node/src/async-wrap.cc

#include "async-wrap.h"
#include "async-wrap-inl.h"
#include "env.h"
#include "env-inl.h"
#include "util.h"
#include "util-inl.h"

#include "uv.h"
#include "v8.h"
#include "v8-profiler.h"

using v8::Boolean;
using v8::Context;
using v8::Function;
using v8::FunctionCallbackInfo;
using v8::HandleScope;
using v8::HeapProfiler;
using v8::Int32;
using v8::Integer;
using v8::Isolate;
using v8::Local;
using v8::MaybeLocal;
using v8::Number;
using v8::Object;
using v8::RetainedObjectInfo;
using v8::TryCatch;
using v8::Value;

namespace node {

static const char* const provider_names[] = {
#define V(PROVIDER)                                                           \
  #PROVIDER,
  NODE_ASYNC_PROVIDER_TYPES(V)
#undef V
};


class RetainedAsyncInfo: public RetainedObjectInfo {
 public:
  explicit RetainedAsyncInfo(uint16_t class_id, AsyncWrap* wrap);

  void Dispose() override;
  bool IsEquivalent(RetainedObjectInfo* other) override;
  intptr_t GetHash() override;
  const char* GetLabel() override;
  intptr_t GetSizeInBytes() override;

 private:
  const char* label_;
  const AsyncWrap* wrap_;
  const int length_;
};


RetainedAsyncInfo::RetainedAsyncInfo(uint16_t class_id, AsyncWrap* wrap)
    : label_(provider_names[class_id - NODE_ASYNC_ID_OFFSET]),
      wrap_(wrap),
      length_(wrap->self_size()) {
}


void RetainedAsyncInfo::Dispose() {
  delete this;
}


bool RetainedAsyncInfo::IsEquivalent(RetainedObjectInfo* other) {
  return label_ == other->GetLabel() &&
          wrap_ == static_cast<RetainedAsyncInfo*>(other)->wrap_;
}


intptr_t RetainedAsyncInfo::GetHash() {
  return reinterpret_cast<intptr_t>(wrap_);
}


const char* RetainedAsyncInfo::GetLabel() {
  return label_;
}


intptr_t RetainedAsyncInfo::GetSizeInBytes() {
  return length_;
}


RetainedObjectInfo* WrapperInfo(uint16_t class_id, Local<Value> wrapper) {
  // No class_id should be the provider type of NONE.
  CHECK_NE(NODE_ASYNC_ID_OFFSET, class_id);
  CHECK(wrapper->IsObject());
  CHECK(!wrapper.IsEmpty());

  Local<Object> object = wrapper.As<Object>();
  CHECK_GT(object->InternalFieldCount(), 0);

  AsyncWrap* wrap = Unwrap<AsyncWrap>(object);
  CHECK_NE(nullptr, wrap);

  return new RetainedAsyncInfo(class_id, wrap);
}


// end RetainedAsyncInfo


static void EnableHooksJS(const FunctionCallbackInfo<Value>& args) {
  Environment* env = Environment::GetCurrent(args);
  Local<Function> init_fn = env->async_hooks_init_function();
  if (init_fn.IsEmpty() || !init_fn->IsFunction())
    return env->ThrowTypeError("init callback is not assigned to a function");
  env->async_hooks()->set_enable_callbacks(1);
}


static void DisableHooksJS(const FunctionCallbackInfo<Value>& args) {
  Environment* env = Environment::GetCurrent(args);
  env->async_hooks()->set_enable_callbacks(0);
}


static void SetupHooks(const FunctionCallbackInfo<Value>& args) {
  Environment* env = Environment::GetCurrent(args);

  if (env->async_hooks()->callbacks_enabled())
    return env->ThrowError("hooks should not be set while also enabled");
  if (!args[0]->IsObject())
    return env->ThrowTypeError("first argument must be an object");

  Local<Object> fn_obj = args[0].As<Object>();

