n-api: implement napi_run_script

Fixes: nodejs/abi-stable-node#51
PR-URL: #15216
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com
Reviewed-By: James M Snell <jasnell.gmail.com>
Reviewed-By: Michael Dawson <mhdawson@ca.ibm.com>
Reviewed-By: Timothy Gu <timothygu99@gmail.com>

doc/api/n-api.md

@@ -43,6 +43,7 @@ The documentation for N-API is structured as follows:
 * [Object Wrap][]
 * [Asynchronous Operations][]
 * [Promises][]
+* [Script Execution][]
 
 The N-API is a C API that ensures ABI stability across Node.js versions
 and different compiler levels. However, we also understand that a C++
@@ -3556,6 +3557,25 @@ NAPI_EXTERN napi_status napi_is_promise(napi_env env,
 - `[out] is_promise`: Flag indicating whether `promise` is a native promise
 object - that is, a promise object created by the underlying engine.
 
+## Script execution
+
+N-API provides an API for executing a string containing JavaScript using the
+underlying JavaScript engine.
+
+### napi_run_script
+<!-- YAML
+added: REPLACEME
+-->
+```C
+NAPI_EXTERN napi_status napi_run_script(napi_env env,
+                                        napi_value script,
+                                        napi_value* result);
+```
+
+- `[in] env`: The environment that the API is invoked under.
+- `[in] script`: A JavaScript string containing the script to execute.
+- `[out] result`: The value resulting from having executed the script.
+
 [Promises]: #n_api_promises
 [Asynchronous Operations]: #n_api_asynchronous_operations
 [Basic N-API Data Types]: #n_api_basic_n_api_data_types
@@ -3565,6 +3585,7 @@ object - that is, a promise object created by the underlying engine.
 [Native Abstractions for Node.js]: https://github.com/nodejs/nan
 [Object Lifetime Management]: #n_api_object_lifetime_management
 [Object Wrap]: #n_api_object_wrap
+[Script Execution]: #n_api_script_execution
 [Section 9.1.6]: https://tc39.github.io/ecma262/#sec-ordinary-object-internal-methods-and-internal-slots-defineownproperty-p-desc
 [Section 12.5.5]: https://tc39.github.io/ecma262/#sec-typeof-operator
 [Section 24.3]: https://tc39.github.io/ecma262/#sec-dataview-objects

src/node_api.cc

@@ -3423,3 +3423,30 @@ NAPI_EXTERN napi_status napi_is_promise(napi_env env,
 
   return napi_clear_last_error(env);
 }
+
+NAPI_EXTERN napi_status napi_run_script(napi_env env,
+                                        napi_value script,
+                                        napi_value* result) {
+  NAPI_PREAMBLE(env);
+  CHECK_ARG(env, script);
+  CHECK_ARG(env, result);
+
+  v8::Local<v8::Value> v8_script = v8impl::V8LocalValueFromJsValue(script);
+
+  if (!v8_script->IsString()) {
+    return napi_set_last_error(env, napi_string_expected);
+  }
+
+  v8::Local<v8::Context> context = env->isolate->GetCurrentContext();
+
+  auto maybe_script = v8::Script::Compile(context,
+      v8::Local<v8::String>::Cast(v8_script));
+  CHECK_MAYBE_EMPTY(env, maybe_script, napi_generic_failure);
+
+  auto script_result =
+      maybe_script.ToLocalChecked()->Run(context);
+  CHECK_MAYBE_EMPTY(env, script_result, napi_generic_failure);
+
+  *result = v8impl::JsValueFromV8LocalValue(script_result.ToLocalChecked());
+  return GET_RETURN_STATUS(env);
+}

src/node_api.h

@@ -562,6 +562,11 @@ NAPI_EXTERN napi_status napi_adjust_external_memory(napi_env env,
                                                     int64_t change_in_bytes,
                                                     int64_t* adjusted_value);
 
+// Runnig a script
+NAPI_EXTERN napi_status napi_run_script(napi_env env,
+                                        napi_value script,
+                                        napi_value* result);
+
 EXTERN_C_END
 
 #endif  // SRC_NODE_API_H_

test/addons-napi/test_general/testNapiRun.js

@@ -0,0 +1,12 @@
+'use strict';
+
+const common = require('../../common');
+const assert = require('assert');
+
+// addon is referenced through the eval expression in testFile
+// eslint-disable-next-line no-unused-vars
+const addon = require(`./build/${common.buildType}/test_general`);
+
+assert.strictEqual(addon.testNapiRun('(41.92 + 0.08);'), 42,
+                   'napi_run_script() works correctly');
+assert.throws(() => addon.testNapiRun({ abc: 'def' }), /string was expected/);

test/addons-napi/test_general/test_general.c

@@ -1,4 +1,5 @@
 #include <node_api.h>
+#include <stdlib.h>
 #include "../common.h"
 
 napi_value testStrictEquals(napi_env env, napi_callback_info info) {
@@ -215,12 +216,24 @@ napi_value testAdjustExternalMemory(napi_env env, napi_callback_info info) {
   return result;
 }
 
+napi_value testNapiRun(napi_env env, napi_callback_info info) {
+  napi_value script, result;
+  size_t argc = 1;
+
+  NAPI_CALL(env, napi_get_cb_info(env, info, &argc, &script, NULL, NULL));
+
+  NAPI_CALL(env, napi_run_script(env, script, &result));
+
+  return result;
+}
+
 void Init(napi_env env, napi_value exports, napi_value module, void* priv) {
   napi_property_descriptor descriptors[] = {
     DECLARE_NAPI_PROPERTY("testStrictEquals", testStrictEquals),
     DECLARE_NAPI_PROPERTY("testGetPrototype", testGetPrototype),
     DECLARE_NAPI_PROPERTY("testGetVersion", testGetVersion),
     DECLARE_NAPI_PROPERTY("testGetNodeVersion", testGetNodeVersion),
+    DECLARE_NAPI_PROPERTY("testNapiRun", testNapiRun),
     DECLARE_NAPI_PROPERTY("doInstanceOf", doInstanceOf),
     DECLARE_NAPI_PROPERTY("getUndefined", getUndefined),
     DECLARE_NAPI_PROPERTY("getNull", getNull),