67 lines
1.5 KiB
Go
67 lines
1.5 KiB
Go
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package config
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import (
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"fmt"
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"reflect"
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"strings"
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)
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// IsZero returns whether or not the parameter is the zero value for its type.
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// If the parameter is a struct, only the exported fields are considered.
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func IsZero(c interface{}) bool {
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return isZero(reflect.ValueOf(c))
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}
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// AssertValid checks the fields in the structure and makes sure that they
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// contain valid values as specified by the 'valid' flag. Empty fields are
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// implicitly valid.
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func AssertValid(c interface{}) error {
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ct := reflect.TypeOf(c)
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cv := reflect.ValueOf(c)
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for i := 0; i < ct.NumField(); i++ {
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ft := ct.Field(i)
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if !isFieldExported(ft) {
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continue
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}
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valid := ft.Tag.Get("valid")
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val := cv.Field(i)
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if !isValid(val, valid) {
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return fmt.Errorf("invalid value \"%v\" for option %q (valid options: %q)", val.Interface(), ft.Name, valid)
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}
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}
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return nil
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}
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func isZero(v reflect.Value) bool {
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switch v.Kind() {
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case reflect.Struct:
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vt := v.Type()
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for i := 0; i < v.NumField(); i++ {
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if isFieldExported(vt.Field(i)) && !isZero(v.Field(i)) {
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return false
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}
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}
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return true
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default:
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return v.Interface() == reflect.Zero(v.Type()).Interface()
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}
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}
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func isFieldExported(f reflect.StructField) bool {
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return f.PkgPath == ""
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}
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func isValid(v reflect.Value, valid string) bool {
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if valid == "" || isZero(v) {
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return true
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}
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vs := fmt.Sprintf("%v", v.Interface())
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for _, valid := range strings.Split(valid, ",") {
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if vs == valid {
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return true
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}
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}
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return false
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}
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