} else if (env->base_object_ctor_template()->HasInstance(entry)) {
// Check if the source MessagePort is being transferred.
if (!source_port.IsEmpty() && entry == source_port) {
ThrowDataCloneException(
context,
FIXED_ONE_BYTE_STRING(env->isolate(),
"Transfer list contains source port"));
return Nothing<bool>();
}
BaseObjectPtr<BaseObject> host_object {
Unwrap<BaseObject>(entry.As<Object>()) };
if (env->message_port_constructor_template()->HasInstance(entry) &&
(!host_object ||
static_cast<MessagePort*>(host_object.get())->IsDetached())) {
ThrowDataCloneException(
context,
FIXED_ONE_BYTE_STRING(
env->isolate(),
"MessagePort in transfer list is already detached"));
return Nothing<bool>();
}
if (std::find(delegate.host_objects_.begin(),
delegate.host_objects_.end(),
host_object) != delegate.host_objects_.end()) {
ThrowDataCloneException(
context,
String::Concat(env->isolate(),
FIXED_ONE_BYTE_STRING(
env->isolate(),
"Transfer list contains duplicate "),
entry.As<Object>()->GetConstructorName()));
return Nothing<bool>();
}
if (host_object && host_object->GetTransferMode() !=
BaseObject::TransferMode::kUntransferable) {
delegate.AddHostObject(host_object);
continue;
}
}
THROW_ERR_INVALID_TRANSFER_OBJECT(env);
return Nothing<bool>();
}
if (delegate.AddNestedHostObjects().IsNothing())
return Nothing<bool>();
serializer.WriteHeader();
if (serializer.WriteValue(context, input).IsNothing()) {
return Nothing<bool>();
}
for (Local<ArrayBuffer> ab : array_buffers) {
// If serialization succeeded, we render it inaccessible in this Isolate.
std::shared_ptr<BackingStore> backing_store = ab->GetBackingStore();
ab->Detach();
array_buffers_.emplace_back(std::move(backing_store));
}
if (delegate.Finish(context).IsNothing())
return Nothing<bool>();
// The serializer gave us a buffer allocated using `malloc()`.
std::pair<uint8_t*, size_t> data = serializer.Release();
CHECK_NOT_NULL(data.first);
main_message_buf_ =
MallocedBuffer<char>(reinterpret_cast<char*>(data.first), data.second);
return Just(true);
}
void Message::MemoryInfo(MemoryTracker* tracker) const {
tracker->TrackField("array_buffers_", array_buffers_);
tracker->TrackField("shared_array_buffers", shared_array_buffers_);
tracker->TrackField("transferables", transferables_);
}
MessagePortData::MessagePortData(MessagePort* owner) : owner_(owner) { }
MessagePortData::~MessagePortData() {
CHECK_NULL(owner_);
Disentangle();
}
void MessagePortData::MemoryInfo(MemoryTracker* tracker) const {
Mutex::ScopedLock lock(mutex_);
tracker->TrackField("incoming_messages", incoming_messages_);
}
void MessagePortData::AddToIncomingQueue(Message&& message) {
// This function will be called by other threads.
Mutex::ScopedLock lock(mutex_);
incoming_messages_.emplace_back(std::move(message));
if (owner_ != nullptr) {
Debug(owner_, "Adding message to incoming queue");
owner_->TriggerAsync();
}
}
void MessagePortData::Entangle(MessagePortData* a, MessagePortData* b) {
CHECK_NULL(a->sibling_);
CHECK_NULL(b->sibling_);
a->sibling_ = b;
b->sibling_ = a;
a->sibling_mutex_ = b->sibling_mutex_;
}
void MessagePortData::Disentangle() {
// Grab a copy of the sibling mutex, then replace it so that each sibling
// has its own sibling_mutex_ now.
std::shared_ptr<Mutex> sibling_mutex = sibling_mutex_;
Mutex::ScopedLock sibling_lock(*sibling_mutex);
sibling_mutex_ = std::make_shared<Mutex>();
MessagePortData* sibling = sibling_;
if (sibling_ != nullptr) {
sibling_->sibling_ = nullptr;
sibling_ = nullptr;
}
// We close MessagePorts after disentanglement, so we enqueue a corresponding
// message and trigger the corresponding uv_async_t to let them know that
// this happened.
