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improved spinner responsiveness to title updates
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@sha1n
sha1n committed Jun 4, 2021
1 parent 5326957 commit 45d88b9
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Showing 2 changed files with 84 additions and 67 deletions.
77 changes: 44 additions & 33 deletions spinner.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,7 @@ import (
"errors"
"fmt"
"io"
"strings"
"sync"
"time"
)
Expand Down Expand Up @@ -56,16 +57,16 @@ func (f *SimpleSpinnerFormatter) CharSeq() []string {
type Spinner interface {
Start() (context.CancelFunc, error)
Stop(string) error
SetTitle(title string)
SetTitle(title string) error
}

type spinner struct {
writer io.Writer
interval time.Duration
mx *sync.RWMutex
titleMx *sync.RWMutex
stateMx *sync.RWMutex
active bool
stopC chan bool
titleC chan string
title string
formatter SpinnerFormatter
}
Expand All @@ -75,10 +76,10 @@ func NewSpinner(writer io.Writer, title string, interval time.Duration, formatte
return &spinner{
writer: writer,
interval: interval,
mx: &sync.RWMutex{},
titleMx: &sync.RWMutex{},
stateMx: &sync.RWMutex{},
active: false,
stopC: make(chan bool),
titleC: make(chan string),
title: title,
formatter: formatter,
}
Expand All @@ -95,8 +96,8 @@ func (s *spinner) writeString(str string) (n int, err error) {

// Start starts the spinner in the background and returns a cancellation handle and an error in case the spinner is already running.
func (s *spinner) Start() (cancel context.CancelFunc, err error) {
s.mx.Lock()
defer s.mx.Unlock()
s.stateMx.Lock()
defer s.stateMx.Unlock()

if s.active {
return nil, errors.New("spinner already active")
Expand All @@ -115,27 +116,39 @@ func (s *spinner) Start() (cancel context.CancelFunc, err error) {

defer s.setActiveSafe(false)

update := func(title string) {
indicatorValue := s.formatter.FormatIndicator(fmt.Sprintf("%v", spinring.Value))
if title != "" {
_, _ = s.writeString(fmt.Sprintf("%s%s %s", TermControlEraseLine, indicatorValue, s.formatter.FormatTitle(title)))
} else {
_, _ = s.writeString(fmt.Sprintf("%s%s", TermControlEraseLine, indicatorValue))
}
}

for {
select {
case <-context.Done():
timer.Stop()
close(s.titleC)

s.printExitMessage("Cancelled...")

return

case <-s.stopC:
timer.Stop()
close(s.titleC)
return

case title := <-s.titleC:
// The title is only written by this routine, so we're safe.
s.title = title
update(title)

case <-timer.C:
spinring = spinring.Next()
title := s.getTitle()
indicatorValue := s.formatter.FormatIndicator(fmt.Sprintf("%v", spinring.Value))
if title != "" {
s.writeString(fmt.Sprintf("%s%s %s", TermControlEraseLine, indicatorValue, s.formatter.FormatTitle(title)))
} else {
s.writeString(fmt.Sprintf("%s%s", TermControlEraseLine, indicatorValue))
}

title := s.title
update(title)
}
}
}()
Expand All @@ -147,8 +160,8 @@ func (s *spinner) Start() (cancel context.CancelFunc, err error) {

// Stop stops the spinner and displays the specified message
func (s *spinner) Stop(message string) (err error) {
s.mx.Lock()
defer s.mx.Unlock()
s.stateMx.Lock()
defer s.stateMx.Unlock()

if !s.active {
err = errors.New("spinner not active")
Expand All @@ -162,23 +175,21 @@ func (s *spinner) Stop(message string) (err error) {
}

// SetTitle updates the spinner text.
func (s *spinner) SetTitle(title string) {
s.titleMx.Lock()
defer s.titleMx.Unlock()

s.title = title
}
func (s *spinner) SetTitle(title string) (err error) {
defer func() {
if recover() != nil {
err = errors.New("spinner not active")
}
}()

func (s *spinner) getTitle() string {
s.titleMx.RLock()
defer s.titleMx.RUnlock()
s.titleC <- strings.TrimSpace(title)

return s.title
return err
}

func (s *spinner) printExitMessage(message string) {
s.writeString(TermControlEraseLine)
s.writeString(message)
_, _ = s.writeString(TermControlEraseLine)
_, _ = s.writeString(message)
}

