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#include "base_object.h"
#include "env-inl.h"
#include "node_realm-inl.h"
namespace node {
using v8::FunctionCallbackInfo;
using v8::FunctionTemplate;
using v8::HandleScope;
using v8::Local;
using v8::Object;
using v8::Value;
using v8::WeakCallbackInfo;
using v8::WeakCallbackType;
BaseObject::BaseObject(Realm* realm, Local<Object> object)
: persistent_handle_(realm->isolate(), object), realm_(realm) {
CHECK_EQ(false, object.IsEmpty());
CHECK_GE(object->InternalFieldCount(), BaseObject::kInternalFieldCount);
SetInternalFields(object, static_cast<void*>(this));
realm->AddCleanupHook(DeleteMe, static_cast<void*>(this));
realm->modify_base_object_count(1);
}
BaseObject::~BaseObject() {
realm()->modify_base_object_count(-1);
realm()->RemoveCleanupHook(DeleteMe, static_cast<void*>(this));
if (UNLIKELY(has_pointer_data())) {
PointerData* metadata = pointer_data();
CHECK_EQ(metadata->strong_ptr_count, 0);
metadata->self = nullptr;
if (metadata->weak_ptr_count == 0) delete metadata;
}
if (persistent_handle_.IsEmpty()) {
// This most likely happened because the weak callback below cleared it.
return;
}
{
HandleScope handle_scope(realm()->isolate());
object()->SetAlignedPointerInInternalField(BaseObject::kSlot, nullptr);
}
}
void BaseObject::MakeWeak() {
if (has_pointer_data()) {
pointer_data()->wants_weak_jsobj = true;
if (pointer_data()->strong_ptr_count > 0) return;
}
persistent_handle_.SetWeak(
this,
[](const WeakCallbackInfo<BaseObject>& data) {
BaseObject* obj = data.GetParameter();
// Clear the persistent handle so that ~BaseObject() doesn't attempt
// to mess with internal fields, since the JS object may have
// transitioned into an invalid state.
// Refs: https://github.com/nodejs/node/issues/18897
obj->persistent_handle_.Reset();
CHECK_IMPLIES(obj->has_pointer_data(),
obj->pointer_data()->strong_ptr_count == 0);
obj->OnGCCollect();
},
WeakCallbackType::kParameter);
}
// This just has to be different from the Chromium ones:
// https://source.chromium.org/chromium/chromium/src/+/main:gin/public/gin_embedders.h;l=18-23;drc=5a758a97032f0b656c3c36a3497560762495501a
// Otherwise, when Node is loaded in an isolate which uses cppgc, cppgc will
// misinterpret the data stored in the embedder fields and try to garbage
// collect them.
uint16_t kNodeEmbedderId = 0x90de;
void BaseObject::LazilyInitializedJSTemplateConstructor(
const FunctionCallbackInfo<Value>& args) {
DCHECK(args.IsConstructCall());
CHECK_GE(args.This()->InternalFieldCount(), BaseObject::kInternalFieldCount);
SetInternalFields(args.This(), nullptr);
}
Local<FunctionTemplate> BaseObject::MakeLazilyInitializedJSTemplate(
Environment* env) {
return MakeLazilyInitializedJSTemplate(env->isolate_data());
}
Local<FunctionTemplate> BaseObject::MakeLazilyInitializedJSTemplate(
IsolateData* isolate_data) {
Local<FunctionTemplate> t = NewFunctionTemplate(
isolate_data->isolate(), LazilyInitializedJSTemplateConstructor);
t->InstanceTemplate()->SetInternalFieldCount(BaseObject::kInternalFieldCount);
return t;
}
BaseObject::PointerData* BaseObject::pointer_data() {
if (!has_pointer_data()) {
PointerData* metadata = new PointerData();
metadata->wants_weak_jsobj = persistent_handle_.IsWeak();
metadata->self = this;
pointer_data_ = metadata;
}
CHECK(has_pointer_data());
return pointer_data_;
}
void BaseObject::decrease_refcount() {
CHECK(has_pointer_data());
PointerData* metadata = pointer_data();
CHECK_GT(metadata->strong_ptr_count, 0);
unsigned int new_refcount = --metadata->strong_ptr_count;
if (new_refcount == 0) {
if (metadata->is_detached) {
OnGCCollect();
} else if (metadata->wants_weak_jsobj && !persistent_handle_.IsEmpty()) {
MakeWeak();
}
}
}
void BaseObject::increase_refcount() {
unsigned int prev_refcount = pointer_data()->strong_ptr_count++;
if (prev_refcount == 0 && !persistent_handle_.IsEmpty())
persistent_handle_.ClearWeak();
}
void BaseObject::DeleteMe(void* data) {
BaseObject* self = static_cast<BaseObject*>(data);
if (self->has_pointer_data() && self->pointer_data()->strong_ptr_count > 0) {
return self->Detach();
}
delete self;
}
bool BaseObject::IsDoneInitializing() const {
return true;
}
Local<Object> BaseObject::WrappedObject() const {
return object();
}
bool BaseObject::IsRootNode() const {
return !persistent_handle_.IsWeak();
}
bool BaseObject::IsNotIndicativeOfMemoryLeakAtExit() const {
return IsWeakOrDetached();
}
} // namespace node
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