VFS in external crate (#297)

* vroom

* Port dir middleware

* Filter rules

* Directory metadata

* Project support

* Enable Lua support

* StringValue support

* CSV

* rbxm, rbxmx, and rbxlx

* JSON models

* Clean up some warnings

* Strip out PathMap

* Unwatch paths when they're reported as removed

* Fix 'rojo upload' behavior

* Upgrade to Insta 0.13.1

* Update dependencies

* Release 0.6.0-alpha.2

* Fix bad merge

* Replace MemoryBackend with InMemoryFs

* Sledgehammer tests into passing for now

* Txt middleware

* Update easy snapshot tests

* Lua tests

* Project middleware tests

* Try to fix test failures by sorting

* Port first set of serve session tests

* Add InMemoryFs::raise_event

* Finish porting serve session tests

* Remove UI code for introspecting VFS for now

* VFS docs

vfs/src/in_memory_fs.rs

@@ -1,32 +1,77 @@
 use std::collections::{BTreeSet, HashMap, VecDeque};
 use std::io;
 use std::path::{Path, PathBuf};
+use std::sync::{Arc, Mutex};
+
+use crossbeam_channel::{Receiver, Sender};
 
 use crate::{DirEntry, Metadata, ReadDir, VfsBackend, VfsEvent, VfsSnapshot};
 
-/// `VfsBackend` that reads from an in-memory filesystem, intended for setting
-/// up testing scenarios quickly.
-#[derive(Debug)]
-pub struct MemoryBackend {
-    entries: HashMap<PathBuf, Entry>,
-    orphans: BTreeSet<PathBuf>,
+/// In-memory filesystem that can be used as a VFS backend.
+///
+/// Internally reference counted to enable giving a copy to
+/// [`Vfs`](struct.Vfs.html) and keeping the original to mutate the filesystem's
+/// state with.
+#[derive(Debug, Clone)]
+pub struct InMemoryFs {
+    inner: Arc<Mutex<InMemoryFsInner>>,
 }
 
-impl MemoryBackend {
+impl InMemoryFs {
+    /// Create a new empty `InMemoryFs`.
     pub fn new() -> Self {
         Self {
-            entries: HashMap::new(),
-            orphans: BTreeSet::new(),
+            inner: Arc::new(Mutex::new(InMemoryFsInner::new())),
         }
     }
 
+    /// Load a [`VfsSnapshot`](enum.VfsSnapshot.html) into a subtree of the
+    /// in-memory filesystem.
+    ///
+    /// This function will return an error if the operations required to apply
+    /// the snapshot result in errors, like trying to create a file inside a
+    /// file.
     pub fn load_snapshot<P: Into<PathBuf>>(
         &mut self,
         path: P,
         snapshot: VfsSnapshot,
     ) -> io::Result<()> {
-        let path = path.into();
+        let mut inner = self.inner.lock().unwrap();
+        inner.load_snapshot(path.into(), snapshot)
+    }
 
+    /// Raises a filesystem change event.
+    ///
+    /// If this `InMemoryFs` is being used as the backend of a
+    /// [`Vfs`](struct.Vfs.html), then any listeners be notified of this event.
+    pub fn raise_event(&mut self, event: VfsEvent) {
+        let inner = self.inner.lock().unwrap();
+        inner.event_sender.send(event).unwrap();
+    }
+}
+
+#[derive(Debug)]
+struct InMemoryFsInner {
+    entries: HashMap<PathBuf, Entry>,
+    orphans: BTreeSet<PathBuf>,
+
+    event_receiver: Receiver<VfsEvent>,
+    event_sender: Sender<VfsEvent>,
+}
+
+impl InMemoryFsInner {
+    fn new() -> Self {
+        let (event_sender, event_receiver) = crossbeam_channel::unbounded();
+
+        Self {
+            entries: HashMap::new(),
+            orphans: BTreeSet::new(),
+            event_receiver,
+            event_sender,
+        }
+    }
+
+    fn load_snapshot(&mut self, path: PathBuf, snapshot: VfsSnapshot) -> io::Result<()> {
         if let Some(parent_path) = path.parent() {
             if let Some(parent_entry) = self.entries.get_mut(parent_path) {
                 if let Entry::Dir { children } = parent_entry {
@@ -84,9 +129,11 @@ enum Entry {
     Dir { children: BTreeSet<PathBuf> },
 }
 
-impl VfsBackend for MemoryBackend {
+impl VfsBackend for InMemoryFs {
     fn read(&mut self, path: &Path) -> io::Result<Vec<u8>> {
-        match self.entries.get(path) {
+        let inner = self.inner.lock().unwrap();
+
+        match inner.entries.get(path) {
             Some(Entry::File { contents }) => Ok(contents.clone()),
             Some(Entry::Dir { .. }) => must_be_file(path),
             None => not_found(path),
@@ -94,8 +141,10 @@ impl VfsBackend for MemoryBackend {
     }
 
     fn write(&mut self, path: &Path, data: &[u8]) -> io::Result<()> {
-        self.load_snapshot(
-            path,
+        let mut inner = self.inner.lock().unwrap();
+
+        inner.load_snapshot(
+            path.to_path_buf(),
             VfsSnapshot::File {
                 contents: data.to_owned(),
             },
@@ -103,7 +152,9 @@ impl VfsBackend for MemoryBackend {
     }
 