func (s *spinner) createSpinnerRing() *ring.Ring {
Expand All @@ -193,15 +204,15 @@ func (s *spinner) createSpinnerRing() *ring.Ring {
}

func (s *spinner) isActiveSafe() bool {
s.mx.RLock()
defer s.mx.RUnlock()
s.stateMx.RLock()
defer s.stateMx.RUnlock()

return s.active
}

func (s *spinner) setActiveSafe(active bool) {
s.mx.Lock()
defer s.mx.Unlock()
s.stateMx.Lock()
defer s.stateMx.Unlock()

s.active = active
}
74 changes: 40 additions & 34 deletions spinner_test.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -54,7 +54,7 @@ func TestSpinnerStopAlreadyStopped(t *testing.T) {
emulatedStdout := new(bytes.Buffer)

spin := NewSpinner(emulatedStdout, "", interval, DefaultSpinnerFormatter())
spin.Start()
_, _ = spin.Start()
err := spin.Stop("")
assert.NoError(t, err)

Expand All @@ -66,8 +66,10 @@ func TestSpinnerStopMessage(t *testing.T) {
emulatedStdout := new(bytes.Buffer)

spin := NewSpinner(emulatedStdout, "", interval, DefaultSpinnerFormatter())
spin.Start()
err := spin.Stop(expectedStopMessage)
_, err := spin.Start()
assert.NoError(t, err)

err = spin.Stop(expectedStopMessage)
assert.NoError(t, err)

assertBufferEventuallyContains(t, emulatedStdout, expectedStopMessage)
Expand Down Expand Up @@ -96,11 +98,25 @@ func TestSpinnerSetTitle(t *testing.T) {

assertBufferEventuallyContains(t, emulatedStdout, expectedInitialTitle)

spin.SetTitle(expectedUpdatedTitle)
assert.NoError(t, spin.SetTitle(expectedUpdatedTitle))

assertBufferEventuallyContains(t, emulatedStdout, expectedUpdatedTitle)
}

func TestSpinnerSetTitleOnStoppedSpinner(t *testing.T) {
expectedInitialTitle := generateRandomString()
expectedUpdatedTitle := generateRandomString()
emulatedStdout := new(bytes.Buffer)

spin := NewSpinner(emulatedStdout, expectedInitialTitle, interval, DefaultSpinnerFormatter())
_, _ = spin.Start()

assertBufferEventuallyContains(t, emulatedStdout, expectedInitialTitle)

assert.NoError(t, spin.Stop(""))
assert.Error(t, spin.SetTitle(expectedUpdatedTitle))
}

func assertBufferEventuallyContains(t *testing.T, outBuffer *bytes.Buffer, expected string) {
assert.Eventually(
t,
Expand Down Expand Up @@ -134,45 +150,35 @@ func assertStoppedEventually(t *testing.T, outBuffer *bytes.Buffer, spinner *spi
)
}

// TODO can this be simplified?
func assertSpinnerCharSequence(t *testing.T, outBuffer *bytes.Buffer) {
charSeq := DefaultSpinnerCharSeq()
readChars := make([]string, len(charSeq))
readCharsCount := 0
readChars := []string{}

readSequence := func() string {
startTime := time.Now()
scan := func() {
for {
s, _ := outBuffer.ReadString(TermControlEraseLine[len(TermControlEraseLine)-1]) // read everything you got
if strippedString := strings.Trim(s, TermControlEraseLine+"\x00"); strippedString != "" {
return strippedString
r, _, e := outBuffer.ReadRune()
print(string(r), ",")
if e != nil {
continue
}

// guard again infinite loop
if time.Now().After(startTime.Add(time.Second * 30)) {
return ""
readChar := string(r)
if len(readChars) == 0 && readChar == charSeq[0] {
readChars = append(readChars, readChar)
} else if len(readChars) > 0 {
for _, ch := range charSeq {
if ch == readChar {
readChars = append(readChars, ch)
}

if len(readChars) == len(charSeq) {
return
}
}
}
}
}

// find the first character in the spinner sequence, so we can validate order properly
for {
strippedString := readSequence()
if strippedString != "" && strippedString == charSeq[0] {
readChars[0] = strippedString
break
}
// guard against infinite loop caused by bugs
readCharsCount++
if readCharsCount > len(charSeq)*2 {
assert.Fail(t, "something went wrong...")
}
}

for i := 1; i < len(charSeq); i++ {
readChars[i] = readSequence()
}
scan()

assert.Equal(t, charSeq, readChars)

}

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