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read builtin: implement -a, -s, -n, -N and -d #865

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read builtin: implement -a, -s, -n, -N and -d #865

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163 changes: 144 additions & 19 deletions interp/builtin.go
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Original file line number Diff line number Diff line change
Expand Up @@ -12,9 +12,12 @@ import (
"io"
"os"
"path/filepath"
"runtime"
"strconv"
"strings"

"golang.org/x/sys/unix"
"golang.org/x/term"
"mvdan.cc/sh/v3/expand"
"mvdan.cc/sh/v3/syntax"
)
Expand Down Expand Up @@ -557,7 +560,12 @@ func (r *Runner) builtinCode(ctx context.Context, pos syntax.Pos, name string, a
r.setErr(returnStatus(code))
case "read":
var prompt string
var readArrayName string
raw := false
delim := []byte("\n")
termNoEcho := false
numBytes := -1
ignoreDelim := false
fp := flagParser{remaining: args}
for fp.more() {
switch flag := fp.flag(); flag {
Expand All @@ -569,39 +577,87 @@ func (r *Runner) builtinCode(ctx context.Context, pos syntax.Pos, name string, a
r.errf("read: -p: option requires an argument\n")
return 2
}
case "-s":
termNoEcho = true
case "-a":
readArrayName = fp.value()
if readArrayName == "" {
r.errf("read: -a: option requires an argument\n")
return 2
}
case "-n", "-N":
numBytesStr := fp.value()
if numBytesStr == "" {
r.errf("read: %s: option requires an integer argument\n", flag)
return 2
}
var err error
numBytes, err = strconv.Atoi(numBytesStr)
if err != nil {
r.errf("read: %s: option requires an integer argument\n", flag)
return 2
}
if flag == "-N" {
ignoreDelim = true
}
case "-d":
delimVal := fp.value()
if delimVal == "" {
r.errf("read: -d: option requires an argument\n")
return 2
}
delim = []byte(delimVal)
default:
r.errf("read: invalid option %q\n", flag)
return 2
}
}

args := fp.args()
for _, name := range args {
if !syntax.ValidName(name) {
r.errf("read: invalid identifier %q\n", name)

if readArrayName != "" {
if len(args) > 0 {
r.errf("read: unable to read both into an array and named args\n")
return 2
}
} else {
for _, name := range args {
if !syntax.ValidName(name) {
r.errf("read: invalid identifier %q\n", name)
return 2
}
}
if len(args) == 0 {
args = append(args, "REPLY")
}
}

if prompt != "" {
r.out(prompt)
}

line, err := r.readLine(raw)
line, err := r.readLine(delim[0], numBytes, raw, termNoEcho, ignoreDelim)
if err != nil {
return 1
}
if len(args) == 0 {
args = append(args, "REPLY")
}

values := expand.ReadFields(r.ecfg, string(line), len(args), raw)
for i, name := range args {
val := ""
if i < len(values) {
val = values[i]
if readArrayName != "" {
var vr expand.Variable
vr.Kind = expand.Indexed
values := expand.ReadFields(r.ecfg, string(line), -1, raw)
for _, val := range values {
vr.List = append(vr.List, val)
}
r.setVarInternal(readArrayName, vr)
} else {
for i, name := range args {
values := expand.ReadFields(r.ecfg, string(line), len(args), raw)
val := ""
if i < len(values) {
val = values[i]
}
r.setVarString(name, val)
}
r.setVarString(name, val)
}

return 0
Expand Down Expand Up @@ -898,11 +954,30 @@ func (r *Runner) printOptLine(name string, enabled bool) {
r.outf("%s\t%s\n", name, status)
}

func (r *Runner) readLine(raw bool) ([]byte, error) {
func (r *Runner) readLine(delim byte, numBytes int, raw bool, termNoEcho bool, ignoreDelim bool) ([]byte, error) {
if r.stdin == nil {
return nil, errors.New("interp: can't read, there's no stdin")
}

