staros/process.go

package staros

import (
	"bytes"
	"context"
	"errors"
	"io"
	"os"
	"os/exec"
	"sync"
	"sync/atomic"
	"time"
)

var errNilCommand = errors.New("nil command")
var errCommandStdinUnavailable = errors.New("command stdin is not available")
var errCommandProcessNotStarted = errors.New("command process is not started")
var errCommandAlreadyStarted = errors.New("command already started")
var errCommandAlreadyReleased = errors.New("command already released")
var errCommandStdinClosed = errors.New("command stdin is closed")
var errCommandAlreadyDetached = errors.New("command already detached")
var errCommandDetached = errors.New("command already detached")
var errCommandRedirectNil = errors.New("command redirect target is nil")

const starCmdUnknownExitCode = -999
const starCmdStreamBuffer = 64

type starCmdStream int

const (
	starCmdStdout starCmdStream = iota
	starCmdStderr
)

// StarCmdOutputStream identifies which process stream produced a chunk.
type StarCmdOutputStream int

const (
	StarCmdOutputStdout StarCmdOutputStream = iota
	StarCmdOutputStderr
)

// StarCmdOutput is a streamed stdout/stderr chunk.
type StarCmdOutput struct {
	Stream StarCmdOutputStream
	Data   []byte
}

type starCmdWriter struct {
	cmd    *StarCmd
	stream starCmdStream
}

func (writer starCmdWriter) Write(data []byte) (int, error) {
	if writer.cmd == nil {
		return 0, errNilCommand
	}
	writer.cmd.lock.Lock()
	writer.cmd.ensureBuffers()
	var redirect io.Writer
	switch writer.stream {
	case starCmdStdout:
		if _, err := writer.cmd.stdoutBuf.Write(data); err != nil {
			writer.cmd.lock.Unlock()
			return 0, err
		}
		writer.cmd.stdout = append(writer.cmd.stdout, data...)
		writer.cmd.publishStreamLocked(starCmdStdout, data)
		redirect = writer.cmd.stdoutRedirect
	case starCmdStderr:
		if _, err := writer.cmd.stderrBuf.Write(data); err != nil {
			writer.cmd.lock.Unlock()
			return 0, err
		}
		writer.cmd.errout = append(writer.cmd.errout, data...)
		writer.cmd.publishStreamLocked(starCmdStderr, data)
		redirect = writer.cmd.stderrRedirect
	default:
		writer.cmd.lock.Unlock()
		return 0, errors.New("unknown command stream")
	}
	writer.cmd.lock.Unlock()
	if redirect != nil {
		writer.cmd.redirectLock.Lock()
		n, err := redirect.Write(data)
		writer.cmd.redirectLock.Unlock()
		if err != nil {
			return n, err
		}
		if n != len(data) {
			return n, io.ErrShortWrite
		}
	}
	return len(data), nil
}

//StarCmd Is Here

type StarCmd struct {
	CMD      *exec.Cmd
	infile   io.WriteCloser
	inclosed bool
	running  int32
	started  int32
	released int32
	detached int32
	//Store AlL of the Standed Outputs
	stdout []byte
	//Store All of the Standed Errors
	errout         []byte
	runerr         error
	exitcode       int
	stdoutBuf      *bytes.Buffer
	stderrBuf      *bytes.Buffer
	lock           sync.Mutex
	prewrite       []string
	prewritetime   time.Duration
	stopctxfunc    context.CancelFunc
	stopctx        context.Context
	doneOnce       sync.Once
	done           chan struct{}
	resultOnce     sync.Once
	resultDone     chan struct{}
	stdoutStream   []chan []byte
	stderrStream   []chan []byte
	outputStream   []chan StarCmdOutput
	streamClosed   bool
	stdoutRedirect io.Writer
	stderrRedirect io.Writer
	redirectLock   sync.Mutex
	closeAfter     []io.Closer
}

func (starcli *StarCmd) ensureBuffers() {
	if starcli.stdoutBuf == nil {
		starcli.stdoutBuf = bytes.NewBuffer(make([]byte, 0))
	}
	if starcli.stderrBuf == nil {
		starcli.stderrBuf = bytes.NewBuffer(make([]byte, 0))
	}
}

func (starcli *StarCmd) ensureStopContext() {
	if starcli.stopctx == nil || starcli.stopctxfunc == nil {
		starcli.stopctx, starcli.stopctxfunc = context.WithCancel(context.Background())
	}
	if starcli.done == nil {
		starcli.done = make(chan struct{})
	}
	if starcli.resultDone == nil {
		starcli.resultDone = make(chan struct{})
	}
}

