lib/memfs: simplify createRoot and scanDir

The createRoot should not open the file, only call to os.Stat.

The scanDir should only accept the node to be scanned and the call to
Open and Close should be inside the method of scanDir not outside of it.

While at it, prefix all returned errors with method names.

2 files changed, 39 insertions, 43 deletions

diff --git a/lib/memfs/memfs.go b/lib/memfs/memfs.go
index 89aee15f..bfa59caa 100644
--- a/lib/memfs/memfs.go
+++ b/lib/memfs/memfs.go
@@ -461,14 +461,16 @@ func (mfs *MemFS) Update(node *Node, newInfo os.FileInfo) {
 	}
 }
 
-func (mfs *MemFS) createRoot(f *os.File) error {
-	fi, err := f.Stat()
+func (mfs *MemFS) createRoot() error {
+	logp := fmt.Sprintf("createRoot %s", mfs.Opts.Root)
+
+	fi, err := os.Stat(mfs.Opts.Root)
 	if err != nil {
-		return err
+		return fmt.Errorf("%s: %w", logp, err)
 	}
 
 	if !fi.IsDir() {
-		return fmt.Errorf("%q must be a directory", mfs.Opts.Root)
+		return fmt.Errorf("%s: must be a directory", logp)
 	}
 
 	mfs.Root = &Node{
@@ -477,9 +479,6 @@ func (mfs *MemFS) createRoot(f *os.File) error {
 		name:    "/",
 		modTime: fi.ModTime(),
 		mode:    fi.Mode(),
-		size:    0,
-		V:       nil,
-		Parent:  nil,
 	}
 	mfs.Root.generateFuncName(mfs.Opts.Root)
 
@@ -539,7 +538,7 @@ func (mfs *MemFS) isIncluded(sysPath string, mode os.FileMode) bool {
 // mount does not have any effect if current directory contains ".go"
 // file generated from GoEmbed().
 //
-func (mfs *MemFS) mount() error {
+func (mfs *MemFS) mount() (err error) {
 	if len(mfs.Opts.Root) == 0 {
 		return nil
 	}
@@ -551,18 +550,12 @@ func (mfs *MemFS) mount() error {
 		}
 	}
 
-	f, err := os.Open(mfs.Opts.Root)
-	if err != nil {
-		return fmt.Errorf("mount: %w", err)
-	}
-
-	err = mfs.createRoot(f)
+	err = mfs.createRoot()
 	if err != nil {
 		return fmt.Errorf("mount: %w", err)
 	}
 
-	err = mfs.scanDir(mfs.Root, f)
-	_ = f.Close()
+	err = mfs.scanDir(mfs.Root)
 	if err != nil {
 		return fmt.Errorf("mount: %w", err)
 	}
@@ -574,10 +567,19 @@ func (mfs *MemFS) mount() error {
 	return nil
 }
 
-func (mfs *MemFS) scanDir(parent *Node, f *os.File) error {
+// scanDir scan the directory node for files and add them to memory file
+// system.
+func (mfs *MemFS) scanDir(node *Node) (err error) {
+	logp := fmt.Sprintf("scanDir %s", node.SysPath)
+
+	f, err := os.Open(node.SysPath)
+	if err != nil {
+		return fmt.Errorf("%s: %w", logp, err)
+	}
+
 	fis, err := f.Readdir(0)
 	if err != nil {
-		return err
+		return fmt.Errorf("%s: %w", logp, err)
 	}
 
 	sort.SliceStable(fis, func(x, y int) bool {
@@ -585,30 +587,35 @@ func (mfs *MemFS) scanDir(parent *Node, f *os.File) error {
 	})
 
 	for _, fi := range fis {
-		leaf, err := mfs.AddChild(parent, fi)
+		child, err := mfs.AddChild(node, fi)
 		if err != nil {
-			return err
+			err = fmt.Errorf("%s: %w", logp, err)
+			goto out
 		}
-		if leaf == nil {
+		if child == nil {
 			continue
 		}
-		if !leaf.mode.IsDir() {
+		if !child.mode.IsDir() {
 			continue
 		}
 
-		fdir, err := os.Open(leaf.SysPath)
+		err = mfs.scanDir(child)
 		if err != nil {
-			return err
+			err = fmt.Errorf("%s: %w", logp, err)
+			goto out
 		}
-
-		err = mfs.scanDir(leaf, fdir)
-		_ = fdir.Close()
-		if err != nil {
-			return err
+	}
+out:
+	errClose := f.Close()
+	if errClose != nil {
+		if err == nil {
+			err = fmt.Errorf("%s: %w", logp, errClose)
+		} else {
+			log.Printf("%s: %s", logp, errClose)
 		}
 	}
 
-	return nil
+	return err
 }
 
 //
@@ -660,18 +667,7 @@ func (mfs *MemFS) refresh(url string) (node *Node, err error) {
 		return nil, err
 	}
 
-	// Path exist on file system, try to refresh directory.
-	f, err := os.Open(mfs.Root.SysPath)
-	if err != nil {
-		return nil, err
-	}
-
-	err = mfs.scanDir(mfs.Root, f)
-	if err != nil {
-		return nil, err
-	}
-
-	err = f.Close()
+	err = mfs.scanDir(mfs.Root)
 	if err != nil {
 		return nil, err
 	}
diff --git a/lib/memfs/memfs_test.go b/lib/memfs/memfs_test.go
index 83d78bb7..50be993c 100644
--- a/lib/memfs/memfs_test.go
+++ b/lib/memfs/memfs_test.go
@@ -66,7 +66,7 @@ func TestNew(t *testing.T) {
 		opts: Options{
 			Root: afile,
 		},
-		expErr: fmt.Sprintf("memfs.New: mount: %q must be a directory", afile),
+		expErr: fmt.Sprintf("memfs.New: mount: createRoot %s: must be a directory", afile),
 	}, {
 		desc: "With directory",
 		opts: Options{