AddToIncomingQueue(Message());
if (sibling != nullptr) {
sibling->AddToIncomingQueue(Message());
}
}
MessagePort::~MessagePort() {
if (data_) Detach();
}
MessagePort::MessagePort(Environment* env,
Local<Context> context,
Local<Object> wrap)
: HandleWrap(env,
wrap,
reinterpret_cast<uv_handle_t*>(&async_),
AsyncWrap::PROVIDER_MESSAGEPORT),
data_(new MessagePortData(this)) {
auto onmessage = [](uv_async_t* handle) {
// Called when data has been put into the queue.
MessagePort* channel = ContainerOf(&MessagePort::async_, handle);
channel->OnMessage();
};
CHECK_EQ(uv_async_init(env->event_loop(),
&async_,
onmessage), 0);
// Reset later to indicate success of the constructor.
bool succeeded = false;
auto cleanup = OnScopeLeave([&]() { if (!succeeded) Close(); });
Local<Value> fn;
if (!wrap->Get(context, env->oninit_symbol()).ToLocal(&fn))
return;
if (fn->IsFunction()) {
Local<Function> init = fn.As<Function>();
if (init->Call(context, wrap, 0, nullptr).IsEmpty())
return;
}
Local<Function> emit_message_fn;
if (!GetEmitMessageFunction(context).ToLocal(&emit_message_fn))
return;
emit_message_fn_.Reset(env->isolate(), emit_message_fn);
succeeded = true;
Debug(this, "Created message port");
}
bool MessagePort::IsDetached() const {
return data_ == nullptr || IsHandleClosing();
}
void MessagePort::TriggerAsync() {
if (IsHandleClosing()) return;
CHECK_EQ(uv_async_send(&async_), 0);
}
void MessagePort::Close(v8::Local<v8::Value> close_callback) {
Debug(this, "Closing message port, data set = %d", static_cast<int>(!!data_));
if (data_) {
// Wrap this call with accessing the mutex, so that TriggerAsync()
// can check IsHandleClosing() without race conditions.
Mutex::ScopedLock sibling_lock(data_->mutex_);
HandleWrap::Close(close_callback);
} else {
HandleWrap::Close(close_callback);
}
}
void MessagePort::New(const FunctionCallbackInfo<Value>& args) {
// This constructor just throws an error. Unfortunately, we can’t use V8’s
// ConstructorBehavior::kThrow, as that also removes the prototype from the
// class (i.e. makes it behave like an arrow function).
Environment* env = Environment::GetCurrent(args);
THROW_ERR_CONSTRUCT_CALL_INVALID(env);
}
MessagePort* MessagePort::New(
Environment* env,
Local<Context> context,
std::unique_ptr<MessagePortData> data) {
Context::Scope context_scope(context);
Local<FunctionTemplate> ctor_templ = GetMessagePortConstructorTemplate(env);
// Construct a new instance, then assign the listener instance and possibly
// the MessagePortData to it.
Local<Object> instance;
if (!ctor_templ->InstanceTemplate()->NewInstance(context).ToLocal(&instance))
return nullptr;
MessagePort* port = new MessagePort(env, context, instance);
CHECK_NOT_NULL(port);
if (port->IsHandleClosing()) {
// Construction failed with an exception.
return nullptr;
}
if (data) {
port->Detach();
port->data_ = std::move(data);
// This lock is here to avoid race conditions with the `owner_` read
// in AddToIncomingQueue(). (This would likely be unproblematic without it,
// but it's better to be safe than sorry.)
