Provide remove_dir_contents

We introduce a new module `portable` to contain it, rather than just
putting it striaght in `lib.rs`.  (Whether to do this seems a matter
of taste.)

This is the caller for unix::_remove_file_dir_contents so we can get rid of the
temporary `#[allow]` annotation.

Signed-off-by: Ian Jackson <[email protected]>

Author: ijackson

README.md

@@ -9,6 +9,9 @@
 A reliable implementation of `remove_dir_all` for Windows. For Unix systems
 re-exports `std::fs::remove_dir_all`.
 
+Also provides `remove_dir_contents` for both Windows and Unix.  This
+removes just the contents of the directory, if it exists.
+
 ```rust,no_run
 extern crate remove_dir_all;
 

src/lib.rs

@@ -2,6 +2,8 @@
 //!
 //! This library provides a reliable implementation of `remove_dir_all` for Windows.
 //! For Unix systems, it re-exports `std::fs::remove_dir_all`.
+//!
+//! It also provides `remove_dir_contents` for both Unix and Windows.
 
 #![deny(missing_debug_implementations)]
 #![deny(missing_docs)]
@@ -22,8 +24,12 @@ mod fs;
 #[cfg(not(windows))]
 mod unix;
 
+mod portable;
+
 #[cfg(windows)]
 pub use self::fs::remove_dir_all;
 
 #[cfg(not(windows))]
 pub use std::fs::remove_dir_all;
+
+pub use portable::remove_dir_contents;

src/portable.rs

@@ -0,0 +1,20 @@
+use std::io;
+use std::path::Path;
+
+#[cfg(windows)]
+use crate::fs::_remove_dir_contents;
+
+#[cfg(not(windows))]
+use crate::unix::_remove_dir_contents;
+
+/// Deletes the contents of `dir_path`, but not the directory iteself.
+///
+/// If `dir_path` is a symlink to a directory, deletes the contents
+/// of that directory.  Fails if `dir_path` does not exist.
+pub fn remove_dir_contents<P: AsRef<Path>>(path: P) -> io::Result<()> {
+    // This wrapper function exists because the core function
+    // for Windows, in crate::fs, returns a PathBuf, which our
+    // caller shouldn't see.
+    _remove_dir_contents(path)?;
+    Ok(())
+}

src/unix.rs

@@ -1,5 +1,3 @@
-#![allow(dead_code)]
-
 use std::fs;
 use std::io;
 use std::path::Path;