initial commit

go.mod

@@ -0,0 +1,3 @@
+module git.milar.in/milarin/statview
+
+go 1.19

print.go

@@ -0,0 +1,32 @@
+package statview
+
+import (
+	"fmt"
+	"io"
+	"strings"
+)
+
+func clearEOL(w io.Writer) {
+	w.Write([]byte{0x1b, 0x5b, 0x4b})
+}
+
+func goUp(w io.Writer) {
+	w.Write([]byte{0x1b, 0x5b, 0x41})
+}
+
+func (v *View[K]) print() {
+	for i := 0; i < v.lastLineAmount; i++ {
+		goUp(v.writer)
+		clearEOL(v.writer)
+	}
+
+	lineAmount := 0
+	for _, task := range v.tasks {
+		if report, ok := v.lastReports[task]; ok {
+			lineAmount += len(strings.Split(report.Text, "\n"))
+			fmt.Fprintln(v.writer, report.Text)
+		}
+	}
+
+	v.lastLineAmount = lineAmount
+}

report.go

@@ -0,0 +1,6 @@
+package statview
+
+type report[K comparable] struct {
+	ID   K
+	Text string
+}

stat_test.go

@@ -0,0 +1,25 @@
+package statview
+
+import (
+	"fmt"
+	"testing"
+	"time"
+)
+
+func TestStat(t *testing.T) {
+	view := New[int]()
+
+	for i := 0; i < 5; i++ {
+		view.Add(i)
+		go func(id int) {
+			defer view.Done(id)
+
+			for p := 0; p <= 100; p++ {
+				view.Report(id, fmt.Sprintf("task %d: %3d%%", id, p))
+				time.Sleep(time.Duration(id+1) * 10 * time.Millisecond)
+			}
+		}(i)
+	}
+
+	view.Show()
+}

view.go

@@ -0,0 +1,79 @@
+package statview
+
+import (
+	"io"
+	"os"
+	"sort"
+	"sync"
+)
+
+type View[K comparable] struct {
+	writer   io.Writer
+	sortFunc func(i, j K) bool
+
+	lastLineAmount int
+	lastReports    map[K]report[K]
+
+	tasks   []K
+	taskMap map[K]struct{}
+
+	wg       *sync.WaitGroup
+	reportCh chan report[K]
+}
+
+func New[K comparable]() *View[K] {
+	return NewForWriter[K](os.Stderr)
+}
+
+func NewForWriter[K comparable](w io.Writer) *View[K] {
+	return &View[K]{
+		writer:  w,
+		tasks:   make([]K, 0),
+		taskMap: map[K]struct{}{},
+
+		reportCh:    make(chan report[K], 100),
+		lastReports: map[K]report[K]{},
+		wg:          &sync.WaitGroup{},
+	}
+}
+
+func (v *View[K]) Show() {
+	go func() {
+		defer close(v.reportCh)
+		v.wg.Wait()
+	}()
+
+	for status := range v.reportCh {
+		v.lastReports[status.ID] = status
+		v.Add(status.ID)
+		v.print()
+	}
+}
+
+func (v *View[K]) SortFunc(f func(i, j K) bool) {
+	v.sortFunc = f
+}
+
+func (v *View[K]) Add(task K) {
+	if _, ok := v.taskMap[task]; ok {
+		return
+	}
+
+	v.wg.Add(1)
+	v.tasks = append(v.tasks, task)
+	v.taskMap[task] = struct{}{}
+
+	if v.sortFunc != nil {
+		sort.Slice(v.tasks, func(i, j int) bool {
+			return v.sortFunc(v.tasks[i], v.tasks[j])
+		})
+	}
+}
+
+func (v *View[K]) Report(task K, status string) {
+	v.reportCh <- report[K]{ID: task, Text: status}
+}
+
+func (v *View[K]) Done(task K) {
+	v.wg.Done()
+}