#include <algorithm>

#include <climits> // INT_MAX

#include <cmath>

#define NAPI_EXPERIMENTAL

#include "env-inl.h"

#include "js_native_api.h"

#include "js_native_api_v8.h"

#include "util-inl.h"

#define CHECK_MAYBE_NOTHING(env, maybe, status) \

RETURN_STATUS_IF_FALSE((env), !((maybe).IsNothing()), (status))

#define CHECK_MAYBE_NOTHING_WITH_PREAMBLE(env, maybe, status) \

RETURN_STATUS_IF_FALSE_WITH_PREAMBLE((env), !((maybe).IsNothing()), (status))

#define CHECK_TO_NUMBER(env, context, result, src) \

CHECK_TO_TYPE((env), Number, (context), (result), (src), napi_number_expected)

// n-api defines NAPI_AUTO_LENGTH as the indicator that a string

// is null terminated. For V8 the equivalent is -1. The assert

// validates that our cast of NAPI_AUTO_LENGTH results in -1 as

// needed by V8.

#define CHECK_NEW_FROM_UTF8_LEN(env, result, str, len) \

do { \

static_assert(static_cast<int>(NAPI_AUTO_LENGTH) == -1, \

"Casting NAPI_AUTO_LENGTH to int must result in -1"); \

RETURN_STATUS_IF_FALSE( \

(env), (len == NAPI_AUTO_LENGTH) || len <= INT_MAX, napi_invalid_arg); \

RETURN_STATUS_IF_FALSE((env), (str) != nullptr, napi_invalid_arg); \

auto str_maybe = v8::String::NewFromUtf8((env)->isolate, \

(str), \

v8::NewStringType::kInternalized, \

static_cast<int>(len)); \

CHECK_MAYBE_EMPTY((env), str_maybe, napi_generic_failure); \

(result) = str_maybe.ToLocalChecked(); \

} while (0)

#define CHECK_NEW_FROM_UTF8(env, result, str) \

CHECK_NEW_FROM_UTF8_LEN((env), (result), (str), NAPI_AUTO_LENGTH)

#define CREATE_TYPED_ARRAY( \

env, type, size_of_element, buffer, byte_offset, length, out) \

do { \

if ((size_of_element) > 1) { \

THROW_RANGE_ERROR_IF_FALSE( \

(env), \

(byte_offset) % (size_of_element) == 0, \

"ERR_NAPI_INVALID_TYPEDARRAY_ALIGNMENT", \

"start offset of " #type \

" should be a multiple of " #size_of_element); \

} \

THROW_RANGE_ERROR_IF_FALSE( \

(env), \

(length) * (size_of_element) + (byte_offset) <= buffer->ByteLength(), \

"ERR_NAPI_INVALID_TYPEDARRAY_LENGTH", \

"Invalid typed array length"); \

(out) = v8::type::New((buffer), (byte_offset), (length)); \

} while (0)

void napi_env__::InvokeFinalizerFromGC(v8impl::RefTracker* finalizer) {

if (module_api_version != NAPI_VERSION_EXPERIMENTAL) {

EnqueueFinalizer(finalizer);

} else {

// The experimental code calls finalizers immediately to release native

// objects as soon as possible. In that state any code that may affect GC

// state causes a fatal error. To work around this issue the finalizer code

// can call node_api_post_finalizer.

auto restore_state = node::OnScopeLeave(

[this, saved = in_gc_finalizer] { in_gc_finalizer = saved; });

in_gc_finalizer = true;

finalizer->Finalize();

}

}

namespace v8impl {

namespace {

template <typename CCharType, typename StringMaker>

napi_status NewString(napi_env env,

const CCharType* str,

size_t length,

napi_value* result,

StringMaker string_maker) {

CHECK_ENV(env);

env->CheckGCAccess();

if (length > 0) CHECK_ARG(env, str);

CHECK_ARG(env, result);

RETURN_STATUS_IF_FALSE(

env, (length == NAPI_AUTO_LENGTH) || length <= INT_MAX, napi_invalid_arg);

auto isolate = env->isolate;

auto str_maybe = string_maker(isolate);

CHECK_MAYBE_EMPTY(env, str_maybe, napi_generic_failure);

