124 lines
2.9 KiB
Go
124 lines
2.9 KiB
Go
package arg
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import (
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"fmt"
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"reflect"
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"strings"
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scalar "github.com/alexflint/go-scalar"
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)
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// setSliceOrMap parses a sequence of strings into a slice or map. If clear is
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// true then any values already in the slice or map are first removed.
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func setSliceOrMap(dest reflect.Value, values []string, clear bool) error {
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if !dest.CanSet() {
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return fmt.Errorf("field is not writable")
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}
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t := dest.Type()
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if t.Kind() == reflect.Ptr {
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dest = dest.Elem()
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t = t.Elem()
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}
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switch t.Kind() {
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case reflect.Slice:
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return setSlice(dest, values, clear)
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case reflect.Map:
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return setMap(dest, values, clear)
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default:
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return fmt.Errorf("setSliceOrMap cannot insert values into a %v", t)
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}
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}
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// setSlice parses a sequence of strings and inserts them into a slice. If clear
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// is true then any values already in the slice are removed.
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func setSlice(dest reflect.Value, values []string, clear bool) error {
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var ptr bool
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elem := dest.Type().Elem()
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if elem.Kind() == reflect.Ptr && !elem.Implements(textUnmarshalerType) {
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ptr = true
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elem = elem.Elem()
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}
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// clear the slice in case default values exist
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if clear && !dest.IsNil() {
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dest.SetLen(0)
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}
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// parse the values one-by-one
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for _, s := range values {
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v := reflect.New(elem)
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if err := scalar.ParseValue(v.Elem(), s); err != nil {
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return err
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}
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if !ptr {
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v = v.Elem()
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}
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dest.Set(reflect.Append(dest, v))
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}
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return nil
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}
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// setMap parses a sequence of name=value strings and inserts them into a map.
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// If clear is true then any values already in the map are removed.
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func setMap(dest reflect.Value, values []string, clear bool) error {
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// determine the key and value type
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var keyIsPtr bool
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keyType := dest.Type().Key()
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if keyType.Kind() == reflect.Ptr && !keyType.Implements(textUnmarshalerType) {
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keyIsPtr = true
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keyType = keyType.Elem()
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}
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var valIsPtr bool
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valType := dest.Type().Elem()
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if valType.Kind() == reflect.Ptr && !valType.Implements(textUnmarshalerType) {
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valIsPtr = true
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valType = valType.Elem()
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}
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// clear the slice in case default values exist
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if clear && !dest.IsNil() {
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for _, k := range dest.MapKeys() {
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dest.SetMapIndex(k, reflect.Value{})
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}
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}
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// allocate the map if it is not allocated
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if dest.IsNil() {
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dest.Set(reflect.MakeMap(dest.Type()))
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}
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// parse the values one-by-one
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for _, s := range values {
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// split at the first equals sign
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pos := strings.Index(s, "=")
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if pos == -1 {
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return fmt.Errorf("cannot parse %q into a map, expected format key=value", s)
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}
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// parse the key
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k := reflect.New(keyType)
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if err := scalar.ParseValue(k.Elem(), s[:pos]); err != nil {
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return err
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}
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if !keyIsPtr {
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k = k.Elem()
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}
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// parse the value
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v := reflect.New(valType)
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if err := scalar.ParseValue(v.Elem(), s[pos+1:]); err != nil {
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return err
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}
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if !valIsPtr {
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v = v.Elem()
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}
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// add it to the map
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dest.SetMapIndex(k, v)
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}
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return nil
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}
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