Implement SMB Durable Handles (Phase 1): Persistent FileId + reconnect + expiration + cleanup

vendor/smb-server/src/backend.rs

@@ -236,3 +236,44 @@ impl ShareBackend for NotSupportedBackend {
         }
     }
 }
+
+/// Null handle for testing purposes.
+pub struct NullHandle;
+
+#[async_trait]
+impl Handle for NullHandle {
+    async fn read(&self, _offset: u64, _len: u32) -> SmbResult<bytes::Bytes> {
+        Err(SmbError::NotSupported)
+    }
+    async fn write(&self, _offset: u64, _data: &[u8]) -> SmbResult<u32> {
+        Err(SmbError::NotSupported)
+    }
+    async fn flush(&self) -> SmbResult<()> {
+        Err(SmbError::NotSupported)
+    }
+    async fn stat(&self) -> SmbResult<FileInfo> {
+        Ok(FileInfo {
+            name: String::new(),
+            end_of_file: 0,
+            allocation_size: 0,
+            creation_time: 0,
+            last_access_time: 0,
+            last_write_time: 0,
+            change_time: 0,
+            is_directory: false,
+            file_index: 0,
+        })
+    }
+    async fn set_times(&self, _times: FileTimes) -> SmbResult<()> {
+        Err(SmbError::NotSupported)
+    }
+    async fn truncate(&self, _len: u64) -> SmbResult<()> {
+        Err(SmbError::NotSupported)
+    }
+    async fn list_dir(&self, _pattern: Option<&str>) -> SmbResult<Vec<DirEntry>> {
+        Err(SmbError::NotSupported)
+    }
+    async fn close(self: Box<Self>) -> SmbResult<()> {
+        Ok(())
+    }
+}