*result = v8impl::JsValueFromV8LocalValue(str_maybe.ToLocalChecked());

return napi_clear_last_error(env);

}

template <typename CharType, typename CreateAPI, typename StringMaker>

napi_status NewExternalString(napi_env env,

CharType* str,

size_t length,

napi_finalize finalize_callback,

void* finalize_hint,

napi_value* result,

bool* copied,

CreateAPI create_api,

StringMaker string_maker) {

napi_status status;

#if defined(V8_ENABLE_SANDBOX)

env->CheckGCAccess();

status = create_api(env, str, length, result);

if (status == napi_ok) {

if (copied != nullptr) {

*copied = true;

}

if (finalize_callback) {

env->CallFinalizer(

finalize_callback, static_cast<CharType*>(str), finalize_hint);

}

}

#else

status = NewString(env, str, length, result, string_maker);

if (status == napi_ok && copied != nullptr) {

*copied = false;

}

#endif // V8_ENABLE_SANDBOX

return status;

}

class TrackedStringResource : public Finalizer, RefTracker {

public:

TrackedStringResource(napi_env env,

napi_finalize finalize_callback,

void* data,

void* finalize_hint)

: Finalizer(env, finalize_callback, data, finalize_hint) {

Link(finalize_callback == nullptr ? &env->reflist

: &env->finalizing_reflist);

}

protected:

// The only time Finalize() gets called before Dispose() is if the

// environment is dying. Finalize() expects that the item will be unlinked,

// so we do it here. V8 will still call Dispose() on us later, so we don't do

// any deleting here. We just null out env_ to avoid passing a stale pointer

// to the user's finalizer when V8 does finally call Dispose().

void Finalize() override {

Unlink();

env_ = nullptr;

}

~TrackedStringResource() {

if (finalize_callback_ == nullptr) return;

if (env_ == nullptr) {

// The environment is dead. Call the finalizer directly.

finalize_callback_(nullptr, finalize_data_, finalize_hint_);

} else {

// The environment is still alive. Let's remove ourselves from its list

// of references and call the user's finalizer.

Unlink();

env_->CallFinalizer(finalize_callback_, finalize_data_, finalize_hint_);

}

}

};

class ExternalOneByteStringResource

: public v8::String::ExternalOneByteStringResource,

TrackedStringResource {

public:

ExternalOneByteStringResource(napi_env env,

char* string,

const size_t length,

napi_finalize finalize_callback,

void* finalize_hint)

: TrackedStringResource(env, finalize_callback, string, finalize_hint),

string_(string),

length_(length) {}

const char* data() const override { return string_; }

size_t length() const override { return length_; }

private:

const char* string_;

const size_t length_;

};

class ExternalStringResource : public v8::String::ExternalStringResource,

TrackedStringResource {

public:

ExternalStringResource(napi_env env,

char16_t* string,

const size_t length,

napi_finalize finalize_callback,

void* finalize_hint)

: TrackedStringResource(env, finalize_callback, string, finalize_hint),

string_(reinterpret_cast<uint16_t*>(string)),

length_(length) {}

const uint16_t* data() const override { return string_; }

size_t length() const override { return length_; }

private:

const uint16_t* string_;

const size_t length_;

};

inline napi_status V8NameFromPropertyDescriptor(

napi_env env,

const napi_property_descriptor* p,

v8::Local<v8::Name>* result) {

if (p->utf8name != nullptr) {

CHECK_NEW_FROM_UTF8(env, *result, p->utf8name);

} else {

v8::Local<v8::Value> property_value =

v8impl::V8LocalValueFromJsValue(p->name);

RETURN_STATUS_IF_FALSE(env, property_value->IsName(), napi_name_expected);

*result = property_value.As<v8::Name>();

}

return napi_ok;

}

// convert from n-api property attributes to v8::PropertyAttribute

inline v8::PropertyAttribute V8PropertyAttributesFromDescriptor(

const napi_property_descriptor* descriptor) {

unsigned int attribute_flags = v8::PropertyAttribute::None;

// The napi_writable attribute is ignored for accessor descriptors, but

// V8 would throw `TypeError`s on assignment with nonexistence of a setter.

