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n-api: clean up binding creation
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* Remove dead code for `GetterCallbackWrapper` and
  `SetterCallbackWrapper`.
* Factor out creation of new `v8::Function`s.
* Factor out creation of new `v8::FunctionTemplate`s.
* Turn `CallbackBundle` into a class, internalizing creation of new
  instances and garbage collection.

Signed-off-by: Gabriel Schulhof <[email protected]>
PR-URL: #36170
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Gabriel Schulhof committed Nov 19, 2020
1 parent 2fd2235 commit 26ee991
Showing 1 changed file with 80 additions and 183 deletions.
263 changes: 80 additions & 183 deletions src/js_native_api_v8.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -419,18 +419,36 @@ inline static napi_status Unwrap(napi_env env,
// calling through N-API.
// Ref: benchmark/misc/function_call
// Discussion (incl. perf. data): https://github.com/nodejs/node/pull/21072
struct CallbackBundle {
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, true, Delete, bundle, nullptr);
return cbdata;
}
napi_env env; // Necessary to invoke C++ NAPI callback
void* cb_data; // The user provided callback data
napi_callback function_or_getter;
napi_callback setter;
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:
CallbackWrapper(napi_value this_arg, size_t args_length, void* data)
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;
Expand All @@ -449,10 +467,10 @@ class CallbackWrapper {
void* _data;
};

template <typename Info, napi_callback CallbackBundle::*FunctionField>
class CallbackWrapperBase : public CallbackWrapper {
public:
CallbackWrapperBase(const Info& cbinfo, const size_t args_length)
inline CallbackWrapperBase(const v8::FunctionCallbackInfo<v8::Value>& cbinfo,
const size_t args_length)
: CallbackWrapper(JsValueFromV8LocalValue(cbinfo.This()),
args_length,
nullptr),
Expand All @@ -462,16 +480,14 @@ class CallbackWrapperBase : public CallbackWrapper {
_data = _bundle->cb_data;
}

napi_value GetNewTarget() override { return nullptr; }

protected:
void InvokeCallback() {
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->*FunctionField;
napi_callback cb = _bundle->cb;

napi_value result;
env->CallIntoModule([&](napi_env env) {
Expand All @@ -483,19 +499,45 @@ class CallbackWrapperBase : public CallbackWrapper {
}
}

const Info& _cbinfo;
const v8::FunctionCallbackInfo<v8::Value>& _cbinfo;
CallbackBundle* _bundle;
};

class FunctionCallbackWrapper
: public CallbackWrapperBase<v8::FunctionCallbackInfo<v8::Value>,
&CallbackBundle::function_or_getter> {
: 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()) {}
Expand Down Expand Up @@ -533,98 +575,6 @@ class FunctionCallbackWrapper
}
};

class GetterCallbackWrapper
: public CallbackWrapperBase<v8::PropertyCallbackInfo<v8::Value>,
&CallbackBundle::function_or_getter> {
public:
static void Invoke(v8::Local<v8::Name> property,
const v8::PropertyCallbackInfo<v8::Value>& info) {
GetterCallbackWrapper cbwrapper(info);
cbwrapper.InvokeCallback();
}

explicit GetterCallbackWrapper(
const v8::PropertyCallbackInfo<v8::Value>& cbinfo)
: CallbackWrapperBase(cbinfo, 0) {}

/*virtual*/
void Args(napi_value* buffer, size_t buffer_length) override {
if (buffer_length > 0) {
napi_value undefined =
v8impl::JsValueFromV8LocalValue(v8::Undefined(_cbinfo.GetIsolate()));
for (size_t i = 0; 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);
}
};

class SetterCallbackWrapper
: public CallbackWrapperBase<v8::PropertyCallbackInfo<void>,
&CallbackBundle::setter> {
public:
static void Invoke(v8::Local<v8::Name> property,
v8::Local<v8::Value> value,
const v8::PropertyCallbackInfo<void>& info) {
SetterCallbackWrapper cbwrapper(info, value);
cbwrapper.InvokeCallback();
}