Mutex::ScopedLock lock(port->data_->mutex_);
port->data_->owner_ = port;
// If the existing MessagePortData object had pending messages, this is
// the easiest way to run that queue.
port->TriggerAsync();
}
return port;
}
MaybeLocal<Value> MessagePort::ReceiveMessage(Local<Context> context,
bool only_if_receiving) {
Message received;
{
// Get the head of the message queue.
Mutex::ScopedLock lock(data_->mutex_);
Debug(this, "MessagePort has message");
bool wants_message = receiving_messages_ || !only_if_receiving;
// We have nothing to do if:
// - There are no pending messages
// - We are not intending to receive messages, and the message we would
// receive is not the final "close" message.
if (data_->incoming_messages_.empty() ||
(!wants_message &&
!data_->incoming_messages_.front().IsCloseMessage())) {
return env()->no_message_symbol();
}
received = std::move(data_->incoming_messages_.front());
data_->incoming_messages_.pop_front();
}
if (received.IsCloseMessage()) {
Close();
return env()->no_message_symbol();
}
if (!env()->can_call_into_js()) return MaybeLocal<Value>();
return received.Deserialize(env(), context);
}
void MessagePort::OnMessage() {
Debug(this, "Running MessagePort::OnMessage()");
HandleScope handle_scope(env()->isolate());
Local<Context> context = object(env()->isolate())->CreationContext();
size_t processing_limit;
{
Mutex::ScopedLock(data_->mutex_);
processing_limit = std::max(data_->incoming_messages_.size(),
static_cast<size_t>(1000));
}
// data_ can only ever be modified by the owner thread, so no need to lock.
// However, the message port may be transferred while it is processing
// messages, so we need to check that this handle still owns its `data_` field
// on every iteration.
while (data_) {
if (processing_limit-- == 0) {
// Prevent event loop starvation by only processing those messages without
// interruption that were already present when the OnMessage() call was
// first triggered, but at least 1000 messages because otherwise the
// overhead of repeatedly triggering the uv_async_t instance becomes
// noticeable, at least on Windows.
// (That might require more investigation by somebody more familiar with
// Windows.)
TriggerAsync();
return;
}
HandleScope handle_scope(env()->isolate());
Context::Scope context_scope(context);
Local<Function> emit_message = PersistentToLocal::Strong(emit_message_fn_);
Local<Value> payload;
Local<Value> message_error;
Local<Value> argv[2];
{
// Catch any exceptions from parsing the message itself (not from
// emitting it) as 'messageeror' events.
TryCatchScope try_catch(env());
if (!ReceiveMessage(context, true).ToLocal(&payload)) {
if (try_catch.HasCaught() && !try_catch.HasTerminated())
message_error = try_catch.Exception();
goto reschedule;
}
}
if (payload == env()->no_message_symbol()) break;
if (!env()->can_call_into_js()) {
Debug(this, "MessagePort drains queue because !can_call_into_js()");
// In this case there is nothing to do but to drain the current queue.
continue;
}
argv[0] = payload;
argv[1] = env()->message_string();
if (MakeCallback(emit_message, arraysize(argv), argv).IsEmpty()) {
reschedule:
if (!message_error.IsEmpty()) {
argv[0] = message_error;
argv[1] = env()->messageerror_string();
USE(MakeCallback(emit_message, arraysize(argv), argv));
}
// Re-schedule OnMessage() execution in case of failure.
if (data_)
TriggerAsync();
return;
}
}
}
void MessagePort::OnClose() {
Debug(this, "MessagePort::OnClose()");
if (data_) {
// Detach() returns move(data_).
