985 lines
31 KiB
Go
985 lines
31 KiB
Go
// Copyright 2014 The Docker & Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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/*
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Package flag implements command-line flag parsing.
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Usage:
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Define flags using flag.String(), Bool(), Int(), etc.
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This declares an integer flag, -f or --flagname, stored in the pointer ip, with type *int.
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import "flag /github.com/dotcloud/docker/pkg/mflag"
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var ip = flag.Int([]string{"f", "-flagname"}, 1234, "help message for flagname")
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If you like, you can bind the flag to a variable using the Var() functions.
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var flagvar int
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func init() {
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// -flaghidden will work, but will be hidden from the usage
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flag.IntVar(&flagvar, []string{"f", "#flaghidden", "-flagname"}, 1234, "help message for flagname")
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}
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Or you can create custom flags that satisfy the Value interface (with
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pointer receivers) and couple them to flag parsing by
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flag.Var(&flagVal, []string{"name"}, "help message for flagname")
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For such flags, the default value is just the initial value of the variable.
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You can also add "deprecated" flags, they are still usable, bur are not shown
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in the usage and will display a warning when you try to use them:
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var ip = flag.Int([]string{"f", "#flagname", "-flagname"}, 1234, "help message for flagname")
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this will display: `Warning: '-flagname' is deprecated, it will be replaced by '--flagname' soon. See usage.` and
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var ip = flag.Int([]string{"f", "#flagname"}, 1234, "help message for flagname")
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will display: `Warning: '-t' is deprecated, it will be removed soon. See usage.`
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You can also group one letter flags, bif you declare
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var v = flag.Bool([]string{"v", "-verbose"}, false, "help message for verbose")
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var s = flag.Bool([]string{"s", "-slow"}, false, "help message for slow")
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you will be able to use the -vs or -sv
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After all flags are defined, call
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flag.Parse()
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to parse the command line into the defined flags.
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Flags may then be used directly. If you're using the flags themselves,
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they are all pointers; if you bind to variables, they're values.
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fmt.Println("ip has value ", *ip)
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fmt.Println("flagvar has value ", flagvar)
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After parsing, the arguments after the flag are available as the
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slice flag.Args() or individually as flag.Arg(i).
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The arguments are indexed from 0 through flag.NArg()-1.
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Command line flag syntax:
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-flag
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-flag=x
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-flag="x"
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-flag='x'
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-flag x // non-boolean flags only
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One or two minus signs may be used; they are equivalent.
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The last form is not permitted for boolean flags because the
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meaning of the command
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cmd -x *
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will change if there is a file called 0, false, etc. You must
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use the -flag=false form to turn off a boolean flag.
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Flag parsing stops just before the first non-flag argument
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("-" is a non-flag argument) or after the terminator "--".
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Integer flags accept 1234, 0664, 0x1234 and may be negative.
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Boolean flags may be 1, 0, t, f, true, false, TRUE, FALSE, True, False.
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Duration flags accept any input valid for time.ParseDuration.
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The default set of command-line flags is controlled by
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top-level functions. The FlagSet type allows one to define
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independent sets of flags, such as to implement subcommands
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in a command-line interface. The methods of FlagSet are
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analogous to the top-level functions for the command-line
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flag set.
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*/
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package mflag
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import (
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"errors"
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"fmt"
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"io"
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"os"
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"sort"
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"strconv"
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"strings"
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"text/tabwriter"
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"time"
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)
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// ErrHelp is the error returned if the flag -help is invoked but no such flag is defined.
