Release 0.6.0-alpha.3

Fixes #280.

CHANGELOG.md

@@ -2,6 +2,18 @@
 
 ## Unreleased Changes for 0.6.x
 
+## [0.6.0 Alpha 3](https://github.com/rojo-rbx/rojo/releases/tag/v0.6.0-alpha.3) (March 13, 2020)
+* Added `--watch` argument to `rojo build`. ([#284](https://github.com/rojo-rbx/rojo/pull/284))
+* Added dark theme support to plugin. ([#241](https://github.com/rojo-rbx/rojo/issues/241))
+* Added a revamped `rojo init` command, which will now create more complete projects.
+* Added the `rojo doc` command, which opens Rojo's documentation in your browser.
+* Fixed many crashes from malformed projects and filesystem edge cases in `rojo serve`.
+* Simplified filesystem access code dramatically.
+* Improved error reporting and logging across the board.
+    * Log messages have a less noisy prefix.
+    * Any thread panicking now causes Rojo to abort instead of existing as a zombie.
+    * Errors now have a list of causes, helping make many errors more clear.
+
 ## [0.6.0 Alpha 2](https://github.com/rojo-rbx/rojo/releases/tag/v0.6.0-alpha.2) (March 6, 2020)
 * Fixed `rojo upload` command always uploading models.
 * Removed `--kind` parameter to `rojo upload`; Rojo now automatically uploads the correct kind of asset based on your project file.

Cargo.lock

@@ -195,7 +195,7 @@ dependencies = [
 name = "clibrojo"
 version = "0.1.0"
 dependencies = [
- "rojo 0.6.0-alpha.2",
+ "rojo 0.6.0-alpha.3",
 ]
 
 [[package]]
@@ -434,18 +434,6 @@ dependencies = [
  "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
-[[package]]
-name = "env_logger"
-version = "0.6.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "atty 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)",
- "humantime 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "regex 1.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "termcolor 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
 [[package]]
 name = "env_logger"
 version = "0.7.1"
@@ -922,6 +910,14 @@ dependencies = [
  "rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "memofs"
+version = "0.1.0"
+dependencies = [
+ "crossbeam-channel 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "notify 4.0.15 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "mime"
 version = "0.3.16"
@@ -1065,6 +1061,14 @@ name = "opaque-debug"
 version = "0.2.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "opener"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "openssl"
 version = "0.10.28"
@@ -1655,8 +1659,9 @@ dependencies = [
 
 [[package]]
 name = "rojo"
-version = "0.6.0-alpha.2"
+version = "0.6.0-alpha.3"
 dependencies = [
+ "backtrace 0.3.45 (registry+https://github.com/rust-lang/crates.io-index)",
  "criterion 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "crossbeam-channel 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "csv 1.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1670,7 +1675,9 @@ dependencies = [
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "maplit 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "memofs 0.1.0",
  "notify 4.0.15 (registry+https://github.com/rust-lang/crates.io-index)",
+ "opener 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "paste 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "pretty_assertions 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rbx_binary 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1707,13 +1714,13 @@ dependencies = [
 name = "rojo-test"
 version = "0.1.0"
 dependencies = [
- "env_logger 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "env_logger 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "insta 0.13.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "paste 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "rbx_dom_weak 1.10.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "reqwest 0.9.24 (registry+https://github.com/rust-lang/crates.io-index)",
- "rojo 0.6.0-alpha.2",
+ "rojo 0.6.0-alpha.3",
  "rojo-insta-ext 0.1.0",
  "serde 1.0.104 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 1.0.48 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2364,14 +2371,6 @@ name = "version_check"
 version = "0.9.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
-[[package]]
-name = "vfs"
-version = "0.1.0"
-dependencies = [
- "crossbeam-channel 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "notify 4.0.15 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
 [[package]]
 name = "walkdir"
 version = "2.3.1"
@@ -2573,7 +2572,6 @@ dependencies = [
 "checksum either 1.5.3 (registry+https://github.com/rust-lang/crates.io-index)" = "bb1f6b1ce1c140482ea30ddd3335fc0024ac7ee112895426e0a629a6c20adfe3"
 "checksum encode_unicode 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)" = "a357d28ed41a50f9c765dbfe56cbc04a64e53e5fc58ba79fbc34c10ef3df831f"
 "checksum encoding_rs 0.8.22 (registry+https://github.com/rust-lang/crates.io-index)" = "cd8d03faa7fe0c1431609dfad7bbe827af30f82e1e2ae6f7ee4fca6bd764bc28"
-"checksum env_logger 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)" = "aafcde04e90a5226a6443b7aabdb016ba2f8307c847d524724bd9b346dd1a2d3"
 "checksum env_logger 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)" = "44533bbbb3bb3c1fa17d9f2e4e38bbbaf8396ba82193c4cb1b6445d711445d36"
 "checksum error-chain 0.12.2 (registry+https://github.com/rust-lang/crates.io-index)" = "d371106cc88ffdfb1eabd7111e432da544f16f3e2d7bf1dfe8bf575f1df045cd"
 "checksum failure 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)" = "b8529c2421efa3066a5cbd8063d2244603824daccb6936b079010bb2aa89464b"
@@ -2645,6 +2643,7 @@ dependencies = [
 "checksum num_cpus 1.12.0 (registry+https://github.com/rust-lang/crates.io-index)" = "46203554f085ff89c235cd12f7075f3233af9b11ed7c9e16dfe2560d03313ce6"
 "checksum oorandom 11.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ebcec7c9c2a95cacc7cd0ecb89d8a8454eca13906f6deb55258ffff0adeb9405"
 "checksum opaque-debug 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "2839e79665f131bdb5782e51f2c6c9599c133c6098982a54c794358bf432529c"
+"checksum opener 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)" = "13117407ca9d0caf3a0e74f97b490a7e64c0ae3aa90a8b7085544d0c37b6f3ae"
 "checksum openssl 0.10.28 (registry+https://github.com/rust-lang/crates.io-index)" = "973293749822d7dd6370d6da1e523b0d1db19f06c459134c658b2a4261378b52"
 "checksum openssl-probe 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "77af24da69f9d9341038eba93a073b1fdaaa1b788221b00a69bce9e762cb32de"
 "checksum openssl-sys 0.9.54 (registry+https://github.com/rust-lang/crates.io-index)" = "1024c0a59774200a555087a6da3f253a9095a5f344e353b212ac4c8b8e450986"

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "rojo"
-version = "0.6.0-alpha.2"
+version = "0.6.0-alpha.3"
 authors = ["Lucien Greathouse <me@lpghatguy.com>"]
 description = "Enables professional-grade development tools for Roblox developers"
 license = "MPL-2.0"
@@ -15,6 +15,12 @@ exclude = [
     "/test-projects/**",
 ]
 
+[profile.dev]
+panic = "abort"
+
+[profile.release]
+panic = "abort"
+
 [features]
 default = []
 
@@ -32,14 +38,14 @@ members = [
     "rojo-test",
     "rojo-insta-ext",
     "clibrojo",
-    "vfs",
+    "memofs",
 ]
 
 default-members = [
     ".",
     "rojo-test",
     "rojo-insta-ext",
-    "vfs",
+    "memofs",
 ]
 
 [lib]
@@ -55,6 +61,9 @@ name = "build"
 harness = false
 
 [dependencies]
+memofs = { version = "0.1.0", path = "memofs" }
+
+backtrace = "0.3"
 crossbeam-channel = "0.4.0"
 csv = "1.1.1"
 env_logger = "0.7.1"
@@ -67,6 +76,7 @@ lazy_static = "1.4.0"
 log = "0.4.8"
 maplit = "1.0.1"
 notify = "4.0.14"
+opener = "0.4.1"
 rbx_binary = "0.5.0"
 rbx_dom_weak = "1.10.1"
 rbx_reflection = "3.3.408"
@@ -80,6 +90,7 @@ serde_json = "1.0"
 snafu = "0.6.0"
 structopt = "0.3.5"
 termcolor = "1.0.5"
+tokio = "0.1.22"
 uuid = { version = "0.8.1", features = ["v4", "serde"] }
 
