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|
package spinner
import (
"fmt"
"os"
"time"
)
var symbolList = []string{
" | ",
" / ",
" – ",
" \\ ",
}
var symbolMap = map[string]string{
" ⏳ ": "\033[37m",
" ⌛ ": "\033[38m",
}
type Spinner struct {
duration time.Duration
trigger interface{}
sentinel interface{}
closed bool
// sigChan: is the pipe that receives the start and stop
sigChan chan interface{}
// waitChan waits till the shutdown has fully propagated
waitChan chan interface{}
}
func New(freq int64) *Spinner {
if freq < 1 {
freq = 10
}
sp := Spinner{
duration: time.Duration(1e9 / freq),
sentinel: nil,
// sigChan will be created on .Start()
sigChan: nil,
waitChan: make(chan interface{}),
}
sp.trigger = &sp
return &sp
}
func (s *Spinner) Start() error {
err := s.spin()
if err == nil {
s.sigChan <- s.trigger
}
return err
}
func (s *Spinner) Stop() {
if !s.closed && s.sigChan != nil {
s.sigChan <- s.sentinel
close(s.sigChan)
<-s.waitChan
s.closed = true
}
}
func (s *Spinner) Reset() {
s.Stop()
s.sigChan = nil
s.closed = true
}
func (s *Spinner) Duration() time.Duration {
return s.duration
}
func (s *Spinner) spin() error {
if s.sigChan != nil { // Already in use
return fmt.Errorf("already in use")
}
s.sigChan = make(chan interface{})
go func() {
// Block till the first symbol comes through
<-s.sigChan
throttle := time.Tick(s.duration)
running := true
for running {
for _, segment := range symbolList {
select {
case in := <-s.sigChan:
if in == s.sentinel {
os.Stderr.Sync()
running = false
s.waitChan <- s.sentinel
break
}
default:
}
// Print it to stderr to avoid symbol getting into piped content
fmt.Fprintf(os.Stderr, "%s\r", segment)
<-throttle
}
}
}()
return nil
}
|