if ((descriptor->getter == nullptr && descriptor->setter == nullptr) &&

(descriptor->attributes & napi_writable) == 0) {

attribute_flags |= v8::PropertyAttribute::ReadOnly;

}

if ((descriptor->attributes & napi_enumerable) == 0) {

attribute_flags |= v8::PropertyAttribute::DontEnum;

}

if ((descriptor->attributes & napi_configurable) == 0) {

attribute_flags |= v8::PropertyAttribute::DontDelete;

}

return static_cast<v8::PropertyAttribute>(attribute_flags);

}

inline napi_deferred JsDeferredFromNodePersistent(

v8impl::Persistent<v8::Value>* local) {

return reinterpret_cast<napi_deferred>(local);

}

inline v8impl::Persistent<v8::Value>* NodePersistentFromJsDeferred(

napi_deferred local) {

return reinterpret_cast<v8impl::Persistent<v8::Value>*>(local);

}

class HandleScopeWrapper {

public:

explicit HandleScopeWrapper(v8::Isolate* isolate) : scope(isolate) {}

private:

v8::HandleScope scope;

};

// In node v0.10 version of v8, there is no EscapableHandleScope and the

// node v0.10 port use HandleScope::Close(Local<T> v) to mimic the behavior

// of a EscapableHandleScope::Escape(Local<T> v), but it is not the same

// semantics. This is an example of where the api abstraction fail to work

// across different versions.

class EscapableHandleScopeWrapper {

public:

explicit EscapableHandleScopeWrapper(v8::Isolate* isolate)

: scope(isolate), escape_called_(false) {}

bool escape_called() const { return escape_called_; }

template <typename T>

v8::Local<T> Escape(v8::Local<T> handle) {

escape_called_ = true;

return scope.Escape(handle);

}

private:

v8::EscapableHandleScope scope;

bool escape_called_;

};

inline napi_handle_scope JsHandleScopeFromV8HandleScope(HandleScopeWrapper* s) {

return reinterpret_cast<napi_handle_scope>(s);

}

inline HandleScopeWrapper* V8HandleScopeFromJsHandleScope(napi_handle_scope s) {

return reinterpret_cast<HandleScopeWrapper*>(s);

}

inline napi_escapable_handle_scope

JsEscapableHandleScopeFromV8EscapableHandleScope(

EscapableHandleScopeWrapper* s) {

return reinterpret_cast<napi_escapable_handle_scope>(s);

}

inline EscapableHandleScopeWrapper*

V8EscapableHandleScopeFromJsEscapableHandleScope(

napi_escapable_handle_scope s) {

return reinterpret_cast<EscapableHandleScopeWrapper*>(s);

}

inline napi_status ConcludeDeferred(napi_env env,

napi_deferred deferred,

napi_value result,

bool is_resolved) {

NAPI_PREAMBLE(env);

CHECK_ARG(env, result);

v8::Local<v8::Context> context = env->context();

v8impl::Persistent<v8::Value>* deferred_ref =

NodePersistentFromJsDeferred(deferred);

v8::Local<v8::Value> v8_deferred =

v8::Local<v8::Value>::New(env->isolate, *deferred_ref);

auto v8_resolver = v8_deferred.As<v8::Promise::Resolver>();

v8::Maybe<bool> success =

is_resolved ? v8_resolver->Resolve(

context, v8impl::V8LocalValueFromJsValue(result))

: v8_resolver->Reject(

context, v8impl::V8LocalValueFromJsValue(result));

delete deferred_ref;

RETURN_STATUS_IF_FALSE(env, success.FromMaybe(false), napi_generic_failure);

return GET_RETURN_STATUS(env);

}

enum UnwrapAction { KeepWrap, RemoveWrap };

inline napi_status Unwrap(napi_env env,

napi_value js_object,

void** result,

UnwrapAction action) {

NAPI_PREAMBLE(env);

CHECK_ARG(env, js_object);

if (action == KeepWrap) {

CHECK_ARG(env, result);

}

v8::Local<v8::Context> context = env->context();

v8::Local<v8::Value> value = v8impl::V8LocalValueFromJsValue(js_object);

RETURN_STATUS_IF_FALSE(env, value->IsObject(), napi_invalid_arg);

v8::Local<v8::Object> obj = value.As<v8::Object>();

auto val = obj->GetPrivate(context, NAPI_PRIVATE_KEY(context, wrapper))