 [target.'cfg(windows)'.dependencies]
@@ -95,5 +106,4 @@ paste = "0.1"
 pretty_assertions = "0.6.1"
 serde_yaml = "0.8.9"
 tempfile = "3.0"
-tokio = "0.1.22"
 walkdir = "2.1"

assets/default-model-project/README.md

@@ -0,0 +1,11 @@
+# {project_name}
+Generated by [Rojo](https://github.com/rojo-rbx/rojo) {rojo_version}.
+
+## Getting Started
+To build this library or plugin, use:
+
+```bash
+rojo build -o "{project_name}.rbxmx"
+```
+
+For more help, check out [the Rojo documentation](https://rojo.space/docs).

assets/default-model-project/default.project.json

@@ -0,0 +1,6 @@
+{
+  "name": "{project_name}",
+  "tree": {
+    "$path": "src"
+  }
+}

assets/default-model-project/gitignore.txt

@@ -0,0 +1,3 @@
+# Roblox Studio lock files
+/*.rbxlx.lock
+/*.rbxl.lock

assets/default-model-project/src-init.lua

@@ -0,0 +1,5 @@
+return {
+	hello = function()
+		print("Hello world, from {project_name}!")
+	end,
+}

assets/default-place-project/README.md

@@ -0,0 +1,17 @@
+# {project_name}
+Generated by [Rojo](https://github.com/rojo-rbx/rojo) {rojo_version}.
+
+## Getting Started
+To build the place from scratch, use:
+
+```bash
+rojo build -o "{project_name}.rbxlx"
+```
+
+Next, open `{project_name}.rbxlx` in Roblox Studio and start the Rojo server:
+
+```bash
+rojo serve
+```
+
+For more help, check out [the Rojo documentation](https://rojo.space/docs).

assets/default-place-project/default.project.json

@@ -1,39 +1,36 @@
 {
-  "name": "[placeholder]",
+  "name": "{project_name}",
   "tree": {
     "$className": "DataModel",
-    "HttpService": {
-      "$className": "HttpService",
-      "$properties": {
-        "HttpEnabled": true
-      }
-    },
-    "Lighting": {
-      "$className": "Lighting",
-      "$properties": {
-        "Ambient": [
-          0,
-          0,
-          0
-        ],
-        "Brightness": 2,
-        "GlobalShadows": true,
-        "Outlines": false,
-        "Technology": "Voxel"
-      }
-    },
+
     "ReplicatedStorage": {
       "$className": "ReplicatedStorage",
-      "Source": {
-        "$path": "src"
+
+      "Common": {
+        "$path": "src/common"
       }
     },
-    "SoundService": {
-      "$className": "SoundService",
-      "$properties": {
-        "RespectFilteringEnabled": true
+
+    "ServerScriptService": {
+      "$className": "ServerScriptService",
+
+      "Server": {
+        "$path": "src/server"
       }
     },
+
+    "StarterPlayer": {
+      "$className": "StarterPlayer",
+
+      "StarterPlayerScripts": {
+        "$className": "StarterPlayerScripts",
+
+        "Client": {
+          "$path": "src/client"
+        }
+      }
+    },
+
     "Workspace": {
       "$className": "Workspace",
       "$properties": {
@@ -61,6 +58,32 @@
           ]
         }
       }
+    },
+    "Lighting": {
+      "$className": "Lighting",
+      "$properties": {
+        "Ambient": [
+          0,
+          0,
+          0
+        ],
+        "Brightness": 2,
+        "GlobalShadows": true,
+        "Outlines": false,
+        "Technology": "Voxel"
+      }
+    },
+    "SoundService": {
+      "$className": "SoundService",
+      "$properties": {
+        "RespectFilteringEnabled": true
+      }
+    },
+    "HttpService": {
+      "$className": "HttpService",
+      "$properties": {
+        "HttpEnabled": true
+      }
     }
   }
 }

assets/default-place-project/gitignore.txt

@@ -0,0 +1,6 @@
+# Project place file
+/{project_name}.rbxlx
+
+# Roblox Studio lock files
+/*.rbxlx.lock
+/*.rbxl.lock

memofs/CHANGELOG.md

@@ -0,0 +1,6 @@
+# memofs Changelog
+
+## Unreleased Changes
+
+## 0.1.0 (2020-03-10)
+* Initial release

memofs/Cargo.toml

@@ -1,11 +1,12 @@
 [package]
-name = "vfs"
+name = "memofs"
+description = "Virtual filesystem with configurable backends."
 version = "0.1.0"
 authors = ["Lucien Greathouse <me@lpghatguy.com>"]
 edition = "2018"
 readme = "README.md"
 license = "MIT"
-homepage = "https://github.com/rojo-rbx/rojo"
+homepage = "https://github.com/rojo-rbx/rojo/tree/master/memofs"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 

memofs/README.md

@@ -0,0 +1,22 @@
+# memofs
+[![Crates.io](https://img.shields.io/crates/v/memofs.svg)](https://crates.io/crates/memofs)
+
+Implementation of a virtual filesystem with a configurable backend and file
+watching.
+
+memofs is currently an unstable minimum viable library. Its primary consumer is
+[Rojo](https://github.com/rojo-rbx/rojo), a build system for Roblox.
+
+### Current Features
+* API similar to `std::fs`
+* Configurable backends
+    * `StdBackend`, which uses `std::fs` and the `notify` crate
+    * `NoopBackend`, which always throws errors
+    * `InMemoryFs`, a simple in-memory filesystem useful for testing
+
+### Future Features
+* Hash-based hierarchical memoization keys (hence the name)
+* Configurable caching (write-through, write-around, write-back)
+
+## License
+memofs is available under the terms of the MIT license. See [LICENSE.txt](LICENSE.txt) or <https://opensource.org/licenses/MIT> for more details.

memofs/README.tpl

@@ -0,0 +1,7 @@
+# {{crate}}
+[![Crates.io](https://img.shields.io/crates/v/memofs.svg)](https://crates.io/crates/memofs)
+
+{{readme}}
+
+## License
+memofs is available under the terms of the MIT license. See [LICENSE.txt](LICENSE.txt) or <https://opensource.org/licenses/MIT> for more details.

memofs/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<()> {

memofs/src/lib.rs

@@ -1,4 +1,23 @@
-mod memory_backend;
+/*!
+Implementation of a virtual filesystem with a configurable backend and file
+watching.
+
+memofs is currently an unstable minimum viable library. Its primary consumer is
+[Rojo](https://github.com/rojo-rbx/rojo), a build system for Roblox.
+
+## Current Features
+* API similar to `std::fs`
+* Configurable backends
+    * `StdBackend`, which uses `std::fs` and the `notify` crate
+    * `NoopBackend`, which always throws errors
+    * `InMemoryFs`, a simple in-memory filesystem useful for testing
+
+## Future Features
+* Hash-based hierarchical memoization keys (hence the name)
+* Configurable caching (write-through, write-around, write-back)
+*/
+
+mod in_memory_fs;
 mod noop_backend;
 mod snapshot;
 mod std_backend;
@@ -7,7 +26,7 @@ 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 +37,9 @@ 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 +126,8 @@ impl Metadata {
     }
 }
 
+/// Represents an event that a filesystem can raise that might need to be
+/// handled.
 #[derive(Debug)]
 #[non_exhaustive]
 pub enum VfsEvent {
@@ -176,6 +197,10 @@ impl VfsInner {
 }
 
 /// A virtual filesystem with a configurable backend.
+///
+/// All operations on the Vfs take a lock on an internal backend. For performing
+/// large batches of operations, it might be more performant to call `lock()`
+/// and use [`VfsLock`](struct.VfsLock.html) instead.
 pub struct Vfs {
     inner: Mutex<VfsInner>,
 }
@@ -197,6 +222,7 @@ impl Vfs {
         }
     }
 
+    /// Manually lock the Vfs, useful for large batches of operations.
     pub fn lock(&self) -> VfsLock<'_> {
         VfsLock {
             inner: self.inner.lock().unwrap(),
@@ -284,7 +310,9 @@ impl Vfs {
     }
 }
 