func (starcli *StarCmd) ensureResultDone() <-chan struct{} {
	if starcli == nil {
		closed := make(chan struct{})
		close(closed)
		return closed
	}
	starcli.lock.Lock()
	starcli.ensureStopContext()
	done := starcli.resultDone
	starcli.lock.Unlock()
	return done
}

func (starcli *StarCmd) signalResultDone() {
	if starcli == nil {
		return
	}
	starcli.resultOnce.Do(func() {
		starcli.lock.Lock()
		starcli.ensureStopContext()
		done := starcli.resultDone
		starcli.lock.Unlock()
		close(done)
	})
}

func (starcli *StarCmd) finish() {
	if starcli == nil {
		return
	}
	starcli.setRunning(false)
	starcli.signalResultDone()
	if starcli.stopctxfunc != nil {
		starcli.stopctxfunc()
	}
	starcli.doneOnce.Do(func() {
		starcli.lock.Lock()
		done := starcli.done
		stdoutStream := starcli.stdoutStream
		stderrStream := starcli.stderrStream
		outputStream := starcli.outputStream
		infile := starcli.infile
		closeAfter := starcli.closeAfter
		starcli.stdoutStream = nil
		starcli.stderrStream = nil
		starcli.outputStream = nil
		starcli.closeAfter = nil
		starcli.streamClosed = true
		if infile != nil && !starcli.inclosed {
			starcli.inclosed = true
		} else {
			infile = nil
		}
		starcli.lock.Unlock()
		for _, stream := range stdoutStream {
			close(stream)
		}
		for _, stream := range stderrStream {
			close(stream)
		}
		for _, stream := range outputStream {
			close(stream)
		}
		if infile != nil {
			_ = infile.Close()
		}
		for _, closer := range closeAfter {
			_ = closer.Close()
		}
		if done != nil {
			close(done)
		}
	})
}

func (starcli *StarCmd) publishStreamLocked(stream starCmdStream, data []byte) {
	if starcli == nil || starcli.streamClosed {
		return
	}
	switch stream {
	case starCmdStdout:
		for _, receiver := range starcli.stdoutStream {
			select {
			case receiver <- append([]byte(nil), data...):
			default:
			}
		}
		for _, receiver := range starcli.outputStream {
			select {
			case receiver <- StarCmdOutput{Stream: StarCmdOutputStdout, Data: append([]byte(nil), data...)}:
			default:
			}
		}
	case starCmdStderr:
		for _, receiver := range starcli.stderrStream {
			select {
			case receiver <- append([]byte(nil), data...):
			default:
			}
		}
		for _, receiver := range starcli.outputStream {
			select {
			case receiver <- StarCmdOutput{Stream: StarCmdOutputStderr, Data: append([]byte(nil), data...)}:
			default:
			}
		}
	}
}

func (starcli *StarCmd) registerByteStream(selectStream starCmdStream) <-chan []byte {
	stream := make(chan []byte, starCmdStreamBuffer)
	if starcli == nil {
		close(stream)
		return stream
	}
	starcli.lock.Lock()
	if starcli.streamClosed {
		close(stream)
	} else {
		switch selectStream {
		case starCmdStdout:
			starcli.stdoutStream = append(starcli.stdoutStream, stream)
		case starCmdStderr:
			starcli.stderrStream = append(starcli.stderrStream, stream)
		default:
			close(stream)
		}
	}
	starcli.lock.Unlock()
	return stream
}

func (starcli *StarCmd) ensureConfigurable() error {
	if starcli == nil || starcli.CMD == nil {
		return errNilCommand
	}
	if atomic.LoadInt32(&starcli.started) != 0 {
		return errCommandAlreadyStarted
	}
	if atomic.LoadInt32(&starcli.detached) != 0 {
		return errCommandDetached
	}
	return nil
}

func Command(command string, args ...string) (*StarCmd, error) {
	return newStarCmd(exec.Command(command, args...))
}

func CommandContext(ctx context.Context, command string, args ...string) (*StarCmd, error) {
	return newStarCmd(exec.CommandContext(ctx, command, args...))
}

