如何检查Rust中的目录是否为空？

Question

我正在使用一个CLI工具，该工具可以避免用现有文件破坏现有目录，但不关心该目录不存在还是为空。

我知道我可以.exists()用来查看是否PathBuf指向现有文件/目录并.is_dir()查看它是否为目录，但是我将如何检查该目录是否为空？

Answer 1

一行代码检查目录是否可读且为空：

PathBuf::from("t").read_dir().map(|mut i| i.next().is_none()).unwrap_or(false);

Answer 2

You can use .read_dir() to get an iterator over the entries of the directory. . and .. are skipped, so if the first next() call on the iterator returns None you know that the directory is empty.

let is_empty = dir_path_buf.read_dir().next()?.is_none();

If you are on Unix (POSIX, really) a different way to do this is to create a new temporary directory and try to rename it to the directory of the PathBuf. The rename() call, different from the mv utility, will rename a directory if the target is non-existent or an empty directory.