-/// A locked handle to a `Vfs`, created by `Vfs::lock`.
+/// A locked handle to a [`Vfs`](struct.Vfs.html), created by `Vfs::lock`.
+///
+/// Implements roughly the same API as [`Vfs`](struct.Vfs.html).
 pub struct VfsLock<'a> {
     inner: MutexGuard<'a, VfsInner>,
 }

memofs/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(),
+        }
+    }
 }

memofs/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),

plugin/src/Components/App.lua

@@ -13,6 +13,7 @@ local Version = require(Plugin.Version)
 local preloadAssets = require(Plugin.preloadAssets)
 local strict = require(Plugin.strict)
 
+local Theme = require(Plugin.Components.Theme)
 local ConnectPanel = require(Plugin.Components.ConnectPanel)
 local ConnectingPanel = require(Plugin.Components.ConnectingPanel)
 local ConnectionActivePanel = require(Plugin.Components.ConnectionActivePanel)
@@ -199,9 +200,11 @@ function App:render()
 		}
 	end
 
-	return Roact.createElement(Roact.Portal, {
-		target = self.dockWidget,
-	}, children)
+	return Roact.createElement(Theme.StudioProvider, nil, {
+		UI = Roact.createElement(Roact.Portal, {
+			target = self.dockWidget,
+		}, children),
+	})
 end
 
 function App:didMount()

plugin/src/Components/ConnectPanel.lua

@@ -4,8 +4,8 @@ local Plugin = Rojo.Plugin
 local Roact = require(Rojo.Roact)
 
 local Config = require(Plugin.Config)
-local Theme = require(Plugin.Theme)
 
+local Theme = require(Plugin.Components.Theme)
 local Panel = require(Plugin.Components.Panel)
 local FitList = require(Plugin.Components.FitList)
 local FitText = require(Plugin.Components.FitText)
@@ -26,136 +26,138 @@ end
 function ConnectPanel:render()
 	local startSession = self.props.startSession
 
-	return e(Panel, nil, {
-		Layout = e("UIListLayout", {
-			SortOrder = Enum.SortOrder.LayoutOrder,
-			HorizontalAlignment = Enum.HorizontalAlignment.Center,
-			VerticalAlignment = Enum.VerticalAlignment.Center,
-		}),
+	return Theme.with(function(theme)
+		return e(Panel, nil, {
+			Layout = e("UIListLayout", {
+				SortOrder = Enum.SortOrder.LayoutOrder,
+				HorizontalAlignment = Enum.HorizontalAlignment.Center,
+				VerticalAlignment = Enum.VerticalAlignment.Center,
+			}),
 
-		Inputs = e(FitList, {
-			containerProps = {
-				BackgroundTransparency = 1,
-				LayoutOrder = 1,
-			},
-			layoutProps = {
-				FillDirection = Enum.FillDirection.Horizontal,
-				Padding = UDim.new(0, 8),
-			},
-			paddingProps = {
-				PaddingTop = UDim.new(0, 20),
-				PaddingBottom = UDim.new(0, 10),
-				PaddingLeft = UDim.new(0, 24),
-				PaddingRight = UDim.new(0, 24),
-			},
-		}, {
-			Address = e(FitList, {
+			Inputs = e(FitList, {
 				containerProps = {
-					LayoutOrder = 1,
 					BackgroundTransparency = 1,
+					LayoutOrder = 1,
 				},
 				layoutProps = {
-					Padding = UDim.new(0, 4),
+					FillDirection = Enum.FillDirection.Horizontal,
+					Padding = UDim.new(0, 8),
+				},
+				paddingProps = {
+					PaddingTop = UDim.new(0, 20),
+					PaddingBottom = UDim.new(0, 10),
+					PaddingLeft = UDim.new(0, 24),
+					PaddingRight = UDim.new(0, 24),
 				},
 			}, {
-				Label = e(FitText, {
-					Kind = "TextLabel",
-					LayoutOrder = 1,
-					BackgroundTransparency = 1,
-					TextXAlignment = Enum.TextXAlignment.Left,
-					Font = Theme.TitleFont,
-					TextSize = 20,
-					Text = "Address",
-					TextColor3 = Theme.PrimaryColor,
+				Address = e(FitList, {
+					containerProps = {
+						LayoutOrder = 1,
+						BackgroundTransparency = 1,
+					},
+					layoutProps = {
+						Padding = UDim.new(0, 4),
+					},
+				}, {
+					Label = e(FitText, {
+						Kind = "TextLabel",
+						LayoutOrder = 1,
+						BackgroundTransparency = 1,
+						TextXAlignment = Enum.TextXAlignment.Left,
+						Font = theme.TitleFont,
+						TextSize = 20,
+						Text = "Address",
+						TextColor3 = theme.Text1,
+					}),
+
+					Input = e(FormTextInput, {
+						layoutOrder = 2,
+						width = UDim.new(0, 220),
+						value = self.state.address,
+						placeholderValue = Config.defaultHost,
+						onValueChange = function(newValue)
+							self:setState({
+								address = newValue,
+							})
+						end,
+					}),
 				}),
 
-				Input = e(FormTextInput, {
-					layoutOrder = 2,
-					width = UDim.new(0, 220),
-					value = self.state.address,
-					placeholderValue = Config.defaultHost,
-					onValueChange = function(newValue)
-						self:setState({
-							address = newValue,
-						})
-					end,
+				Port = e(FitList, {
+					containerProps = {
+						LayoutOrder = 2,
+						BackgroundTransparency = 1,
+					},
+					layoutProps = {
+						Padding = UDim.new(0, 4),
+					},
+				}, {
+					Label = e(FitText, {
+						Kind = "TextLabel",
+						LayoutOrder = 1,
+						BackgroundTransparency = 1,
+						TextXAlignment = Enum.TextXAlignment.Left,
+						Font = theme.TitleFont,
+						TextSize = 20,
+						Text = "Port",
+						TextColor3 = theme.Text1,
+					}),
+
+					Input = e(FormTextInput, {
+						layoutOrder = 2,
+						width = UDim.new(0, 80),
+						value = self.state.port,
+						placeholderValue = Config.defaultPort,
+						onValueChange = function(newValue)
+							self:setState({
+								port = newValue,
+							})
+						end,
+					}),
 				}),
 			}),
 
-			Port = e(FitList, {
+			Buttons = e(FitList, {
+				fitAxes = "Y",
 				containerProps = {
+					BackgroundTransparency = 1,
 					LayoutOrder = 2,
-					BackgroundTransparency = 1,
+					Size = UDim2.new(1, 0, 0, 0),
 				},
 				layoutProps = {
-					Padding = UDim.new(0, 4),
+					FillDirection = Enum.FillDirection.Horizontal,
+					HorizontalAlignment = Enum.HorizontalAlignment.Right,
+					Padding = UDim.new(0, 8),
+				},
+				paddingProps = {
+					PaddingTop = UDim.new(0, 0),
+					PaddingBottom = UDim.new(0, 20),
+					PaddingLeft = UDim.new(0, 24),
+					PaddingRight = UDim.new(0, 24),
 				},
 			}, {
-				Label = e(FitText, {
-					Kind = "TextLabel",
-					LayoutOrder = 1,
-					BackgroundTransparency = 1,
-					TextXAlignment = Enum.TextXAlignment.Left,
-					Font = Theme.TitleFont,
-					TextSize = 20,
-					Text = "Port",
-					TextColor3 = Theme.PrimaryColor,
-				}),
-
-				Input = e(FormTextInput, {
+				e(FormButton, {
 					layoutOrder = 2,
-					width = UDim.new(0, 80),
-					value = self.state.port,
-					placeholderValue = Config.defaultPort,
-					onValueChange = function(newValue)
-						self:setState({
-							port = newValue,
-						})
+					text = "Connect",
+					onClick = function()
+						if startSession ~= nil then
+							local address = self.state.address
+							if address:len() == 0 then
+								address = Config.defaultHost
+							end
+
+							local port = self.state.port
+							if port:len() == 0 then
+								port = Config.defaultPort
+							end
+
+							startSession(address, port)
+						end
 					end,
 				}),
 			}),
-		}),
-
-		Buttons = e(FitList, {
-			fitAxes = "Y",
-			containerProps = {
-				BackgroundTransparency = 1,
-				LayoutOrder = 2,
-				Size = UDim2.new(1, 0, 0, 0),
-			},
-			layoutProps = {
-				FillDirection = Enum.FillDirection.Horizontal,
-				HorizontalAlignment = Enum.HorizontalAlignment.Right,
-				Padding = UDim.new(0, 8),
-			},
-			paddingProps = {
-				PaddingTop = UDim.new(0, 0),
-				PaddingBottom = UDim.new(0, 20),
-				PaddingLeft = UDim.new(0, 24),
-				PaddingRight = UDim.new(0, 24),
-			},
-		}, {
-			e(FormButton, {
-				layoutOrder = 2,
-				text = "Connect",
-				onClick = function()
-					if startSession ~= nil then
-						local address = self.state.address
-						if address:len() == 0 then
-							address = Config.defaultHost
-						end
-
-						local port = self.state.port
-						if port:len() == 0 then
-							port = Config.defaultPort
-						end
-
-						startSession(address, port)
-					end
-				end,
-			}),
-		}),
-	})
+		})
+	end)
 end
 
 return ConnectPanel

plugin/src/Components/ConnectingPanel.lua

@@ -2,8 +2,7 @@ local Roact = require(script:FindFirstAncestor("Rojo").Roact)
 
 local Plugin = script:FindFirstAncestor("Plugin")
 