Detach()->Disentangle();
}
}
std::unique_ptr<MessagePortData> MessagePort::Detach() {
CHECK(data_);
Mutex::ScopedLock lock(data_->mutex_);
data_->owner_ = nullptr;
return std::move(data_);
}
BaseObject::TransferMode MessagePort::GetTransferMode() const {
if (IsDetached())
return BaseObject::TransferMode::kUntransferable;
return BaseObject::TransferMode::kTransferable;
}
std::unique_ptr<TransferData> MessagePort::TransferForMessaging() {
Close();
return Detach();
}
BaseObjectPtr<BaseObject> MessagePortData::Deserialize(
Environment* env,
Local<Context> context,
std::unique_ptr<TransferData> self) {
return BaseObjectPtr<MessagePort> { MessagePort::New(
env, context,
static_unique_pointer_cast<MessagePortData>(std::move(self))) };
}
Maybe<bool> MessagePort::PostMessage(Environment* env,
Local<Context> context,
Local<Value> message_v,
const TransferList& transfer_v) {
Isolate* isolate = env->isolate();
Local<Object> obj = object(isolate);
Message msg;
// Per spec, we need to both check if transfer list has the source port, and
// serialize the input message, even if the MessagePort is closed or detached.
Maybe<bool> serialization_maybe =
msg.Serialize(env, context, message_v, transfer_v, obj);
if (data_ == nullptr) {
return serialization_maybe;
}
if (serialization_maybe.IsNothing()) {
return Nothing<bool>();
}
Mutex::ScopedLock lock(*data_->sibling_mutex_);
bool doomed = false;
// Check if the target port is posted to itself.
if (data_->sibling_ != nullptr) {
for (const auto& transferable : msg.transferables()) {
if (data_->sibling_ == transferable.get()) {
doomed = true;
ProcessEmitWarning(env, "The target port was posted to itself, and "
"the communication channel was lost");
break;
}
}
}
if (data_->sibling_ == nullptr || doomed)
return Just(true);
data_->sibling_->AddToIncomingQueue(std::move(msg));
return Just(true);
}
static Maybe<bool> ReadIterable(Environment* env,
Local<Context> context,
// NOLINTNEXTLINE(runtime/references)
TransferList& transfer_list,
Local<Value> object) {
if (!object->IsObject()) return Just(false);
if (object->IsArray()) {
Local<Array> arr = object.As<Array>();
size_t length = arr->Length();
transfer_list.AllocateSufficientStorage(length);
for (size_t i = 0; i < length; i++) {
if (!arr->Get(context, i).ToLocal(&transfer_list[i]))
return Nothing<bool>();
}
return Just(true);
}
Isolate* isolate = env->isolate();
Local<Value> iterator_method;
if (!object.As<Object>()->Get(context, Symbol::GetIterator(isolate))
.ToLocal(&iterator_method)) return Nothing<bool>();
if (!iterator_method->IsFunction()) return Just(false);
Local<Value> iterator;
if (!iterator_method.As<Function>()->Call(context, object, 0, nullptr)
.ToLocal(&iterator)) return Nothing<bool>();
if (!iterator->IsObject()) return Just(false);
Local<Value> next;
if (!iterator.As<Object>()->Get(context, env->next_string()).ToLocal(&next))
return Nothing<bool>();
if (!next->IsFunction()) return Just(false);
std::vector<Local<Value>> entries;
while (env->can_call_into_js()) {
Local<Value> result;
if (!next.As<Function>()->Call(context, iterator, 0, nullptr)
.ToLocal(&result)) return Nothing<bool>();
if (!result->IsObject()) return Just(false);
Local<Value> done;
if (!result.As<Object>()->Get(context, env->done_string()).ToLocal(&done))
return Nothing<bool>();
if (done->BooleanValue(isolate)) break;
Local<Value> val;
if (!result.As<Object>()->Get(context, env->value_string()).ToLocal(&val))
return Nothing<bool>();
entries.push_back(val);
}
transfer_list.AllocateSufficientStorage(entries.size());
std::copy(entries.begin(), entries.end(), &transfer_list[0]);
return Just(true);
}
void MessagePort::PostMessage(const FunctionCallbackInfo<Value>& args) {
Environment* env = Environment::GetCurrent(args);
Local<Object> obj = args.This();
Local<Context> context = obj->CreationContext();
if (args.Length() == 0) {
return THROW_ERR_MISSING_ARGS(env, "Not enough arguments to "
"MessagePort.postMessage");
}
if (!args[1]->IsNullOrUndefined() && !args[1]->IsObject()) {
// Browsers ignore null or undefined, and otherwise accept an array or an
// options object.
