(refactor): The closed field type is changed from atomic.Value to…

… `*gtype.Bool` type, and the `Proceed` method is modified to return an unreasonable error: `context.Canceled`

contrib/registry/file/file_discovery.go

@@ -10,6 +10,7 @@ import (
 	"context"
 
 	"github.com/gogf/gf/v2/container/gmap"
+	"github.com/gogf/gf/v2/container/gtype"
 	"github.com/gogf/gf/v2/frame/g"
 	"github.com/gogf/gf/v2/net/gsvc"
 	"github.com/gogf/gf/v2/os/gfile"
@@ -55,9 +56,10 @@ func (r *Registry) Watch(ctx context.Context, key string) (watcher gsvc.Watcher,
 		prefix:    key,
 		discovery: r,
 		ch:        make(chan gsvc.Service, 100),
+		closed:    gtype.NewBool(false),
 	}
 	_, err = gfsnotify.Add(r.path, func(event *gfsnotify.Event) {
-		if fileWatcher.closed.Load() != nil {
+		if fileWatcher.closed.Val() {
 			return
 		}
 		if event.IsChmod() {

contrib/registry/file/file_watcher.go

@@ -8,8 +8,9 @@ package file
 
 import (
 	"context"
-	"sync/atomic"
 
+	"github.com/gogf/gf/v2/container/gtype"
+	"github.com/gogf/gf/v2/errors/gerror"
 	"github.com/gogf/gf/v2/net/gsvc"
 )
 
@@ -18,25 +19,24 @@ type Watcher struct {
 	prefix    string            // Watched prefix key, not file name prefix.
 	discovery gsvc.Discovery    // Service discovery.
 	ch        chan gsvc.Service // Changes that caused by inotify.
-	closed    atomic.Value      // Whether the channel has been closed
+	closed    *gtype.Bool       // Whether the channel has been closed
 }
 
 // Proceed proceeds watch in blocking way.
 // It returns all complete services that watched by `key` if any change.
 func (w *Watcher) Proceed() (services []gsvc.Service, err error) {
-	if w.closed.Load() == nil {
-		<-w.ch
-		return w.discovery.Search(context.Background(), gsvc.SearchInput{
-			Prefix: w.prefix,
-		})
+	if w.closed.Val() {
+		return nil, gerror.New("discovery service was closed")
 	}
-	return nil, context.Canceled
+	<-w.ch
+	return w.discovery.Search(context.Background(), gsvc.SearchInput{
+		Prefix: w.prefix,
+	})
 }
 
 // Close closes the watcher.
 func (w *Watcher) Close() error {
-	if w.closed.Load() == nil {
-		w.closed.Store(true)
+	if w.closed.Cas(false, true) {
 		close(w.ch)
 	}
 	return nil