.ToLocalChecked();

RETURN_STATUS_IF_FALSE(env, val->IsExternal(), napi_invalid_arg);

Reference* reference =

static_cast<v8impl::Reference*>(val.As<v8::External>()->Value());

if (result) {

*result = reference->Data();

}

if (action == RemoveWrap) {

CHECK(obj->DeletePrivate(context, NAPI_PRIVATE_KEY(context, wrapper))

.FromJust());

if (reference->ownership() == Ownership::kUserland) {

// When the wrap is been removed, the finalizer should be reset.

reference->ResetFinalizer();

} else {

delete reference;

}

}

return GET_RETURN_STATUS(env);

}

//=== Function napi_callback wrapper =================================

// Use this data structure to associate callback data with each N-API function

// exposed to JavaScript. The structure is stored in a v8::External which gets

// passed into our callback wrapper. This reduces the performance impact of

// calling through N-API.

// Ref: benchmark/misc/function_call

// Discussion (incl. perf. data): https://github.com/nodejs/node/pull/21072

class CallbackBundle {

public:

// Creates an object to be made available to the static function callback

// wrapper, used to retrieve the native callback function and data pointer.

static inline v8::Local<v8::Value> New(napi_env env,

napi_callback cb,

void* data) {

CallbackBundle* bundle = new CallbackBundle();

bundle->cb = cb;

bundle->cb_data = data;

bundle->env = env;

v8::Local<v8::Value> cbdata = v8::External::New(env->isolate, bundle);

Reference::New(

env, cbdata, 0, Ownership::kRuntime, Delete, bundle, nullptr);

return cbdata;

}

napi_env env; // Necessary to invoke C++ NAPI callback

void* cb_data; // The user provided callback data

napi_callback cb;

private:

static void Delete(napi_env env, void* data, void* hint) {

CallbackBundle* bundle = static_cast<CallbackBundle*>(data);

delete bundle;

}

};

// Base class extended by classes that wrap V8 function and property callback

// info.

class CallbackWrapper {

public:

inline CallbackWrapper(napi_value this_arg, size_t args_length, void* data)

: _this(this_arg), _args_length(args_length), _data(data) {}

virtual napi_value GetNewTarget() = 0;

virtual void Args(napi_value* buffer, size_t bufferlength) = 0;

virtual void SetReturnValue(napi_value value) = 0;

napi_value This() { return _this; }

size_t ArgsLength() { return _args_length; }

void* Data() { return _data; }

protected:

const napi_value _this;

const size_t _args_length;

void* _data;

};

class CallbackWrapperBase : public CallbackWrapper {

public:

inline CallbackWrapperBase(const v8::FunctionCallbackInfo<v8::Value>& cbinfo,

const size_t args_length)

: CallbackWrapper(

JsValueFromV8LocalValue(cbinfo.This()), args_length, nullptr),

_cbinfo(cbinfo) {

_bundle = reinterpret_cast<CallbackBundle*>(

cbinfo.Data().As<v8::External>()->Value());

_data = _bundle->cb_data;

}

protected:

inline void InvokeCallback() {

napi_callback_info cbinfo_wrapper = reinterpret_cast<napi_callback_info>(

static_cast<CallbackWrapper*>(this));

// All other pointers we need are stored in `_bundle`

napi_env env = _bundle->env;

napi_callback cb = _bundle->cb;

napi_value result = nullptr;

bool exceptionOccurred = false;

env->CallIntoModule([&](napi_env env) { result = cb(env, cbinfo_wrapper); },

[&](napi_env env, v8::Local<v8::Value> value) {

exceptionOccurred = true;

if (env->terminatedOrTerminating()) {

return;

}

env->isolate->ThrowException(value);

});

if (!exceptionOccurred && (result != nullptr)) {

this->SetReturnValue(result);

}

}

const v8::FunctionCallbackInfo<v8::Value>& _cbinfo;

CallbackBundle* _bundle;

};

class FunctionCallbackWrapper : public CallbackWrapperBase {

public:

static void Invoke(const v8::FunctionCallbackInfo<v8::Value>& info) {

FunctionCallbackWrapper cbwrapper(info);

cbwrapper.InvokeCallback();

