50 lines
1.4 KiB
Go
50 lines
1.4 KiB
Go
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package prepared_query
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import (
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"fmt"
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"reflect"
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)
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// visitor is a function that will get called for each string element of a
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// structure.
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type visitor func(path string, v reflect.Value) error
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// visit calls the visitor function for each string it finds, and will descend
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// recursively into structures and slices. If any visitor returns an error then
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// the search will stop and that error will be returned.
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func visit(path string, v reflect.Value, t reflect.Type, fn visitor) error {
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switch v.Kind() {
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case reflect.String:
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return fn(path, v)
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case reflect.Struct:
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for i := 0; i < v.NumField(); i++ {
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vf := v.Field(i)
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tf := t.Field(i)
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newPath := fmt.Sprintf("%s.%s", path, tf.Name)
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if err := visit(newPath, vf, tf.Type, fn); err != nil {
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return err
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}
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}
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case reflect.Slice:
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for i := 0; i < v.Len(); i++ {
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vi := v.Index(i)
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ti := vi.Type()
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newPath := fmt.Sprintf("%s[%d]", path, i)
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if err := visit(newPath, vi, ti, fn); err != nil {
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return err
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}
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}
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}
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return nil
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}
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// walk finds all the string elements of a given structure (and its sub-
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// structures) and calls the visitor function. Each string found will get
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// a unique path computed. If any visitor returns an error then the search
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// will stop and that error will be returned.
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func walk(obj interface{}, fn visitor) error {
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v := reflect.ValueOf(obj).Elem()
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t := v.Type()
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return visit("", v, t, fn)
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}
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