lib/memfs: stop all Watcher spawn by DirWatcher

Previously, the Watcher goroutine will stopped only if the file is
being deleted.
If the DirWatcher stopped manually, by calling Stop method, the
Watcher goroutine will still running in the background.

This changes record all spawned Watcher and stop it when files inside
a deleted directory or when Stop called.

lib/memfs/dirwatcher.go

@@ -30,7 +30,7 @@ type DirWatcher struct {
 	// consumed.
 	qFileChanges chan NodeState
 
-	qrun chan bool
+	qrun chan struct{}
 
 	root *Node
 	fs   *MemFS
@@ -41,6 +41,10 @@ type DirWatcher struct {
 	// information.
 	dirs map[string]*Node
 
+	// fileWatcher contains active watcher for file with Node.Path as
+	// key.
+	fileWatcher map[string]*Watcher
+
 	// This struct embed Options to map the directory to be watched
 	// into memory.
 	//
@@ -95,9 +99,11 @@ func (dw *DirWatcher) init() (err error) {
 	dw.C = dw.qchanges
 
 	dw.qFileChanges = make(chan NodeState, dirWatcherQueueSize)
-	dw.qrun = make(chan bool, 1)
+	dw.qrun = make(chan struct{})
 
 	dw.dirs = make(map[string]*Node)
+	dw.fileWatcher = make(map[string]*Watcher)
+
 	dw.mapSubdirs(dw.root)
 
 	return nil
@@ -121,7 +127,17 @@ func (dw *DirWatcher) Start() (err error) {
 
 // Stop watching changes on directory.
 func (dw *DirWatcher) Stop() {
-	dw.qrun <- false
+	// Stop all file watchers.
+	var watcher *Watcher
+	for _, watcher = range dw.fileWatcher {
+		watcher.Stop()
+	}
+
+	select {
+	case dw.qrun <- struct{}{}:
+		<-dw.qrun
+	default:
+	}
 }
 
 // dirsKeys return all the key in field dirs sorted in ascending order.
@@ -145,8 +161,9 @@ func (dw *DirWatcher) mapSubdirs(node *Node) {
 	var (
 		logp = `DirWatcher.mapSubdirs`
 
-		child *Node
-		err   error
+		child   *Node
+		watcher *Watcher
+		err     error
 	)
 
 	for _, child = range node.Childs {
@@ -157,10 +174,12 @@ func (dw *DirWatcher) mapSubdirs(node *Node) {
 			dw.mapSubdirs(child)
 			continue
 		}
-		_, err = newWatcher(node, child, dw.Delay, dw.qFileChanges)
+		watcher, err = newWatcher(node, child, dw.Delay, dw.qFileChanges)
 		if err != nil {
 			log.Printf("%s %q: %s", logp, child.SysPath, err)
+			continue
 		}
+		dw.fileWatcher[child.Path] = watcher
 	}
 }
 
@@ -172,10 +191,14 @@ func (dw *DirWatcher) onCreated(parent, child *Node) (err error) {
 		dw.dirsLocker.Unlock()
 	} else {
 		// Start watching the file for modification.
-		_, err = newWatcher(parent, childInfo, dw.Delay, dw.qFileChanges)
+		var watcher *Watcher
+
+		watcher, err = newWatcher(parent, child, dw.Delay, dw.qFileChanges)
 		if err != nil {
 			return fmt.Errorf(`onCreated: %w`, err)
 		}
+
+		dw.fileWatcher[child.Path] = watcher
 	}
 
 	var ns = NodeState{
@@ -194,7 +217,8 @@ func (dw *DirWatcher) onCreated(parent, child *Node) (err error) {
 // childs if its a directory.
 func (dw *DirWatcher) onDelete(node *Node) {
 	var (
-		child *Node
+		child   *Node
+		watcher *Watcher
 	)
 	for _, child = range node.Childs {
 		if child.IsDir() {
@@ -217,6 +241,13 @@ func (dw *DirWatcher) onDelete(node *Node) {
 		dw.dirsLocker.Lock()
 		delete(dw.dirs, node.Path)
 		dw.dirsLocker.Unlock()
+	} else {
+		// Stop the file watcher.
+		watcher = dw.fileWatcher[node.Path]
+		if watcher != nil {
+			watcher.Stop()
+			delete(dw.fileWatcher, node.Path)
+		}
 	}
 	dw.fs.RemoveChild(node.Parent, node)
 
@@ -470,6 +501,10 @@ func (dw *DirWatcher) start() {
 			node, err = dw.fs.Get(ns.Node.Path)
 			if err != nil {
 				log.Printf("%s: on file changes %s: %s", logp, ns.Node.Path, err)
+				var watcher = dw.fileWatcher[ns.Node.Path]
+				if watcher != nil {
+					watcher.Stop()
+				}
 			} else {
 				ns.Node = *node
 				switch ns.State {
@@ -485,6 +520,8 @@ func (dw *DirWatcher) start() {
 		case <-dw.qrun:
 			ever = false
 			ticker.Stop()
+			// Signal back to the Stop caller.
+			dw.qrun <- struct{}{}
 		}
 	}
 }

lib/memfs/dirwatcher_test.go

@@ -10,6 +10,7 @@ import (
 	"testing"
 	"time"
 
+	libstrings "github.com/shuLhan/share/lib/strings"
 	"github.com/shuLhan/share/lib/test"
 )
 
@@ -28,9 +29,9 @@ func TestDirWatcher_renameDirectory(t *testing.T) {
 	//
 	// Create a directory with its content to be watched.
 	//
-	//	rootDir
-	//	|_ subDir
-	//	   |_ subDirFile
+	//	rootDir/
+	//	|_ subDir/
+	//	   |_ testfile
 	//
 
 	rootDir = t.TempDir()
@@ -68,9 +69,18 @@ func TestDirWatcher_renameDirectory(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	<-dw.C
-	<-dw.C
-	<-dw.C
+	var ns NodeState
+	ns = <-dw.C // newsubdir created.
+	t.Logf(`0: %s %s`, ns.State, ns.Node.Path)
+
+	ns = <-dw.C // newsubdir/testfile created.
+	t.Logf(`1: %s %s`, ns.State, ns.Node.Path)
+
+	ns = <-dw.C // subdir/testfile removed.
+	t.Logf(`2: %s %s`, ns.State, ns.Node.Path)
+
+	ns = <-dw.C // subdir removed.
+	t.Logf(`3: %s %s`, ns.State, ns.Node.Path)
 
 	dw.Stop()
 
@@ -142,9 +152,22 @@ func TestDirWatcher_removeDirSymlink(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
+
+	var oneOf = []string{`/sub`, `/sub/index.html`}
+
+	got = <-dw.C
+	test.Assert(t, `RemoveAll state`, FileStateDeleted, got.State)
+	if !libstrings.IsContain(oneOf, got.Node.Path) {
+		t.Fatalf(`expecting one of %v, got %q`, oneOf, got.Node.Path)
+	}
+
 	got = <-dw.C
 	test.Assert(t, `RemoveAll state`, FileStateDeleted, got.State)
-	test.Assert(t, `RemoveAll path`, `/sub/index.html`, got.Node.Path)
+	if !libstrings.IsContain(oneOf, got.Node.Path) {
+		t.Fatalf(`expecting one of %v, got %q`, oneOf, got.Node.Path)
+	}
+
+	dw.Stop()
 }
 
 func TestDirWatcher_withSymlink(t *testing.T) {