src: error reporting on CPUUsage

Currently we are returning the stringified error code while in other
process methods we are throwin a UVException and only exclusion is in
the CPUUsage. Converted it to follow the convention.

doc/api/errors.md

@@ -729,11 +729,6 @@ when an error occurs (and is caught) during the creation of the
 context, for example, when the allocation fails or the maximum call stack
 size is reached when the context is created.
 
-<a id="ERR_CPU_USAGE"></a>
-### `ERR_CPU_USAGE`
-
-The native call from `process.cpuUsage` could not be processed.
-
 <a id="ERR_CRYPTO_CUSTOM_ENGINE_NOT_SUPPORTED"></a>
 ### `ERR_CRYPTO_CUSTOM_ENGINE_NOT_SUPPORTED`
 
@@ -2725,6 +2720,11 @@ removed: v10.0.0
 Used when an attempt is made to use a `zlib` object after it has already been
 closed.
 
+<a id="ERR_CPU_USAGE"></a>
+### `ERR_CPU_USAGE`
+
+The native call from `process.cpuUsage` could not be processed.
+
 [ES Module]: esm.md
 [ICU]: intl.md#intl_internationalization_support
 [Node.js error codes]: #nodejs-error-codes

lib/internal/errors.js

@@ -787,7 +787,6 @@ E('ERR_CHILD_PROCESS_STDIO_MAXBUFFER', '%s maxBuffer length exceeded',
 E('ERR_CONSOLE_WRITABLE_STREAM',
   'Console expects a writable stream instance for %s', TypeError);
 E('ERR_CONTEXT_NOT_INITIALIZED', 'context used is not initialized', Error);
-E('ERR_CPU_USAGE', 'Unable to obtain cpu usage %s', Error);
 E('ERR_CRYPTO_CUSTOM_ENGINE_NOT_SUPPORTED',
   'Custom engines not supported by this OpenSSL', Error);
 E('ERR_CRYPTO_ECDH_INVALID_FORMAT', 'Invalid ECDH format: %s', TypeError);

lib/internal/process/per_thread.js

@@ -25,7 +25,6 @@ const {
   errnoException,
   codes: {
     ERR_ASSERTION,
-    ERR_CPU_USAGE,
     ERR_INVALID_ARG_TYPE,
     ERR_INVALID_ARG_VALUE,
     ERR_OUT_OF_RANGE,
@@ -129,10 +128,7 @@ function wrapProcessMethods(binding) {
     }
 
     // Call the native function to get the current values.
-    const errmsg = _cpuUsage(cpuValues);
-    if (errmsg) {
-      throw new ERR_CPU_USAGE(errmsg);
-    }
+    _cpuUsage(cpuValues);
 
     // If a previous value was passed in, return diff of current from previous.
     if (prevValue) {

src/node_process_methods.cc

@@ -95,15 +95,13 @@ static void Chdir(const FunctionCallbackInfo<Value>& args) {
 // Returns those values as Float64 microseconds in the elements of the array
 // passed to the function.
 static void CPUUsage(const FunctionCallbackInfo<Value>& args) {
+  Environment* env = Environment::GetCurrent(args);
   uv_rusage_t rusage;
 
   // Call libuv to get the values we'll return.
   int err = uv_getrusage(&rusage);
-  if (err) {
-    // On error, return the strerror version of the error code.
-    Local<String> errmsg = OneByteString(args.GetIsolate(), uv_strerror(err));
-    return args.GetReturnValue().Set(errmsg);
-  }
+  if (err)
+    return env->ThrowUVException(err, "uv_getrusage");
 
   // Get the double array pointer from the Float64Array argument.
   CHECK(args[0]->IsFloat64Array());