func newStarCmd(cmd *exec.Cmd) (*StarCmd, error) {
	var err error
	shell := &StarCmd{
		CMD:          cmd,
		prewritetime: time.Millisecond * 200,
		stdoutBuf:    bytes.NewBuffer(make([]byte, 0)),
		stderrBuf:    bytes.NewBuffer(make([]byte, 0)),
		done:         make(chan struct{}),
		resultDone:   make(chan struct{}),
		exitcode:     starCmdUnknownExitCode,
	}
	shell.stopctx, shell.stopctxfunc = context.WithCancel(context.Background())
	shell.infile, err = shell.CMD.StdinPipe()
	if err != nil {
		return shell, err
	}
	shell.CMD.Stdout = starCmdWriter{cmd: shell, stream: starCmdStdout}
	shell.CMD.Stderr = starCmdWriter{cmd: shell, stream: starCmdStderr}
	return shell, nil
}

func (starcli *StarCmd) NowLineOutput() (string, error) {
	if starcli == nil {
		return "", errNilCommand
	}
	starcli.lock.Lock()
	defer starcli.lock.Unlock()
	starcli.ensureBuffers()
	buf, _ := starcli.stdoutBuf.ReadBytes('\n')
	buferr, _ := starcli.stderrBuf.ReadBytes(byte('\n'))
	if len(buferr) != 0 {
		return string(buf), errors.New(string(buferr))
	}
	return string(buf), nil
}

func (starcli *StarCmd) NowLineStdOut() string {
	if starcli == nil {
		return ""
	}
	starcli.lock.Lock()
	defer starcli.lock.Unlock()
	starcli.ensureBuffers()
	buf, _ := starcli.stdoutBuf.ReadBytes('\n')
	return string(buf)
}

func (starcli *StarCmd) NowLineStdErr() error {
	if starcli == nil {
		return errNilCommand
	}
	starcli.lock.Lock()
	defer starcli.lock.Unlock()
	starcli.ensureBuffers()
	buferr, _ := starcli.stderrBuf.ReadBytes(byte('\n'))
	if len(buferr) != 0 {
		return errors.New(string(buferr))
	}
	return nil
}

func (starcli *StarCmd) NowAllOutput() (string, error) {
	if starcli == nil {
		return "", errNilCommand
	}
	var outstr string
	starcli.lock.Lock()
	defer starcli.lock.Unlock()
	starcli.ensureBuffers()
	buf := make([]byte, starcli.stdoutBuf.Len())
	n, _ := starcli.stdoutBuf.Read(buf)
	runerr := starcli.runerr
	if n != 0 {
		outstr = string(buf[:n])
	}
	if runerr != nil {
		return outstr, runerr
	}
	buf = make([]byte, starcli.stderrBuf.Len())
	n, _ = starcli.stderrBuf.Read(buf)
	if n != 0 {
		return outstr, errors.New(string(buf[:n]))
	}
	return outstr, nil
}

func (starcli *StarCmd) NowStdOut() string {
	if starcli == nil {
		return ""
	}
	var outstr string
	starcli.lock.Lock()
	defer starcli.lock.Unlock()
	starcli.ensureBuffers()
	buf := make([]byte, starcli.stdoutBuf.Len())
	n, _ := starcli.stdoutBuf.Read(buf)
	if n != 0 {
		outstr = string(buf[:n])
	}
	return outstr
}

func (starcli *StarCmd) NowStdErr() error {
	if starcli == nil {
		return errNilCommand
	}
	starcli.lock.Lock()
	defer starcli.lock.Unlock()
	starcli.ensureBuffers()
	buf := make([]byte, starcli.stderrBuf.Len())
	n, _ := starcli.stderrBuf.Read(buf)
	if n != 0 {
		return errors.New(string(buf[:n]))
	}
	return nil
}

func (starcli *StarCmd) AllOutPut() (string, error) {
	if starcli == nil {
		return "", errNilCommand
	}
	starcli.lock.Lock()
	defer starcli.lock.Unlock()
	err := starcli.runerr
	if err == nil && len(starcli.errout) != 0 {
		err = errors.New(string(starcli.errout))
	}
	return string(starcli.stdout), err
}

func (starcli *StarCmd) AllStdOut() string {
	if starcli == nil {
		return ""
	}
	starcli.lock.Lock()
	defer starcli.lock.Unlock()
	return string(starcli.stdout)
}

func (starcli *StarCmd) AllStdErr() error {
	if starcli == nil {
		return errNilCommand
	}
	starcli.lock.Lock()
	defer starcli.lock.Unlock()
	err := starcli.runerr
	if err == nil && len(starcli.errout) != 0 {
		err = errors.New(string(starcli.errout))
	}
	return err
}

