CopyFile 复制文件.

Create 可以新建文件/目录 注: 需要外部调用 Close 进行关闭.

GetSize 获取文件大小.

IsDir reports whether the named file is a directory.

IsExist returns a boolean indicating whether a file or directory exist.

IsNotExist returns a boolean indicating whether a file or directory not exist.

PostOrder has directories visited after their contents.

PreOrder has directories visited before their contents.

IsDirectory reports whether the named file is a directory.

PathSeparator can be used to override the operating system separator.

FileTree represents a directory in a filesystem-tree structure.

VisitFunc is the type for a callback to visit the entries on a directory and its subdirectories.

VisitOrder is a two-valued flag used to control how directories are visited.