     fn read_dir(&mut self, path: &Path) -> io::Result<ReadDir> {
-        match self.entries.get(path) {
+        let inner = self.inner.lock().unwrap();
+
+        match inner.entries.get(path) {
             Some(Entry::Dir { children }) => {
                 let iter = children
                     .clone()
@@ -120,9 +171,11 @@ impl VfsBackend for MemoryBackend {
     }
 
     fn remove_file(&mut self, path: &Path) -> io::Result<()> {
-        match self.entries.get(path) {
+        let mut inner = self.inner.lock().unwrap();
+
+        match inner.entries.get(path) {
             Some(Entry::File { .. }) => {
-                self.remove(path.to_owned());
+                inner.remove(path.to_owned());
                 Ok(())
             }
             Some(Entry::Dir { .. }) => must_be_file(path),
@@ -131,9 +184,11 @@ impl VfsBackend for MemoryBackend {
     }
 
     fn remove_dir_all(&mut self, path: &Path) -> io::Result<()> {
-        match self.entries.get(path) {
+        let mut inner = self.inner.lock().unwrap();
+
+        match inner.entries.get(path) {
             Some(Entry::Dir { .. }) => {
-                self.remove(path.to_owned());
+                inner.remove(path.to_owned());
                 Ok(())
             }
             Some(Entry::File { .. }) => must_be_dir(path),
@@ -142,7 +197,9 @@ impl VfsBackend for MemoryBackend {
     }
 
     fn metadata(&mut self, path: &Path) -> io::Result<Metadata> {
-        match self.entries.get(path) {
+        let inner = self.inner.lock().unwrap();
+
+        match inner.entries.get(path) {
             Some(Entry::File { .. }) => Ok(Metadata { is_file: true }),
             Some(Entry::Dir { .. }) => Ok(Metadata { is_file: false }),
             None => not_found(path),
@@ -150,7 +207,9 @@ impl VfsBackend for MemoryBackend {
     }
 
     fn event_receiver(&self) -> crossbeam_channel::Receiver<VfsEvent> {
-        crossbeam_channel::never()
+        let inner = self.inner.lock().unwrap();
+
+        inner.event_receiver.clone()
     }
 
     fn watch(&mut self, _path: &Path) -> io::Result<()> {

vfs/src/lib.rs

@@ -1,4 +1,4 @@
-mod memory_backend;
+mod in_memory_fs;
 mod noop_backend;
 mod snapshot;
 mod std_backend;
@@ -7,7 +7,7 @@ use std::io;
 use std::path::{Path, PathBuf};
 use std::sync::{Arc, Mutex, MutexGuard};
 
-pub use memory_backend::MemoryBackend;
+pub use in_memory_fs::InMemoryFs;
 pub use noop_backend::NoopBackend;
 pub use snapshot::VfsSnapshot;
 pub use std_backend::StdBackend;
@@ -18,9 +18,9 @@ mod sealed {
     /// Sealing trait for VfsBackend.
     pub trait Sealed {}
 
-    impl Sealed for MemoryBackend {}
     impl Sealed for NoopBackend {}
     impl Sealed for StdBackend {}
+    impl Sealed for InMemoryFs {}
 }
 
 /// Trait that transforms `io::Result<T>` into `io::Result<Option<T>>`.
@@ -107,6 +107,8 @@ impl Metadata {
     }
 }
 
+/// Represents an event that a filesystem can raise that might need to be
+/// handled.
 #[derive(Debug)]
 #[non_exhaustive]
 pub enum VfsEvent {

vfs/src/snapshot.rs

@@ -1,5 +1,8 @@
 use std::collections::BTreeMap;
 
+/// A slice of a tree of files. Can be loaded into an
+/// [`InMemoryFs`](struct.InMemoryFs.html).
+#[derive(Debug)]
 #[non_exhaustive]
 pub enum VfsSnapshot {
     File {
@@ -26,4 +29,16 @@ impl VfsSnapshot {
                 .collect(),
         }
     }
+
+    pub fn empty_file() -> Self {
+        Self::File {
+            contents: Vec::new(),
+        }
+    }
+
+    pub fn empty_dir() -> Self {
+        Self::Dir {
+            children: BTreeMap::new(),
+        }
+    }
 }

vfs/src/std_backend.rs

@@ -63,11 +63,14 @@ impl VfsBackend for StdBackend {
     }
 
     fn read_dir(&mut self, path: &Path) -> io::Result<ReadDir> {
-        let inner = fs::read_dir(path)?.map(|entry| {
-            Ok(DirEntry {
-                path: entry?.path(),
-            })
-        });
+        let entries: Result<Vec<_>, _> = fs::read_dir(path)?.collect();
+        let mut entries = entries?;
+
+        entries.sort_by_cached_key(|entry| entry.file_name());
+
+        let inner = entries
+            .into_iter()
+            .map(|entry| Ok(DirEntry { path: entry.path() }));
 
         Ok(ReadDir {
             inner: Box::new(inner),