readline/std.go

199 lines
3.6 KiB
Go

package readline
import (
"fmt"
"io"
"os"
"sync"
"sync/atomic"
)
var (
Stdin io.ReadCloser = os.Stdin
Stdout io.WriteCloser = os.Stdout
Stderr io.WriteCloser = os.Stderr
)
var (
std *Instance
stdOnce sync.Once
)
// global instance will not submit history automatic
func getInstance() *Instance {
stdOnce.Do(func() {
std, _ = NewEx(&Config{
DisableAutoSaveHistory: true,
})
})
return std
}
// let readline load history from filepath
// and try to persist history into disk
// set fp to "" to prevent readline persisting history to disk
// so the `AddHistory` will return nil error forever.
func SetHistoryPath(fp string) {
ins := getInstance()
cfg := ins.Config.Clone()
cfg.HistoryFile = fp
ins.SetConfig(cfg)
}
// set auto completer to global instance
func SetAutoComplete(completer AutoCompleter) {
ins := getInstance()
cfg := ins.Config.Clone()
cfg.AutoComplete = completer
ins.SetConfig(cfg)
}
// add history to global instance manually
// raise error only if `SetHistoryPath` is set with a non-empty path
func AddHistory(content string) error {
ins := getInstance()
return ins.SaveHistory(content)
}
func Password(prompt fmt.Stringer) ([]byte, error) {
ins := getInstance()
return ins.ReadPassword(prompt)
}
// readline with global configs
func Line(prompt fmt.Stringer) (string, error) {
ins := getInstance()
ins.SetPrompt(prompt)
return ins.Readline()
}
type CancelableStdin struct {
r io.Reader
mutex sync.Mutex
stop chan struct{}
closed int32
notify chan struct{}
data []byte
read int
err error
}
func NewCancelableStdin(r io.Reader) *CancelableStdin {
c := &CancelableStdin{
r: r,
notify: make(chan struct{}),
stop: make(chan struct{}),
}
go c.ioloop()
return c
}
func (c *CancelableStdin) ioloop() {
loop:
for {
select {
case <-c.notify:
c.read, c.err = c.r.Read(c.data)
select {
case c.notify <- struct{}{}:
case <-c.stop:
break loop
}
case <-c.stop:
break loop
}
}
}
func (c *CancelableStdin) Read(b []byte) (n int, err error) {
c.mutex.Lock()
defer c.mutex.Unlock()
if atomic.LoadInt32(&c.closed) == 1 {
return 0, io.EOF
}
c.data = b
select {
case c.notify <- struct{}{}:
case <-c.stop:
return 0, io.EOF
}
select {
case <-c.notify:
return c.read, c.err
case <-c.stop:
return 0, io.EOF
}
}
func (c *CancelableStdin) Close() error {
if atomic.CompareAndSwapInt32(&c.closed, 0, 1) {
close(c.stop)
}
return nil
}
// FillableStdin is a stdin reader which can prepend some data before
// reading into the real stdin
type FillableStdin struct {
sync.Mutex
stdin io.Reader
stdinBuffer io.ReadCloser
buf []byte
bufErr error
}
// NewFillableStdin gives you FillableStdin
func NewFillableStdin(stdin io.Reader) (io.ReadCloser, io.Writer) {
r, w := io.Pipe()
s := &FillableStdin{
stdinBuffer: r,
stdin: stdin,
}
s.ioloop()
return s, w
}
func (s *FillableStdin) ioloop() {
go func() {
for {
bufR := make([]byte, 100)
var n int
n, s.bufErr = s.stdinBuffer.Read(bufR)
if s.bufErr != nil {
if s.bufErr == io.ErrClosedPipe {
break
}
}
s.Lock()
s.buf = append(s.buf, bufR[:n]...)
s.Unlock()
}
}()
}
// Read will read from the local buffer and if no data, read from stdin
func (s *FillableStdin) Read(p []byte) (n int, err error) {
s.Lock()
i := len(s.buf)
if len(p) < i {
i = len(p)
}
if i > 0 {
n := copy(p, s.buf)
s.buf = s.buf[:0]
cerr := s.bufErr
s.bufErr = nil
s.Unlock()
return n, cerr
}
s.Unlock()
n, err = s.stdin.Read(p)
return n, err
}
func (s *FillableStdin) Close() error {
s.stdinBuffer.Close()
return nil
}