return THROW_ERR_INVALID_ARG_TYPE(env,
"Optional transferList argument must be an iterable");
}
TransferList transfer_list;
if (args[1]->IsObject()) {
bool was_iterable;
if (!ReadIterable(env, context, transfer_list, args[1]).To(&was_iterable))
return;
if (!was_iterable) {
Local<Value> transfer_option;
if (!args[1].As<Object>()->Get(context, env->transfer_string())
.ToLocal(&transfer_option)) return;
if (!transfer_option->IsUndefined()) {
if (!ReadIterable(env, context, transfer_list, transfer_option)
.To(&was_iterable)) return;
if (!was_iterable) {
return THROW_ERR_INVALID_ARG_TYPE(env,
"Optional options.transfer argument must be an iterable");
}
}
}
}
MessagePort* port = Unwrap<MessagePort>(args.This());
// Even if the backing MessagePort object has already been deleted, we still
// want to serialize the message to ensure spec-compliant behavior w.r.t.
// transfers.
if (port == nullptr) {
Message msg;
USE(msg.Serialize(env, context, args[0], transfer_list, obj));
return;
}
Maybe<bool> res = port->PostMessage(env, context, args[0], transfer_list);
if (res.IsJust())
args.GetReturnValue().Set(res.FromJust());
}
void MessagePort::Start() {
Debug(this, "Start receiving messages");
receiving_messages_ = true;
Mutex::ScopedLock lock(data_->mutex_);
if (!data_->incoming_messages_.empty())
TriggerAsync();
}
void MessagePort::Stop() {
Debug(this, "Stop receiving messages");
receiving_messages_ = false;
}
void MessagePort::Start(const FunctionCallbackInfo<Value>& args) {
MessagePort* port;
ASSIGN_OR_RETURN_UNWRAP(&port, args.This());
if (!port->data_) {
return;
}
port->Start();
}
void MessagePort::Stop(const FunctionCallbackInfo<Value>& args) {
MessagePort* port;
CHECK(args[0]->IsObject());
ASSIGN_OR_RETURN_UNWRAP(&port, args[0].As<Object>());
if (!port->data_) {
return;
}
port->Stop();
}
void MessagePort::Drain(const FunctionCallbackInfo<Value>& args) {
MessagePort* port;
ASSIGN_OR_RETURN_UNWRAP(&port, args[0].As<Object>());
port->OnMessage();
}
void MessagePort::ReceiveMessage(const FunctionCallbackInfo<Value>& args) {
Environment* env = Environment::GetCurrent(args);
if (!args[0]->IsObject() ||
!env->message_port_constructor_template()->HasInstance(args[0])) {
return THROW_ERR_INVALID_ARG_TYPE(env,
"The \"port\" argument must be a MessagePort instance");
}
MessagePort* port = Unwrap<MessagePort>(args[0].As<Object>());
if (port == nullptr) {
// Return 'no messages' for a closed port.
