Current File : //usr/local/go119/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"
"reflect"
"sort"
"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.Experiment.All(), ",")
} else {
// If the enabled experiments differ from the baseline,
// include that difference.
if goexperiment := buildcfg.Experiment.String(); 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()
}
type debugField struct {
name string
help string
val interface{} // *int or *string
}
type DebugFlag struct {
tab map[string]debugField
any *bool
debugSSA DebugSSA
}
// A DebugSSA function is called to set a -d ssa/... option.
// If nil, those options are reported as invalid options.
// If DebugSSA returns a non-empty string, that text is reported as a compiler error.
// If phase is "help", it should print usage information and terminate the process.
type DebugSSA func(phase, flag string, val int, valString string) string
// NewDebugFlag constructs a DebugFlag for the fields of debug, which
// must be a pointer to a struct.
//
// Each field of *debug is a different value, named for the lower-case of the field name.
// Each field must be an int or string and must have a `help` struct tag.
// There may be an "Any bool" field, which will be set if any debug flags are set.
//
// The returned flag takes a comma-separated list of settings.
// Each setting is name=value; for ints, name is short for name=1.
//
// If debugSSA is non-nil, any debug flags of the form ssa/... will be
// passed to debugSSA for processing.
func NewDebugFlag(debug interface{}, debugSSA DebugSSA) *DebugFlag {
flag := &DebugFlag{
tab: make(map[string]debugField),
debugSSA: debugSSA,
}
v := reflect.ValueOf(debug).Elem()
t := v.Type()
for i := 0; i < t.NumField(); i++ {
f := t.Field(i)
ptr := v.Field(i).Addr().Interface()
if f.Name == "Any" {
switch ptr := ptr.(type) {
default:
panic("debug.Any must have type bool")
case *bool:
flag.any = ptr
}
continue
}
name := strings.ToLower(f.Name)
help := f.Tag.Get("help")
if help == "" {
panic(fmt.Sprintf("debug.%s is missing help text", f.Name))
}
switch ptr.(type) {
default:
panic(fmt.Sprintf("debug.%s has invalid type %v (must be int or string)", f.Name, f.Type))
case *int, *string:
// ok
}
flag.tab[name] = debugField{name, help, ptr}
}
return flag
}
func (f *DebugFlag) Set(debugstr string) error {
if debugstr == "" {
return nil
}
if f.any != nil {
*f.any = true
}
for _, name := range strings.Split(debugstr, ",") {
if name == "" {
continue
}
// display help about the debug option itself and quit
if name == "help" {
fmt.Print(debugHelpHeader)
maxLen, names := 0, []string{}
if f.debugSSA != nil {
maxLen = len("ssa/help")
}
for name := range f.tab {
if len(name) > maxLen {
maxLen = len(name)
}
names = append(names, name)
}
sort.Strings(names)
// Indent multi-line help messages.
nl := fmt.Sprintf("\n\t%-*s\t", maxLen, "")
for _, name := range names {
help := f.tab[name].help
fmt.Printf("\t%-*s\t%s\n", maxLen, name, strings.Replace(help, "\n", nl, -1))
}
if f.debugSSA != nil {
// ssa options have their own help
fmt.Printf("\t%-*s\t%s\n", maxLen, "ssa/help", "print help about SSA debugging")
}
os.Exit(0)
}
val, valstring, haveInt := 1, "", true
if i := strings.IndexAny(name, "=:"); i >= 0 {
var err error
name, valstring = name[:i], name[i+1:]
val, err = strconv.Atoi(valstring)
if err != nil {
val, haveInt = 1, false
}
}
if t, ok := f.tab[name]; ok {
switch vp := t.val.(type) {
case nil:
// Ignore
case *string:
*vp = valstring
case *int:
if !haveInt {
log.Fatalf("invalid debug value %v", name)
}
*vp = val
default:
panic("bad debugtab type")
}
} else if f.debugSSA != nil && strings.HasPrefix(name, "ssa/") {
// expect form ssa/phase/flag
// e.g. -d=ssa/generic_cse/time
// _ in phase name also matches space
phase := name[4:]
flag := "debug" // default flag is debug
if i := strings.Index(phase, "/"); i >= 0 {
flag = phase[i+1:]
phase = phase[:i]
}
err := f.debugSSA(phase, flag, val, valstring)
if err != "" {
log.Fatalf(err)
}
} else {
return fmt.Errorf("unknown debug key %s\n", name)
}
}
return nil
}
const debugHelpHeader = `usage: -d arg[,arg]* and arg is <key>[=<value>]
<key> is one of:
`
func (f *DebugFlag) String() string {
return ""
}
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