// If we are using a custom delimiter and stdin is a terminal put the
// terminal in one character at a time mode so we can read single characters
// rather than a whole line of input.
if delim != '\n' && runtime.GOOS != "windows" {
if f, ok := r.stdin.(*os.File); ok && term.IsTerminal(int(f.Fd())) {
oldState, err := termMakeOneChar(int(f.Fd()))
if err != nil {
return nil, err
}
defer termRestore(int(f.Fd()), oldState)
if termNoEcho {
_, err := termMakeNoEcho(int(f.Fd()))
if err != nil {
return nil, err
}
}
}
}

var line []byte
esc := false

Expand All @@ -915,26 +990,76 @@ func (r *Runner) readLine(raw bool) ([]byte, error) {
case !raw && b == '\\':
line = append(line, b)
esc = !esc
case !raw && b == '\n' && esc:
case !raw && b == delim && esc:
// line continuation
line = line[len(line)-1:]
esc = false
case b == '\n':
case b == delim && !ignoreDelim:
return line, nil
default:
line = append(line, b)
esc = false
}
}
if err == io.EOF && len(line) > 0 {
switch {
case err == nil && len(line) == numBytes:
return line, nil
}
if err != nil {
case err == io.EOF && len(line) > 0:
return line, nil
case err != nil:
return nil, err
}
}
}

// termMakeOneChar sets the terminal to one character at a time mode, this code
// is identical to term.MakeRaw except the state of echo is not altered.
func termMakeOneChar(fd int) (*unix.Termios, error) {
termios, err := unix.IoctlGetTermios(fd, unix.TCGETS)
if err != nil {
return nil, err
}

oldState := *termios

termios.Iflag &^= unix.IGNBRK | unix.BRKINT | unix.PARMRK | unix.ISTRIP | unix.INLCR | unix.IGNCR | unix.ICRNL | unix.IXON
termios.Oflag &^= unix.OPOST
termios.Lflag &^= unix.ICANON | unix.ISIG | unix.IEXTEN
termios.Cflag &^= unix.CSIZE | unix.PARENB
termios.Cflag |= unix.CS8
termios.Cc[unix.VMIN] = 1
termios.Cc[unix.VTIME] = 0
if err := unix.IoctlSetTermios(fd, unix.TCSETS, termios); err != nil {
return nil, err
}

return &oldState, nil
}

// termMakeNoEcho disables terminal echo.
func termMakeNoEcho(fd int) (*unix.Termios, error) {
termios, err := unix.IoctlGetTermios(fd, unix.TCGETS)
if err != nil {
return nil, err
}

oldState := *termios

// Flags stolen from Bash's tt_setnoecho.
termios.Lflag &^= unix.ECHO | unix.ECHOK | unix.ECHONL
if err := unix.IoctlSetTermios(fd, unix.TCSETS, termios); err != nil {
return nil, err
}

return &oldState, nil
}

// termRestore, like term.Restore, restores the terminal state, but uses a
// *unix.Termios param, rather than a term.State type.
func termRestore(fd int, termios *unix.Termios) error {
return unix.IoctlSetTermios(fd, unix.TCSETS, termios)
}

func (r *Runner) changeDir(ctx context.Context, path string) int {
if path == "" {
path = "."
Expand Down
31 changes: 30 additions & 1 deletion interp/interp_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -2776,7 +2776,26 @@ set +o pipefail
"read -r -p 'Prompt and raw flag together: ' a <<< '\\a\\b\\c'; echo $a",
"Prompt and raw flag together: \\a\\b\\c\n #IGNORE bash requires a terminal",
},

{
`read -a butter <<< 'a b c'; for x in "${butter[@]}"; do echo "$x"; done`,
"a\nb\nc\n",
},
{
`read -d b x<<< 'abc'; echo "$x"`,
"a\n",
},
{
`read -n 3 x<<< 'abcdefg'; echo "$x"`,
"abc\n",
},
{
`read -n 3 -d b x<<< 'abcdefg'; echo "$x"`,
"a\n",
},
{
`read -N 4 -d b x<<< 'abcdefg'; echo "$x"`,
"abcd\n",
},
// getopts
{
"getopts",
Expand Down Expand Up @@ -3214,6 +3233,16 @@ hello, world
`mapfile -t -d "" < <(printf "a\0b\n"); for x in "${MAPFILE[@]}"; do echo "$x"; done`,
"a\nb\n\n",
},
// read -N with stopping at EOF
{
`read -N 3 x < <(printf 'ab'); echo "$x"`,
"ab\n",
},
// read 4 bytes and ignore the default delimiter
{
`read -N 4 x < <(printf 'ab\ncdefg'); echo "$x"`,
"ab\nc\n",
},
}

var runTestsWindows = []runTest{
Expand Down