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// Copyright 2019 Google Inc. All rights reserved.
//
// 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.
package proptools
import (
"fmt"
"reflect"
"strings"
)
// HasTag returns true if a StructField has a tag in the form `name:"foo,value"`.
func HasTag(field reflect.StructField, name, value string) bool {
tag := field.Tag.Get(name)
for len(tag) > 0 {
idx := strings.Index(tag, ",")
if idx < 0 {
return tag == value
}
if tag[:idx] == value {
return true
}
tag = tag[idx+1:]
}
return false
}
// PropertyIndexesWithTag returns the indexes of all properties (in the form used by reflect.Value.FieldByIndex) that
// are tagged with the given key and value, including ones found in embedded structs or pointers to structs.
func PropertyIndexesWithTag(ps interface{}, key, value string) [][]int {
t := reflect.TypeOf(ps)
if !isStructPtr(t) {
panic(fmt.Errorf("type %s is not a pointer to a struct", t))
}
t = t.Elem()
return propertyIndexesWithTag(t, key, value)
}
func propertyIndexesWithTag(t reflect.Type, key, value string) [][]int {
var indexes [][]int
for i := 0; i < t.NumField(); i++ {
field := t.Field(i)
ft := field.Type
if isStruct(ft) || isStructPtr(ft) || isSliceOfStruct(ft) {
if ft.Kind() == reflect.Ptr || ft.Kind() == reflect.Slice || ft.Kind() == reflect.Map {
ft = ft.Elem()
}
subIndexes := propertyIndexesWithTag(ft, key, value)
for _, sub := range subIndexes {
sub = append([]int{i}, sub...)
indexes = append(indexes, sub)
}
} else if HasTag(field, key, value) {
indexes = append(indexes, field.Index)
}
}
return indexes
}
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