Fix get_metadata on windows

The MetadataExt functions are nightly-only right now so we need to call
the windows api ourselves to get the device number.  The winapi_util
package has a nice wrapper to do this for us.

The get_device function doesn't appear to be used anywhere so I removed
it.

src/utils/platform.rs

@@ -1,4 +1,5 @@
 use jwalk::DirEntry;
+#[allow(unused_imports)]
 use std::fs;
 use std::io;
 
@@ -23,12 +24,17 @@ pub fn get_metadata(d: &DirEntry, use_apparent_size: bool) -> Option<(u64, Optio
 }
 
 #[cfg(target_family = "windows")]
-pub fn get_metadata(d: &DirEntry, use_apparent_size: bool) -> Option<(u64, Option<(u64, u64)>)> {
-    use std::os::windows::fs::MetadataExt;
-    d.metadata.as_ref().unwrap().as_ref().ok().map(|md| {
-        let windows_equivalent_of_inode = Some((md.file_index(), md.volume_serial_number()));
-        (md.file_size(), windows_equivalent_of_inode)
-    })
+pub fn get_metadata(d: &DirEntry, _use_apparent_size: bool) -> Option<(u64, Option<(u64, u64)>)> {
+    use winapi_util::file::information;
+    use winapi_util::Handle;
+
+    let h = Handle::from_path(d.path()).ok()?;
+    let info = information(&h).ok()?;
+
+    Some((
+        info.file_size(),
+        Some((info.file_index(), info.volume_serial_number())),
+    ))
 }
 
 #[cfg(all(not(target_family = "windows"), not(target_family = "unix")))]
@@ -49,13 +55,11 @@ pub fn get_filesystem(file_path: &str) -> Result<u64, io::Error> {
 }
 
 #[cfg(target_family = "windows")]
-pub fn get_device(file_path: &str) -> Result<u64, io::Error> {
-    use std::os::windows::fs::MetadataExt;
-    let metadata = fs::metadata(file_path)?;
-    Ok(metadata.volume_serial_number())
-}
+pub fn get_filesystem(file_path: &str) -> Result<u64, io::Error> {
+    use winapi_util::file::information;
+    use winapi_util::Handle;
 
-#[cfg(all(not(target_family = "windows"), not(target_family = "unix")))]
-pub fn get_device(file_path: &str) -> Result<u64, io::Error> {
-    None
+    let h = Handle::from_path(file_path)?;
+    let info = information(&h)?;
+    Ok(info.volume_serial_number())
 }