-local Theme = require(Plugin.Theme)
-
+local Theme = require(Plugin.Components.Theme)
 local Panel = require(Plugin.Components.Panel)
 local FitText = require(Plugin.Components.FitText)
 
@@ -12,23 +11,25 @@ local e = Roact.createElement
 local ConnectingPanel = Roact.Component:extend("ConnectingPanel")
 
 function ConnectingPanel:render()
-	return e(Panel, nil, {
-		Layout = Roact.createElement("UIListLayout", {
-			HorizontalAlignment = Enum.HorizontalAlignment.Center,
-			VerticalAlignment = Enum.VerticalAlignment.Center,
-			SortOrder = Enum.SortOrder.LayoutOrder,
-			Padding = UDim.new(0, 8),
-		}),
+	return Theme.with(function(theme)
+		return e(Panel, nil, {
+			Layout = Roact.createElement("UIListLayout", {
+				HorizontalAlignment = Enum.HorizontalAlignment.Center,
+				VerticalAlignment = Enum.VerticalAlignment.Center,
+				SortOrder = Enum.SortOrder.LayoutOrder,
+				Padding = UDim.new(0, 8),
+			}),
 
-		Text = e(FitText, {
-			Padding = Vector2.new(12, 6),
-			Font = Theme.ButtonFont,
-			TextSize = 18,
-			Text = "Connecting...",
-			TextColor3 = Theme.PrimaryColor,
-			BackgroundTransparency = 1,
-		}),
-	})
+			Text = e(FitText, {
+				Padding = Vector2.new(12, 6),
+				Font = theme.ButtonFont,
+				TextSize = 18,
+				Text = "Connecting...",
+				TextColor3 = theme.Text1,
+				BackgroundTransparency = 1,
+			}),
+		})
+	end)
 end
 
 return ConnectingPanel

plugin/src/Components/ConnectionActivePanel.lua

@@ -2,8 +2,7 @@ local Roact = require(script:FindFirstAncestor("Rojo").Roact)
 
 local Plugin = script:FindFirstAncestor("Plugin")
 
-local Theme = require(Plugin.Theme)
-
+local Theme = require(Plugin.Components.Theme)
 local Panel = require(Plugin.Components.Panel)
 local FitText = require(Plugin.Components.FitText)
 local FormButton = require(Plugin.Components.FormButton)
@@ -15,32 +14,34 @@ local ConnectionActivePanel = Roact.Component:extend("ConnectionActivePanel")
 function ConnectionActivePanel:render()
 	local stopSession = self.props.stopSession
 
-	return e(Panel, nil, {
-		Layout = Roact.createElement("UIListLayout", {
-			HorizontalAlignment = Enum.HorizontalAlignment.Center,
-			VerticalAlignment = Enum.VerticalAlignment.Center,
-			SortOrder = Enum.SortOrder.LayoutOrder,
-			Padding = UDim.new(0, 8),
-		}),
+	return Theme.with(function(theme)
+		return e(Panel, nil, {
+			Layout = Roact.createElement("UIListLayout", {
+				HorizontalAlignment = Enum.HorizontalAlignment.Center,
+				VerticalAlignment = Enum.VerticalAlignment.Center,
+				SortOrder = Enum.SortOrder.LayoutOrder,
+				Padding = UDim.new(0, 8),
+			}),
 
-		Text = e(FitText, {
-			Padding = Vector2.new(12, 6),
-			Font = Theme.ButtonFont,
-			TextSize = 18,
-			Text = "Connected to Live-Sync Server",
-			TextColor3 = Theme.PrimaryColor,
-			BackgroundTransparency = 1,
-		}),
+			Text = e(FitText, {
+				Padding = Vector2.new(12, 6),
+				Font = theme.ButtonFont,
+				TextSize = 18,
+				Text = "Connected to Live-Sync Server",
+				TextColor3 = theme.Text1,
+				BackgroundTransparency = 1,
+			}),
 
-		DisconnectButton = e(FormButton, {
-			layoutOrder = 2,
-			text = "Disconnect",
-			secondary = true,
-			onClick = function()
-				stopSession()
-			end,
-		}),
-	})
+			DisconnectButton = e(FormButton, {
+				layoutOrder = 2,
+				text = "Disconnect",
+				secondary = true,
+				onClick = function()
+					stopSession()
+				end,
+			}),
+		})
+	end)
 end
 
 return ConnectionActivePanel

plugin/src/Components/ErrorPanel.lua

@@ -2,8 +2,7 @@ local Roact = require(script:FindFirstAncestor("Rojo").Roact)
 
 local Plugin = script:FindFirstAncestor("Plugin")
 
-local Theme = require(Plugin.Theme)
-
+local Theme = require(Plugin.Components.Theme)
 local Panel = require(Plugin.Components.Panel)
 local FitText = require(Plugin.Components.FitText)
 local FitScrollingFrame = require(Plugin.Components.FitScrollingFrame)
@@ -20,50 +19,52 @@ function ErrorPanel:render()
 	local errorMessage = self.props.errorMessage
 	local onDismiss = self.props.onDismiss
 
-	return e(Panel, nil, {
-		Layout = Roact.createElement("UIListLayout", {
-			HorizontalAlignment = Enum.HorizontalAlignment.Center,
-			VerticalAlignment = Enum.VerticalAlignment.Center,
-			SortOrder = Enum.SortOrder.LayoutOrder,
-			Padding = UDim.new(0, 8),
-		}),
-
-		ErrorContainer = e(FitScrollingFrame, {
-			containerProps = {
-				BackgroundTransparency = 1,
-				BorderSizePixel = 0,
-				Size = UDim2.new(1, -HOR_PADDING * 2, 1, -BUTTON_HEIGHT),
-				Position = UDim2.new(0, HOR_PADDING, 0, 0),
-				ScrollBarImageColor3 = Theme.PrimaryColor,
-				VerticalScrollBarInset = Enum.ScrollBarInset.ScrollBar,
-				ScrollingDirection = Enum.ScrollingDirection.Y,
-			},
-		}, {
-			Text = e(FitText, {
-				Size = UDim2.new(1, 0, 0, 0),
-
-				LayoutOrder = 1,
-				TextXAlignment = Enum.TextXAlignment.Left,
-				TextYAlignment = Enum.TextYAlignment.Top,
-				FitAxis = "Y",
-				Font = Theme.ButtonFont,
-				TextSize = 18,
-				Text = errorMessage,
-				TextWrap = true,
-				TextColor3 = Theme.PrimaryColor,
-				BackgroundTransparency = 1,
+	return Theme.with(function(theme)
+		return e(Panel, nil, {
+			Layout = Roact.createElement("UIListLayout", {
+				HorizontalAlignment = Enum.HorizontalAlignment.Center,
+				VerticalAlignment = Enum.VerticalAlignment.Center,
+				SortOrder = Enum.SortOrder.LayoutOrder,
+				Padding = UDim.new(0, 8),
 			}),
-		}),
 