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var ErrHelp = errors.New("flag: help requested")
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// ErrRetry is the error returned if you need to try letter by letter
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var ErrRetry = errors.New("flag: retry")
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// -- bool Value
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type boolValue bool
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func newBoolValue(val bool, p *bool) *boolValue {
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*p = val
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return (*boolValue)(p)
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}
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func (b *boolValue) Set(s string) error {
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v, err := strconv.ParseBool(s)
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*b = boolValue(v)
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return err
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}
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func (b *boolValue) Get() interface{} { return bool(*b) }
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func (b *boolValue) String() string { return fmt.Sprintf("%v", *b) }
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func (b *boolValue) IsBoolFlag() bool { return true }
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// optional interface to indicate boolean flags that can be
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// supplied without "=value" text
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type boolFlag interface {
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Value
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IsBoolFlag() bool
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}
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// -- int Value
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type intValue int
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func newIntValue(val int, p *int) *intValue {
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*p = val
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return (*intValue)(p)
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}
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func (i *intValue) Set(s string) error {
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v, err := strconv.ParseInt(s, 0, 64)
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*i = intValue(v)
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return err
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}
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func (i *intValue) Get() interface{} { return int(*i) }
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func (i *intValue) String() string { return fmt.Sprintf("%v", *i) }
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// -- int64 Value
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type int64Value int64
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func newInt64Value(val int64, p *int64) *int64Value {
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*p = val
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return (*int64Value)(p)
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}
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func (i *int64Value) Set(s string) error {
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v, err := strconv.ParseInt(s, 0, 64)
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*i = int64Value(v)
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return err
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}
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func (i *int64Value) Get() interface{} { return int64(*i) }
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func (i *int64Value) String() string { return fmt.Sprintf("%v", *i) }
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// -- uint Value
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type uintValue uint
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func newUintValue(val uint, p *uint) *uintValue {
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*p = val
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return (*uintValue)(p)
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}
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func (i *uintValue) Set(s string) error {
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v, err := strconv.ParseUint(s, 0, 64)
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*i = uintValue(v)
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return err
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}
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func (i *uintValue) Get() interface{} { return uint(*i) }
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func (i *uintValue) String() string { return fmt.Sprintf("%v", *i) }
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// -- uint64 Value
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type uint64Value uint64
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func newUint64Value(val uint64, p *uint64) *uint64Value {
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*p = val
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return (*uint64Value)(p)
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}
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func (i *uint64Value) Set(s string) error {
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v, err := strconv.ParseUint(s, 0, 64)
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*i = uint64Value(v)
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return err
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}
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func (i *uint64Value) Get() interface{} { return uint64(*i) }
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func (i *uint64Value) String() string { return fmt.Sprintf("%v", *i) }
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// -- string Value
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type stringValue string
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func newStringValue(val string, p *string) *stringValue {
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*p = val
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return (*stringValue)(p)
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}
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func (s *stringValue) Set(val string) error {
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*s = stringValue(val)
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return nil
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}
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func (s *stringValue) Get() interface{} { return string(*s) }
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func (s *stringValue) String() string { return fmt.Sprintf("%s", *s) }
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// -- float64 Value
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type float64Value float64
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func newFloat64Value(val float64, p *float64) *float64Value {
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*p = val
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return (*float64Value)(p)
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}
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func (f *float64Value) Set(s string) error {
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v, err := strconv.ParseFloat(s, 64)
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*f = float64Value(v)
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return err
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}
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func (f *float64Value) Get() interface{} { return float64(*f) }
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func (f *float64Value) String() string { return fmt.Sprintf("%v", *f) }
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// -- time.Duration Value
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type durationValue time.Duration
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func newDurationValue(val time.Duration, p *time.Duration) *durationValue {
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*p = val
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return (*durationValue)(p)
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}
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func (d *durationValue) Set(s string) error {
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v, err := time.ParseDuration(s)
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*d = durationValue(v)
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return err
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}
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func (d *durationValue) Get() interface{} { return time.Duration(*d) }
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func (d *durationValue) String() string { return (*time.Duration)(d).String() }
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// Value is the interface to the dynamic value stored in a flag.
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// (The default value is represented as a string.)
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//
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// If a Value has an IsBoolFlag() bool method returning true,
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// the command-line parser makes -name equivalent to -name=true
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// rather than using the next command-line argument.
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type Value interface {
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String() string
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Set(string) error
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}
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// Getter is an interface that allows the contents of a Value to be retrieved.
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// It wraps the Value interface, rather than being part of it, because it
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// appeared after Go 1 and its compatibility rules. All Value types provided
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// by this package satisfy the Getter interface.
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type Getter interface {
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Value
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Get() interface{}
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}
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// ErrorHandling defines how to handle flag parsing errors.
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type ErrorHandling int
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const (
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ContinueOnError ErrorHandling = iota
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ExitOnError
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PanicOnError
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)
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// A FlagSet represents a set of defined flags. The zero value of a FlagSet
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// has no name and has ContinueOnError error handling.
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type FlagSet struct {
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// Usage is the function called when an error occurs while parsing flags.
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// The field is a function (not a method) that may be changed to point to
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// a custom error handler.
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Usage func()
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name string
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parsed bool
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actual map[string]*Flag
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formal map[string]*Flag
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args []string // arguments after flags
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errorHandling ErrorHandling
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output io.Writer // nil means stderr; use out() accessor
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}
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// A Flag represents the state of a flag.
