1 files changed, 201 insertions, 0 deletions
diff --git a/src/cmd/internal/objabi/flag.go b/src/cmd/internal/objabi/flag.go
new file mode 100644
index 0000000..3fd73f3
--- /dev/null
+++ b/src/cmd/internal/objabi/flag.go
@@ -0,0 +1,201 @@
+// 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"
+	"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")
+
+	// If there's an active experiment, include that,
+	// to distinguish go1.10.2 with an experiment
+	// from go1.10.2 without an experiment.
+	p := Expstring()
+	if p == DefaultExpstring() {
+		p = ""
+	}
+	sep := ""
+	if p != "" {
+		sep = " "
+	}
+
+	// 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(Version, "devel") {
+			p += " buildID=" + buildID
+		}
+	}
+
+	fmt.Printf("%s version %s%s%s\n", name, Version, sep, 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()
+}