bbgo_origin/pkg/dynamic/field.go

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package dynamic
import (
"errors"
"reflect"
"strings"
)
func HasField(rs reflect.Value, fieldName string) (field reflect.Value, ok bool) {
field = rs.FieldByName(fieldName)
return field, field.IsValid()
}
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func LookupSymbolField(rs reflect.Value) (string, bool) {
if rs.Kind() == reflect.Ptr {
rs = rs.Elem()
}
field := rs.FieldByName("Symbol")
if !field.IsValid() {
return "", false
}
if field.Kind() != reflect.String {
return "", false
}
return field.String(), true
}
// Used by bbgo/interact_modify.go
func GetModifiableFields(val reflect.Value, callback func(tagName, name string)) {
if val.Kind() == reflect.Ptr {
val = val.Elem()
}
if !val.IsValid() {
return
}
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num := val.Type().NumField()
for i := 0; i < num; i++ {
t := val.Type().Field(i)
if !t.IsExported() {
continue
}
if t.Anonymous {
GetModifiableFields(val.Field(i), callback)
}
modifiable := t.Tag.Get("modifiable")
if modifiable != "true" {
continue
}
jsonTag := t.Tag.Get("json")
if jsonTag == "" || jsonTag == "-" {
continue
}
name := strings.Split(jsonTag, ",")[0]
callback(name, t.Name)
}
}
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var zeroValue reflect.Value = reflect.Zero(reflect.TypeOf(0))
func GetModifiableField(val reflect.Value, name string) (reflect.Value, bool) {
if val.Kind() == reflect.Ptr {
if val.IsNil() {
return zeroValue, false
}
}
if val.Kind() != reflect.Struct {
return zeroValue, false
}
if !val.IsValid() {
return zeroValue, false
}
field, ok := val.Type().FieldByName(name)
if !ok {
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return zeroValue, ok
}
if field.Tag.Get("modifiable") != "true" {
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return zeroValue, false
}
jsonTag := field.Tag.Get("json")
if jsonTag == "" || jsonTag == "-" {
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return zeroValue, false
}
value, err := FieldByIndexErr(val, field.Index)
if err != nil {
return zeroValue, false
}
return value, true
}
// Modified from golang 1.19.1 reflect to eliminate all possible panic
func FieldByIndexErr(v reflect.Value, index []int) (reflect.Value, error) {
if len(index) == 1 {
return v.Field(index[0]), nil
}
if v.Kind() != reflect.Struct {
return zeroValue, errors.New("should receive a Struct")
}
for i, x := range index {
if i > 0 {
if v.Kind() == reflect.Ptr && v.Type().Elem().Kind() == reflect.Struct {
if v.IsNil() {
return zeroValue, errors.New("reflect: indirection through nil pointer to embedded struct field ")
}
v = v.Elem()
}
}
v = v.Field(x)
}
return v, nil
}