args.GetReturnValue().Set(
Environment::GetCurrent(args)->no_message_symbol());
return;
}
MaybeLocal<Value> payload =
port->ReceiveMessage(port->object()->CreationContext(), false);
if (!payload.IsEmpty())
args.GetReturnValue().Set(payload.ToLocalChecked());
}
void MessagePort::MoveToContext(const FunctionCallbackInfo<Value>& args) {
Environment* env = Environment::GetCurrent(args);
if (!args[0]->IsObject() ||
!env->message_port_constructor_template()->HasInstance(args[0])) {
return THROW_ERR_INVALID_ARG_TYPE(env,
"The \"port\" argument must be a MessagePort instance");
}
MessagePort* port = Unwrap<MessagePort>(args[0].As<Object>());
if (port == nullptr || port->IsHandleClosing()) {
Isolate* isolate = env->isolate();
THROW_ERR_CLOSED_MESSAGE_PORT(isolate);
return;
}
Local<Value> context_arg = args[1];
ContextifyContext* context_wrapper;
if (!context_arg->IsObject() ||
(context_wrapper = ContextifyContext::ContextFromContextifiedSandbox(
env, context_arg.As<Object>())) == nullptr) {
return THROW_ERR_INVALID_ARG_TYPE(env, "Invalid context argument");
}
std::unique_ptr<MessagePortData> data;
if (!port->IsDetached())
data = port->Detach();
Context::Scope context_scope(context_wrapper->context());
MessagePort* target =
MessagePort::New(env, context_wrapper->context(), std::move(data));
if (target != nullptr)
args.GetReturnValue().Set(target->object());
}
void MessagePort::Entangle(MessagePort* a, MessagePort* b) {
Entangle(a, b->data_.get());
}
void MessagePort::Entangle(MessagePort* a, MessagePortData* b) {
MessagePortData::Entangle(a->data_.get(), b);
}
void MessagePort::MemoryInfo(MemoryTracker* tracker) const {
tracker->TrackField("data", data_);
tracker->TrackField("emit_message_fn", emit_message_fn_);
}
Local<FunctionTemplate> GetMessagePortConstructorTemplate(Environment* env) {
// Factor generating the MessagePort JS constructor into its own piece
// of code, because it is needed early on in the child environment setup.
Local<FunctionTemplate> templ = env->message_port_constructor_template();
if (!templ.IsEmpty())
return templ;
{
Local<FunctionTemplate> m = env->NewFunctionTemplate(MessagePort::New);
m->SetClassName(env->message_port_constructor_string());
m->InstanceTemplate()->SetInternalFieldCount(
MessagePort::kInternalFieldCount);
m->Inherit(HandleWrap::GetConstructorTemplate(env));
env->SetProtoMethod(m, "postMessage", MessagePort::PostMessage);
env->SetProtoMethod(m, "start", MessagePort::Start);
env->set_message_port_constructor_template(m);
}
return GetMessagePortConstructorTemplate(env);
}
JSTransferable::JSTransferable(Environment* env, Local<Object> obj)
: BaseObject(env, obj) {
MakeWeak();
}
void JSTransferable::New(const FunctionCallbackInfo<Value>& args) {
CHECK(args.IsConstructCall());
new JSTransferable(Environment::GetCurrent(args), args.This());
}
JSTransferable::TransferMode JSTransferable::GetTransferMode() const {
// Implement `kClone in this ? kCloneable : kTransferable`.
HandleScope handle_scope(env()->isolate());
errors::TryCatchScope ignore_exceptions(env());
bool has_clone;
if (!object()->Has(env()->context(),
env()->messaging_clone_symbol()).To(&has_clone)) {
return TransferMode::kUntransferable;
}
return has_clone ? TransferMode::kCloneable : TransferMode::kTransferable;
}
std::unique_ptr<TransferData> JSTransferable::TransferForMessaging() {
return TransferOrClone(TransferMode::kTransferable);
}
std::unique_ptr<TransferData> JSTransferable::CloneForMessaging() const {
return TransferOrClone(TransferMode::kCloneable);
}
std::unique_ptr<TransferData> JSTransferable::TransferOrClone(
TransferMode mode) const {
// Call `this[symbol]()` where `symbol` is `kClone` or `kTransfer`,
// which should return an object with `data` and `deserializeInfo` properties;
// `data` is written to the serializer later, and `deserializeInfo` is stored
// on the `TransferData` instance as a string.
