output: hide the cursor when updating (#456)

LawnGnome · web-flow · commit 4844011f4061 · 2021-02-04T08:37:30.000-08:00
diff --git a/internal/output/block.go b/internal/output/block.go
@@ -34,8 +34,8 @@ func newBlock(indent int, o *Output) *Block {
 }
 
 func (b *Block) Close() {
-	b.unwrapped.lock.Lock()
-	defer b.unwrapped.lock.Unlock()
+	b.unwrapped.Lock()
+	defer b.unwrapped.Unlock()
 
 	// This is a little tricky: output from Writer methods includes a trailing
 	// newline, so we need to trim that so we don't output extra blank lines.
diff --git a/internal/output/output.go b/internal/output/output.go
@@ -47,6 +47,8 @@ type Output struct {
 	lock sync.Mutex
 }
 
+var _ sync.Locker = &Output{}
+
 type OutputOpts struct {
 	// ForceColor ignores all terminal detection and enabled coloured output.
 	ForceColor bool
@@ -90,6 +92,23 @@ func NewOutput(w io.Writer, opts OutputOpts) *Output {
 	return o
 }
 
+func (o *Output) Lock() {
+	o.lock.Lock()
+
+	// Hide the cursor while we update: this reduces the jitteriness of the
+	// whole thing, and some terminals are smart enough to make the update we're
+	// about to render atomic if the cursor is hidden for a short length of
+	// time.
+	o.w.Write([]byte("\033[?25l"))
+}
+
+func (o *Output) Unlock() {
+	// Show the cursor once more.
+	o.w.Write([]byte("\033[?25h"))
+
+	o.lock.Unlock()
+}
+
 func (o *Output) Verbose(s string) {
 	if o.opts.Verbose {
 		o.Write(s)
@@ -109,21 +128,21 @@ func (o *Output) VerboseLine(line FancyLine) {
 }
 
 func (o *Output) Write(s string) {
-	o.lock.Lock()
-	defer o.lock.Unlock()
+	o.Lock()
+	defer o.Unlock()
 	fmt.Fprintln(o.w, s)
 }
 
 func (o *Output) Writef(format string, args ...interface{}) {
-	o.lock.Lock()
-	defer o.lock.Unlock()
+	o.Lock()
+	defer o.Unlock()
 	fmt.Fprintf(o.w, format, o.caps.formatArgs(args)...)
 	fmt.Fprint(o.w, "\n")
 }
 
 func (o *Output) WriteLine(line FancyLine) {
-	o.lock.Lock()
-	defer o.lock.Unlock()
+	o.Lock()
+	defer o.Unlock()
 	line.write(o.w, o.caps)
 }
 
diff --git a/internal/output/pending_tty.go b/internal/output/pending_tty.go
@@ -33,8 +33,8 @@ func (p *pendingTTY) VerboseLine(line FancyLine) {
 }
 
 func (p *pendingTTY) Write(s string) {
-	p.o.lock.Lock()
-	defer p.o.lock.Unlock()
+	p.o.Lock()
+	defer p.o.Unlock()
 
 	p.o.moveUp(1)
 	p.o.clearCurrentLine()
@@ -43,8 +43,8 @@ func (p *pendingTTY) Write(s string) {
 }
 
 func (p *pendingTTY) Writef(format string, args ...interface{}) {
-	p.o.lock.Lock()
-	defer p.o.lock.Unlock()
+	p.o.Lock()
+	defer p.o.Unlock()
 
 	p.o.moveUp(1)
 	p.o.clearCurrentLine()
@@ -54,8 +54,8 @@ func (p *pendingTTY) Writef(format string, args ...interface{}) {
 }
 
 func (p *pendingTTY) WriteLine(line FancyLine) {
-	p.o.lock.Lock()
-	defer p.o.lock.Unlock()
+	p.o.Lock()
+	defer p.o.Unlock()
 
 	p.o.moveUp(1)
 	p.o.clearCurrentLine()
@@ -64,8 +64,8 @@ func (p *pendingTTY) WriteLine(line FancyLine) {
 }
 
 func (p *pendingTTY) Update(s string) {
-	p.o.lock.Lock()
-	defer p.o.lock.Unlock()
+	p.o.Lock()
+	defer p.o.Unlock()
 
 	p.line.format = "%s"
 	p.line.args = []interface{}{s}
@@ -76,8 +76,8 @@ func (p *pendingTTY) Update(s string) {
 }
 
 func (p *pendingTTY) Updatef(format string, args ...interface{}) {
-	p.o.lock.Lock()
-	defer p.o.lock.Unlock()
+	p.o.Lock()
+	defer p.o.Unlock()
 
 	p.line.format = format
 	p.line.args = args
@@ -90,8 +90,8 @@ func (p *pendingTTY) Updatef(format string, args ...interface{}) {
 func (p *pendingTTY) Complete(message FancyLine) {
 	p.spinner.stop()
 
-	p.o.lock.Lock()
-	defer p.o.lock.Unlock()
+	p.o.Lock()
+	defer p.o.Unlock()
 
 	p.o.moveUp(1)
 	p.o.clearCurrentLine()
@@ -103,8 +103,8 @@ func (p *pendingTTY) Close() { p.Destroy() }
 func (p *pendingTTY) Destroy() {
 	p.spinner.stop()
 