func (starcli *StarCmd) setRunning(alive bool) {
	if starcli == nil {
		return
	}
	if alive {
		atomic.StoreInt32(&starcli.running, 1)
		return
	}
	atomic.StoreInt32(&starcli.running, 0)
}
func (starcli *StarCmd) Start() error {
	if starcli == nil || starcli.CMD == nil {
		return errNilCommand
	}
	if atomic.LoadInt32(&starcli.detached) != 0 {
		return errCommandDetached
	}
	starcli.lock.Lock()
	starcli.ensureBuffers()
	starcli.ensureStopContext()
	starcli.lock.Unlock()
	if !atomic.CompareAndSwapInt32(&starcli.started, 0, 1) {
		return errCommandAlreadyStarted
	}
	if err := starcli.CMD.Start(); err != nil {
		starcli.lock.Lock()
		starcli.runerr = err
		starcli.exitcode = -1
		starcli.lock.Unlock()
		starcli.signalResultDone()
		starcli.finish()
		return err
	}
	starcli.setRunning(true)
	go func() {
		err := starcli.CMD.Wait()
		if err != nil {
			starcli.lock.Lock()
			starcli.runerr = err
			starcli.lock.Unlock()
		}
		if starcli.CMD.ProcessState != nil {
			starcli.lock.Lock()
			starcli.exitcode = starcli.CMD.ProcessState.ExitCode()
			starcli.lock.Unlock()
		}
		starcli.signalResultDone()
		starcli.finish()
	}()
	go func(ctx context.Context) {
		starcli.lock.Lock()
		prewrite := append([]string(nil), starcli.prewrite...)
		prewritetime := starcli.prewritetime
		starcli.lock.Unlock()
		for _, v := range prewrite {
			select {
			case <-ctx.Done():
				return
			default:
			}
			_ = starcli.WriteCmdE(v)
			time.Sleep(prewritetime)
		}
	}(starcli.stopctx)
	return nil
}

func (starcli *StarCmd) IsRunning() bool {
	if starcli == nil {
		return false
	}
	return 0 != atomic.LoadInt32(&starcli.running)
}

func (starcli *StarCmd) runError() error {
	if starcli == nil {
		return errNilCommand
	}
	starcli.lock.Lock()
	defer starcli.lock.Unlock()
	return starcli.runerr
}

func (starcli *StarCmd) ensureWaitable() error {
	if starcli == nil || starcli.CMD == nil {
		return errNilCommand
	}
	if atomic.LoadInt32(&starcli.started) == 0 {
		return errCommandProcessNotStarted
	}
	return nil
}

// Stopped returns a channel that is closed after the command reaches its final state.
func (starcli *StarCmd) Stopped() <-chan struct{} {
	if starcli == nil {
		closed := make(chan struct{})
		close(closed)
		return closed
	}
	starcli.lock.Lock()
	starcli.ensureStopContext()
	done := starcli.done
	starcli.lock.Unlock()
	return done
}

// Stoped returns a channel that is closed after the command reaches its final state.
//
// Deprecated: use Stopped.
func (starcli *StarCmd) Stoped() <-chan struct{} {
	return starcli.Stopped()
}

// Wait blocks until the command reaches its final state and returns the process wait error.
func (starcli *StarCmd) Wait() error {
	if err := starcli.ensureWaitable(); err != nil {
		return err
	}
	<-starcli.ensureResultDone()
	return starcli.runError()
}

// WaitContext blocks until the command reaches its final state or ctx is done.
func (starcli *StarCmd) WaitContext(ctx context.Context) error {
	if err := starcli.ensureWaitable(); err != nil {
		return err
	}
	if ctx == nil {
		return starcli.Wait()
	}
	resultDone := starcli.ensureResultDone()
	select {
	case <-resultDone:
		return starcli.runError()
	default:
	}
	select {
	case <-resultDone:
		return starcli.runError()
	case <-ctx.Done():
		select {
		case <-resultDone:
			return starcli.runError()
		default:
		}
		return ctx.Err()
	}
}

// WaitTimeout blocks until the command reaches its final state or tm elapses.
func (starcli *StarCmd) WaitTimeout(tm time.Duration) error {
	if err := starcli.ensureWaitable(); err != nil {
		return err
	}
	if tm <= 0 {
		select {
		case <-starcli.ensureResultDone():
			return starcli.runError()
		default:
			return ERR_TIMEOUT
		}
	}
	timer := time.NewTimer(tm)
	defer timer.Stop()
	resultDone := starcli.ensureResultDone()
	select {
	case <-resultDone:
		return starcli.runError()
	case <-timer.C:
		select {
		case <-resultDone:
			return starcli.runError()
		default:
			return ERR_TIMEOUT
		}
	}
}

