Expose is_same_file function.

A case could be made for splitting this out into a separate crate,
but I'm fine with keeping it part of walkdir for now.

src/lib.rs

@@ -100,7 +100,7 @@ use std::path::{Path, PathBuf};
 use std::result;
 use std::vec;
 
-use same_file::is_same_file;
+pub use same_file::is_same_file;
 
 mod same_file;
 #[cfg(test)] mod tests;

src/same_file.rs

@@ -16,8 +16,31 @@ use std::path::Path;
 //
 // ---AG
 
-#[cfg(unix)]
+/// Returns true if the two file paths may correspond to the same file.
+///
+/// If there was a problem accessing either file path, then an error is
+/// returned.
+///
+/// Note that it's possible for this to produce a false positive on some
+/// platforms. Namely, this can return true even if the two file paths *don't*
+/// resolve to the same file.
+///
+/// # Example
+///
+/// ```rust,no_run
+/// use walkdir::is_same_file;
+///
+/// assert!(is_same_file("./foo", "././foo").unwrap_or(false));
+/// ```
 pub fn is_same_file<P, Q>(
+    path1: P,
+    path2: Q,
+) -> io::Result<bool> where P: AsRef<Path>, Q: AsRef<Path> {
+    impl_is_same_file(path1, path2)
+}
+
+#[cfg(unix)]
+fn impl_is_same_file<P, Q>(
     p1: P,
     p2: Q,
 ) -> io::Result<bool>
@@ -31,7 +54,7 @@ where P: AsRef<Path>, Q: AsRef<Path> {
 }
 
 #[cfg(windows)]
-pub fn is_same_file<P, Q>(
+fn impl_is_same_file<P, Q>(
     p1: P,
     p2: Q,
 ) -> io::Result<bool>