  Local<Value> init_v = fn_obj->Get(
      env->context(),
      FIXED_ONE_BYTE_STRING(env->isolate(), "init")).ToLocalChecked();
  Local<Value> pre_v = fn_obj->Get(
      env->context(),
      FIXED_ONE_BYTE_STRING(env->isolate(), "pre")).ToLocalChecked();
  Local<Value> post_v = fn_obj->Get(
      env->context(),
      FIXED_ONE_BYTE_STRING(env->isolate(), "post")).ToLocalChecked();
  Local<Value> destroy_v = fn_obj->Get(
      env->context(),
      FIXED_ONE_BYTE_STRING(env->isolate(), "destroy")).ToLocalChecked();

  if (!init_v->IsFunction())
    return env->ThrowTypeError("init callback must be a function");

  env->set_async_hooks_init_function(init_v.As<Function>());

  if (pre_v->IsFunction())
    env->set_async_hooks_pre_function(pre_v.As<Function>());
  if (post_v->IsFunction())
    env->set_async_hooks_post_function(post_v.As<Function>());
  if (destroy_v->IsFunction())
    env->set_async_hooks_destroy_function(destroy_v.As<Function>());
}


void AsyncWrap::Initialize(Local<Object> target,
                           Local<Value> unused,
                           Local<Context> context) {
  Environment* env = Environment::GetCurrent(context);
  Isolate* isolate = env->isolate();
  HandleScope scope(isolate);

  env->SetMethod(target, "setupHooks", SetupHooks);
  env->SetMethod(target, "disable", DisableHooksJS);
  env->SetMethod(target, "enable", EnableHooksJS);

  Local<Object> async_providers = Object::New(isolate);
#define V(PROVIDER)                                                           \
  async_providers->Set(FIXED_ONE_BYTE_STRING(isolate, #PROVIDER),             \
      Integer::New(isolate, AsyncWrap::PROVIDER_ ## PROVIDER));
  NODE_ASYNC_PROVIDER_TYPES(V)
#undef V
  target->Set(FIXED_ONE_BYTE_STRING(isolate, "Providers"), async_providers);

  env->set_async_hooks_init_function(Local<Function>());
  env->set_async_hooks_pre_function(Local<Function>());
  env->set_async_hooks_post_function(Local<Function>());
  env->set_async_hooks_destroy_function(Local<Function>());
}


void AsyncWrap::DestroyIdsCb(uv_idle_t* handle) {
  uv_idle_stop(handle);

  Environment* env = Environment::from_destroy_ids_idle_handle(handle);
  // None of the V8 calls done outside the HandleScope leak a handle. If this
  // changes in the future then the SealHandleScope wrapping the uv_run()
  // will catch this can cause the process to abort.
  HandleScope handle_scope(env->isolate());
  Context::Scope context_scope(env->context());
  Local<Function> fn = env->async_hooks_destroy_function();

  if (fn.IsEmpty())
    return env->destroy_ids_list()->clear();

  TryCatch try_catch(env->isolate());

  std::vector<int64_t> destroy_ids_list;
  destroy_ids_list.swap(*env->destroy_ids_list());
  for (auto current_id : destroy_ids_list) {
    // Want each callback to be cleaned up after itself, instead of cleaning
    // them all up after the while() loop completes.
    HandleScope scope(env->isolate());
    Local<Value> argv = Number::New(env->isolate(), current_id);
    MaybeLocal<Value> ret = fn->Call(
        env->context(), Undefined(env->isolate()), 1, &argv);

    if (ret.IsEmpty()) {
      ClearFatalExceptionHandlers(env);
      FatalException(env->isolate(), try_catch);
    }
  }

  env->destroy_ids_list()->clear();
}


void LoadAsyncWrapperInfo(Environment* env) {
  HeapProfiler* heap_profiler = env->isolate()->GetHeapProfiler();
#define V(PROVIDER)                                                           \
  heap_profiler->SetWrapperClassInfoProvider(                                 \
      (NODE_ASYNC_ID_OFFSET + AsyncWrap::PROVIDER_ ## PROVIDER), WrapperInfo);
  NODE_ASYNC_PROVIDER_TYPES(V)
#undef V
}


AsyncWrap::AsyncWrap(Environment* env,
                     Local<Object> object,
                     ProviderType provider,
                     AsyncWrap* parent)
    : BaseObject(env, object), bits_(static_cast<uint32_t>(provider) << 1),
      uid_(env->get_async_wrap_uid()) {
  CHECK_NE(provider, PROVIDER_NONE);
  CHECK_GE(object->InternalFieldCount(), 1);

  // Shift provider value over to prevent id collision.
  persistent().SetWrapperClassId(NODE_ASYNC_ID_OFFSET + provider);

  Local<Function> init_fn = env->async_hooks_init_function();

  // No init callback exists, no reason to go on.
  if (init_fn.IsEmpty())
    return;

  // If async wrap callbacks are disabled and no parent was passed that has
  // run the init callback then return.
  if (!env->async_wrap_callbacks_enabled() &&
      (parent == nullptr || !parent->ran_init_callback()))
    return;

