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// Copyright 2019 The Hugo Authors. 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 types
import (
"encoding/json"
"fmt"
"html/template"
"reflect"
"github.com/spf13/cast"
)
// ToStringSlicePreserveString is the same as ToStringSlicePreserveStringE,
// but it never fails.
func ToStringSlicePreserveString(v interface{}) []string {
vv, _ := ToStringSlicePreserveStringE(v)
return vv
}
// ToStringSlicePreserveStringE converts v to a string slice.
// If v is a string, it will be wrapped in a string slice.
func ToStringSlicePreserveStringE(v interface{}) ([]string, error) {
if v == nil {
return nil, nil
}
if sds, ok := v.(string); ok {
return []string{sds}, nil
}
result, err := cast.ToStringSliceE(v)
if err == nil {
return result, nil
}
// Probably []int or similar. Fall back to reflect.
vv := reflect.ValueOf(v)
switch vv.Kind() {
case reflect.Slice, reflect.Array:
result = make([]string, vv.Len())
for i := 0; i < vv.Len(); i++ {
s, err := cast.ToStringE(vv.Index(i).Interface())
if err != nil {
return nil, err
}
result[i] = s
}
return result, nil
default:
return nil, fmt.Errorf("failed to convert %T to a string slice", v)
}
}
// TypeToString converts v to a string if it's a valid string type.
// Note that this will not try to convert numeric values etc.,
// use ToString for that.
func TypeToString(v interface{}) (string, bool) {
switch s := v.(type) {
case string:
return s, true
case template.HTML:
return string(s), true
case template.CSS:
return string(s), true
case template.HTMLAttr:
return string(s), true
case template.JS:
return string(s), true
case template.JSStr:
return string(s), true
case template.URL:
return string(s), true
case template.Srcset:
return string(s), true
}
return "", false
}
// ToString converts v to a string.
func ToString(v interface{}) string {
s, _ := ToStringE(v)
return s
}
// ToStringE converts v to a string.
func ToStringE(v interface{}) (string, error) {
if s, ok := TypeToString(v); ok {
return s, nil
}
switch s := v.(type) {
case json.RawMessage:
return string(s), nil
default:
return cast.ToStringE(v)
}
}
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