xerrgroup

Author: myxy99

xerrgroup/xerrgroup.go

@@ -10,11 +10,11 @@ import (
 	"sync"
 )
 
-// A Group is a collection of goroutines working on subtasks that are part of
+// A group is a collection of goroutines working on subtasks that are part of
 // the same overall task.
 //
-// A zero Group is valid and does not cancel on error.
-type Group struct {
+// A zero group is valid and does not cancel on error.
+type group struct {
 	cancel func()
 
 	wg sync.WaitGroup
@@ -23,23 +23,35 @@ type Group struct {
 	err     error
 }
 
-func NewErrGroup() *Group {
-	return &Group{}
+type OptionFunc func(o *group)
+
+func NewErrGroup(of ...OptionFunc) *group {
+	o := new(group)
+	for _, optionFunc := range of {
+		optionFunc(o)
+	}
+	return o
+}
+
+func SetCancel(f func()) OptionFunc {
+	return func(o *group) {
+		o.cancel = f
+	}
 }
 
 // WithContext returns a new Group and an associated Context derived from ctx.
 //
 // The derived Context is canceled the first time a function passed to Go
 // returns a non-nil error or the first time Wait returns, whichever occurs
 // first.
-func WithContext(ctx context.Context) (*Group, context.Context) {
+func WithContext(ctx context.Context) (*group, context.Context) {
 	ctx, cancel := context.WithCancel(ctx)
-	return &Group{cancel: cancel}, ctx
+	return &group{cancel: cancel}, ctx
 }
 
 // Wait blocks until all function calls from the Go method have returned, then
 // returns the first non-nil error (if any) from them.
-func (g *Group) Wait() error {
+func (g *group) Wait() error {
 	g.wg.Wait()
 	if g.cancel != nil {
 		g.cancel()
@@ -51,7 +63,7 @@ func (g *Group) Wait() error {
 //
 // The first call to return a non-nil error cancels the group; its error will be
 // returned by Wait.
-func (g *Group) Go(f func() error) {
+func (g *group) Go(f func() error) {
 	g.wg.Add(1)
 
 	go func() {