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|
package awsutil
import (
"reflect"
"regexp"
"strconv"
"strings"
)
var indexRe = regexp.MustCompile(`(.+)\[(-?\d+)?\]$`)
func rValuesAtPath(v interface{}, path string, create bool) []reflect.Value {
pathparts := strings.Split(path, "||")
if len(pathparts) > 1 {
for _, pathpart := range pathparts {
vals := rValuesAtPath(v, pathpart, create)
if vals != nil && len(vals) > 0 {
return vals
}
}
return nil
}
values := []reflect.Value{reflect.Indirect(reflect.ValueOf(v))}
components := strings.Split(path, ".")
for len(values) > 0 && len(components) > 0 {
var index *int64
var indexStar bool
c := strings.TrimSpace(components[0])
if c == "" { // no actual component, illegal syntax
return nil
} else if c != "*" && strings.ToLower(c[0:1]) == c[0:1] {
// TODO normalize case for user
return nil // don't support unexported fields
}
// parse this component
if m := indexRe.FindStringSubmatch(c); m != nil {
c = m[1]
if m[2] == "" {
index = nil
indexStar = true
} else {
i, _ := strconv.ParseInt(m[2], 10, 32)
index = &i
indexStar = false
}
}
nextvals := []reflect.Value{}
for _, value := range values {
// pull component name out of struct member
if value.Kind() != reflect.Struct {
continue
}
if c == "*" { // pull all members
for i := 0; i < value.NumField(); i++ {
if f := reflect.Indirect(value.Field(i)); f.IsValid() {
nextvals = append(nextvals, f)
}
}
continue
}
value = value.FieldByName(c)
if create && value.Kind() == reflect.Ptr && value.IsNil() {
value.Set(reflect.New(value.Type().Elem()))
value = value.Elem()
} else {
value = reflect.Indirect(value)
}
if value.IsValid() {
nextvals = append(nextvals, value)
}
}
values = nextvals
if indexStar || index != nil {
nextvals = []reflect.Value{}
for _, value := range values {
value := reflect.Indirect(value)
if value.Kind() != reflect.Slice {
continue
}
if indexStar { // grab all indices
for i := 0; i < value.Len(); i++ {
idx := reflect.Indirect(value.Index(i))
if idx.IsValid() {
nextvals = append(nextvals, idx)
}
}
continue
}
// pull out index
i := int(*index)
if i >= value.Len() { // check out of bounds
if create {
// TODO resize slice
} else {
continue
}
} else if i < 0 { // support negative indexing
i = value.Len() + i
}
value = reflect.Indirect(value.Index(i))
if value.IsValid() {
nextvals = append(nextvals, value)
}
}
values = nextvals
}
components = components[1:]
}
return values
}
// ValuesAtPath returns a list of objects at the lexical path inside of a structure
func ValuesAtPath(i interface{}, path string) []interface{} {
if rvals := rValuesAtPath(i, path, false); rvals != nil {
vals := make([]interface{}, len(rvals))
for i, rval := range rvals {
vals[i] = rval.Interface()
}
return vals
}
return nil
}
// SetValueAtPath sets an object at the lexical path inside of a structure
func SetValueAtPath(i interface{}, path string, v interface{}) {
if rvals := rValuesAtPath(i, path, true); rvals != nil {
for _, rval := range rvals {
rval.Set(reflect.ValueOf(v))
}
}
}
|