}

static inline napi_status NewFunction(napi_env env,

napi_callback cb,

void* cb_data,

v8::Local<v8::Function>* result) {

v8::Local<v8::Value> cbdata = v8impl::CallbackBundle::New(env, cb, cb_data);

RETURN_STATUS_IF_FALSE(env, !cbdata.IsEmpty(), napi_generic_failure);

v8::MaybeLocal<v8::Function> maybe_function =

v8::Function::New(env->context(), Invoke, cbdata);

CHECK_MAYBE_EMPTY(env, maybe_function, napi_generic_failure);

*result = maybe_function.ToLocalChecked();

return napi_clear_last_error(env);

}

static inline napi_status NewTemplate(

napi_env env,

napi_callback cb,

void* cb_data,

v8::Local<v8::FunctionTemplate>* result,

v8::Local<v8::Signature> sig = v8::Local<v8::Signature>()) {

v8::Local<v8::Value> cbdata = v8impl::CallbackBundle::New(env, cb, cb_data);

RETURN_STATUS_IF_FALSE(env, !cbdata.IsEmpty(), napi_generic_failure);

*result = v8::FunctionTemplate::New(env->isolate, Invoke, cbdata, sig);

return napi_clear_last_error(env);

}

explicit FunctionCallbackWrapper(

const v8::FunctionCallbackInfo<v8::Value>& cbinfo)

: CallbackWrapperBase(cbinfo, cbinfo.Length()) {}

napi_value GetNewTarget() override {

if (_cbinfo.IsConstructCall()) {

return v8impl::JsValueFromV8LocalValue(_cbinfo.NewTarget());

} else {

return nullptr;

}

}

/*virtual*/

void Args(napi_value* buffer, size_t buffer_length) override {

size_t i = 0;

size_t min = std::min(buffer_length, _args_length);

for (; i < min; i += 1) {

buffer[i] = v8impl::JsValueFromV8LocalValue(_cbinfo[i]);

}

if (i < buffer_length) {

napi_value undefined =

v8impl::JsValueFromV8LocalValue(v8::Undefined(_cbinfo.GetIsolate()));

for (; i < buffer_length; i += 1) {

buffer[i] = undefined;

}

}

}

/*virtual*/

void SetReturnValue(napi_value value) override {

v8::Local<v8::Value> val = v8impl::V8LocalValueFromJsValue(value);

_cbinfo.GetReturnValue().Set(val);

}

};

inline napi_status Wrap(napi_env env,

napi_value js_object,

void* native_object,

napi_finalize finalize_cb,

void* finalize_hint,

napi_ref* result) {

NAPI_PREAMBLE(env);

CHECK_ARG(env, js_object);

v8::Local<v8::Context> context = env->context();

v8::Local<v8::Value> value = v8impl::V8LocalValueFromJsValue(js_object);

RETURN_STATUS_IF_FALSE(env, value->IsObject(), napi_invalid_arg);

v8::Local<v8::Object> obj = value.As<v8::Object>();

// If we've already wrapped this object, we error out.

RETURN_STATUS_IF_FALSE(

env,

!obj->HasPrivate(context, NAPI_PRIVATE_KEY(context, wrapper)).FromJust(),

napi_invalid_arg);

v8impl::Reference* reference = nullptr;

if (result != nullptr) {

// The returned reference should be deleted via napi_delete_reference()

// ONLY in response to the finalize callback invocation. (If it is deleted

// before then, then the finalize callback will never be invoked.)

// Therefore a finalize callback is required when returning a reference.

CHECK_ARG(env, finalize_cb);

reference = v8impl::Reference::New(env,

obj,

0,

v8impl::Ownership::kUserland,

finalize_cb,

native_object,

finalize_hint);

*result = reinterpret_cast<napi_ref>(reference);

} else {

// Create a self-deleting reference.

reference = v8impl::Reference::New(

env,

obj,

0,

v8impl::Ownership::kRuntime,

finalize_cb,

native_object,

finalize_cb == nullptr ? nullptr : finalize_hint);

}

CHECK(obj->SetPrivate(context,

NAPI_PRIVATE_KEY(context, wrapper),

v8::External::New(env->isolate, reference))

.FromJust());

return GET_RETURN_STATUS(env);

}

// In JavaScript, weak references can be created for object types (Object,

// Function, and external Object) and for local symbols that are created with

// the `Symbol` function call. Global symbols created with the `Symbol.for`

// method cannot be weak references because they are never collected.