-		DismissButton = e(FormButton, {
-			layoutOrder = 2,
-			text = "Dismiss",
-			secondary = true,
-			onClick = function()
-				onDismiss()
-			end,
-		}),
-	})
+			ErrorContainer = e(FitScrollingFrame, {
+				containerProps = {
+					BackgroundTransparency = 1,
+					BorderSizePixel = 0,
+					Size = UDim2.new(1, -HOR_PADDING * 2, 1, -BUTTON_HEIGHT),
+					Position = UDim2.new(0, HOR_PADDING, 0, 0),
+					ScrollBarImageColor3 = theme.Text1,
+					VerticalScrollBarInset = Enum.ScrollBarInset.ScrollBar,
+					ScrollingDirection = Enum.ScrollingDirection.Y,
+				},
+			}, {
+				Text = e(FitText, {
+					Size = UDim2.new(1, 0, 0, 0),
+
+					LayoutOrder = 1,
+					TextXAlignment = Enum.TextXAlignment.Left,
+					TextYAlignment = Enum.TextYAlignment.Top,
+					FitAxis = "Y",
+					Font = theme.ButtonFont,
+					TextSize = 18,
+					Text = errorMessage,
+					TextWrap = true,
+					TextColor3 = theme.Text1,
+					BackgroundTransparency = 1,
+				}),
+			}),
+
+			DismissButton = e(FormButton, {
+				layoutOrder = 2,
+				text = "Dismiss",
+				secondary = true,
+				onClick = function()
+					onDismiss()
+				end,
+			}),
+		})
+	end)
 end
 
 return ErrorPanel

plugin/src/Components/FormButton.lua

@@ -4,7 +4,7 @@ local Plugin = Rojo.Plugin
 local Roact = require(Rojo.Roact)
 
 local Assets = require(Plugin.Assets)
-local Theme = require(Plugin.Theme)
+local Theme = require(Plugin.Components.Theme)
 local FitList = require(Plugin.Components.FitList)
 local FitText = require(Plugin.Components.FitText)
 
@@ -20,43 +20,45 @@ local function FormButton(props)
 	local textColor
 	local backgroundColor
 
-	if props.secondary then
-		textColor = Theme.AccentColor
-		backgroundColor = Theme.SecondaryColor
-	else
-		textColor = Theme.SecondaryColor
-		backgroundColor = Theme.AccentColor
-	end
+	return Theme.with(function(theme)
+		if props.secondary then
+			textColor = theme.Brand1
+			backgroundColor = theme.Background2
+		else
+			textColor = theme.TextOnAccent
+			backgroundColor = theme.Brand1
+		end
 
-	return e(FitList, {
-		containerKind = "ImageButton",
-		containerProps = {
-			LayoutOrder = layoutOrder,
-			BackgroundTransparency = 1,
-			Image = RoundBox.asset,
-			ImageRectOffset = RoundBox.offset,
-			ImageRectSize = RoundBox.size,
-			SliceCenter = RoundBox.center,
-			ScaleType = Enum.ScaleType.Slice,
-			ImageColor3 = backgroundColor,
+		return e(FitList, {
+			containerKind = "ImageButton",
+			containerProps = {
+				LayoutOrder = layoutOrder,
+				BackgroundTransparency = 1,
+				Image = RoundBox.asset,
+				ImageRectOffset = RoundBox.offset,
+				ImageRectSize = RoundBox.size,
+				SliceCenter = RoundBox.center,
+				ScaleType = Enum.ScaleType.Slice,
+				ImageColor3 = backgroundColor,
 
-			[Roact.Event.Activated] = function()
-				if onClick ~= nil then
-					onClick()
-				end
-			end,
-		},
-	}, {
-		Text = e(FitText, {
-			Kind = "TextLabel",
-			Text = text,
-			TextSize = 18,
-			TextColor3 = textColor,
-			Font = Theme.ButtonFont,
-			Padding = Vector2.new(16, 8),
-			BackgroundTransparency = 1,
-		}),
-	})
+				[Roact.Event.Activated] = function()
+					if onClick ~= nil then
+						onClick()
+					end
+				end,
+			},
+		}, {
+			Text = e(FitText, {
+				Kind = "TextLabel",
+				Text = text,
+				TextSize = 18,
+				TextColor3 = textColor,
+				Font = theme.ButtonFont,
+				Padding = Vector2.new(16, 8),
+				BackgroundTransparency = 1,
+			}),
+		})
+	end)
 end
 
 return FormButton

plugin/src/Components/FormTextInput.lua

@@ -4,7 +4,7 @@ local Plugin = Rojo.Plugin
 local Roact = require(Rojo.Roact)
 
 local Assets = require(Plugin.Assets)
-local Theme = require(Plugin.Theme)
+local Theme = require(Plugin.Components.Theme)
 
 local e = Roact.createElement
 
@@ -35,46 +35,48 @@ function FormTextInput:render()
 		shownPlaceholder = placeholderValue
 	end
 
-	return e("ImageLabel", {
-		LayoutOrder = layoutOrder,
-		Image = RoundBox.asset,
-		ImageRectOffset = RoundBox.offset,
-		ImageRectSize = RoundBox.size,
-		ScaleType = Enum.ScaleType.Slice,
-		SliceCenter = RoundBox.center,
-		ImageColor3 = Theme.SecondaryColor,
-		Size = UDim2.new(width.Scale, width.Offset, 0, TEXT_SIZE + PADDING * 2),
-		BackgroundTransparency = 1,
-	}, {
-		InputInner = e("TextBox", {
+	return Theme.with(function(theme)
+		return e("ImageLabel", {
+			LayoutOrder = layoutOrder,
+			Image = RoundBox.asset,
+			ImageRectOffset = RoundBox.offset,
+			ImageRectSize = RoundBox.size,
+			ScaleType = Enum.ScaleType.Slice,
+			SliceCenter = RoundBox.center,
+			ImageColor3 = theme.Background2,
+			Size = UDim2.new(width.Scale, width.Offset, 0, TEXT_SIZE + PADDING * 2),
 			BackgroundTransparency = 1,
-			Size = UDim2.new(1, -PADDING * 2, 1, -PADDING * 2),
-			Position = UDim2.new(0.5, 0, 0.5, 0),
-			AnchorPoint = Vector2.new(0.5, 0.5),
-			Font = Theme.InputFont,
-			ClearTextOnFocus = false,
-			TextXAlignment = Enum.TextXAlignment.Center,
-			TextSize = TEXT_SIZE,
-			Text = value,
-			PlaceholderText = shownPlaceholder,
-			PlaceholderColor3 = Theme.LightTextColor,
-			TextColor3 = Theme.PrimaryColor,
+		}, {
+			InputInner = e("TextBox", {
+				BackgroundTransparency = 1,
+				Size = UDim2.new(1, -PADDING * 2, 1, -PADDING * 2),
+				Position = UDim2.new(0.5, 0, 0.5, 0),
+				AnchorPoint = Vector2.new(0.5, 0.5),
+				Font = theme.InputFont,
+				ClearTextOnFocus = false,
+				TextXAlignment = Enum.TextXAlignment.Center,
+				TextSize = TEXT_SIZE,
+				Text = value,
+				PlaceholderText = shownPlaceholder,
+				PlaceholderColor3 = theme.Text2,
+				TextColor3 = theme.Text1,
 