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type Flag struct {
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Names []string // name as it appears on command line
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Usage string // help message
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Value Value // value as set
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DefValue string // default value (as text); for usage message
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}
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type flagSlice []string
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func (p flagSlice) Len() int { return len(p) }
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func (p flagSlice) Less(i, j int) bool {
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pi, pj := strings.ToLower(p[i]), strings.ToLower(p[j])
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if pi[0] == '-' {
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pi = pi[1:]
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}
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if pj[0] == '-' {
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pj = pj[1:]
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}
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return pi < pj
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}
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func (p flagSlice) Swap(i, j int) { p[i], p[j] = p[j], p[i] }
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// sortFlags returns the flags as a slice in lexicographical sorted order.
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func sortFlags(flags map[string]*Flag) []*Flag {
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var list flagSlice
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for _, f := range flags {
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fName := strings.TrimPrefix(f.Names[0], "#")
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if len(f.Names) == 1 {
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list = append(list, fName)
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continue
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}
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found := false
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for _, name := range list {
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if name == fName {
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found = true
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break
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}
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}
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if !found {
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list = append(list, fName)
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}
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}
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sort.Sort(list)
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result := make([]*Flag, len(list))
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for i, name := range list {
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result[i] = flags[name]
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}
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return result
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}
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func (f *FlagSet) out() io.Writer {
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if f.output == nil {
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return os.Stderr
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}
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return f.output
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}
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// SetOutput sets the destination for usage and error messages.
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// If output is nil, os.Stderr is used.
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func (f *FlagSet) SetOutput(output io.Writer) {
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f.output = output
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}
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// VisitAll visits the flags in lexicographical order, calling fn for each.
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// It visits all flags, even those not set.
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func (f *FlagSet) VisitAll(fn func(*Flag)) {
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for _, flag := range sortFlags(f.formal) {
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fn(flag)
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}
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}
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// VisitAll visits the command-line flags in lexicographical order, calling
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// fn for each. It visits all flags, even those not set.
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func VisitAll(fn func(*Flag)) {
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CommandLine.VisitAll(fn)
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}
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// Visit visits the flags in lexicographical order, calling fn for each.
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// It visits only those flags that have been set.
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func (f *FlagSet) Visit(fn func(*Flag)) {
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for _, flag := range sortFlags(f.actual) {
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fn(flag)
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}
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}
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// Visit visits the command-line flags in lexicographical order, calling fn
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// for each. It visits only those flags that have been set.
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func Visit(fn func(*Flag)) {
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CommandLine.Visit(fn)
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}
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// Lookup returns the Flag structure of the named flag, returning nil if none exists.
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func (f *FlagSet) Lookup(name string) *Flag {
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return f.formal[name]
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}
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// Lookup returns the Flag structure of the named command-line flag,
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// returning nil if none exists.
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func Lookup(name string) *Flag {
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return CommandLine.formal[name]
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}
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// Set sets the value of the named flag.
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func (f *FlagSet) Set(name, value string) error {
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flag, ok := f.formal[name]
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if !ok {
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return fmt.Errorf("no such flag -%v", name)
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}
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err := flag.Value.Set(value)
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if err != nil {
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return err
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}
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if f.actual == nil {
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f.actual = make(map[string]*Flag)
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}
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f.actual[name] = flag
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return nil
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}
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// Set sets the value of the named command-line flag.
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func Set(name, value string) error {
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return CommandLine.Set(name, value)
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}
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// PrintDefaults prints, to standard error unless configured
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// otherwise, the default values of all defined flags in the set.
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func (f *FlagSet) PrintDefaults() {
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writer := tabwriter.NewWriter(f.out(), 20, 1, 3, ' ', 0)
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f.VisitAll(func(flag *Flag) {
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format := " -%s=%s"
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if _, ok := flag.Value.(*stringValue); ok {
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// put quotes on the value
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format = " -%s=%q"
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}
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names := []string{}
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for _, name := range flag.Names {
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if name[0] != '#' {
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names = append(names, name)
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}
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}
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if len(names) > 0 {
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fmt.Fprintf(writer, format, strings.Join(names, ", -"), flag.DefValue)
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for i, line := range strings.Split(flag.Usage, "\n") {
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if i != 0 {
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line = " " + line
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}
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fmt.Fprintln(writer, "\t", line)
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}
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// start := fmt.Sprintf(format, strings.Join(names, ", -"), flag.DefValue)
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// fmt.Fprintln(f.out(), start, strings.Replace(flag.Usage, "\n", "\n"+strings.Repeat(" ", len(start)+1), -1))
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}
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})
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writer.Flush()
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}
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// PrintDefaults prints to standard error the default values of all defined command-line flags.