//

// Currently, V8 has no API to detect if a symbol is local or global.

// Until we have a V8 API for it, we consider that all symbols can be weak.

// This matches the current Node-API behavior.

inline bool CanBeHeldWeakly(v8::Local<v8::Value> value) {

return value->IsObject() || value->IsSymbol();

}

} // end of anonymous namespace

void Finalizer::ResetFinalizer() {

finalize_callback_ = nullptr;

finalize_data_ = nullptr;

finalize_hint_ = nullptr;

}

TrackedFinalizer::TrackedFinalizer(napi_env env,

napi_finalize finalize_callback,

void* finalize_data,

void* finalize_hint)

: Finalizer(env, finalize_callback, finalize_data, finalize_hint),

RefTracker() {

Link(finalize_callback == nullptr ? &env->reflist : &env->finalizing_reflist);

}

TrackedFinalizer* TrackedFinalizer::New(napi_env env,

napi_finalize finalize_callback,

void* finalize_data,

void* finalize_hint) {

return new TrackedFinalizer(

env, finalize_callback, finalize_data, finalize_hint);

}

// When a TrackedFinalizer is being deleted, it may have been queued to call its

// finalizer.

TrackedFinalizer::~TrackedFinalizer() {

// Remove from the env's tracked list.

Unlink();

// Try to remove the finalizer from the scheduled second pass callback.

env_->DequeueFinalizer(this);

}

void TrackedFinalizer::Finalize() {

FinalizeCore(/*deleteMe:*/ true);

}

void TrackedFinalizer::FinalizeCore(bool deleteMe) {

// Swap out the field finalize_callback so that it can not be accidentally

// called more than once.

napi_finalize finalize_callback = finalize_callback_;

void* finalize_data = finalize_data_;

void* finalize_hint = finalize_hint_;

ResetFinalizer();

// Either the RefBase is going to be deleted in the finalize_callback or not,

// it should be removed from the tracked list.

Unlink();

// If the finalize_callback is present, it should either delete the

// derived RefBase, or the RefBase ownership was set to Ownership::kRuntime

// and the deleteMe parameter is true.

if (finalize_callback != nullptr) {

env_->CallFinalizer(finalize_callback, finalize_data, finalize_hint);

}

if (deleteMe) {

delete this;

}

}

// Wrapper around v8impl::Persistent that implements reference counting.

RefBase::RefBase(napi_env env,

uint32_t initial_refcount,

Ownership ownership,

napi_finalize finalize_callback,

void* finalize_data,

void* finalize_hint)

: TrackedFinalizer(env, finalize_callback, finalize_data, finalize_hint),

refcount_(initial_refcount),

ownership_(ownership) {}

RefBase* RefBase::New(napi_env env,

uint32_t initial_refcount,

Ownership ownership,

napi_finalize finalize_callback,

void* finalize_data,

void* finalize_hint) {

return new RefBase(env,

initial_refcount,

ownership,

finalize_callback,

finalize_data,

finalize_hint);

}

void* RefBase::Data() {

return finalize_data_;

}

uint32_t RefBase::Ref() {

return ++refcount_;

}

uint32_t RefBase::Unref() {

if (refcount_ == 0) {

return 0;

}

return --refcount_;

}

uint32_t RefBase::RefCount() {

return refcount_;

}

void RefBase::Finalize() {

// If the RefBase is not Ownership::kRuntime, userland code should delete it.

// Delete it if it is Ownership::kRuntime.

