From 0db3a9f0f6b6173cc3aa4cb1f9a7933e91d91c53 Mon Sep 17 00:00:00 2001
From: John Guo <john@johng.cn>
Date: Wed, 24 Nov 2021 22:27:09 +0800
Subject: [PATCH] improve package gcmd

---
 os/gcmd/gcmd_command_object.go | 60 ++++++++++++++++++++--------------
 1 file changed, 36 insertions(+), 24 deletions(-)

diff --git a/os/gcmd/gcmd_command_object.go b/os/gcmd/gcmd_command_object.go
index 7f6a6abf8..4957d6cd2 100644
--- a/os/gcmd/gcmd_command_object.go
+++ b/os/gcmd/gcmd_command_object.go
@@ -246,6 +246,42 @@ func newCommandFromMethod(object interface{}, method reflect.Value) (command Com
 	return
 }
 
+func newOptionsFromInput(object interface{}) (options []Option, err error) {
+	var (
+		fields []gstructs.Field
+	)
+	fields, err = gstructs.Fields(gstructs.FieldsInput{
+		Pointer:         object,
+		RecursiveOption: gstructs.RecursiveOptionEmbeddedNoTag,
+	})
+	for _, field := range fields {
+		var (
+			option   = Option{}
+			metaData = field.TagMap()
+		)
+		if err = gconv.Scan(metaData, &option); err != nil {
+			return nil, err
+		}
+		if option.Name == "" {
+			option.Name = field.Name()
+		}
+		if option.Name == helpOptionName {
+			return nil, gerror.Newf(
+				`option name "%s" is already token by built-in options`,
+				option.Name,
+			)
+		}
+		if option.Short == helpOptionNameShort {
+			return nil, gerror.Newf(
+				`short option name "%s" is already token by built-in options`,
+				option.Short,
+			)
+		}
+		options = append(options, option)
+	}
+	return
+}
+
 // mergeDefaultStructValue merges the request parameters with default values from struct tag definition.
 func mergeDefaultStructValue(data map[string]interface{}, pointer interface{}) error {
 	tagFields, err := gstructs.TagFields(pointer, defaultValueTags)
@@ -270,27 +306,3 @@ func mergeDefaultStructValue(data map[string]interface{}, pointer interface{}) e
 	}
 	return nil
 }
-
-func newOptionsFromInput(object interface{}) (options []Option, err error) {
-	var (
-		fields []gstructs.Field
-	)
-	fields, err = gstructs.Fields(gstructs.FieldsInput{
-		Pointer:         object,
-		RecursiveOption: gstructs.RecursiveOptionEmbeddedNoTag,
-	})
-	for _, field := range fields {
-		var (
-			option   = Option{}
-			metaData = field.TagMap()
-		)
-		if err = gconv.Scan(metaData, &option); err != nil {
-			return nil, err
-		}
-		if option.Name == "" {
-			option.Name = field.Name()
-		}
-		options = append(options, option)
-	}
-	return
-}