feat(storage-server): add StorageServer<F: FileSystem> with BlockDevice trait, mock adapters, and tests

crates/servers/storage-server/src/filesystem.rs

@@ -0,0 +1,46 @@
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct FileHandle(u16);
+
+impl FileHandle {
+    pub const fn new(id: u16) -> Self {
+        Self(id)
+    }
+
+    pub const fn raw(&self) -> u16 {
+        self.0
+    }
+}
+
+#[derive(Debug, Clone, Copy)]
+pub struct DirEntry {
+    pub name: [u8; 32],
+    pub name_len: u8,
+    pub size: u32,
+    pub is_dir: bool,
+}
+
+impl DirEntry {
+    pub fn empty() -> Self {
+        Self {
+            name: [0; 32],
+            name_len: 0,
+            size: 0,
+            is_dir: false,
+        }
+    }
+
+    pub fn name_bytes(&self) -> &[u8] {
+        &self.name[..self.name_len as usize]
+    }
+}
+
+pub trait FileSystem {
+    fn open(&mut self, path: &[u8]) -> Option<FileHandle>;
+    fn read(&mut self, handle: FileHandle, buf: &mut [u8]) -> Option<usize>;
+    fn write(&mut self, handle: FileHandle, buf: &[u8]) -> Option<usize>;
+    fn close(&mut self, handle: FileHandle);
+    fn list_dir(&mut self, path: &[u8], entries: &mut [DirEntry]) -> Option<usize>;
+    fn create(&mut self, path: &[u8]) -> Option<FileHandle>;
+    fn delete(&mut self, path: &[u8]) -> bool;
+    fn file_size(&mut self, handle: FileHandle) -> Option<usize>;
+}