Implement app update orchestration (T-402)

app-modern/platform/windows/wait.go

@@ -0,0 +1,64 @@
+package windows
+
+import (
+	"context"
+	"fmt"
+	"time"
+)
+
+const exitPollInterval = 250 * time.Millisecond
+
+type exitWaitClock interface {
+	Now() time.Time
+	Wait(context.Context, time.Duration) error
+}
+
+type systemExitWaitClock struct{}
+
+func (systemExitWaitClock) Now() time.Time {
+	return time.Now()
+}
+
+func (systemExitWaitClock) Wait(ctx context.Context, duration time.Duration) error {
+	timer := time.NewTimer(duration)
+	defer timer.Stop()
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	case <-timer.C:
+		return nil
+	}
+}
+
+func waitForExit(ctx context.Context, timeout time.Duration, running func() (bool, error), clock exitWaitClock) error {
+	if ctx == nil {
+		return fmt.Errorf("wait context is required")
+	}
+	if timeout <= 0 {
+		return fmt.Errorf("exit timeout must be positive")
+	}
+	if err := ctx.Err(); err != nil {
+		return err
+	}
+	deadline := clock.Now().Add(timeout)
+	for {
+		isRunning, err := running()
+		if err != nil {
+			return err
+		}
+		if !isRunning {
+			return nil
+		}
+		remaining := deadline.Sub(clock.Now())
+		if remaining <= 0 {
+			return context.DeadlineExceeded
+		}
+		interval := exitPollInterval
+		if remaining < interval {
+			interval = remaining
+		}
+		if err := clock.Wait(ctx, interval); err != nil {
+			return err
+		}
+	}
+}