src,lib: introduce util.getSystemErrorMessage(err)

This patch adds a new utility function which provides human-readable string description of the given system error code. Signed-off-by: Juan José Arboleda <[email protected]> PR-URL: #54075 Reviewed-By: James M Snell <[email protected]> Reviewed-By: Luigi Pinca <[email protected]> Reviewed-By: Yagiz Nizipli <[email protected]>

Author: juanarbol

doc/api/util.md

@@ -463,6 +463,26 @@ fs.access('file/that/does/not/exist', (err) =>{
 });
 ```
 
+## `util.getSystemErrorMessage(err)`
+
+<!-- YAML
+added: REPLACEME
+-->
+
+*`err`{number}
+* Returns:{string}
+
+Returns the string message for a numeric error code that comes from a Node.js
+API.
+The mapping between error codes and string messages is platform-dependent.
+
+```js
+fs.access('file/that/does/not/exist', (err) =>{
+constname=util.getSystemErrorMessage(err.errno);
+console.error(name); // no such file or directory
+});
+```
+
 ## `util.inherits(constructor, superConstructor)`
 
 <!-- YAML

lib/internal/util.js

@@ -386,6 +386,10 @@ function getCWDURL(){
 returncachedURL;
 }
 
+functiongetSystemErrorMessage(err){
+returnlazyUv().getErrorMessage(err);
+}
+
 functiongetSystemErrorName(err){
 constentry=uvErrmapGet(err);
 returnentry ? entry[0] : `Unknown system error ${err}`;
@@ -880,6 +884,7 @@ module.exports ={
  getStructuredStack,
  getSystemErrorMap,
  getSystemErrorName,
+ getSystemErrorMessage,
  guessHandleType,
  isError,
  isUnderNodeModules,

lib/util.js

@@ -81,6 +81,7 @@ const{
  deprecate,
  getSystemErrorMap,
 getSystemErrorName: internalErrorName,
+getSystemErrorMessage: internalErrorMessage,
  promisify,
  defineLazyProperties,
 }=require('internal/util');
@@ -269,6 +270,18 @@ function callbackify(original){
 returncallbackified;
 }
 
+/**
+ * @param{number} err
+ * @returns{string}
+ */
+functiongetSystemErrorMessage(err){
+validateNumber(err,'err');
+if(err>=0||!NumberIsSafeInteger(err)){
+thrownewERR_OUT_OF_RANGE('err','a negative integer',err);
+}
+returninternalErrorMessage(err);
+}
+
 /**
  * @param{number} err
  * @returns{string}
@@ -343,6 +356,7 @@ module.exports ={
  getCallSite,
  getSystemErrorMap,
  getSystemErrorName,
+ getSystemErrorMessage,
  inherits,
  inspect,
 isArray: deprecate(ArrayIsArray,

src/uv.cc

@@ -59,6 +59,15 @@ using v8::ReadOnly;
 using v8::String;
 using v8::Value;
 
+voidGetErrMessage(const FunctionCallbackInfo<Value>& args){
+ Environment* env = Environment::GetCurrent(args);
+int err = args[0].As<v8::Int32>()->Value();
+CHECK_LT(err, 0);
+char message[50];
+uv_strerror_r(err, message, sizeof(message));
+ args.GetReturnValue().Set(OneByteString(env->isolate(), message));
+}
+
 voidErrName(const FunctionCallbackInfo<Value>& args){
  Environment* env = Environment::GetCurrent(args);
 if (env->options()->pending_deprecation && env->EmitErrNameWarning()){
@@ -70,8 +79,7 @@ void ErrName(const FunctionCallbackInfo<Value>& args){
 "DEP0119").IsNothing())
 return;
  }
-int err;
-if (!args[0]->Int32Value(env->context()).To(&err)) return;
+int err = args[0].As<v8::Int32>()->Value();
 CHECK_LT(err, 0);
 char name[50];
 uv_err_name_r(err, name, sizeof(name));
@@ -128,11 +136,13 @@ void Initialize(Local<Object> target,
  }
 
 SetMethod(context, target, "getErrorMap", GetErrMap);
+SetMethod(context, target, "getErrorMessage", GetErrMessage);
 }
 
 voidRegisterExternalReferences(ExternalReferenceRegistry* registry){
  registry->Register(ErrName);
  registry->Register(GetErrMap);
+ registry->Register(GetErrMessage);
 }
 } // namespace uv
 } // namespace node

test/parallel/test-uv-errno.js

@@ -5,6 +5,7 @@ const common = require('../common');
 constassert=require('assert');
 const{
  getSystemErrorName,
+ getSystemErrorMessage,
  _errnoException
 }=require('util');
 
@@ -13,6 +14,7 @@ const uv = internalBinding('uv');
 constkeys=Object.keys(uv);
 
 assert.strictEqual(uv.errname(-111111),'Unknown system error -111111');
+assert.strictEqual(uv.getErrorMessage(-111111),'Unknown system error -111111');
 
 keys.forEach((key)=>{
 if(!key.startsWith('UV_'))
@@ -21,6 +23,8 @@ keys.forEach((key) =>{
 consterr=_errnoException(uv[key],'test');
 constname=uv.errname(uv[key]);
 assert.strictEqual(getSystemErrorName(uv[key]),name);
+assert.notStrictEqual(getSystemErrorMessage(uv[key]),
+`Unknown system error ${key}`);
 assert.strictEqual(err.code,name);
 assert.strictEqual(err.code,getSystemErrorName(err.errno));
 assert.strictEqual(err.message,`test ${name}`);
@@ -53,3 +57,4 @@ function runTest(fn){
 
 runTest(_errnoException);
 runTest(getSystemErrorName);
+runTest(getSystemErrorMessage);