lib/memfs: realign struct Node, Options, PathNode, and on unit tests

The realign save storage spaces on struct,

* Node: from 240 to 224 bytes (-16 bytes)
* Options: from 112 to 104 bytes (-8 bytes)
* PathNode: from 16 to 8 bytes (-8 bytes)

5 files changed, 28 insertions, 23 deletions

diff --git a/lib/memfs/memfs_test.go b/lib/memfs/memfs_test.go
index fb259bd3..ec5fb8b2 100644
--- a/lib/memfs/memfs_test.go
+++ b/lib/memfs/memfs_test.go
@@ -54,9 +54,9 @@ func TestNew(t *testing.T) {
 
 	cases := []struct {
 		desc       string
-		opts       Options
 		expErr     string
 		expMapKeys []string
+		opts       Options
 	}{{
 		desc:   "With empty dir",
 		expErr: "open : no such file or directory",
@@ -241,10 +241,10 @@ func TestMemFS_AddFile(t *testing.T) {
 
 func TestMemFS_Get(t *testing.T) {
 	cases := []struct {
+		expErr         error
 		path           string
 		expV           []byte
 		expContentType []string
-		expErr         error
 	}{{
 		path: "/",
 	}, {
@@ -553,9 +553,9 @@ func TestMerge(t *testing.T) {
 	}
 
 	cases := []struct {
+		exp    *MemFS
 		desc   string
 		params []*MemFS
-		exp    *MemFS
 	}{{
 		desc:   "with the same instance",
 		params: []*MemFS{mfsDirect, mfsDirect},
diff --git a/lib/memfs/node.go b/lib/memfs/node.go
index 4311102d..233a20d3 100644
--- a/lib/memfs/node.go
+++ b/lib/memfs/node.go
@@ -31,24 +31,29 @@ var (
 // Node represent a single file.
 //
 type Node struct {
+	modTime time.Time // ModTime contains file modification time.
+
 	os.FileInfo
 	http.File
 
-	SysPath     string  // The original file path in system.
-	Path        string  // Absolute file path in memory.
-	Content     []byte  // Content of file.
-	ContentType string  // File type per MIME, for example "application/json".
-	Parent      *Node   // Pointer to parent directory.
-	Childs      []*Node // List of files in directory.
-	GenFuncName string  // The function name for embedded Go code.
+	Parent *Node // Pointer to parent directory.
+
+	SysPath     string // The original file path in system.
+	Path        string // Absolute file path in memory.
+	name        string // File name.
+	ContentType string // File type per MIME, for example "application/json".
+	GenFuncName string // The function name for embedded Go code.
+
+	Childs []*Node // List of files in directory.
+
+	Content []byte // Content of file.
+	plainv  []byte // Content of file in plain text.
+	lowerv  []byte // Content of file in lower cases.
+
+	size int64 // Size of file.
+	off  int64 // The cursor position when doing Read or Seek.
 
-	name    string      // File name.
-	modTime time.Time   // ModTime contains file modification time.
-	mode    os.FileMode // File mode.
-	size    int64       // Size of file.
-	plainv  []byte      // Content of file in plain text.
-	lowerv  []byte      // Content of file in lower cases.
-	off     int64       // The cursor position when doing Read or Seek.
+	mode os.FileMode // File mode.
 }
 
 //
diff --git a/lib/memfs/node_test.go b/lib/memfs/node_test.go
index 0a625d03..5f1d703b 100644
--- a/lib/memfs/node_test.go
+++ b/lib/memfs/node_test.go
@@ -24,10 +24,10 @@ func TestNode_Read(t *testing.T) {
 
 	cases := []struct {
 		desc     string
+		expError string
 		p        []byte
 		exp      []byte
 		expN     int
-		expError string
 	}{{
 		desc: "With empty p",
 	}, {
@@ -176,11 +176,11 @@ func TestNode_Seek(t *testing.T) {
 	}
 
 	cases := []struct {
+		expError error
 		desc     string
 		offset   int64
 		whence   int
 		exp      int64
-		expError error
 	}{{
 		desc:     "With invalid whence",
 		offset:   5,
diff --git a/lib/memfs/options.go b/lib/memfs/options.go
index eeca7f2e..f85bbf8c 100644
--- a/lib/memfs/options.go
+++ b/lib/memfs/options.go
@@ -9,6 +9,9 @@ const (
 )
 
 type Options struct {
+	// EmbedOptions for GoEmbed.
+	Embed EmbedOptions
+
 	// Root contains path to directory where its contents will be mapped
 	// to memory.
 	Root string
@@ -24,9 +27,6 @@ type Options struct {
 	// memory, the MemFS will behave as directory tree.
 	MaxFileSize int64
 
-	// EmbedOptions for GoEmbed.
-	Embed EmbedOptions
-
 	// Development define a flag to bypass file in memory.
 	// If its true, any call to Get will result in direct read to file
 	// system.
diff --git a/lib/memfs/pathnode.go b/lib/memfs/pathnode.go
index f702c01a..df7d6c0f 100644
--- a/lib/memfs/pathnode.go
+++ b/lib/memfs/pathnode.go
@@ -15,8 +15,8 @@ import (
 // PathNode contains a mapping between path and Node.
 //
 type PathNode struct {
-	mu sync.Mutex
 	v  map[string]*Node
+	mu sync.Mutex
 }
 
 //