62 lines
1.5 KiB
Go
62 lines
1.5 KiB
Go
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package mxj
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import (
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"errors"
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"strings"
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)
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// RenameKey renames a key in a Map.
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// It works only for nested maps.
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// It doesn't work for cases when the key is in a list.
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func (mv Map) RenameKey(path string, newName string) error {
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var v bool
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var err error
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if v, err = mv.Exists(path); err == nil && !v {
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return errors.New("RenameKey: path not found: " + path)
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} else if err != nil {
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return err
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}
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if v, err = mv.Exists(parentPath(path) + "." + newName); err == nil && v {
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return errors.New("RenameKey: key already exists: " + newName)
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} else if err != nil {
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return err
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}
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m := map[string]interface{}(mv)
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return renameKey(m, path, newName)
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}
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func renameKey(m interface{}, path string, newName string) error {
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val, err := prevValueByPath(m, path)
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if err != nil {
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return err
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}
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oldName := lastKey(path)
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val[newName] = val[oldName]
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delete(val, oldName)
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return nil
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}
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// returns a value which contains a last key in the path
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// For example: prevValueByPath("a.b.c", {a{b{c: 3}}}) returns {c: 3}
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func prevValueByPath(m interface{}, path string) (map[string]interface{}, error) {
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keys := strings.Split(path, ".")
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switch mValue := m.(type) {
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case map[string]interface{}:
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for key, value := range mValue {
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if key == keys[0] {
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if len(keys) == 1 {
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return mValue, nil
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} else {
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// keep looking for the full path to the key
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return prevValueByPath(value, strings.Join(keys[1:], "."))
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}
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}
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}
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}
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return nil, errors.New("prevValueByPath: didn't find path – " + path)
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}
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