lts/src/api/callback.cc
#include "node.h"
#include "async_wrap-inl.h"
#include "env-inl.h"
#include "v8.h"
namespace node {
using v8::Context;
using v8::EscapableHandleScope;
using v8::Function;
using v8::HandleScope;
using v8::Isolate;
using v8::Local;
using v8::MaybeLocal;
using v8::MicrotasksScope;
using v8::NewStringType;
using v8::Object;
using v8::String;
using v8::Value;
CallbackScope::CallbackScope(Isolate* isolate,
Local<Object> object,
async_context asyncContext)
: private_(new InternalCallbackScope(Environment::GetCurrent(isolate),
object,
asyncContext)),
try_catch_(isolate) {
try_catch_.SetVerbose(true);
}
CallbackScope::~CallbackScope() {
if (try_catch_.HasCaught())
private_->MarkAsFailed();
delete private_;
}
InternalCallbackScope::InternalCallbackScope(AsyncWrap* async_wrap, int flags)
: InternalCallbackScope(async_wrap->env(),
async_wrap->object(),
{ async_wrap->get_async_id(),
async_wrap->get_trigger_async_id() },
flags) {}
InternalCallbackScope::InternalCallbackScope(Environment* env,
Local<Object> object,
const async_context& asyncContext,
int flags)
: env_(env),
async_context_(asyncContext),
object_(object),
skip_hooks_(flags & kSkipAsyncHooks),
skip_task_queues_(flags & kSkipTaskQueues) {
CHECK_NOT_NULL(env);
env->PushAsyncCallbackScope();
if (!env->can_call_into_js()) {
failed_ = true;
return;
}
HandleScope handle_scope(env->isolate());
// If you hit this assertion, you forgot to enter the v8::Context first.
CHECK_EQ(Environment::GetCurrent(env->isolate()), env);
env->async_hooks()->push_async_context(
async_context_.async_id, async_context_.trigger_async_id, object);
pushed_ids_ = true;
if (asyncContext.async_id != 0 && !skip_hooks_) {
// No need to check a return value because the application will exit if
// an exception occurs.
AsyncWrap::EmitBefore(env, asyncContext.async_id);
}
}
InternalCallbackScope::~InternalCallbackScope() {
Close();
env_->PopAsyncCallbackScope();
}
void InternalCallbackScope::Close() {
if (closed_) return;
closed_ = true;
if (!env_->can_call_into_js()) return;
auto perform_stopping_check = [&]() {
if (env_->is_stopping()) {
MarkAsFailed();
env_->async_hooks()->clear_async_id_stack();
}
};
perform_stopping_check();
if (!failed_ && async_context_.async_id != 0 && !skip_hooks_) {
AsyncWrap::EmitAfter(env_, async_context_.async_id);
}
if (pushed_ids_)
env_->async_hooks()->pop_async_context(async_context_.async_id);
if (failed_) return;
if (env_->async_callback_scope_depth() > 1 || skip_task_queues_) {
return;
}
TickInfo* tick_info = env_->tick_info();
if (!env_->can_call_into_js()) return;
auto weakref_cleanup = OnScopeLeave([&]() { env_->RunWeakRefCleanup(); });
if (!tick_info->has_tick_scheduled()) {
MicrotasksScope::PerformCheckpoint(env_->isolate());
perform_stopping_check();
}
// Make sure the stack unwound properly. If there are nested MakeCallback's
// then it should return early and not reach this code.
if (env_->async_hooks()->fields()[AsyncHooks::kTotals]) {
CHECK_EQ(env_->execution_async_id(), 0);
CHECK_EQ(env_->trigger_async_id(), 0);
}
if (!tick_info->has_tick_scheduled() && !tick_info->has_rejection_to_warn()) {
return;
}
HandleScope handle_scope(env_->isolate());
Local<Object> process = env_->process_object();
if (!env_->can_call_into_js()) return;
Local<Function> tick_callback = env_->tick_callback_function();
// The tick is triggered before JS land calls SetTickCallback
// to initializes the tick callback during bootstrap.
