61 lines
1.5 KiB
Go
61 lines
1.5 KiB
Go
// The options package provides a way to pass unstructured sets of options to a
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// component expecting a strongly-typed configuration structure.
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package options
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import (
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"fmt"
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"reflect"
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)
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type NoSuchFieldError struct {
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Field string
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Type string
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}
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func (e NoSuchFieldError) Error() string {
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return fmt.Sprintf("no field %q in type %q", e.Field, e.Type)
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}
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type CannotSetFieldError struct {
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Field string
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Type string
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}
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func (e CannotSetFieldError) Error() string {
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return fmt.Sprintf("cannot set field %q of type %q", e.Field, e.Type)
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}
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type Generic map[string]interface{}
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func NewGeneric() Generic {
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return make(Generic)
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}
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func GenerateFromModel(options Generic, model interface{}) (interface{}, error) {
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modType := reflect.TypeOf(model)
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// If the model is of pointer type, we need to dereference for New.
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resType := reflect.TypeOf(model)
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if modType.Kind() == reflect.Ptr {
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resType = resType.Elem()
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}
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// Populate the result structure with the generic layout content.
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res := reflect.New(resType)
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for name, value := range options {
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field := res.Elem().FieldByName(name)
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if !field.IsValid() {
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return nil, NoSuchFieldError{name, resType.String()}
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}
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if !field.CanSet() {
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return nil, CannotSetFieldError{name, resType.String()}
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}
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field.Set(reflect.ValueOf(value))
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}
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// If the model is not of pointer type, return content of the result.
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if modType.Kind() == reflect.Ptr {
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return res.Interface(), nil
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}
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return res.Elem().Interface(), nil
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}
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