Current File : //usr/local/go/src/cmd/internal/objabi/flag.go
// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package objabi
import (
"bytes"
"flag"
"fmt"
"internal/buildcfg"
"io"
"io/ioutil"
"log"
"os"
"strconv"
"strings"
)
func Flagcount(name, usage string, val *int) {
flag.Var((*count)(val), name, usage)
}
func Flagfn1(name, usage string, f func(string)) {
flag.Var(fn1(f), name, usage)
}
func Flagprint(w io.Writer) {
flag.CommandLine.SetOutput(w)
flag.PrintDefaults()
}
func Flagparse(usage func()) {
flag.Usage = usage
os.Args = expandArgs(os.Args)
flag.Parse()
}
// expandArgs expands "response files" arguments in the provided slice.
//
// A "response file" argument starts with '@' and the rest of that
// argument is a filename with CR-or-CRLF-separated arguments. Each
// argument in the named files can also contain response file
// arguments. See Issue 18468.
//
// The returned slice 'out' aliases 'in' iff the input did not contain
// any response file arguments.
//
// TODO: handle relative paths of recursive expansions in different directories?
// Is there a spec for this? Are relative paths allowed?
func expandArgs(in []string) (out []string) {
// out is nil until we see a "@" argument.
for i, s := range in {
if strings.HasPrefix(s, "@") {
if out == nil {
out = make([]string, 0, len(in)*2)
out = append(out, in[:i]...)
}
slurp, err := ioutil.ReadFile(s[1:])
if err != nil {
log.Fatal(err)
}
args := strings.Split(strings.TrimSpace(strings.Replace(string(slurp), "\r", "", -1)), "\n")
for i, arg := range args {
args[i] = DecodeArg(arg)
}
out = append(out, expandArgs(args)...)
} else if out != nil {
out = append(out, s)
}
}
if out == nil {
return in
}
return
}
func AddVersionFlag() {
flag.Var(versionFlag{}, "V", "print version and exit")
}
var buildID string // filled in by linker
type versionFlag struct{}
func (versionFlag) IsBoolFlag() bool { return true }
func (versionFlag) Get() interface{} { return nil }
func (versionFlag) String() string { return "" }
func (versionFlag) Set(s string) error {
name := os.Args[0]
name = name[strings.LastIndex(name, `/`)+1:]
name = name[strings.LastIndex(name, `\`)+1:]
name = strings.TrimSuffix(name, ".exe")
p := ""
if s == "goexperiment" {
// test/run.go uses this to discover the full set of
// experiment tags. Report everything.
p = " X:" + strings.Join(buildcfg.AllExperiments(), ",")
} else {
// If the enabled experiments differ from the defaults,
// include that difference.
if goexperiment := buildcfg.GOEXPERIMENT(); goexperiment != "" {
p = " X:" + goexperiment
}
}
// The go command invokes -V=full to get a unique identifier
// for this tool. It is assumed that the release version is sufficient
// for releases, but during development we include the full
// build ID of the binary, so that if the compiler is changed and
// rebuilt, we notice and rebuild all packages.
if s == "full" {
if strings.HasPrefix(buildcfg.Version, "devel") {
p += " buildID=" + buildID
}
}
fmt.Printf("%s version %s%s\n", name, buildcfg.Version, p)
os.Exit(0)
return nil
}
// count is a flag.Value that is like a flag.Bool and a flag.Int.
// If used as -name, it increments the count, but -name=x sets the count.
// Used for verbose flag -v.
type count int
func (c *count) String() string {
return fmt.Sprint(int(*c))
}
func (c *count) Set(s string) error {
switch s {
case "true":
*c++
case "false":
*c = 0
default:
n, err := strconv.Atoi(s)
if err != nil {
return fmt.Errorf("invalid count %q", s)
}
*c = count(n)
}
return nil
}
func (c *count) Get() interface{} {
return int(*c)
}
func (c *count) IsBoolFlag() bool {
return true
}
func (c *count) IsCountFlag() bool {
return true
}
type fn1 func(string)
func (f fn1) Set(s string) error {
f(s)
return nil
}
func (f fn1) String() string { return "" }
// DecodeArg decodes an argument.
//
// This function is public for testing with the parallel encoder.
func DecodeArg(arg string) string {
// If no encoding, fastpath out.
if !strings.ContainsAny(arg, "\\\n") {
return arg
}
// We can't use strings.Builder as this must work at bootstrap.
var b bytes.Buffer
var wasBS bool
for _, r := range arg {
if wasBS {
switch r {
case '\\':
b.WriteByte('\\')
case 'n':
b.WriteByte('\n')
default:
// This shouldn't happen. The only backslashes that reach here
// should encode '\n' and '\\' exclusively.
panic("badly formatted input")
}
} else if r == '\\' {
wasBS = true
continue
} else {
b.WriteRune(r)
}
wasBS = false
}
return b.String()
}
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