lib/memfs: include empty directory

Even thought empty directory does not contains file, from the parent
node _it is_ part of their content.

Also, there is a use case where memfs use as virtual file system (VFS),
as a layer with file system, where user can view list of directory,
create a directory or file on the fly.
If we skip scanning empty directory, that directory will not be visible.

4 files changed, 84 insertions, 4 deletions

diff --git a/lib/memfs/internal/test/embed/embed_test.go b/lib/memfs/internal/test/embed/embed_test.go
index f36f5638..01dd0133 100644
--- a/lib/memfs/internal/test/embed/embed_test.go
+++ b/lib/memfs/internal/test/embed/embed_test.go
@@ -101,12 +101,27 @@ func generate_testdata_exclude() *memfs.Node {
 	node.SetModTimeUnix(1633792794, 467899662)
 	node.SetName("exclude")
 	node.SetSize(0)
+	node.AddChild(_memFS_getNode(memFS, "/exclude/dir", generate_testdata_exclude_dir))
 	node.AddChild(_memFS_getNode(memFS, "/exclude/index-link.css", generate_testdata_exclude_index_link_css))
 	node.AddChild(_memFS_getNode(memFS, "/exclude/index-link.html", generate_testdata_exclude_index_link_html))
 	node.AddChild(_memFS_getNode(memFS, "/exclude/index-link.js", generate_testdata_exclude_index_link_js))
 	return node
 }
 
+func generate_testdata_exclude_dir() *memfs.Node {
+	var node = &memfs.Node{
+		SysPath:     "testdata/exclude/dir",
+		Path:        "/exclude/dir",
+		ContentType: "",
+		GenFuncName: "generate_testdata_exclude_dir",
+	}
+	node.SetMode(2147484096)
+	node.SetModTimeUnix(1629620045, 798024232)
+	node.SetName("dir")
+	node.SetSize(0)
+	return node
+}
+
 func generate_testdata_exclude_index_link_css() *memfs.Node {
 	var node = &memfs.Node{
 		SysPath:     "testdata/exclude/index-link.css",
@@ -163,12 +178,27 @@ func generate_testdata_include() *memfs.Node {
 	node.SetModTimeUnix(1629623653, 749800911)
 	node.SetName("include")
 	node.SetSize(0)
+	node.AddChild(_memFS_getNode(memFS, "/include/dir", generate_testdata_include_dir))
 	node.AddChild(_memFS_getNode(memFS, "/include/index.css", generate_testdata_include_index_css))
 	node.AddChild(_memFS_getNode(memFS, "/include/index.html", generate_testdata_include_index_html))
 	node.AddChild(_memFS_getNode(memFS, "/include/index.js", generate_testdata_include_index_js))
 	return node
 }
 
+func generate_testdata_include_dir() *memfs.Node {
+	var node = &memfs.Node{
+		SysPath:     "testdata/include/dir",
+		Path:        "/include/dir",
+		ContentType: "",
+		GenFuncName: "generate_testdata_include_dir",
+	}
+	node.SetMode(2147484096)
+	node.SetModTimeUnix(1564836597, 0)
+	node.SetName("dir")
+	node.SetSize(0)
+	return node
+}
+
 func generate_testdata_include_index_css() *memfs.Node {
 	var node = &memfs.Node{
 		SysPath:     "testdata/include/index.css",
@@ -288,7 +318,7 @@ func init() {
 	memFS = &memfs.MemFS{
 		PathNodes: memfs.NewPathNode(),
 		Opts: &memfs.Options{
-			Root: "testdata",
+			Root:        "testdata",
 			MaxFileSize: 5242880,
 			Includes: []string{
 			},
@@ -297,7 +327,7 @@ func init() {
 				`.*/node_save$`,
 			},
 			Embed: memfs.EmbedOptions{
-				CommentHeader:  `// SPDX-FileCopyrightText: 2022 Shulhan <ms@kilabit.info>
+				CommentHeader: `// SPDX-FileCopyrightText: 2022 Shulhan <ms@kilabit.info>
 // SPDX-License-Identifier: AGPL-3.0-or-later
 `,
 				PackageName:    "embed",
@@ -319,6 +349,8 @@ func init() {
 		_memFS_getNode(memFS, "/direct/add/file2", generate_testdata_direct_add_file2))
 	memFS.PathNodes.Set("/exclude",
 		_memFS_getNode(memFS, "/exclude", generate_testdata_exclude))
+	memFS.PathNodes.Set("/exclude/dir",
+		_memFS_getNode(memFS, "/exclude/dir", generate_testdata_exclude_dir))
 	memFS.PathNodes.Set("/exclude/index-link.css",
 		_memFS_getNode(memFS, "/exclude/index-link.css", generate_testdata_exclude_index_link_css))
 	memFS.PathNodes.Set("/exclude/index-link.html",
@@ -327,6 +359,8 @@ func init() {
 		_memFS_getNode(memFS, "/exclude/index-link.js", generate_testdata_exclude_index_link_js))
 	memFS.PathNodes.Set("/include",
 		_memFS_getNode(memFS, "/include", generate_testdata_include))
+	memFS.PathNodes.Set("/include/dir",
+		_memFS_getNode(memFS, "/include/dir", generate_testdata_include_dir))
 	memFS.PathNodes.Set("/include/index.css",
 		_memFS_getNode(memFS, "/include/index.css", generate_testdata_include_index_css))
 	memFS.PathNodes.Set("/include/index.html",
@@ -343,4 +377,9 @@ func init() {
 		_memFS_getNode(memFS, "/plain", generate_testdata_plain))
 