SetterCallbackWrapper(const v8::PropertyCallbackInfo<void>& cbinfo,
const v8::Local<v8::Value>& value)
: CallbackWrapperBase(cbinfo, 1), _value(value) {}

/*virtual*/
void Args(napi_value* buffer, size_t buffer_length) override {
if (buffer_length > 0) {
buffer[0] = v8impl::JsValueFromV8LocalValue(_value);

if (buffer_length > 1) {
napi_value undefined = v8impl::JsValueFromV8LocalValue(
v8::Undefined(_cbinfo.GetIsolate()));
for (size_t i = 1; i < buffer_length; i += 1) {
buffer[i] = undefined;
}
}
}
}

/*virtual*/
void SetReturnValue(napi_value value) override {
// Ignore any value returned from a setter callback.
}

private:
const v8::Local<v8::Value>& _value;
};

static void DeleteCallbackBundle(napi_env env, void* data, void* hint) {
CallbackBundle* bundle = static_cast<CallbackBundle*>(data);
delete bundle;
}

// Creates an object to be made available to the static function callback
// wrapper, used to retrieve the native callback function and data pointer.
static
v8::Local<v8::Value> CreateFunctionCallbackData(napi_env env,
napi_callback cb,
void* data) {
CallbackBundle* bundle = new CallbackBundle();
bundle->function_or_getter = cb;
bundle->cb_data = data;
bundle->env = env;
v8::Local<v8::Value> cbdata = v8::External::New(env->isolate, bundle);
Reference::New(env, cbdata, 0, true, DeleteCallbackBundle, bundle, nullptr);

return cbdata;
}

enum WrapType {
retrievable,
anonymous
Expand Down Expand Up @@ -746,22 +696,12 @@ napi_status napi_create_function(napi_env env,
CHECK_ARG(env, result);
CHECK_ARG(env, cb);

v8::Isolate* isolate = env->isolate;
v8::Local<v8::Function> return_value;
v8::EscapableHandleScope scope(isolate);
v8::Local<v8::Value> cbdata =
v8impl::CreateFunctionCallbackData(env, cb, callback_data);

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

v8::Local<v8::Context> context = env->context();
v8::MaybeLocal<v8::Function> maybe_function =
v8::Function::New(context,
v8impl::FunctionCallbackWrapper::Invoke,
cbdata);
CHECK_MAYBE_EMPTY(env, maybe_function, napi_generic_failure);

return_value = scope.Escape(maybe_function.ToLocalChecked());
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;
Expand Down Expand Up @@ -793,13 +733,9 @@ napi_status napi_define_class(napi_env env,
v8::Isolate* isolate = env->isolate;

v8::EscapableHandleScope scope(isolate);
v8::Local<v8::Value> cbdata =
v8impl::CreateFunctionCallbackData(env, constructor, callback_data);

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

v8::Local<v8::FunctionTemplate> tpl = v8::FunctionTemplate::New(
isolate, v8impl::FunctionCallbackWrapper::Invoke, cbdata);
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);
Expand Down Expand Up @@ -829,18 +765,12 @@ napi_status napi_define_class(napi_env env,
v8::Local<v8::FunctionTemplate> getter_tpl;
v8::Local<v8::FunctionTemplate> setter_tpl;
if (p->getter != nullptr) {
v8::Local<v8::Value> getter_data =
v8impl::CreateFunctionCallbackData(env, p->getter, p->data);

getter_tpl = v8::FunctionTemplate::New(
isolate, v8impl::FunctionCallbackWrapper::Invoke, getter_data);
STATUS_CALL(v8impl::FunctionCallbackWrapper::NewTemplate(
env, p->getter, p->data, &getter_tpl));
}
if (p->setter != nullptr) {
v8::Local<v8::Value> setter_data =
v8impl::CreateFunctionCallbackData(env, p->setter, p->data);