// StdoutChan returns a channel that receives future stdout chunks until Stopped closes.
func (starcli *StarCmd) StdoutChan() <-chan []byte {
	return starcli.registerByteStream(starCmdStdout)
}

// StderrChan returns a channel that receives future stderr chunks until Stopped closes.
func (starcli *StarCmd) StderrChan() <-chan []byte {
	return starcli.registerByteStream(starCmdStderr)
}

// OutputChan returns a channel that receives future stdout and stderr chunks until Stopped closes.
func (starcli *StarCmd) OutputChan() <-chan StarCmdOutput {
	stream := make(chan StarCmdOutput, starCmdStreamBuffer)
	if starcli == nil {
		close(stream)
		return stream
	}
	starcli.lock.Lock()
	if starcli.streamClosed {
		close(stream)
	} else {
		starcli.outputStream = append(starcli.outputStream, stream)
	}
	starcli.lock.Unlock()
	return stream
}

// RedirectStdout mirrors stdout into writer while keeping StarCmd output capture enabled.
func (starcli *StarCmd) RedirectStdout(writer io.Writer) error {
	if writer == nil {
		return errCommandRedirectNil
	}
	if err := starcli.ensureConfigurable(); err != nil {
		return err
	}
	starcli.lock.Lock()
	starcli.stdoutRedirect = writer
	starcli.lock.Unlock()
	return nil
}

// RedirectStderr mirrors stderr into writer while keeping StarCmd error capture enabled.
func (starcli *StarCmd) RedirectStderr(writer io.Writer) error {
	if writer == nil {
		return errCommandRedirectNil
	}
	if err := starcli.ensureConfigurable(); err != nil {
		return err
	}
	starcli.lock.Lock()
	starcli.stderrRedirect = writer
	starcli.lock.Unlock()
	return nil
}

// RedirectOutput mirrors stdout and stderr into writer while keeping StarCmd capture enabled.
func (starcli *StarCmd) RedirectOutput(writer io.Writer) error {
	if writer == nil {
		return errCommandRedirectNil
	}
	if err := starcli.ensureConfigurable(); err != nil {
		return err
	}
	starcli.lock.Lock()
	starcli.stdoutRedirect = writer
	starcli.stderrRedirect = writer
	starcli.lock.Unlock()
	return nil
}

// RedirectStdin replaces the managed stdin pipe with reader.
func (starcli *StarCmd) RedirectStdin(reader io.Reader) error {
	if reader == nil {
		return errCommandRedirectNil
	}
	if err := starcli.ensureConfigurable(); err != nil {
		return err
	}
	starcli.lock.Lock()
	if starcli.infile != nil && !starcli.inclosed {
		if err := starcli.infile.Close(); err != nil {
			starcli.lock.Unlock()
			return err
		}
	}
	starcli.CMD.Stdin = reader
	starcli.infile = nil
	starcli.inclosed = true
	starcli.lock.Unlock()
	return nil
}

func (starcli *StarCmd) addCloseAfter(closer io.Closer) {
	if starcli == nil || closer == nil {
		return
	}
	starcli.lock.Lock()
	starcli.closeAfter = append(starcli.closeAfter, closer)
	starcli.lock.Unlock()
}

// RedirectStdoutFile mirrors stdout into path while keeping StarCmd output capture enabled.
func (starcli *StarCmd) RedirectStdoutFile(path string) error {
	if err := starcli.ensureConfigurable(); err != nil {
		return err
	}
	file, err := os.OpenFile(path, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0644)
	if err != nil {
		return err
	}
	if err := starcli.RedirectStdout(file); err != nil {
		_ = file.Close()
		return err
	}
	starcli.addCloseAfter(file)
	return nil
}

// RedirectStderrFile mirrors stderr into path while keeping StarCmd error capture enabled.
func (starcli *StarCmd) RedirectStderrFile(path string) error {
	if err := starcli.ensureConfigurable(); err != nil {
		return err
	}
	file, err := os.OpenFile(path, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0644)
	if err != nil {
		return err
	}
	if err := starcli.RedirectStderr(file); err != nil {
		_ = file.Close()
		return err
	}
	starcli.addCloseAfter(file)
	return nil
}