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func PrintDefaults() {
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CommandLine.PrintDefaults()
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}
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// defaultUsage is the default function to print a usage message.
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func defaultUsage(f *FlagSet) {
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if f.name == "" {
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fmt.Fprintf(f.out(), "Usage:\n")
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} else {
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fmt.Fprintf(f.out(), "Usage of %s:\n", f.name)
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}
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f.PrintDefaults()
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}
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// NOTE: Usage is not just defaultUsage(CommandLine)
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// because it serves (via godoc flag Usage) as the example
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// for how to write your own usage function.
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// Usage prints to standard error a usage message documenting all defined command-line flags.
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// The function is a variable that may be changed to point to a custom function.
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var Usage = func() {
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fmt.Fprintf(os.Stderr, "Usage of %s:\n", os.Args[0])
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PrintDefaults()
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}
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// NFlag returns the number of flags that have been set.
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func (f *FlagSet) NFlag() int { return len(f.actual) }
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// NFlag returns the number of command-line flags that have been set.
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func NFlag() int { return len(CommandLine.actual) }
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// Arg returns the i'th argument. Arg(0) is the first remaining argument
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// after flags have been processed.
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func (f *FlagSet) Arg(i int) string {
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if i < 0 || i >= len(f.args) {
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return ""
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}
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return f.args[i]
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}
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// Arg returns the i'th command-line argument. Arg(0) is the first remaining argument
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// after flags have been processed.
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func Arg(i int) string {
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return CommandLine.Arg(i)
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}
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// NArg is the number of arguments remaining after flags have been processed.
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func (f *FlagSet) NArg() int { return len(f.args) }
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// NArg is the number of arguments remaining after flags have been processed.
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func NArg() int { return len(CommandLine.args) }
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// Args returns the non-flag arguments.
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func (f *FlagSet) Args() []string { return f.args }
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// Args returns the non-flag command-line arguments.
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func Args() []string { return CommandLine.args }
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// BoolVar defines a bool flag with specified name, default value, and usage string.
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// The argument p points to a bool variable in which to store the value of the flag.
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func (f *FlagSet) BoolVar(p *bool, names []string, value bool, usage string) {
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f.Var(newBoolValue(value, p), names, usage)
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}
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// BoolVar defines a bool flag with specified name, default value, and usage string.
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// The argument p points to a bool variable in which to store the value of the flag.
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func BoolVar(p *bool, names []string, value bool, usage string) {
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CommandLine.Var(newBoolValue(value, p), names, usage)
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}
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// Bool defines a bool flag with specified name, default value, and usage string.
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// The return value is the address of a bool variable that stores the value of the flag.
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func (f *FlagSet) Bool(names []string, value bool, usage string) *bool {
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p := new(bool)
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f.BoolVar(p, names, value, usage)
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return p
|
|
}
|
|
|
|
// Bool defines a bool flag with specified name, default value, and usage string.
|
|
// The return value is the address of a bool variable that stores the value of the flag.
|
|
func Bool(names []string, value bool, usage string) *bool {
|
|
return CommandLine.Bool(names, value, usage)
|
|
}
|
|
|
|
// IntVar defines an int flag with specified name, default value, and usage string.
|
|
// The argument p points to an int variable in which to store the value of the flag.
|
|
func (f *FlagSet) IntVar(p *int, names []string, value int, usage string) {
|
|
f.Var(newIntValue(value, p), names, usage)
|
|
}
|
|
|
|
// IntVar defines an int flag with specified name, default value, and usage string.
|
|
// The argument p points to an int variable in which to store the value of the flag.
|
|
func IntVar(p *int, names []string, value int, usage string) {
|
|
CommandLine.Var(newIntValue(value, p), names, usage)
|
|
}
|
|
|
|
// Int defines an int flag with specified name, default value, and usage string.
|
|
// The return value is the address of an int variable that stores the value of the flag.
|
|
func (f *FlagSet) Int(names []string, value int, usage string) *int {
|
|
p := new(int)
|
|
f.IntVar(p, names, value, usage)
|
|
return p
|
|
}
|
|
|
|
// Int defines an int flag with specified name, default value, and usage string.
|
|
// The return value is the address of an int variable that stores the value of the flag.
|
|
func Int(names []string, value int, usage string) *int {
|
|
return CommandLine.Int(names, value, usage)
|
|
}
|
|
|
|
// Int64Var defines an int64 flag with specified name, default value, and usage string.
