unified task package

common/task/task.go

@@ -0,0 +1,137 @@
+package task
+
+import (
+	"context"
+
+	"v2ray.com/core/common/signal"
+)
+
+type Task func() error
+
+type executionContext struct {
+	ctx       context.Context
+	task      Task
+	onSuccess Task
+	onFailure Task
+}
+
+func (c *executionContext) executeTask() error {
+	if c.ctx == nil && c.task == nil {
+		return nil
+	}
+
+	if c.ctx == nil {
+		return c.task()
+	}
+
+	if c.task == nil {
+		<-c.ctx.Done()
+		return c.ctx.Err()
+	}
+
+	return executeParallel(func() error {
+		<-c.ctx.Done()
+		return c.ctx.Err()
+	}, c.task)
+}
+
+func (c *executionContext) run() error {
+	err := c.executeTask()
+	if err == nil && c.onSuccess != nil {
+		return c.onSuccess()
+	}
+	if err != nil && c.onFailure != nil {
+		return c.onFailure()
+	}
+	return err
+}
+
+type ExecutionOption func(*executionContext)
+
+func WithContext(ctx context.Context) ExecutionOption {
+	return func(c *executionContext) {
+		c.ctx = ctx
+	}
+}
+
+func Parallel(tasks ...Task) ExecutionOption {
+	return func(c *executionContext) {
+		c.task = func() error {
+			return executeParallel(tasks...)
+		}
+	}
+}
+
+func Sequential(tasks ...Task) ExecutionOption {
+	return func(c *executionContext) {
+		c.task = func() error {
+			return execute(tasks...)
+		}
+	}
+}
+
+func OnSuccess(task Task) ExecutionOption {
+	return func(c *executionContext) {
+		c.onSuccess = task
+	}
+}
+
+func OnFailure(task Task) ExecutionOption {
+	return func(c *executionContext) {
+		c.onFailure = task
+	}
+}
+
+func Single(task Task, opts ExecutionOption) Task {
+	return Run(append([]ExecutionOption{Sequential(task)}, opts)...)
+}
+
+func Run(opts ...ExecutionOption) Task {
+	var c executionContext
+	for _, opt := range opts {
+		opt(&c)
+	}
+	return func() error {
+		return c.run()
+	}
+}
+
+// execute runs a list of tasks sequentially, returns the first error encountered or nil if all tasks pass.
+func execute(tasks ...Task) error {
+	for _, task := range tasks {
+		if err := task(); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// executeParallel executes a list of tasks asynchronously, returns the first error encountered or nil if all tasks pass.
+func executeParallel(tasks ...Task) error {
+	n := len(tasks)
+	s := signal.NewSemaphore(n)
+	done := make(chan error, 1)
+
+	for _, task := range tasks {
+		<-s.Wait()
+		go func(f func() error) {
+			if err := f(); err != nil {
+				select {
+				case done <- err:
+				default:
+				}
+			}
+			s.Signal()
+		}(task)
+	}
+
+	for i := 0; i < n; i++ {
+		select {
+		case err := <-done:
+			return err
+		case <-s.Wait():
+		}
+	}
+
+	return nil
+}