  HandleScope scope(env->isolate());

  Local<Value> argv[] = {
    Number::New(env->isolate(), get_uid()),
    Int32::New(env->isolate(), provider),
    Null(env->isolate()),
    Null(env->isolate())
  };

  if (parent != nullptr) {
    argv[2] = Number::New(env->isolate(), parent->get_uid());
    argv[3] = parent->object();
  }

  TryCatch try_catch(env->isolate());

  MaybeLocal<Value> ret =
      init_fn->Call(env->context(), object, arraysize(argv), argv);

  if (ret.IsEmpty()) {
    ClearFatalExceptionHandlers(env);
    FatalException(env->isolate(), try_catch);
  }

  bits_ |= 1;  // ran_init_callback() is true now.
}


AsyncWrap::~AsyncWrap() {
  if (!ran_init_callback())
    return;

  if (env()->destroy_ids_list()->empty())
    uv_idle_start(env()->destroy_ids_idle_handle(), DestroyIdsCb);

  env()->destroy_ids_list()->push_back(get_uid());
}


Local<Value> AsyncWrap::MakeCallback(const Local<Function> cb,
                                     int argc,
                                     Local<Value>* argv) {
  CHECK(env()->context() == env()->isolate()->GetCurrentContext());

  Local<Function> pre_fn = env()->async_hooks_pre_function();
  Local<Function> post_fn = env()->async_hooks_post_function();
  Local<Value> uid = Number::New(env()->isolate(), get_uid());
  Local<Object> context = object();
  Local<Object> domain;
  bool has_domain = false;

  Environment::AsyncCallbackScope callback_scope(env());

  if (env()->using_domains()) {
    Local<Value> domain_v = context->Get(env()->domain_string());
    has_domain = domain_v->IsObject();
    if (has_domain) {
      domain = domain_v.As<Object>();
      if (domain->Get(env()->disposed_string())->IsTrue())
        return Local<Value>();
    }
  }

  if (has_domain) {
    Local<Value> enter_v = domain->Get(env()->enter_string());
    if (enter_v->IsFunction()) {
      if (enter_v.As<Function>()->Call(domain, 0, nullptr).IsEmpty()) {
        FatalError("node::AsyncWrap::MakeCallback",
                   "domain enter callback threw, please report this");
      }
    }
  }

  if (ran_init_callback() && !pre_fn.IsEmpty()) {
    TryCatch try_catch(env()->isolate());
    MaybeLocal<Value> ar = pre_fn->Call(env()->context(), context, 1, &uid);
    if (ar.IsEmpty()) {
      ClearFatalExceptionHandlers(env());
      FatalException(env()->isolate(), try_catch);
      return Local<Value>();
    }
  }

  Local<Value> ret = cb->Call(context, argc, argv);

  if (ran_init_callback() && !post_fn.IsEmpty()) {
    Local<Value> did_throw = Boolean::New(env()->isolate(), ret.IsEmpty());
    Local<Value> vals[] = { uid, did_throw };
    TryCatch try_catch(env()->isolate());
    MaybeLocal<Value> ar =
        post_fn->Call(env()->context(), context, arraysize(vals), vals);
    if (ar.IsEmpty()) {
      ClearFatalExceptionHandlers(env());
      FatalException(env()->isolate(), try_catch);
      return Local<Value>();
    }
  }

  if (ret.IsEmpty()) {
    return ret;
  }

  if (has_domain) {
    Local<Value> exit_v = domain->Get(env()->exit_string());
    if (exit_v->IsFunction()) {
      if (exit_v.As<Function>()->Call(domain, 0, nullptr).IsEmpty()) {
        FatalError("node::AsyncWrap::MakeCallback",
                   "domain exit callback threw, please report this");
      }
    }
  }

  if (callback_scope.in_makecallback()) {
    return ret;
  }

  Environment::TickInfo* tick_info = env()->tick_info();

  if (tick_info->length() == 0) {
    env()->isolate()->RunMicrotasks();
  }

  Local<Object> process = env()->process_object();

  if (tick_info->length() == 0) {
    tick_info->set_index(0);
    return ret;
  }

  if (env()->tick_callback_function()->Call(process, 0, nullptr).IsEmpty()) {
    return Local<Value>();
  }

  return ret;
}

}  // namespace node

NODE_MODULE_CONTEXT_AWARE_BUILTIN(async_wrap, node::AsyncWrap::Initialize)