setter_tpl = v8::FunctionTemplate::New(
isolate, v8impl::FunctionCallbackWrapper::Invoke, setter_data);
STATUS_CALL(v8impl::FunctionCallbackWrapper::NewTemplate(
env, p->setter, p->data, &setter_tpl));
}

tpl->PrototypeTemplate()->SetAccessorProperty(
Expand All @@ -850,16 +780,9 @@ napi_status napi_define_class(napi_env env,
attributes,
v8::AccessControl::DEFAULT);
} else if (p->method != nullptr) {
v8::Local<v8::Value> cbdata =
v8impl::CreateFunctionCallbackData(env, p->method, p->data);

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

v8::Local<v8::FunctionTemplate> t =
v8::FunctionTemplate::New(isolate,
v8impl::FunctionCallbackWrapper::Invoke,
cbdata,
v8::Signature::New(isolate, tpl));
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 {
Expand Down Expand Up @@ -1264,33 +1187,16 @@ napi_status napi_define_properties(napi_env env,
STATUS_CALL(v8impl::V8NameFromPropertyDescriptor(env, p, &property_name));

if (p->getter != nullptr || p->setter != nullptr) {
v8::Local<v8::Value> local_getter;
v8::Local<v8::Value> local_setter;
v8::Local<v8::Function> local_getter;
v8::Local<v8::Function> local_setter;

if (p->getter != nullptr) {
v8::Local<v8::Value> getter_data =
v8impl::CreateFunctionCallbackData(env, p->getter, p->data);
CHECK_MAYBE_EMPTY(env, getter_data, napi_generic_failure);

v8::MaybeLocal<v8::Function> maybe_getter =
v8::Function::New(context,
v8impl::FunctionCallbackWrapper::Invoke,
getter_data);
CHECK_MAYBE_EMPTY(env, maybe_getter, napi_generic_failure);

local_getter = maybe_getter.ToLocalChecked();
STATUS_CALL(v8impl::FunctionCallbackWrapper::NewFunction(
env, p->getter, p->data, &local_getter));
}
if (p->setter != nullptr) {
v8::Local<v8::Value> setter_data =
v8impl::CreateFunctionCallbackData(env, p->setter, p->data);
CHECK_MAYBE_EMPTY(env, setter_data, napi_generic_failure);

v8::MaybeLocal<v8::Function> maybe_setter =
v8::Function::New(context,
v8impl::FunctionCallbackWrapper::Invoke,
setter_data);
CHECK_MAYBE_EMPTY(env, maybe_setter, napi_generic_failure);
local_setter = maybe_setter.ToLocalChecked();
STATUS_CALL(v8impl::FunctionCallbackWrapper::NewFunction(
env, p->setter, p->data, &local_setter));
}

v8::PropertyDescriptor descriptor(local_getter, local_setter);
Expand All @@ -1305,19 +1211,10 @@ napi_status napi_define_properties(napi_env env,
return napi_set_last_error(env, napi_invalid_arg);
}
} else if (p->method != nullptr) {
v8::Local<v8::Value> cbdata =
v8impl::CreateFunctionCallbackData(env, p->method, p->data);

CHECK_MAYBE_EMPTY(env, cbdata, napi_generic_failure);

v8::MaybeLocal<v8::Function> maybe_fn =
v8::Function::New(context,
v8impl::FunctionCallbackWrapper::Invoke,
cbdata);

CHECK_MAYBE_EMPTY(env, maybe_fn, napi_generic_failure);

v8::PropertyDescriptor descriptor(maybe_fn.ToLocalChecked(),
v8::Local<v8::Function> method;
STATUS_CALL(v8impl::FunctionCallbackWrapper::NewFunction(
env, p->method, p->data, &method));
v8::PropertyDescriptor descriptor(method,
(p->attributes & napi_writable) != 0);
descriptor.set_enumerable((p->attributes & napi_enumerable) != 0);
descriptor.set_configurable((p->attributes & napi_configurable) != 0);
Expand Down

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