task package: replace waitgroup with channel, fix stuck

internal/task/impl.go

@@ -0,0 +1,75 @@
+package task
+
+import (
+	"errors"
+	"fmt"
+	"sync/atomic"
+	"time"
+)
+
+func (t *Task) addCallback(about string, fn func(), waitSubTasks bool) {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	if t.callbacks == nil {
+		t.callbacks = make(map[*Callback]struct{})
+		t.callbacksDone = make(chan struct{})
+	}
+	t.callbacks[&Callback{fn, about, waitSubTasks}] = struct{}{}
+}
+
+func (t *Task) addChildCount() {
+	if atomic.AddUint32(&t.children, 1) == 1 {
+		t.mu.Lock()
+		if t.childrenDone == nil {
+			t.childrenDone = make(chan struct{})
+		}
+		t.mu.Unlock()
+	}
+}
+
+func (t *Task) subChildCount() {
+	if atomic.AddUint32(&t.children, ^uint32(0)) == 0 {
+		close(t.childrenDone)
+	}
+}
+
+func (t *Task) runCallbacks() {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	if len(t.callbacks) == 0 {
+		return
+	}
+	for c := range t.callbacks {
+		if c.waitChildren {
+			waitWithTimeout(t.childrenDone)
+		}
+		t.invokeWithRecover(c.fn, c.about)
+		delete(t.callbacks, c)
+	}
+	close(t.callbacksDone)
+}
+
+func waitWithTimeout(ch <-chan struct{}) bool {
+	if ch == nil {
+		return true
+	}
+	select {
+	case <-ch:
+		return true
+	case <-time.After(taskTimeout):
+		return false
+	}
+}
+
+func fmtCause(cause any) error {
+	switch cause := cause.(type) {
+	case nil:
+		return nil
+	case error:
+		return cause
+	case string:
+		return errors.New(cause)
+	default:
+		return fmt.Errorf("%v", cause)
+	}
+}