 	memFS.Root = memFS.PathNodes.Get("/")
+
+	var err = memFS.Init()
+	if err != nil {
+		panic("memFS: " + err.Error())
+	}
 }
diff --git a/lib/memfs/internal/test/embed/memfs_embed_test.go b/lib/memfs/internal/test/embed/memfs_embed_test.go
index 5cd447d4..a7a5d789 100644
--- a/lib/memfs/internal/test/embed/memfs_embed_test.go
+++ b/lib/memfs/internal/test/embed/memfs_embed_test.go
@@ -101,6 +101,7 @@ func TestNode_Readdir(t *testing.T) {
 	}, {
 		path: "/exclude",
 		exp: []string{
+			"dir",
 			"index-link.css",
 			"index-link.html",
 			"index-link.js",
@@ -108,6 +109,7 @@ func TestNode_Readdir(t *testing.T) {
 	}, {
 		path: "/include",
 		exp: []string{
+			"dir",
 			"index.css",
 			"index.html",
 			"index.js",
diff --git a/lib/memfs/internal/test/embed_disable_modtime/embed_test.go b/lib/memfs/internal/test/embed_disable_modtime/embed_test.go
index dcdc562b..05bb83ed 100644
--- a/lib/memfs/internal/test/embed_disable_modtime/embed_test.go
+++ b/lib/memfs/internal/test/embed_disable_modtime/embed_test.go
@@ -93,12 +93,26 @@ func generate_testdata_exclude() *memfs.Node {
 	node.SetMode(2147484141)
 	node.SetName("exclude")
 	node.SetSize(0)
+	node.AddChild(_memFS_getNode(memFS, "/exclude/dir", generate_testdata_exclude_dir))
 	node.AddChild(_memFS_getNode(memFS, "/exclude/index-link.css", generate_testdata_exclude_index_link_css))
 	node.AddChild(_memFS_getNode(memFS, "/exclude/index-link.html", generate_testdata_exclude_index_link_html))
 	node.AddChild(_memFS_getNode(memFS, "/exclude/index-link.js", generate_testdata_exclude_index_link_js))
 	return node
 }
 
+func generate_testdata_exclude_dir() *memfs.Node {
+	var node = &memfs.Node{
+		SysPath:     "testdata/exclude/dir",
+		Path:        "/exclude/dir",
+		ContentType: "",
+		GenFuncName: "generate_testdata_exclude_dir",
+	}
+	node.SetMode(2147484096)
+	node.SetName("dir")
+	node.SetSize(0)
+	return node
+}
+
 func generate_testdata_exclude_index_link_css() *memfs.Node {
 	var node = &memfs.Node{
 		SysPath:     "testdata/exclude/index-link.css",
@@ -151,12 +165,26 @@ func generate_testdata_include() *memfs.Node {
 	node.SetMode(2147484141)
 	node.SetName("include")
 	node.SetSize(0)
+	node.AddChild(_memFS_getNode(memFS, "/include/dir", generate_testdata_include_dir))
 	node.AddChild(_memFS_getNode(memFS, "/include/index.css", generate_testdata_include_index_css))
 	node.AddChild(_memFS_getNode(memFS, "/include/index.html", generate_testdata_include_index_html))
 	node.AddChild(_memFS_getNode(memFS, "/include/index.js", generate_testdata_include_index_js))
 	return node
 }
 