|
|
// The argument p points to an int64 variable in which to store the value of the flag.
|
|
func (f *FlagSet) Int64Var(p *int64, names []string, value int64, usage string) {
|
|
f.Var(newInt64Value(value, p), names, usage)
|
|
}
|
|
|
|
// Int64Var defines an int64 flag with specified name, default value, and usage string.
|
|
// The argument p points to an int64 variable in which to store the value of the flag.
|
|
func Int64Var(p *int64, names []string, value int64, usage string) {
|
|
CommandLine.Var(newInt64Value(value, p), names, usage)
|
|
}
|
|
|
|
// Int64 defines an int64 flag with specified name, default value, and usage string.
|
|
// The return value is the address of an int64 variable that stores the value of the flag.
|
|
func (f *FlagSet) Int64(names []string, value int64, usage string) *int64 {
|
|
p := new(int64)
|
|
f.Int64Var(p, names, value, usage)
|
|
return p
|
|
}
|
|
|
|
// Int64 defines an int64 flag with specified name, default value, and usage string.
|
|
// The return value is the address of an int64 variable that stores the value of the flag.
|
|
func Int64(names []string, value int64, usage string) *int64 {
|
|
return CommandLine.Int64(names, value, usage)
|
|
}
|
|
|
|
// UintVar defines a uint flag with specified name, default value, and usage string.
|
|
// The argument p points to a uint variable in which to store the value of the flag.
|
|
func (f *FlagSet) UintVar(p *uint, names []string, value uint, usage string) {
|
|
f.Var(newUintValue(value, p), names, usage)
|
|
}
|
|
|
|
// UintVar defines a uint flag with specified name, default value, and usage string.
|
|
// The argument p points to a uint variable in which to store the value of the flag.
|
|
func UintVar(p *uint, names []string, value uint, usage string) {
|
|
CommandLine.Var(newUintValue(value, p), names, usage)
|
|
}
|
|
|
|
// Uint defines a uint flag with specified name, default value, and usage string.
|
|
// The return value is the address of a uint variable that stores the value of the flag.
|
|
func (f *FlagSet) Uint(names []string, value uint, usage string) *uint {
|
|
p := new(uint)
|
|
f.UintVar(p, names, value, usage)
|
|
return p
|
|
}
|
|
|
|
// Uint defines a uint flag with specified name, default value, and usage string.
|
|
// The return value is the address of a uint variable that stores the value of the flag.
|
|
func Uint(names []string, value uint, usage string) *uint {
|
|
return CommandLine.Uint(names, value, usage)
|
|
}
|
|
|
|
// Uint64Var defines a uint64 flag with specified name, default value, and usage string.
|
|
// The argument p points to a uint64 variable in which to store the value of the flag.
|
|
func (f *FlagSet) Uint64Var(p *uint64, names []string, value uint64, usage string) {
|
|
f.Var(newUint64Value(value, p), names, usage)
|
|
}
|
|
|
|
// Uint64Var defines a uint64 flag with specified name, default value, and usage string.
|
|
// The argument p points to a uint64 variable in which to store the value of the flag.
|
|
func Uint64Var(p *uint64, names []string, value uint64, usage string) {
|
|
CommandLine.Var(newUint64Value(value, p), names, usage)
|
|
}
|
|
|
|
// Uint64 defines a uint64 flag with specified name, default value, and usage string.
|
|
// The return value is the address of a uint64 variable that stores the value of the flag.
|
|
func (f *FlagSet) Uint64(names []string, value uint64, usage string) *uint64 {
|
|
p := new(uint64)
|
|
f.Uint64Var(p, names, value, usage)
|
|
return p
|
|
}
|
|
|
|
// Uint64 defines a uint64 flag with specified name, default value, and usage string.
|
|
// The return value is the address of a uint64 variable that stores the value of the flag.
|
|
func Uint64(names []string, value uint64, usage string) *uint64 {
|
|
return CommandLine.Uint64(names, value, usage)
|
|
}
|
|
|
|
// StringVar defines a string flag with specified name, default value, and usage string.
|
|
// The argument p points to a string variable in which to store the value of the flag.
|
|
func (f *FlagSet) StringVar(p *string, names []string, value string, usage string) {
|
|
f.Var(newStringValue(value, p), names, usage)
|
|
}
|
|
|
|
// StringVar defines a string flag with specified name, default value, and usage string.
|
|
// The argument p points to a string variable in which to store the value of the flag.