-			[Roact.Change.Text] = function(rbx)
-				onValueChange(rbx.Text)
-			end,
-			[Roact.Event.Focused] = function()
-				self:setState({
-					focused = true,
-				})
-			end,
-			[Roact.Event.FocusLost] = function()
-				self:setState({
-					focused = false,
-				})
-			end,
-		}),
-	})
+				[Roact.Change.Text] = function(rbx)
+					onValueChange(rbx.Text)
+				end,
+				[Roact.Event.Focused] = function()
+					self:setState({
+						focused = true,
+					})
+				end,
+				[Roact.Event.FocusLost] = function()
+					self:setState({
+						focused = false,
+					})
+				end,
+			}),
+		})
+	end)
 end
 
 return FormTextInput

plugin/src/Components/Panel.lua

@@ -3,6 +3,7 @@ local Roact = require(script:FindFirstAncestor("Rojo").Roact)
 local Plugin = script:FindFirstAncestor("Plugin")
 
 local RojoFooter = require(Plugin.Components.RojoFooter)
+local Theme = require(Plugin.Components.Theme)
 
 local e = Roact.createElement
 
@@ -13,22 +14,25 @@ function Panel:init()
 end
 
 function Panel:render()
-	return e("Frame", {
-		Size = UDim2.new(1, 0, 1, 0),
-		BackgroundTransparency = 1,
-	}, {
-		Layout = Roact.createElement("UIListLayout", {
-			HorizontalAlignment = Enum.HorizontalAlignment.Center,
-			SortOrder = Enum.SortOrder.LayoutOrder,
-		}),
+	return Theme.with(function(theme)
+		return e("Frame", {
+			Size = UDim2.new(1, 0, 1, 0),
+			BackgroundColor3 = theme.Background1,
+			BorderSizePixel = 1,
+		}, {
+			Layout = Roact.createElement("UIListLayout", {
+				HorizontalAlignment = Enum.HorizontalAlignment.Center,
+				SortOrder = Enum.SortOrder.LayoutOrder,
+			}),
 
-		Body = e("Frame", {
-			Size = UDim2.new(0, 360, 1, -32),
-			BackgroundTransparency = 1,
-		}, self.props[Roact.Children]),
+			Body = e("Frame", {
+				Size = UDim2.new(0, 360, 1, -32),
+				BackgroundTransparency = 1,
+			}, self.props[Roact.Children]),
 
-		Footer = e(RojoFooter),
-	})
+			Footer = e(RojoFooter),
+		})
+	end)
 end
 
 return Panel

plugin/src/Components/RojoFooter.lua

@@ -6,7 +6,7 @@ local Roact = require(Rojo.Roact)
 local Config = require(Plugin.Config)
 local Version = require(Plugin.Version)
 local Assets = require(Plugin.Assets)
-local Theme = require(Plugin.Theme)
+local Theme = require(Plugin.Components.Theme)
 
 local e = Roact.createElement
 
@@ -18,50 +18,53 @@ function RojoFooter:init()
 end
 
 function RojoFooter:render()
-	return e("Frame", {
-		LayoutOrder = 3,
-		Size = UDim2.new(1, 0, 0, 32),
-		BackgroundColor3 = Theme.SecondaryColor,
-		BorderSizePixel = 0,
-	}, {
-		Padding = e("UIPadding", {
-			PaddingTop = UDim.new(0, 4),
-			PaddingBottom = UDim.new(0, 4),
-			PaddingLeft = UDim.new(0, 8),
-			PaddingRight = UDim.new(0, 8),
-		}),
-
-		LogoContainer = e("Frame", {
-			BackgroundTransparency = 1,
-
-			Size = UDim2.new(0, 0, 0, 32),
+	return Theme.with(function(theme)
+		return e("Frame", {
+			LayoutOrder = 3,
+			Size = UDim2.new(1, 0, 0, 32),
+			BackgroundColor3 = theme.Background2,
+			BorderSizePixel = 0,
+			ZIndex = 2,
 		}, {
-			Logo = e("ImageLabel", {
-				Image = Assets.Images.Logo,
-				Size = UDim2.new(0, 80, 0, 40),
-				ScaleType = Enum.ScaleType.Fit,
-				BackgroundTransparency = 1,
-				Position = UDim2.new(0, 0, 1, -10),
-				AnchorPoint = Vector2.new(0, 1),
+			Padding = e("UIPadding", {
+				PaddingTop = UDim.new(0, 4),
+				PaddingBottom = UDim.new(0, 4),
+				PaddingLeft = UDim.new(0, 8),
+				PaddingRight = UDim.new(0, 8),
 			}),
-		}),
 
-		Version = e("TextLabel", {
-			Position = UDim2.new(1, 0, 0, 0),
-			Size = UDim2.new(0, 0, 1, 0),
-			AnchorPoint = Vector2.new(1, 0),
-			Font = Theme.TitleFont,
-			TextSize = 18,
-			Text = Version.display(Config.version),
-			TextXAlignment = Enum.TextXAlignment.Right,
-			TextColor3 = Theme.LightTextColor,
-			BackgroundTransparency = 1,
+			LogoContainer = e("Frame", {
+				BackgroundTransparency = 1,
 
-			[Roact.Change.AbsoluteSize] = function(rbx)
-				self.setFooterVersionSize(rbx.AbsoluteSize)
-			end,
-		}),
-	})
+				Size = UDim2.new(0, 0, 0, 32),
+			}, {
+				Logo = e("ImageLabel", {
+					Image = Assets.Images.Logo,
+					Size = UDim2.new(0, 80, 0, 40),
+					ScaleType = Enum.ScaleType.Fit,
+					BackgroundTransparency = 1,
+					Position = UDim2.new(0, 0, 1, -10),
+					AnchorPoint = Vector2.new(0, 1),
+				}),
+			}),
+
+			Version = e("TextLabel", {
+				Position = UDim2.new(1, 0, 0, 0),
+				Size = UDim2.new(0, 0, 1, 0),
+				AnchorPoint = Vector2.new(1, 0),
+				Font = theme.TitleFont,
+				TextSize = 18,
+				Text = Version.display(Config.version),
+				TextXAlignment = Enum.TextXAlignment.Right,
+				TextColor3 = theme.Text2,
+				BackgroundTransparency = 1,
+
+				[Roact.Change.AbsoluteSize] = function(rbx)
+					self.setFooterVersionSize(rbx.AbsoluteSize)
+				end,
+			}),
+		})
+	end)
 end
 
 return RojoFooter

plugin/src/Components/Theme.lua

@@ -0,0 +1,104 @@
+--[[
+	Theming system taking advantage of Roact's new context API.
+
+	Doesn't use colors provided by Studio and instead just branches on theme
+	name. This isn't exactly best practice.
+]]
+
+local Studio = settings():GetService("Studio")
+
+local Rojo = script:FindFirstAncestor("Rojo")
+
+local Roact = require(Rojo.Roact)
+local Log = require(Rojo.Log)
+
+local strict = require(script.Parent.Parent.strict)
+
+local lightTheme = strict("Theme", {
+	ButtonFont = Enum.Font.GothamSemibold,
+	InputFont = Enum.Font.Code,
+	TitleFont = Enum.Font.GothamBold,
+	MainFont = Enum.Font.Gotham,
+
+	Brand1 = Color3.fromRGB(225, 56, 53),
+
+	Text1 = Color3.fromRGB(64, 64, 64),
+	Text2 = Color3.fromRGB(160, 160, 160),
+	TextOnAccent = Color3.fromRGB(235, 235, 235),
+
+	Background1 = Color3.fromRGB(255, 255, 255),
+	Background2 = Color3.fromRGB(235, 235, 235),
+})
+
+local darkTheme = strict("Theme", {
+	ButtonFont = Enum.Font.GothamSemibold,
+	InputFont = Enum.Font.Code,
+	TitleFont = Enum.Font.GothamBold,
+	MainFont = Enum.Font.Gotham,
+
+	Brand1 = Color3.fromRGB(225, 56, 53),
+
+	Text1 = Color3.fromRGB(235, 235, 235),
+	Text2 = Color3.fromRGB(200, 200, 200),
+	TextOnAccent = Color3.fromRGB(235, 235, 235),
+
+	Background1 = Color3.fromRGB(48, 48, 48),
+	Background2 = Color3.fromRGB(64, 64, 64),
+})
+
+local Context = Roact.createContext(lightTheme)
+
+local StudioProvider = Roact.Component:extend("StudioProvider")
+
+-- Pull the current theme from Roblox Studio and update state with it.
+function StudioProvider:updateTheme()
+	local studioTheme = Studio.Theme
+
+	if studioTheme.Name == "Light" then
+		self:setState({
+			theme = lightTheme,
+		})
+	elseif studioTheme.Name == "Dark" then
+		self:setState({
+			theme = darkTheme,
+		})
+	else
+		Log.warn("Unexpected theme '{}'' -- falling back to light theme!", studioTheme.Name)
+
+		self:setState({
+			theme = lightTheme,
+		})
+	end
+end
+
+function StudioProvider:init()
+	self:updateTheme()
+end
+
+function StudioProvider:render()
+	return Roact.createElement(Context.Provider, {
+		value = self.state.theme,
+	}, self.props[Roact.Children])
+end
+
+function StudioProvider:didMount()
+	self.connection = Studio.ThemeChanged:Connect(function()
+		self:updateTheme()
+	end)
+end
+
+function StudioProvider:willUnmount()
+	self.connection:Disconnect()
+end
+
+local function with(callback)
+	return Roact.createElement(Context.Consumer, {
+		render = callback,
+	})
+end
+
+return {
+	StudioProvider = StudioProvider,
+	Consumer = Context.Consumer,
+	with = with,
+}

