Permalink
Browse files

n-api: cache Symbol.hasInstance

This improves the performance of napi_instanceof() by retrieving
Symbol.hasInstance from the global object once and then storing a
persistent reference to it in the env.

PR-URL: #12246
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
  • Loading branch information...
gabrielschulhof authored and mhdawson committed Mar 31, 2017
1 parent ca8ccb9 commit 8fbace163afbd61b5efc57cf94414be904bf0188
Showing with 41 additions and 20 deletions.
  1. +41 −20 src/node_api.cc
View
@@ -23,12 +23,16 @@ void napi_clear_last_error(napi_env env);
class napi_env__ {
public:
explicit napi_env__(v8::Isolate* _isolate): isolate(_isolate), last_error() {}
explicit napi_env__(v8::Isolate* _isolate): isolate(_isolate),
has_instance_available(true), last_error() {}
~napi_env__() {
last_exception.Reset();
has_instance.Reset();
}
v8::Isolate* isolate;
v8::Persistent<v8::Value> last_exception;
v8::Persistent<v8::Value> has_instance;
bool has_instance_available;
napi_extended_error_info last_error;
};
@@ -2156,28 +2160,43 @@ napi_status napi_instanceof(napi_env env,
return napi_set_last_error(env, napi_function_expected);
}
napi_value value, js_result;
napi_status status;
napi_valuetype value_type;
if (env->has_instance_available) {
napi_value value, js_result, has_instance = nullptr;
napi_status status;
napi_valuetype value_type;
// Get "Symbol" from the global object
status = napi_get_global(env, &value);
if (status != napi_ok) return status;
status = napi_get_named_property(env, value, "Symbol", &value);
if (status != napi_ok) return status;
status = napi_typeof(env, value, &value_type);
if (status != napi_ok) return status;
// Get "Symbol" from the global object
if (env->has_instance.IsEmpty()) {
status = napi_get_global(env, &value);
if (status != napi_ok) return status;
status = napi_get_named_property(env, value, "Symbol", &value);
if (status != napi_ok) return status;
status = napi_typeof(env, value, &value_type);
if (status != napi_ok) return status;
// Get "hasInstance" from Symbol
if (value_type == napi_function) {
status = napi_get_named_property(env, value, "hasInstance", &value);
if (status != napi_ok) return status;
status = napi_typeof(env, value, &value_type);
if (status != napi_ok) return status;
// Get "hasInstance" from Symbol
if (value_type == napi_function) {
status = napi_get_named_property(env, value, "hasInstance", &value);
if (status != napi_ok) return status;
status = napi_typeof(env, value, &value_type);
if (status != napi_ok) return status;
// Store Symbol.hasInstance in a global persistent reference
if (value_type == napi_symbol) {
env->has_instance.Reset(env->isolate,
v8impl::V8LocalValueFromJsValue(value));
if (status != napi_ok) return status;
has_instance = value;
}
}
} else {
has_instance = v8impl::JsValueFromV8LocalValue(
v8::Local<v8::Value>::New(env->isolate, env->has_instance));
if (status != napi_ok) return status;
}
// Retrieve the function at the Symbol(hasInstance) key of the constructor
if (value_type == napi_symbol) {
status = napi_get_property(env, constructor, value, &value);
if (has_instance) {
status = napi_get_property(env, constructor, has_instance, &value);
if (status != napi_ok) return status;
status = napi_typeof(env, value, &value_type);
if (status != napi_ok) return status;
@@ -2191,6 +2210,8 @@ napi_status napi_instanceof(napi_env env,
return napi_get_value_bool(env, js_result, result);
}
}
env->has_instance_available = false;
}
// If running constructor[Symbol.hasInstance](object) did not work, we perform

0 comments on commit 8fbace1

Please sign in to comment.