CHECK(!tick_callback.IsEmpty());
if (tick_callback->Call(env_->context(), process, 0, nullptr).IsEmpty()) {
failed_ = true;
}
perform_stopping_check();
}
MaybeLocal<Value> InternalMakeCallback(Environment* env,
Local<Object> resource,
Local<Object> recv,
const Local<Function> callback,
int argc,
Local<Value> argv[],
async_context asyncContext) {
CHECK(!recv.IsEmpty());
#ifdef DEBUG
for (int i = 0; i < argc; i++)
CHECK(!argv[i].IsEmpty());
#endif
Local<Function> hook_cb = env->async_hooks_callback_trampoline();
int flags = InternalCallbackScope::kNoFlags;
int hook_count = 0;
if (!hook_cb.IsEmpty()) {
flags = InternalCallbackScope::kSkipAsyncHooks;
AsyncHooks* async_hooks = env->async_hooks();
hook_count = async_hooks->fields()[AsyncHooks::kBefore] +
async_hooks->fields()[AsyncHooks::kAfter];
}
InternalCallbackScope scope(env, resource, asyncContext, flags);
if (scope.Failed()) {
return MaybeLocal<Value>();
}
MaybeLocal<Value> ret;
if (hook_count != 0) {
MaybeStackBuffer<Local<Value>, 16> args(2 + argc);
args[0] = v8::Number::New(env->isolate(), asyncContext.async_id);
args[1] = callback;
for (int i = 0; i < argc; i++) {
args[i + 2] = argv[i];
}
ret = hook_cb->Call(env->context(), recv, args.length(), &args[0]);
} else {
ret = callback->Call(env->context(), recv, argc, argv);
}
if (ret.IsEmpty()) {
scope.MarkAsFailed();
return MaybeLocal<Value>();
}
scope.Close();
if (scope.Failed()) {
return MaybeLocal<Value>();
}
return ret;
}
// Public MakeCallback()s
MaybeLocal<Value> MakeCallback(Isolate* isolate,
Local<Object> recv,
const char* method,
int argc,
Local<Value> argv[],
async_context asyncContext) {
Local<String> method_string =
String::NewFromUtf8(isolate, method, NewStringType::kNormal)
.ToLocalChecked();
return MakeCallback(isolate, recv, method_string, argc, argv, asyncContext);
}
MaybeLocal<Value> MakeCallback(Isolate* isolate,
Local<Object> recv,
Local<String> symbol,
int argc,
Local<Value> argv[],
async_context asyncContext) {
Local<Value> callback_v =
recv->Get(isolate->GetCurrentContext(), symbol).ToLocalChecked();
if (callback_v.IsEmpty()) return Local<Value>();
if (!callback_v->IsFunction()) return Local<Value>();
Local<Function> callback = callback_v.As<Function>();
return MakeCallback(isolate, recv, callback, argc, argv, asyncContext);
}
MaybeLocal<Value> MakeCallback(Isolate* isolate,
Local<Object> recv,
Local<Function> callback,
int argc,
Local<Value> argv[],
async_context asyncContext) {
// Observe the following two subtleties:
//
// 1. The environment is retrieved from the callback function's context.
// 2. The context to enter is retrieved from the environment.
//
// Because of the AssignToContext() call in src/node_contextify.cc,
// the two contexts need not be the same.
Environment* env = Environment::GetCurrent(callback->CreationContext());
CHECK_NOT_NULL(env);
Context::Scope context_scope(env->context());
MaybeLocal<Value> ret =
InternalMakeCallback(env, recv, recv, callback, argc, argv, asyncContext);
if (ret.IsEmpty() && env->async_callback_scope_depth() == 0) {
// This is only for legacy compatibility and we may want to look into
// removing/adjusting it.
return Undefined(env->isolate());
}
return ret;
}
// Legacy MakeCallback()s
Local<Value> MakeCallback(Isolate* isolate,
Local<Object> recv,
const char* method,
int argc,
Local<Value>* argv) {
EscapableHandleScope handle_scope(isolate);
return handle_scope.Escape(
MakeCallback(isolate, recv, method, argc, argv, {0, 0})
.FromMaybe(Local<Value>()));
}
Local<Value> MakeCallback(Isolate* isolate,
Local<Object> recv,
Local<String> symbol,
int argc,
Local<Value>* argv) {
EscapableHandleScope handle_scope(isolate);
return handle_scope.Escape(
MakeCallback(isolate, recv, symbol, argc, argv, {0, 0})
.FromMaybe(Local<Value>()));
}
Local<Value> MakeCallback(Isolate* isolate,
Local<Object> recv,
Local<Function> callback,
int argc,
Local<Value>* argv) {
EscapableHandleScope handle_scope(isolate);
return handle_scope.Escape(
MakeCallback(isolate, recv, callback, argc, argv, {0, 0})
.FromMaybe(Local<Value>()));
}
} // namespace node