// RedirectOutputFile mirrors stdout and stderr into path while keeping StarCmd capture enabled.
func (starcli *StarCmd) RedirectOutputFile(path string) error {
	if err := starcli.ensureConfigurable(); err != nil {
		return err
	}
	file, err := os.OpenFile(path, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0644)
	if err != nil {
		return err
	}
	if err := starcli.RedirectOutput(file); err != nil {
		_ = file.Close()
		return err
	}
	starcli.addCloseAfter(file)
	return nil
}

// RedirectStdinFile replaces the managed stdin pipe with path opened for reading.
func (starcli *StarCmd) RedirectStdinFile(path string) error {
	if err := starcli.ensureConfigurable(); err != nil {
		return err
	}
	file, err := os.Open(path)
	if err != nil {
		return err
	}
	if err := starcli.RedirectStdin(file); err != nil {
		_ = file.Close()
		return err
	}
	starcli.addCloseAfter(file)
	return nil
}

func (starcli *StarCmd) Exec(cmd string, wait int) (string, error) {
	if err := starcli.WriteCmdE(cmd); err != nil {
		return "", err
	}
	time.Sleep(time.Millisecond * time.Duration(wait))
	return starcli.NowAllOutput()
}

func (starcli *StarCmd) WriteCmd(cmdstr string) {
	_ = starcli.WriteCmdE(cmdstr)
}

// WriteStdinE writes raw bytes to stdin without appending a newline.
func (starcli *StarCmd) WriteStdinE(data []byte) error {
	if starcli == nil {
		return errNilCommand
	}
	starcli.lock.Lock()
	infile := starcli.infile
	inclosed := starcli.inclosed
	starcli.lock.Unlock()
	if infile == nil {
		return errCommandStdinUnavailable
	}
	if inclosed {
		return errCommandStdinClosed
	}
	_, err := infile.Write(data)
	return err
}

// WriteStdinStringE writes raw text to stdin without appending a newline.
func (starcli *StarCmd) WriteStdinStringE(data string) error {
	return starcli.WriteStdinE([]byte(data))
}

// WriteStdinLineE writes text to stdin and appends one newline.
func (starcli *StarCmd) WriteStdinLineE(data string) error {
	return starcli.WriteStdinStringE(data + "\n")
}

func (starcli *StarCmd) WriteCmdE(cmdstr string) error {
	return starcli.WriteStdinLineE(cmdstr)
}

func (starcli *StarCmd) CloseStdin() {
	_ = starcli.CloseStdinE()
}

func (starcli *StarCmd) CloseStdinE() error {
	if starcli == nil {
		return errNilCommand
	}
	starcli.lock.Lock()
	infile := starcli.infile
	if infile == nil {
		starcli.lock.Unlock()
		return errCommandStdinUnavailable
	}
	if starcli.inclosed {
		starcli.lock.Unlock()
		return errCommandStdinClosed
	}
	starcli.inclosed = true
	starcli.lock.Unlock()
	return infile.Close()
}

func (starcli *StarCmd) PreWrite(cmd ...string) {
	if starcli == nil {
		return
	}
	starcli.lock.Lock()
	defer starcli.lock.Unlock()
	for _, v := range cmd {
		starcli.prewrite = append(starcli.prewrite, v)
	}
}

func (starcli *StarCmd) PreWriteInterval(dt time.Duration) {
	if starcli == nil {
		return
	}
	starcli.lock.Lock()
	defer starcli.lock.Unlock()
	starcli.prewritetime = dt
}

func (starcli *StarCmd) ExitCode() int {
	if starcli == nil {
		return starCmdUnknownExitCode
	}
	starcli.lock.Lock()
	defer starcli.lock.Unlock()
	return starcli.exitcode
}

func (starcli *StarCmd) Kill() error {
	if starcli == nil || starcli.CMD == nil || starcli.CMD.Process == nil {
		return errCommandProcessNotStarted
	}
	err := starcli.CMD.Process.Kill()
	if err != nil {
		return err
	}
	return nil
}

func (starcli *StarCmd) GetPid() int {
	if starcli == nil || starcli.CMD == nil || starcli.CMD.Process == nil {
		return -1
	}
	return starcli.CMD.Process.Pid
}

func (starcli *StarCmd) Signal(sig os.Signal) error {
	if starcli == nil || starcli.CMD == nil || starcli.CMD.Process == nil {
		return errCommandProcessNotStarted
	}
	return starcli.CMD.Process.Signal(sig)
}