|
|
func StringVar(p *string, names []string, value string, usage string) {
|
|
CommandLine.Var(newStringValue(value, p), names, usage)
|
|
}
|
|
|
|
// String defines a string flag with specified name, default value, and usage string.
|
|
// The return value is the address of a string variable that stores the value of the flag.
|
|
func (f *FlagSet) String(names []string, value string, usage string) *string {
|
|
p := new(string)
|
|
f.StringVar(p, names, value, usage)
|
|
return p
|
|
}
|
|
|
|
// String defines a string flag with specified name, default value, and usage string.
|
|
// The return value is the address of a string variable that stores the value of the flag.
|
|
func String(names []string, value string, usage string) *string {
|
|
return CommandLine.String(names, value, usage)
|
|
}
|
|
|
|
// Float64Var defines a float64 flag with specified name, default value, and usage string.
|
|
// The argument p points to a float64 variable in which to store the value of the flag.
|
|
func (f *FlagSet) Float64Var(p *float64, names []string, value float64, usage string) {
|
|
f.Var(newFloat64Value(value, p), names, usage)
|
|
}
|
|
|
|
// Float64Var defines a float64 flag with specified name, default value, and usage string.
|
|
// The argument p points to a float64 variable in which to store the value of the flag.
|
|
func Float64Var(p *float64, names []string, value float64, usage string) {
|
|
CommandLine.Var(newFloat64Value(value, p), names, usage)
|
|
}
|
|
|
|
// Float64 defines a float64 flag with specified name, default value, and usage string.
|
|
// The return value is the address of a float64 variable that stores the value of the flag.
|
|
func (f *FlagSet) Float64(names []string, value float64, usage string) *float64 {
|
|
p := new(float64)
|
|
f.Float64Var(p, names, value, usage)
|
|
return p
|
|
}
|
|
|
|
// Float64 defines a float64 flag with specified name, default value, and usage string.
|
|
// The return value is the address of a float64 variable that stores the value of the flag.
|
|
func Float64(names []string, value float64, usage string) *float64 {
|
|
return CommandLine.Float64(names, value, usage)
|
|
}
|
|
|
|
// DurationVar defines a time.Duration flag with specified name, default value, and usage string.
|
|
// The argument p points to a time.Duration variable in which to store the value of the flag.
|
|
func (f *FlagSet) DurationVar(p *time.Duration, names []string, value time.Duration, usage string) {
|
|
f.Var(newDurationValue(value, p), names, usage)
|
|
}
|
|
|
|
// DurationVar defines a time.Duration flag with specified name, default value, and usage string.
|
|
// The argument p points to a time.Duration variable in which to store the value of the flag.
|
|
func DurationVar(p *time.Duration, names []string, value time.Duration, usage string) {
|
|
CommandLine.Var(newDurationValue(value, p), names, usage)
|
|
}
|
|
|
|
// Duration defines a time.Duration flag with specified name, default value, and usage string.
|
|
// The return value is the address of a time.Duration variable that stores the value of the flag.
|
|
func (f *FlagSet) Duration(names []string, value time.Duration, usage string) *time.Duration {
|
|
p := new(time.Duration)
|
|
f.DurationVar(p, names, value, usage)
|
|
return p
|
|
}
|
|
|
|
// Duration defines a time.Duration flag with specified name, default value, and usage string.
|
|
// The return value is the address of a time.Duration variable that stores the value of the flag.
|
|
func Duration(names []string, value time.Duration, usage string) *time.Duration {
|
|
return CommandLine.Duration(names, value, usage)
|
|
}
|
|
|
|
// Var defines a flag with the specified name and usage string. The type and
|
|
// value of the flag are represented by the first argument, of type Value, which
|
|
// typically holds a user-defined implementation of Value. For instance, the
|
|
// caller could create a flag that turns a comma-separated string into a slice
|
|
// of strings by giving the slice the methods of Value; in particular, Set would
|
|
// decompose the comma-separated string into the slice.
|
|
func (f *FlagSet) Var(value Value, names []string, usage string) {
|
|
// Remember the default value as a string; it won't change.