-	p.o.lock.Lock()
-	defer p.o.lock.Unlock()
+	p.o.Lock()
+	defer p.o.Unlock()
 
 	p.o.moveUp(1)
 	p.o.clearCurrentLine()
@@ -122,8 +122,8 @@ func newPendingTTY(message FancyLine, o *Output) *pendingTTY {
 	go func() {
 		for s := range p.spinner.C {
 			func() {
-				p.o.lock.Lock()
-				defer p.o.lock.Unlock()
+				p.o.Lock()
+				defer p.o.Unlock()
 
 				p.updateEmoji(s)
 
diff --git a/internal/output/progress_tty.go b/internal/output/progress_tty.go
@@ -30,8 +30,8 @@ type progressTTY struct {
 func (p *progressTTY) Complete() {
 	p.spinner.stop()
 
-	p.o.lock.Lock()
-	defer p.o.lock.Unlock()
+	p.o.Lock()
+	defer p.o.Unlock()
 
 	for _, bar := range p.bars {
 		bar.Value = bar.Max
@@ -44,8 +44,8 @@ func (p *progressTTY) Close() { p.Destroy() }
 func (p *progressTTY) Destroy() {
 	p.spinner.stop()
 
-	p.o.lock.Lock()
-	defer p.o.lock.Unlock()
+	p.o.Lock()
+	defer p.o.Unlock()
 
 	p.moveToOrigin()
 	for i := 0; i < len(p.bars); i += 1 {
@@ -57,17 +57,17 @@ func (p *progressTTY) Destroy() {
 }
 
 func (p *progressTTY) SetLabel(i int, label string) {
-	p.o.lock.Lock()
-	defer p.o.lock.Unlock()
+	p.o.Lock()
+	defer p.o.Unlock()
 
 	p.bars[i].Label = label
 	p.bars[i].labelWidth = runewidth.StringWidth(label)
 	p.drawInSitu()
 }
 
 func (p *progressTTY) SetLabelAndRecalc(i int, label string) {
-	p.o.lock.Lock()
-	defer p.o.lock.Unlock()
+	p.o.Lock()
+	defer p.o.Unlock()
 
 	p.bars[i].Label = label
 	p.bars[i].labelWidth = runewidth.StringWidth(label)
@@ -77,8 +77,8 @@ func (p *progressTTY) SetLabelAndRecalc(i int, label string) {
 }
 
 func (p *progressTTY) SetValue(i int, v float64) {
-	p.o.lock.Lock()
-	defer p.o.lock.Unlock()
+	p.o.Lock()
+	defer p.o.Unlock()
 
 	p.bars[i].Value = v
 	p.drawInSitu()
@@ -103,8 +103,8 @@ func (p *progressTTY) VerboseLine(line FancyLine) {
 }
 
 func (p *progressTTY) Write(s string) {
-	p.o.lock.Lock()
-	defer p.o.lock.Unlock()
+	p.o.Lock()
+	defer p.o.Unlock()
 
 	p.moveToOrigin()
 	p.o.clearCurrentLine()
@@ -113,8 +113,8 @@ func (p *progressTTY) Write(s string) {
 }
 
 func (p *progressTTY) Writef(format string, args ...interface{}) {
-	p.o.lock.Lock()
-	defer p.o.lock.Unlock()
+	p.o.Lock()
+	defer p.o.Unlock()
 
 	p.moveToOrigin()
 	p.o.clearCurrentLine()
@@ -124,8 +124,8 @@ func (p *progressTTY) Writef(format string, args ...interface{}) {
 }
 
 func (p *progressTTY) WriteLine(line FancyLine) {
-	p.o.lock.Lock()
-	defer p.o.lock.Unlock()
+	p.o.Lock()
+	defer p.o.Unlock()
 
 	p.moveToOrigin()
 	p.o.clearCurrentLine()
@@ -151,8 +151,8 @@ func newProgressTTY(bars []*ProgressBar, o *Output, opts *ProgressOpts) *progres
 	p.determineEmojiWidth()
 	p.determineLabelWidth()
 
-	p.o.lock.Lock()
-	defer p.o.lock.Unlock()
+	p.o.Lock()
+	defer p.o.Unlock()
 
 	p.draw()
 
@@ -165,8 +165,8 @@ func newProgressTTY(bars []*ProgressBar, o *Output, opts *ProgressOpts) *progres
 			func() {
 				p.pendingEmoji = s
 
-				p.o.lock.Lock()
-				defer p.o.lock.Unlock()
+				p.o.Lock()
+				defer p.o.Unlock()
 
 				p.moveToOrigin()
 				p.draw()
diff --git a/internal/output/progress_with_status_bars_tty.go b/internal/output/progress_with_status_bars_tty.go

Original file line number	Diff line number	Diff line change
`@@ -34,8 +34,8 @@ func newBlock(indent int, o Output) Block {`
`34`	`34`	`}`
`35`	`35`
`36`	`36`	`func (b *Block) Close() {`
`37`		`- b.unwrapped.lock.Lock()`
`38`		`- defer b.unwrapped.lock.Unlock()`
	`37`	`+ b.unwrapped.Lock()`
	`38`	`+ defer b.unwrapped.Unlock()`
`39`	`39`
`40`	`40`	`// This is a little tricky: output from Writer methods includes a trailing`
`41`	`41`	`// newline, so we need to trim that so we don't output extra blank lines.`