plugin/src/Config.lua

@@ -5,7 +5,7 @@ local isDevBuild = script.Parent.Parent:FindFirstChild("ROJO_DEV_BUILD") ~= nil
 return strict("Config", {
 	isDevBuild = isDevBuild,
 	codename = "Epiphany",
-	version = {0, 6, 0, "-alpha.2"},
+	version = {0, 6, 0, "-alpha.3"},
 	expectedServerVersionString = "0.6.0 or newer",
 	protocolVersion = 3,
 	defaultHost = "localhost",

plugin/src/Theme.lua

@@ -1,14 +0,0 @@
-local strict = require(script.Parent.strict)
-
-return strict("Theme", {
-	ButtonFont = Enum.Font.GothamSemibold,
-	InputFont = Enum.Font.Code,
-	TitleFont = Enum.Font.GothamBold,
-	MainFont = Enum.Font.Gotham,
-
-	AccentColor = Color3.fromRGB(225, 56, 53),
-	AccentLightColor = Color3.fromRGB(255, 146, 145),
-	PrimaryColor = Color3.fromRGB(64, 64, 64),
-	SecondaryColor = Color3.fromRGB(235, 235, 235),
-	LightTextColor = Color3.fromRGB(160, 160, 160),
-})

plugin/src/init.server.lua

@@ -19,7 +19,7 @@ local app = Roact.createElement(App, {
 	plugin = plugin,
 })
 
-local tree = Roact.mount(app, game:GetService("CoreGui"), "Rojo UI")
+local tree = Roact.mount(app, nil, "Rojo UI")
 
 plugin.Unloading:Connect(function()
 	Roact.unmount(tree)

rojo-test/Cargo.toml

@@ -11,7 +11,7 @@ default = []
 unstable_glob_ignore_paths = []
 
 [dependencies]
-env_logger = "0.6.2"
+env_logger = "0.7.1"
 insta = { version = "0.13.1", features = ["redactions"] }
 log = "0.4.8"
 paste = "0.1.5"

src/bin.rs

@@ -1,65 +1,93 @@
-use std::{error::Error, panic, process};
+use std::{env, error::Error, panic, process};
 
-use log::error;
+use backtrace::Backtrace;
 use structopt::StructOpt;
 
 use librojo::cli::{self, Options, Subcommand};
 
-fn main() {
-    let options = Options::from_args();
-
-    {
-        let log_filter = match options.verbosity {
-            0 => "warn",
-            1 => "warn,librojo=info",
-            2 => "warn,librojo=trace",
-            _ => "trace",
-        };
-
-        let log_env = env_logger::Env::default().default_filter_or(log_filter);
-
-        env_logger::Builder::from_env(log_env)
-            .format_timestamp(None)
-            .init();
-    }
-
-    let panic_result = panic::catch_unwind(|| {
-        if let Err(err) = run(options.subcommand) {
-            log::error!("{}", err);
-            process::exit(1);
-        }
-    });
-
-    if let Err(error) = panic_result {
-        let message = match error.downcast_ref::<&str>() {
-            Some(message) => message.to_string(),
-            None => match error.downcast_ref::<String>() {
-                Some(message) => message.clone(),
-                None => "<no message>".to_string(),
-            },
-        };
-
-        show_crash_message(&message);
-        process::exit(1);
-    }
-}
-
 fn run(subcommand: Subcommand) -> Result<(), Box<dyn Error>> {
     match subcommand {
         Subcommand::Init(init_options) => cli::init(init_options)?,
         Subcommand::Serve(serve_options) => cli::serve(serve_options)?,
         Subcommand::Build(build_options) => cli::build(build_options)?,
         Subcommand::Upload(upload_options) => cli::upload(upload_options)?,
+        Subcommand::Doc => cli::doc()?,
     }
 
     Ok(())
 }
 
-fn show_crash_message(message: &str) {
-    error!("Rojo crashed!");
-    error!("This is a bug in Rojo.");
-    error!("");
-    error!("Please consider filing a bug: https://github.com/rojo-rbx/rojo/issues");
-    error!("");
-    error!("Details: {}", message);
+fn main() {
+    panic::set_hook(Box::new(|panic_info| {
+        // PanicInfo's payload is usually a &'static str or String.
+        // See: https://doc.rust-lang.org/beta/std/panic/struct.PanicInfo.html#method.payload
+        let message = match panic_info.payload().downcast_ref::<&str>() {
+            Some(message) => message.to_string(),
+            None => match panic_info.payload().downcast_ref::<String>() {
+                Some(message) => message.clone(),
+                None => "<no message>".to_string(),
+            },
+        };
+
+        log::error!("Rojo crashed!");
+        log::error!("This is probably a Rojo bug.");
+        log::error!("");
+        log::error!(
+            "Please consider filing an issue: {}/issues",
+            env!("CARGO_PKG_REPOSITORY")
+        );
+        log::error!("");
+        log::error!("Details: {}", message);
+
+        if let Some(location) = panic_info.location() {
+            log::error!("in file {} on line {}", location.file(), location.line());
+        }
+
+        // When using the backtrace crate, we need to check the RUST_BACKTRACE
+        // environment variable ourselves. Once we switch to the (currently
+        // unstable) std::backtrace module, we won't need to do this anymore.
+        let should_backtrace = env::var("RUST_BACKTRACE")
+            .map(|var| var == "1")
+            .unwrap_or(false);
+
+        if should_backtrace {
+            eprintln!("{:?}", Backtrace::new());
+        } else {
+            eprintln!(
+                "note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace."
+            );
+        }
+
+        process::exit(1);
+    }));
+
+    let options = Options::from_args();
+
+    let log_filter = match options.verbosity {
+        0 => "warn",
+        1 => "warn,librojo=info",
+        2 => "warn,librojo=trace",
+        _ => "trace",
+    };
+
+    let log_env = env_logger::Env::default().default_filter_or(log_filter);
+
+    env_logger::Builder::from_env(log_env)
+        .format_module_path(false)
+        .format_timestamp(None)
+        // Indent following lines equal to the log level label, like `[ERROR] `
+        .format_indent(Some(8))
+        .init();
+
+    if let Err(err) = run(options.subcommand) {
+        log::error!("{}", err);
+
+        let mut current_err: &dyn Error = &*err;
+        while let Some(source) = current_err.source() {
+            log::error!("  caused by {}", source);
+            current_err = &*source;
+        }
+
+        process::exit(1);
+    }
 }

src/change_processor.rs

@@ -5,15 +5,16 @@ use std::{
 
 use crossbeam_channel::{select, Receiver, RecvError, Sender};
 use jod_thread::JoinHandle;
+use memofs::{IoResultExt, Vfs, VfsEvent};
 use rbx_dom_weak::{RbxId, RbxValue};
 
 use crate::{
+    error::ErrorDisplay,
     message_queue::MessageQueue,
     snapshot::{
         apply_patch_set, compute_patch_set, AppliedPatchSet, InstigatingSource, PatchSet, RojoTree,
     },
     snapshot_middleware::{snapshot_from_vfs, snapshot_project_node},
-    vfs::{FsResultExt, Vfs, VfsEvent, VfsFetcher},
 };
 