|
|
flag := &Flag{names, usage, value, value.String()}
|
|
for _, name := range names {
|
|
name = strings.TrimPrefix(name, "#")
|
|
_, alreadythere := f.formal[name]
|
|
if alreadythere {
|
|
var msg string
|
|
if f.name == "" {
|
|
msg = fmt.Sprintf("flag redefined: %s", name)
|
|
} else {
|
|
msg = fmt.Sprintf("%s flag redefined: %s", f.name, name)
|
|
}
|
|
fmt.Fprintln(f.out(), msg)
|
|
panic(msg) // Happens only if flags are declared with identical names
|
|
}
|
|
if f.formal == nil {
|
|
f.formal = make(map[string]*Flag)
|
|
}
|
|
f.formal[name] = flag
|
|
}
|
|
}
|
|
|
|
// Var defines a flag with the specified name and usage string. The type and
|
|
// value of the flag are represented by the first argument, of type Value, which
|
|
// typically holds a user-defined implementation of Value. For instance, the
|
|
// caller could create a flag that turns a comma-separated string into a slice
|
|
// of strings by giving the slice the methods of Value; in particular, Set would
|
|
// decompose the comma-separated string into the slice.
|
|
func Var(value Value, names []string, usage string) {
|
|
CommandLine.Var(value, names, usage)
|
|
}
|
|
|
|
// failf prints to standard error a formatted error and usage message and
|
|
// returns the error.
|
|
func (f *FlagSet) failf(format string, a ...interface{}) error {
|
|
err := fmt.Errorf(format, a...)
|
|
fmt.Fprintln(f.out(), err)
|
|
f.usage()
|
|
return err
|
|
}
|
|
|
|
// usage calls the Usage method for the flag set, or the usage function if
|
|
// the flag set is CommandLine.
|
|
func (f *FlagSet) usage() {
|
|
if f == CommandLine {
|
|
Usage()
|
|
} else if f.Usage == nil {
|
|
defaultUsage(f)
|
|
} else {
|
|
f.Usage()
|
|
}
|
|
}
|
|
|
|
func trimQuotes(str string) string {
|
|
type quote struct {
|
|
start, end byte
|
|
}
|
|
|
|
// All valid quote types.
|
|
quotes := []quote{
|
|
// Double quotes
|
|
{
|
|
start: '"',
|
|
end: '"',
|
|
},
|
|
|
|
// Single quotes
|
|
{
|
|
start: '\'',
|
|
end: '\'',
|
|
},
|
|
}
|
|
|
|
for _, quote := range quotes {
|
|
// Only strip if outermost match.
|
|
if str[0] == quote.start && str[len(str)-1] == quote.end {
|
|
str = str[1 : len(str)-1]
|
|
break
|
|
}
|
|
}
|
|
|
|
return str
|
|
}
|
|
|
|
// parseOne parses one flag. It reports whether a flag was seen.
|
|
func (f *FlagSet) parseOne() (bool, string, error) {
|
|
if len(f.args) == 0 {
|
|
return false, "", nil
|
|
}
|
|
s := f.args[0]
|
|
if len(s) == 0 || s[0] != '-' || len(s) == 1 {
|
|
return false, "", nil
|
|
}
|
|
if s[1] == '-' && len(s) == 2 { // "--" terminates the flags
|
|
f.args = f.args[1:]
|
|
return false, "", nil
|
|
}
|
|
name := s[1:]
|
|
if len(name) == 0 || name[0] == '=' {
|
|
return false, "", f.failf("bad flag syntax: %s", s)
|
|
}
|
|
|
|
// it's a flag. does it have an argument?
|
|
f.args = f.args[1:]
|
|
has_value := false
|
|
value := ""
|
|
for i := 1; i < len(name); i++ { // equals cannot be first
|
|
if name[i] == '=' {
|
|
value = trimQuotes(name[i+1:])
|
|
has_value = true
|
|
name = name[0:i]
|
|
break
|
|
}
|
|
}
|
|
m := f.formal
|
|
flag, alreadythere := m[name] // BUG
|
|
if !alreadythere {
|
|
if name == "-help" || name == "help" || name == "h" { // special case for nice help message.
|
|
f.usage()
|
|
return false, "", ErrHelp
|
|
}
|
|
if len(name) > 0 && name[0] == '-' {
|
|
return false, "", f.failf("flag provided but not defined: -%s", name)
|
|
}
|
|
return false, name, ErrRetry
|
|
}
|
|
if fv, ok := flag.Value.(boolFlag); ok && fv.IsBoolFlag() { // special case: doesn't need an arg
|
|
if has_value {
|
|
if err := fv.Set(value); err != nil {
|
|
return false, "", f.failf("invalid boolean value %q for -%s: %v", value, name, err)
|
|
}
|
|
} else {
|
|
fv.Set("true")
|
|
}
|
|
} else {
|
|
// It must have a value, which might be the next argument.
