46 lines
931 B
Go
46 lines
931 B
Go
// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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// Package flagtype defines flag.Value types.
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package flagtype
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import (
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"errors"
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"flag"
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"fmt"
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"math"
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"strconv"
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"strings"
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)
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type portValue struct{ n *uint16 }
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func PortValue(dst *uint16, defaultPort uint16) flag.Value {
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*dst = defaultPort
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return portValue{dst}
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}
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func (p portValue) String() string {
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if p.n == nil {
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return ""
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}
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return fmt.Sprint(*p.n)
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}
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func (p portValue) Set(v string) error {
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if v == "" {
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return errors.New("can't be the empty string")
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}
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if strings.Contains(v, ":") {
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return errors.New("expecting just a port number, without a colon")
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}
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n, err := strconv.ParseUint(v, 10, 64) // use 64 instead of 16 to return nicer error message
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if err != nil {
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return fmt.Errorf("not a valid number")
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}
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if n > math.MaxUint16 {
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return errors.New("out of range for port number")
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}
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*p.n = uint16(n)
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return nil
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}
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