Implement new file device interface

This is a complete redesign of the file device. The most notable
addition is the ability to ascend and descend the file tree.

1 files changed, 36 insertions, 0 deletions

diff --git a/src/devices/file/entry.rs b/src/devices/file/entry.rs
new file mode 100644
index 0000000..a91ae82
--- /dev/null
+++ b/src/devices/file/entry.rs
@@ -0,0 +1,36 @@
+use crate::*;
+
+use std::cmp::Ordering;
+
+pub enum Entry {
+    File(BufferedFile),
+    Directory(DirectoryListing),
+}
+
+#[derive(Copy, Clone, PartialEq, Eq)]
+pub enum EntryType {
+    File,
+    Directory,
+}
+
+impl PartialOrd for EntryType {
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+        match (self, other) {
+            (EntryType::Directory, EntryType::Directory) => Some(Ordering::Equal  ),
+            (EntryType::Directory, EntryType::File     ) => Some(Ordering::Less   ),
+            (EntryType::File,      EntryType::Directory) => Some(Ordering::Greater),
+            (EntryType::File,      EntryType::File     ) => Some(Ordering::Equal  ),
+        }
+    }
+}
+
+impl Ord for EntryType {
+    fn cmp(&self, other: &Self) -> Ordering {
+        match (self, other) {
+            (EntryType::Directory, EntryType::Directory) => Ordering::Equal  ,
+            (EntryType::Directory, EntryType::File     ) => Ordering::Less   ,
+            (EntryType::File,      EntryType::Directory) => Ordering::Greater,
+            (EntryType::File,      EntryType::File     ) => Ordering::Equal  ,
+        }
+    }
+}