|
|
if !has_value && len(f.args) > 0 {
|
|
// value is the next arg
|
|
has_value = true
|
|
value, f.args = f.args[0], f.args[1:]
|
|
}
|
|
if !has_value {
|
|
return false, "", f.failf("flag needs an argument: -%s", name)
|
|
}
|
|
if err := flag.Value.Set(value); err != nil {
|
|
return false, "", f.failf("invalid value %q for flag -%s: %v", value, name, err)
|
|
}
|
|
}
|
|
if f.actual == nil {
|
|
f.actual = make(map[string]*Flag)
|
|
}
|
|
f.actual[name] = flag
|
|
for i, n := range flag.Names {
|
|
if n == fmt.Sprintf("#%s", name) {
|
|
replacement := ""
|
|
for j := i; j < len(flag.Names); j++ {
|
|
if flag.Names[j][0] != '#' {
|
|
replacement = flag.Names[j]
|
|
break
|
|
}
|
|
}
|
|
if replacement != "" {
|
|
fmt.Fprintf(f.out(), "Warning: '-%s' is deprecated, it will be replaced by '-%s' soon. See usage.\n", name, replacement)
|
|
} else {
|
|
fmt.Fprintf(f.out(), "Warning: '-%s' is deprecated, it will be removed soon. See usage.\n", name)
|
|
}
|
|
}
|
|
}
|
|
return true, "", nil
|
|
}
|
|
|
|
// Parse parses flag definitions from the argument list, which should not
|
|
// include the command name. Must be called after all flags in the FlagSet
|
|
// are defined and before flags are accessed by the program.
|
|
// The return value will be ErrHelp if -help was set but not defined.
|
|
func (f *FlagSet) Parse(arguments []string) error {
|
|
f.parsed = true
|
|
f.args = arguments
|
|
for {
|
|
seen, name, err := f.parseOne()
|
|
if seen {
|
|
continue
|
|
}
|
|
if err == nil {
|
|
break
|
|
}
|
|
if err == ErrRetry {
|
|
if len(name) > 1 {
|
|
err = nil
|
|
for _, letter := range strings.Split(name, "") {
|
|
f.args = append([]string{"-" + letter}, f.args...)
|
|
seen2, _, err2 := f.parseOne()
|
|
if seen2 {
|
|
continue
|
|
}
|
|
if err2 != nil {
|
|
err = f.failf("flag provided but not defined: -%s", name)
|
|
break
|
|
}
|
|
}
|
|
if err == nil {
|
|
continue
|
|
}
|
|
} else {
|
|
err = f.failf("flag provided but not defined: -%s", name)
|
|
}
|
|
}
|
|
switch f.errorHandling {
|
|
case ContinueOnError:
|
|
return err
|
|
case ExitOnError:
|
|
os.Exit(2)
|
|
case PanicOnError:
|
|
panic(err)
|
|
}
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// Parsed reports whether f.Parse has been called.
|
|
func (f *FlagSet) Parsed() bool {
|
|
return f.parsed
|
|
}
|
|
|
|
// Parse parses the command-line flags from os.Args[1:]. Must be called
|
|
// after all flags are defined and before flags are accessed by the program.
|
|
func Parse() {
|
|
// Ignore errors; CommandLine is set for ExitOnError.
|
|
CommandLine.Parse(os.Args[1:])
|
|
}
|
|
|
|
// Parsed returns true if the command-line flags have been parsed.
|
|
func Parsed() bool {
|
|
return CommandLine.Parsed()
|
|
}
|
|
|
|
// CommandLine is the default set of command-line flags, parsed from os.Args.
|
|
// The top-level functions such as BoolVar, Arg, and on are wrappers for the
|
|
// methods of CommandLine.
|
|
var CommandLine = NewFlagSet(os.Args[0], ExitOnError)
|
|
|
|
// NewFlagSet returns a new, empty flag set with the specified name and
|
|
// error handling property.
|
|
func NewFlagSet(name string, errorHandling ErrorHandling) *FlagSet {
|
|
f := &FlagSet{
|
|
name: name,
|
|
errorHandling: errorHandling,
|
|
}
|
|
return f
|
|
}
|
|
|
|
// Init sets the name and error handling property for a flag set.
|
|
// By default, the zero FlagSet uses an empty name and the
|
|
// ContinueOnError error handling policy.
|
|
func (f *FlagSet) Init(name string, errorHandling ErrorHandling) {
|
|
f.name = name
|
|
f.errorHandling = errorHandling
|
|
}
|