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|
package awsutil
import (
"reflect"
"regexp"
"strconv"
"strings"
"github.com/jmespath/go-jmespath"
)
var indexRe = regexp.MustCompile(`(.+)\[(-?\d+)?\]$`)
// rValuesAtPath returns a slice of values found in value v. The values
// in v are explored recursively so all nested values are collected.
func rValuesAtPath(v interface{}, path string, createPath, caseSensitive, nilTerm bool) []reflect.Value {
pathparts := strings.Split(path, "||")
if len(pathparts) > 1 {
for _, pathpart := range pathparts {
vals := rValuesAtPath(v, pathpart, createPath, caseSensitive, nilTerm)
if 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 caseSensitive && 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.FieldByNameFunc(func(name string) bool {
if c == name {
return true
} else if !caseSensitive && strings.ToLower(name) == strings.ToLower(c) {
return true
}
return false
})
if nilTerm && value.Kind() == reflect.Ptr && len(components[1:]) == 0 {
if !value.IsNil() {
value.Set(reflect.Zero(value.Type()))
}
return []reflect.Value{value}
}
if createPath && value.Kind() == reflect.Ptr && value.IsNil() {
// TODO if the value is the terminus it should not be created
// if the value to be set to its position is nil.
value.Set(reflect.New(value.Type().Elem()))
value = value.Elem()
} else {
value = reflect.Indirect(value)
}
if value.Kind() == reflect.Slice || value.Kind() == reflect.Map {
if !createPath && value.IsNil() {
value = reflect.ValueOf(nil)
}
}
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 createPath {
// TODO resize slice
} else {
continue
}
} else if i < 0 { // support negative indexing
i = value.Len() + i
}
value = reflect.Indirect(value.Index(i))
if value.Kind() == reflect.Slice || value.Kind() == reflect.Map {
if !createPath && value.IsNil() {
value = reflect.ValueOf(nil)
}
}
if value.IsValid() {
nextvals = append(nextvals, value)
}
}
values = nextvals
}
components = components[1:]
}
return values
}
// ValuesAtPath returns a list of values at the case insensitive lexical
// path inside of a structure.
func ValuesAtPath(i interface{}, path string) ([]interface{}, error) {
result, err := jmespath.Search(path, i)
if err != nil {
return nil, err
}
v := reflect.ValueOf(result)
if !v.IsValid() || (v.Kind() == reflect.Ptr && v.IsNil()) {
return nil, nil
}
if s, ok := result.([]interface{}); ok {
return s, err
}
if v.Kind() == reflect.Map && v.Len() == 0 {
return nil, nil
}
if v.Kind() == reflect.Slice {
out := make([]interface{}, v.Len())
for i := 0; i < v.Len(); i++ {
out[i] = v.Index(i).Interface()
}
return out, nil
}
return []interface{}{result}, nil
}
// SetValueAtPath sets a value at the case insensitive lexical path inside
// of a structure.
func SetValueAtPath(i interface{}, path string, v interface{}) {
if rvals := rValuesAtPath(i, path, true, false, v == nil); rvals != nil {
for _, rval := range rvals {
if rval.Kind() == reflect.Ptr && rval.IsNil() {
continue
}
setValue(rval, v)
}
}
}
func setValue(dstVal reflect.Value, src interface{}) {
if dstVal.Kind() == reflect.Ptr {
dstVal = reflect.Indirect(dstVal)
}
srcVal := reflect.ValueOf(src)
if !srcVal.IsValid() { // src is literal nil
if dstVal.CanAddr() {
// Convert to pointer so that pointer's value can be nil'ed
// dstVal = dstVal.Addr()
}
dstVal.Set(reflect.Zero(dstVal.Type()))
} else if srcVal.Kind() == reflect.Ptr {
if srcVal.IsNil() {
srcVal = reflect.Zero(dstVal.Type())
} else {
srcVal = reflect.ValueOf(src).Elem()
}
dstVal.Set(srcVal)
} else {
dstVal.Set(srcVal)
}
}
|
