Refactored StaticFS()

- different approach to disable directory listing.

fs.go

@@ -0,0 +1,37 @@
+package gin
+
+import (
+	"net/http"
+	"os"
+)
+
+type (
+	onlyfilesFS struct {
+		fs http.FileSystem
+	}
+	neuteredReaddirFile struct {
+		http.File
+	}
+)
+
+func Dir(root string, listDirectory bool) http.FileSystem {
+	fs := http.Dir(root)
+	if listDirectory {
+		return fs
+	} else {
+		return &onlyfilesFS{fs}
+	}
+}
+
+func (fs onlyfilesFS) Open(name string) (http.File, error) {
+	f, err := fs.fs.Open(name)
+	if err != nil {
+		return nil, err
+	}
+	return neuteredReaddirFile{f}, nil
+}
+
+func (f neuteredReaddirFile) Readdir(count int) ([]os.FileInfo, error) {
+	// this disables directory listing
+	return nil, nil
+}