FinalizeCore(/*deleteMe:*/ ownership_ == Ownership::kRuntime);

}

template <typename... Args>

Reference::Reference(napi_env env, v8::Local<v8::Value> value, Args&&... args)

: RefBase(env, std::forward<Args>(args)...),

persistent_(env->isolate, value),

can_be_weak_(CanBeHeldWeakly(value)) {

if (RefCount() == 0) {

SetWeak();

}

}

Reference::~Reference() {

// Reset the handle. And no weak callback will be invoked.

persistent_.Reset();

}

Reference* Reference::New(napi_env env,

v8::Local<v8::Value> value,

uint32_t initial_refcount,

Ownership ownership,

napi_finalize finalize_callback,

void* finalize_data,

void* finalize_hint) {

return new Reference(env,

value,

initial_refcount,

ownership,

finalize_callback,

finalize_data,

finalize_hint);

}

uint32_t Reference::Ref() {

// When the persistent_ is cleared in the WeakCallback, and a second pass

// callback is pending, return 0 unconditionally.

if (persistent_.IsEmpty()) {

return 0;

}

uint32_t refcount = RefBase::Ref();

if (refcount == 1 && can_be_weak_) {

persistent_.ClearWeak();

}

return refcount;

}

uint32_t Reference::Unref() {

// When the persistent_ is cleared in the WeakCallback, and a second pass

// callback is pending, return 0 unconditionally.

if (persistent_.IsEmpty()) {

return 0;

}

uint32_t old_refcount = RefCount();

uint32_t refcount = RefBase::Unref();

if (old_refcount == 1 && refcount == 0) {

SetWeak();

}

return refcount;

}

v8::Local<v8::Value> Reference::Get() {

if (persistent_.IsEmpty()) {

return v8::Local<v8::Value>();

} else {

return v8::Local<v8::Value>::New(env_->isolate, persistent_);

}

}

void Reference::Finalize() {

// Unconditionally reset the persistent handle so that no weak callback will

// be invoked again.

persistent_.Reset();

// Chain up to perform the rest of the finalization.

RefBase::Finalize();

}

// Mark the reference as weak and eligible for collection

// by the gc.

void Reference::SetWeak() {

if (can_be_weak_) {

persistent_.SetWeak(this, WeakCallback, v8::WeakCallbackType::kParameter);

} else {

persistent_.Reset();

}

}

// The N-API finalizer callback may make calls into the engine. V8's heap is

// not in a consistent state during the weak callback, and therefore it does

// not support calls back into it. Enqueue the invocation of the finalizer.

void Reference::WeakCallback(const v8::WeakCallbackInfo<Reference>& data) {

Reference* reference = data.GetParameter();

// The reference must be reset during the weak callback as the API protocol.

reference->persistent_.Reset();

reference->env_->InvokeFinalizerFromGC(reference);

}

} // end of namespace v8impl

// Warning: Keep in-sync with napi_status enum

static const char* error_messages[] = {

nullptr,

"Invalid argument",

"An object was expected",

"A string was expected",

"A string or symbol was expected",

"A function was expected",

"A number was expected",

"A boolean was expected",

"An array was expected",

"Unknown failure",

"An exception is pending",

"The async work item was cancelled",

"napi_escape_handle already called on scope",

"Invalid handle scope usage",

"Invalid callback scope usage",

"Thread-safe function queue is full",

"Thread-safe function handle is closing",

"A bigint was expected",

"A date was expected",

"An arraybuffer was expected",

"A detachable arraybuffer was expected",

"Main thread would deadlock",

"External buffers are not allowed",

"Cannot run JavaScript",

};

napi_status NAPI_CDECL napi_get_last_error_info(

napi_env env, const napi_extended_error_info** result) {

CHECK_ENV(env);

CHECK_ARG(env, result);

// The value of the constant below must be updated to reference the last

// message in the `napi_status` enum each time a new error message is added.

// We don't have a napi_status_last as this would result in an ABI

// change each time a message was added.

const int last_status = napi_cannot_run_js;

static_assert(NAPI_ARRAYSIZE(error_messages) == last_status + 1,

"Count of error messages must match count of error values");

CHECK_LE(env->last_error.error_code, last_status);

// Wait until someone requests the last error information to fetch the error

// message string

env->last_error.error_message = error_messages[env->last_error.error_code];

if (env->last_error.error_code == napi_ok) {

napi_clear_last_error(env);

}

*result = &(env->last_error);

return napi_ok;

}

napi_status NAPI_CDECL napi_create_function(napi_env env,

const char* utf8name,

size_t length,

napi_callback cb,

void* callback_data,

napi_value* result) {

NAPI_PREAMBLE(env);

