forked from Shiloh/githaven
66 lines
1.9 KiB
Go
66 lines
1.9 KiB
Go
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// Copyright 2020 The Gitea Authors. All rights reserved.
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// Use of this source code is governed by a MIT-style
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// license that can be found in the LICENSE file.
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package storage
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import (
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"encoding/json"
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"reflect"
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)
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// Mappable represents an interface that can MapTo another interface
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type Mappable interface {
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MapTo(v interface{}) error
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}
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// toConfig will attempt to convert a given configuration cfg into the provided exemplar type.
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//
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// It will tolerate the cfg being passed as a []byte or string of a json representation of the
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// exemplar or the correct type of the exemplar itself
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func toConfig(exemplar, cfg interface{}) (interface{}, error) {
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// First of all check if we've got the same type as the exemplar - if so it's all fine.
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if reflect.TypeOf(cfg).AssignableTo(reflect.TypeOf(exemplar)) {
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return cfg, nil
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}
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// Now if not - does it provide a MapTo function we can try?
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if mappable, ok := cfg.(Mappable); ok {
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newVal := reflect.New(reflect.TypeOf(exemplar))
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if err := mappable.MapTo(newVal.Interface()); err == nil {
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return newVal.Elem().Interface(), nil
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}
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// MapTo has failed us ... let's try the json route ...
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}
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// OK we've been passed a byte array right?
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configBytes, ok := cfg.([]byte)
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if !ok {
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// oh ... it's a string then?
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var configStr string
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configStr, ok = cfg.(string)
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configBytes = []byte(configStr)
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}
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if !ok {
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// hmm ... can we marshal it to json?
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var err error
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configBytes, err = json.Marshal(cfg)
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ok = (err == nil)
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}
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if !ok {
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// no ... we've tried hard enough at this point - throw an error!
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return nil, ErrInvalidConfiguration{cfg: cfg}
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}
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// OK unmarshal the byte array into a new copy of the exemplar
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newVal := reflect.New(reflect.TypeOf(exemplar))
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if err := json.Unmarshal(configBytes, newVal.Interface()); err != nil {
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// If we can't unmarshal it then return an error!
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return nil, ErrInvalidConfiguration{cfg: cfg, err: err}
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}
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return newVal.Elem().Interface(), nil
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}
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