progress

progress/progress.go

@@ -0,0 +1,65 @@
+package progress
+
+import (
+	"fmt"
+	"io"
+	"sync"
+	"time"
+)
+
+type State interface {
+	String() string
+}
+
+type Progress struct {
+	mu  sync.Mutex
+	pos int
+	w   io.Writer
+
+	ticker *time.Ticker
+	states []State
+}
+
+func NewProgress(w io.Writer) *Progress {
+	p := &Progress{pos: -1, w: w}
+	go p.start()
+	return p
+}
+
+func (p *Progress) Stop() {
+	if p.ticker != nil {
+		p.ticker.Stop()
+		p.ticker = nil
+		p.render()
+	}
+}
+
+func (p *Progress) Add(key string, state State) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
+	p.states = append(p.states, state)
+}
+
+func (p *Progress) render() error {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
+	fmt.Fprintf(p.w, "\033[%dA", p.pos)
+	for _, state := range p.states {
+		fmt.Fprintln(p.w, state.String())
+	}
+
+	if len(p.states) > 0 {
+		p.pos = len(p.states)
+	}
+
+	return nil
+}
+
+func (p *Progress) start() {
+	p.ticker = time.NewTicker(100 * time.Millisecond)
+	for range p.ticker.C {
+		p.render()
+	}
+}