+func generate_testdata_include_dir() *memfs.Node {
+	var node = &memfs.Node{
+		SysPath:     "testdata/include/dir",
+		Path:        "/include/dir",
+		ContentType: "",
+		GenFuncName: "generate_testdata_include_dir",
+	}
+	node.SetMode(2147484096)
+	node.SetName("dir")
+	node.SetSize(0)
+	return node
+}
+
 func generate_testdata_include_index_css() *memfs.Node {
 	var node = &memfs.Node{
 		SysPath:     "testdata/include/index.css",
@@ -269,7 +297,7 @@ func init() {
 	memFS = &memfs.MemFS{
 		PathNodes: memfs.NewPathNode(),
 		Opts: &memfs.Options{
-			Root: "testdata",
+			Root:        "testdata",
 			MaxFileSize: 5242880,
 			Includes: []string{
 			},
@@ -278,7 +306,7 @@ func init() {
 				`.*/node_save$`,
 			},
 			Embed: memfs.EmbedOptions{
-				CommentHeader:  ``,
+				CommentHeader: ``,
 				PackageName:    "embed",
 				VarName:        "memFS",
 				GoFileName:     "./internal/test/embed_disable_modtime/embed_test.go",
@@ -298,6 +326,8 @@ func init() {
 		_memFS_getNode(memFS, "/direct/add/file2", generate_testdata_direct_add_file2))
 	memFS.PathNodes.Set("/exclude",
 		_memFS_getNode(memFS, "/exclude", generate_testdata_exclude))
+	memFS.PathNodes.Set("/exclude/dir",
+		_memFS_getNode(memFS, "/exclude/dir", generate_testdata_exclude_dir))
 	memFS.PathNodes.Set("/exclude/index-link.css",
 		_memFS_getNode(memFS, "/exclude/index-link.css", generate_testdata_exclude_index_link_css))
 	memFS.PathNodes.Set("/exclude/index-link.html",
@@ -306,6 +336,8 @@ func init() {
 		_memFS_getNode(memFS, "/exclude/index-link.js", generate_testdata_exclude_index_link_js))
 	memFS.PathNodes.Set("/include",
 		_memFS_getNode(memFS, "/include", generate_testdata_include))
+	memFS.PathNodes.Set("/include/dir",
+		_memFS_getNode(memFS, "/include/dir", generate_testdata_include_dir))
 	memFS.PathNodes.Set("/include/index.css",
 		_memFS_getNode(memFS, "/include/index.css", generate_testdata_include_index_css))
 	memFS.PathNodes.Set("/include/index.html",
@@ -322,4 +354,9 @@ func init() {
 		_memFS_getNode(memFS, "/plain", generate_testdata_plain))
 
 	memFS.Root = memFS.PathNodes.Get("/")
+
+	var err = memFS.Init()
+	if err != nil {
+		panic("memFS: " + err.Error())
+	}
 }
diff --git a/lib/memfs/internal/test/embed_disable_modtime/memfs_embed_test.go b/lib/memfs/internal/test/embed_disable_modtime/memfs_embed_test.go
index 5cd447d4..a7a5d789 100644
--- a/lib/memfs/internal/test/embed_disable_modtime/memfs_embed_test.go
+++ b/lib/memfs/internal/test/embed_disable_modtime/memfs_embed_test.go
@@ -101,6 +101,7 @@ func TestNode_Readdir(t *testing.T) {
 	}, {
 		path: "/exclude",
 		exp: []string{
+			"dir",
 			"index-link.css",
 			"index-link.html",
 			"index-link.js",
@@ -108,6 +109,7 @@ func TestNode_Readdir(t *testing.T) {
 	}, {
 		path: "/include",
 		exp: []string{
+			"dir",
 			"index.css",
 			"index.html",
 			"index.js",