CHECK_ARG(env, result);

CHECK_ARG(env, cb);

v8::Local<v8::Function> return_value;

v8::EscapableHandleScope scope(env->isolate);

v8::Local<v8::Function> fn;

STATUS_CALL(v8impl::FunctionCallbackWrapper::NewFunction(

env, cb, callback_data, &fn));

return_value = scope.Escape(fn);

if (utf8name != nullptr) {

v8::Local<v8::String> name_string;

CHECK_NEW_FROM_UTF8_LEN(env, name_string, utf8name, length);

return_value->SetName(name_string);

}

*result = v8impl::JsValueFromV8LocalValue(return_value);

return GET_RETURN_STATUS(env);

}

napi_status NAPI_CDECL

napi_define_class(napi_env env,

const char* utf8name,

size_t length,

napi_callback constructor,

void* callback_data,

size_t property_count,

const napi_property_descriptor* properties,

napi_value* result) {

NAPI_PREAMBLE(env);

CHECK_ARG(env, result);

CHECK_ARG(env, constructor);

if (property_count > 0) {

CHECK_ARG(env, properties);

}

v8::Isolate* isolate = env->isolate;

v8::EscapableHandleScope scope(isolate);

v8::Local<v8::FunctionTemplate> tpl;

STATUS_CALL(v8impl::FunctionCallbackWrapper::NewTemplate(

env, constructor, callback_data, &tpl));

v8::Local<v8::String> name_string;

CHECK_NEW_FROM_UTF8_LEN(env, name_string, utf8name, length);

tpl->SetClassName(name_string);

size_t static_property_count = 0;

for (size_t i = 0; i < property_count; i++) {

const napi_property_descriptor* p = properties + i;

if ((p->attributes & napi_static) != 0) {

// Static properties are handled separately below.

static_property_count++;

continue;

}

v8::Local<v8::Name> property_name;

STATUS_CALL(v8impl::V8NameFromPropertyDescriptor(env, p, &property_name));

v8::PropertyAttribute attributes =

v8impl::V8PropertyAttributesFromDescriptor(p);

// This code is similar to that in napi_define_properties(); the

// difference is it applies to a template instead of an object,

// and preferred PropertyAttribute for lack of PropertyDescriptor

// support on ObjectTemplate.

if (p->getter != nullptr || p->setter != nullptr) {

v8::Local<v8::FunctionTemplate> getter_tpl;

v8::Local<v8::FunctionTemplate> setter_tpl;

if (p->getter != nullptr) {

STATUS_CALL(v8impl::FunctionCallbackWrapper::NewTemplate(

env, p->getter, p->data, &getter_tpl));

}

if (p->setter != nullptr) {

STATUS_CALL(v8impl::FunctionCallbackWrapper::NewTemplate(

env, p->setter, p->data, &setter_tpl));

}

tpl->PrototypeTemplate()->SetAccessorProperty(property_name,

getter_tpl,

setter_tpl,

attributes,

v8::AccessControl::DEFAULT);

} else if (p->method != nullptr) {

v8::Local<v8::FunctionTemplate> t;

STATUS_CALL(v8impl::FunctionCallbackWrapper::NewTemplate(

env, p->method, p->data, &t, v8::Signature::New(isolate, tpl)));

tpl->PrototypeTemplate()->Set(property_name, t, attributes);

} else {

v8::Local<v8::Value> value = v8impl::V8LocalValueFromJsValue(p->value);

tpl->PrototypeTemplate()->Set(property_name, value, attributes);

}

}

v8::Local<v8::Context> context = env->context();

*result = v8impl::JsValueFromV8LocalValue(

scope.Escape(tpl->GetFunction(context).ToLocalChecked()));

if (static_property_count > 0) {

std::vector<napi_property_descriptor> static_descriptors;

static_descriptors.reserve(static_property_count);

for (size_t i = 0; i < property_count; i++) {

const napi_property_descriptor* p = properties + i;

if ((p->attributes & napi_static) != 0) {

static_descriptors.push_back(*p);

}

}

STATUS_CALL(napi_define_properties(

env, *result, static_descriptors.size(), static_descriptors.data()));

}

return GET_RETURN_STATUS(env);