HandleScope handle_scope(env()->isolate());
Local<Context> context = env()->isolate()->GetCurrentContext();
Local<Symbol> method_name = mode == TransferMode::kCloneable ?
env()->messaging_clone_symbol() : env()->messaging_transfer_symbol();
Local<Value> method;
if (!object()->Get(context, method_name).ToLocal(&method)) {
return {};
}
if (method->IsFunction()) {
Local<Value> result_v;
if (!method.As<Function>()->Call(
context, object(), 0, nullptr).ToLocal(&result_v)) {
return {};
}
if (result_v->IsObject()) {
Local<Object> result = result_v.As<Object>();
Local<Value> data;
Local<Value> deserialize_info;
if (!result->Get(context, env()->data_string()).ToLocal(&data) ||
!result->Get(context, env()->deserialize_info_string())
.ToLocal(&deserialize_info)) {
return {};
}
Utf8Value deserialize_info_str(env()->isolate(), deserialize_info);
if (*deserialize_info_str == nullptr) return {};
return std::make_unique<Data>(
*deserialize_info_str, Global<Value>(env()->isolate(), data));
}
}
if (mode == TransferMode::kTransferable)
return TransferOrClone(TransferMode::kCloneable);
else
return {};
}
Maybe<BaseObjectList>
JSTransferable::NestedTransferables() const {
// Call `this[kTransferList]()` and return the resulting list of BaseObjects.
HandleScope handle_scope(env()->isolate());
Local<Context> context = env()->isolate()->GetCurrentContext();
Local<Symbol> method_name = env()->messaging_transfer_list_symbol();
Local<Value> method;
if (!object()->Get(context, method_name).ToLocal(&method)) {
return Nothing<BaseObjectList>();
}
if (!method->IsFunction()) return Just(BaseObjectList {});
Local<Value> list_v;
if (!method.As<Function>()->Call(
context, object(), 0, nullptr).ToLocal(&list_v)) {
return Nothing<BaseObjectList>();
}
if (!list_v->IsArray()) return Just(BaseObjectList {});
Local<Array> list = list_v.As<Array>();
BaseObjectList ret;
for (size_t i = 0; i < list->Length(); i++) {
Local<Value> value;
if (!list->Get(context, i).ToLocal(&value))
return Nothing<BaseObjectList>();
if (env()->base_object_ctor_template()->HasInstance(value))
ret.emplace_back(Unwrap<BaseObject>(value));
}
return Just(ret);
}
Maybe<bool> JSTransferable::FinalizeTransferRead(
Local<Context> context, ValueDeserializer* deserializer) {
// Call `this[kDeserialize](data)` where `data` comes from the return value
// of `this[kTransfer]()` or `this[kClone]()`.
HandleScope handle_scope(env()->isolate());
Local<Value> data;
if (!deserializer->ReadValue(context).ToLocal(&data)) return Nothing<bool>();
Local<Symbol> method_name = env()->messaging_deserialize_symbol();
Local<Value> method;
if (!object()->Get(context, method_name).ToLocal(&method)) {
return Nothing<bool>();
}
if (!method->IsFunction()) return Just(true);
if (method.As<Function>()->Call(context, object(), 1, &data).IsEmpty()) {
return Nothing<bool>();
}
return Just(true);
}
JSTransferable::Data::Data(std::string&& deserialize_info,
v8::Global<v8::Value>&& data)
: deserialize_info_(std::move(deserialize_info)),
data_(std::move(data)) {}
BaseObjectPtr<BaseObject> JSTransferable::Data::Deserialize(
Environment* env,
Local<Context> context,
std::unique_ptr<TransferData> self) {
// Create the JS wrapper object that will later be filled with data passed to
// the `[kDeserialize]()` method on it. This split is necessary, because here
// we need to create an object with the right prototype and internal fields,
// but the actual JS data stored in the serialized data can only be read at
// the end of the stream, after the main message has been read.
