Major Subsystem Rewrite (Reconciler Mk5) (#217)

server/src/imfs/fetcher.rs

@@ -0,0 +1,32 @@
+use std::{
+    io,
+    path::{Path, PathBuf},
+};
+
+use crossbeam_channel::Receiver;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum FileType {
+    File,
+    Directory,
+}
+
+// TODO: Use our own event type instead of notify's.
+pub type ImfsEvent = notify::DebouncedEvent;
+
+/// The generic interface that `Imfs` uses to lazily read files from the disk.
+/// In tests, it's stubbed out to do different versions of absolutely nothing
+/// depending on the test.
+pub trait ImfsFetcher {
+    fn file_type(&mut self, path: &Path) -> io::Result<FileType>;
+    fn read_children(&mut self, path: &Path) -> io::Result<Vec<PathBuf>>;
+    fn read_contents(&mut self, path: &Path) -> io::Result<Vec<u8>>;
+
+    fn create_directory(&mut self, path: &Path) -> io::Result<()>;
+    fn write_file(&mut self, path: &Path, contents: &[u8]) -> io::Result<()>;
+    fn remove(&mut self, path: &Path) -> io::Result<()>;
+
+    fn watch(&mut self, path: &Path);
+    fn unwatch(&mut self, path: &Path);
+    fn receiver(&self) -> Receiver<ImfsEvent>;
+}