| // Copyright Istio Authors |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| /* |
| struct.go contains functions for traversing and modifying trees of Go structs. |
| */ |
| package tpath |
| |
| import ( |
| "fmt" |
| "reflect" |
| "strconv" |
| ) |
| |
| import ( |
| "google.golang.org/protobuf/types/known/structpb" |
| ) |
| |
| import ( |
| "github.com/apache/dubbo-go-pixiu/operator/pkg/util" |
| ) |
| |
| // GetFromStructPath returns the value at path from the given node, or false if the path does not exist. |
| func GetFromStructPath(node interface{}, path string) (interface{}, bool, error) { |
| return getFromStructPath(node, util.PathFromString(path)) |
| } |
| |
| // getFromStructPath is the internal implementation of GetFromStructPath which recurses through a tree of Go structs |
| // given a path. It terminates when the end of the path is reached or a path element does not exist. |
| func getFromStructPath(node interface{}, path util.Path) (interface{}, bool, error) { |
| scope.Debugf("getFromStructPath path=%s, node(%T)", path, node) |
| if len(path) == 0 { |
| scope.Debugf("getFromStructPath returning node(%T)%v", node, node) |
| return node, !util.IsValueNil(node), nil |
| } |
| // For protobuf types, switch them out with standard types; otherwise we will traverse protobuf internals rather |
| // than the standard representation |
| if v, ok := node.(*structpb.Struct); ok { |
| node = v.AsMap() |
| } |
| if v, ok := node.(*structpb.Value); ok { |
| node = v.AsInterface() |
| } |
| val := reflect.ValueOf(node) |
| kind := reflect.TypeOf(node).Kind() |
| var structElems reflect.Value |
| |
| switch kind { |
| case reflect.Map: |
| if path[0] == "" { |
| return nil, false, fmt.Errorf("getFromStructPath path %s, empty map key value", path) |
| } |
| mapVal := val.MapIndex(reflect.ValueOf(path[0])) |
| if !mapVal.IsValid() { |
| return nil, false, fmt.Errorf("getFromStructPath path %s, path does not exist", path) |
| } |
| return getFromStructPath(mapVal.Interface(), path[1:]) |
| case reflect.Slice: |
| idx, err := strconv.Atoi(path[0]) |
| if err != nil { |
| return nil, false, fmt.Errorf("getFromStructPath path %s, expected index number, got %s", path, path[0]) |
| } |
| return getFromStructPath(val.Index(idx).Interface(), path[1:]) |
| case reflect.Ptr: |
| structElems = reflect.ValueOf(node).Elem() |
| if !util.IsStruct(structElems) { |
| return nil, false, fmt.Errorf("getFromStructPath path %s, expected struct ptr, got %T", path, node) |
| } |
| default: |
| return nil, false, fmt.Errorf("getFromStructPath path %s, unsupported type %T", path, node) |
| } |
| |
| if util.IsNilOrInvalidValue(structElems) { |
| return nil, false, nil |
| } |
| |
| for i := 0; i < structElems.NumField(); i++ { |
| fieldName := structElems.Type().Field(i).Name |
| |
| if fieldName != path[0] { |
| continue |
| } |
| |
| fv := structElems.Field(i) |
| return getFromStructPath(fv.Interface(), path[1:]) |
| } |
| |
| return nil, false, nil |
| } |
| |
| // SetFromPath sets out with the value at path from node. out is not set if the path doesn't exist or the value is nil. |
| // All intermediate along path must be type struct ptr. Out must be either a struct ptr or map ptr. |
| // TODO: move these out to a separate package (istio/istio#15494). |
| func SetFromPath(node interface{}, path string, out interface{}) (bool, error) { |
| val, found, err := GetFromStructPath(node, path) |
| if err != nil { |
| return false, err |
| } |
| if !found { |
| return false, nil |
| } |
| |
| return true, Set(val, out) |
| } |
| |
| // Set sets out with the value at path from node. out is not set if the path doesn't exist or the value is nil. |
| func Set(val, out interface{}) error { |
| // Special case: map out type must be set through map ptr. |
| if util.IsMap(val) && util.IsMapPtr(out) { |
| reflect.ValueOf(out).Elem().Set(reflect.ValueOf(val)) |
| return nil |
| } |
| if util.IsSlice(val) && util.IsSlicePtr(out) { |
| reflect.ValueOf(out).Elem().Set(reflect.ValueOf(val)) |
| return nil |
| } |
| |
| if reflect.TypeOf(val) != reflect.TypeOf(out) { |
| return fmt.Errorf("setFromPath from type %T != to type %T, %v", val, out, util.IsSlicePtr(out)) |
| } |
| |
| if !reflect.ValueOf(out).CanSet() { |
| return fmt.Errorf("can't set %v(%T) to out type %T", val, val, out) |
| } |
| reflect.ValueOf(out).Set(reflect.ValueOf(val)) |
| return nil |
| } |