if (context != env->context()) {
THROW_ERR_MESSAGE_TARGET_CONTEXT_UNAVAILABLE(env);
return {};
}
HandleScope handle_scope(env->isolate());
Local<Value> info;
if (!ToV8Value(context, deserialize_info_).ToLocal(&info)) return {};
Local<Value> ret;
CHECK(!env->messaging_deserialize_create_object().IsEmpty());
if (!env->messaging_deserialize_create_object()->Call(
context, Null(env->isolate()), 1, &info).ToLocal(&ret) ||
!env->base_object_ctor_template()->HasInstance(ret)) {
return {};
}
return BaseObjectPtr<BaseObject> { Unwrap<BaseObject>(ret) };
}
Maybe<bool> JSTransferable::Data::FinalizeTransferWrite(
Local<Context> context, ValueSerializer* serializer) {
HandleScope handle_scope(context->GetIsolate());
auto ret = serializer->WriteValue(context, PersistentToLocal::Strong(data_));
data_.Reset();
return ret;
}
namespace {
static void SetDeserializerCreateObjectFunction(
const FunctionCallbackInfo<Value>& args) {
Environment* env = Environment::GetCurrent(args);
CHECK(args[0]->IsFunction());
env->set_messaging_deserialize_create_object(args[0].As<Function>());
}
static void MessageChannel(const FunctionCallbackInfo<Value>& args) {
Environment* env = Environment::GetCurrent(args);
if (!args.IsConstructCall()) {
THROW_ERR_CONSTRUCT_CALL_REQUIRED(env);
return;
}
Local<Context> context = args.This()->CreationContext();
Context::Scope context_scope(context);
MessagePort* port1 = MessagePort::New(env, context);
if (port1 == nullptr) return;
MessagePort* port2 = MessagePort::New(env, context);
if (port2 == nullptr) {
port1->Close();
return;
}
MessagePort::Entangle(port1, port2);
args.This()->Set(context, env->port1_string(), port1->object())
.Check();
args.This()->Set(context, env->port2_string(), port2->object())
.Check();
}
static void InitMessaging(Local<Object> target,
Local<Value> unused,
Local<Context> context,
void* priv) {
Environment* env = Environment::GetCurrent(context);
{
Local<String> message_channel_string =
FIXED_ONE_BYTE_STRING(env->isolate(), "MessageChannel");
Local<FunctionTemplate> templ = env->NewFunctionTemplate(MessageChannel);
templ->SetClassName(message_channel_string);
target->Set(context,
message_channel_string,
templ->GetFunction(context).ToLocalChecked()).Check();
}
{
Local<String> js_transferable_string =
FIXED_ONE_BYTE_STRING(env->isolate(), "JSTransferable");
Local<FunctionTemplate> t = env->NewFunctionTemplate(JSTransferable::New);
t->Inherit(BaseObject::GetConstructorTemplate(env));
t->SetClassName(js_transferable_string);
t->InstanceTemplate()->SetInternalFieldCount(
JSTransferable::kInternalFieldCount);
target->Set(context,
js_transferable_string,
t->GetFunction(context).ToLocalChecked()).Check();
}
target->Set(context,
env->message_port_constructor_string(),
GetMessagePortConstructorTemplate(env)
->GetFunction(context).ToLocalChecked()).Check();
// These are not methods on the MessagePort prototype, because
// the browser equivalents do not provide them.
env->SetMethod(target, "stopMessagePort", MessagePort::Stop);
env->SetMethod(target, "drainMessagePort", MessagePort::Drain);
env->SetMethod(target, "receiveMessageOnPort", MessagePort::ReceiveMessage);
env->SetMethod(target, "moveMessagePortToContext",
MessagePort::MoveToContext);
env->SetMethod(target, "setDeserializerCreateObjectFunction",
SetDeserializerCreateObjectFunction);
{
Local<Function> domexception = GetDOMException(context).ToLocalChecked();
target
->Set(context,
FIXED_ONE_BYTE_STRING(env->isolate(), "DOMException"),
domexception)
.Check();
}
}
} // anonymous namespace
} // namespace worker
} // namespace node
NODE_MODULE_CONTEXT_AWARE_INTERNAL(messaging, node::worker::InitMessaging)
|