 /// Owns the connection between Rojo's VFS and its DOM by holding onto another
@@ -43,14 +44,14 @@ pub struct ChangeProcessor {
 impl ChangeProcessor {
     /// Spin up the ChangeProcessor, connecting it to the given tree, VFS, and
     /// outbound message queue.
-    pub fn start<F: VfsFetcher + Send + Sync + 'static>(
+    pub fn start(
         tree: Arc<Mutex<RojoTree>>,
-        vfs: Arc<Vfs<F>>,
+        vfs: Arc<Vfs>,
         message_queue: Arc<MessageQueue<AppliedPatchSet>>,
         tree_mutation_receiver: Receiver<PatchSet>,
     ) -> Self {
         let (shutdown_sender, shutdown_receiver) = crossbeam_channel::bounded(1);
-        let vfs_receiver = vfs.change_receiver();
+        let vfs_receiver = vfs.event_receiver();
         let task = JobThreadContext {
             tree,
             vfs,
@@ -107,25 +108,25 @@ impl Drop for ChangeProcessor {
 }
 
 /// Contains all of the state needed to synchronize the DOM and VFS.
-struct JobThreadContext<F> {
+struct JobThreadContext {
     /// A handle to the DOM we're managing.
     tree: Arc<Mutex<RojoTree>>,
 
     /// A handle to the VFS we're managing.
-    vfs: Arc<Vfs<F>>,
+    vfs: Arc<Vfs>,
 
     /// Whenever changes are applied to the DOM, we should push those changes
     /// into this message queue to inform any connected clients.
     message_queue: Arc<MessageQueue<AppliedPatchSet>>,
 }
 
-impl<F: VfsFetcher> JobThreadContext<F> {
+impl JobThreadContext {
     fn handle_vfs_event(&self, event: VfsEvent) {
         log::trace!("Vfs event: {:?}", event);
 
         // Update the VFS immediately with the event.
         self.vfs
-            .commit_change(&event)
+            .commit_event(&event)
             .expect("Error applying VFS change");
 
         // For a given VFS event, we might have many changes to different parts
@@ -135,7 +136,7 @@ impl<F: VfsFetcher> JobThreadContext<F> {
             let mut applied_patches = Vec::new();
 
             match event {
-                VfsEvent::Created(path) | VfsEvent::Modified(path) | VfsEvent::Removed(path) => {
+                VfsEvent::Create(path) | VfsEvent::Write(path) | VfsEvent::Remove(path) => {
                     // Find the nearest ancestor to this path that has
                     // associated instances in the tree. This helps make sure
                     // that we handle additions correctly, especially if we
@@ -164,6 +165,7 @@ impl<F: VfsFetcher> JobThreadContext<F> {
                         }
                     }
                 }
+                _ => log::warn!("Unhandled VFS event: {:?}", event),
             }
 
             applied_patches
@@ -262,11 +264,7 @@ impl<F: VfsFetcher> JobThreadContext<F> {
     }
 }
 
-fn compute_and_apply_changes<F: VfsFetcher>(
-    tree: &mut RojoTree,
-    vfs: &Vfs<F>,
-    id: RbxId,
-) -> Option<AppliedPatchSet> {
+fn compute_and_apply_changes(tree: &mut RojoTree, vfs: &Vfs, id: RbxId) -> Option<AppliedPatchSet> {
     let metadata = tree
         .get_metadata(id)
         .expect("metadata missing for instance present in tree");
@@ -288,21 +286,24 @@ fn compute_and_apply_changes<F: VfsFetcher>(
     // file/folder in the first place.
     let applied_patch_set = match instigating_source {
         InstigatingSource::Path(path) => {
-            let maybe_entry = vfs
-                .get(path)
-                .with_not_found()
-                .expect("unexpected VFS error");
+            let maybe_meta = vfs.metadata(path).with_not_found().unwrap();
 
-            match maybe_entry {
-                Some(entry) => {
+            match maybe_meta {
+                Some(_meta) => {
                     // Our instance was previously created from a path and
                     // that path still exists. We can generate a snapshot
                     // starting at that path and use it as the source for
                     // our patch.
 
-                    let snapshot = snapshot_from_vfs(&metadata.context, &vfs, &entry)
-                        .expect("snapshot failed")
-                        .expect("snapshot did not return an instance");
+                    let snapshot = match snapshot_from_vfs(&metadata.context, &vfs, &path) {
+                        Ok(maybe_snapshot) => {
+                            maybe_snapshot.expect("snapshot did not return an instance")
+                        }
+                        Err(err) => {
+                            log::error!("Snapshot error: {}", ErrorDisplay(err));
+                            return None;
+                        }
+                    };
 
                     let patch_set = compute_patch_set(&snapshot, &tree, id);
                     apply_patch_set(tree, patch_set)
@@ -326,15 +327,21 @@ fn compute_and_apply_changes<F: VfsFetcher>(
             // there might be information associated with our instance from
             // the project file, we snapshot the entire project node again.
 
-            let snapshot = snapshot_project_node(
+            let snapshot_result = snapshot_project_node(
                 &metadata.context,
                 &project_path,
                 instance_name,
                 project_node,
                 &vfs,
-            )
-            .expect("snapshot failed")
-            .expect("snapshot did not return an instance");
+            );
+
+            let snapshot = match snapshot_result {
+                Ok(maybe_snapshot) => maybe_snapshot.expect("snapshot did not return an instance"),
+                Err(err) => {
+                    log::error!("Snapshot error: {}", ErrorDisplay(err));
+                    return None;
+                }
+            };
 
             let patch_set = compute_patch_set(&snapshot, &tree, id);
             apply_patch_set(tree, patch_set)

src/cli/build.rs

@@ -3,13 +3,12 @@ use std::{
     io::{self, BufWriter, Write},
 };
 
+use memofs::Vfs;
 use snafu::{ResultExt, Snafu};
+use tokio::runtime::Runtime;
 
 use crate::{
-    cli::BuildCommand,
-    common_setup,
-    project::ProjectError,
-    vfs::{RealFetcher, Vfs, WatchMode},
+    cli::BuildCommand, project::ProjectError, serve_session::ServeSession, snapshot::RojoTree,
 };
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
@@ -71,18 +70,41 @@ pub fn build(options: BuildCommand) -> Result<(), BuildError> {
 }
 
 fn build_inner(options: BuildCommand) -> Result<(), Error> {
-    let output_kind = detect_output_kind(&options).ok_or(Error::UnknownOutputKind)?;
+    log::trace!("Constructing in-memory filesystem");
 
+    let vfs = Vfs::new_default();
+
+    let session = ServeSession::new(vfs, &options.absolute_project());
+    let mut cursor = session.message_queue().cursor();
+
+    {
+        let tree = session.tree();
+        write_model(&tree, &options)?;
+    }
+
+    if options.watch {
+        let mut rt = Runtime::new().unwrap();
+
+        loop {
+            let receiver = session.message_queue().subscribe(cursor);
+            let (new_cursor, _patch_set) = rt.block_on(receiver).unwrap();
+            cursor = new_cursor;
+
+            let tree = session.tree();
+            write_model(&tree, &options)?;
+        }
+    }
+
+    Ok(())
+}
+
+fn write_model(tree: &RojoTree, options: &BuildCommand) -> Result<(), Error> {
+    let output_kind = detect_output_kind(&options).ok_or(Error::UnknownOutputKind)?;
     log::debug!("Hoping to generate file of type {:?}", output_kind);
 
-    log::trace!("Constructing in-memory filesystem");
-    let vfs = Vfs::new(RealFetcher::new(WatchMode::Disabled));
-
-    let (_maybe_project, tree) = common_setup::start(&options.absolute_project(), &vfs);
     let root_id = tree.get_root_id();
 
     log::trace!("Opening output file for write");
-
     let file = File::create(&options.output).context(Io)?;
     let mut file = BufWriter::new(file);
 
@@ -121,7 +143,5 @@ fn build_inner(options: BuildCommand) -> Result<(), Error> {
 
     file.flush().context(Io)?;
 
-    log::trace!("Done!");
-
     Ok(())
 }

src/cli/doc.rs

@@ -0,0 +1,26 @@
+use opener::{open, OpenError};
+use snafu::Snafu;
+
+#[derive(Debug, Snafu)]
+pub struct DocError(Error);
+
+#[derive(Debug, Snafu)]
+enum Error {
+    Open { source: OpenError },
+}
+
+impl From<OpenError> for Error {
+    fn from(source: OpenError) -> Self {
+        Error::Open { source }
+    }
+}
+
+pub fn doc() -> Result<(), DocError> {
+    doc_inner()?;
+    Ok(())
+}
+
+fn doc_inner() -> Result<(), Error> {
+    open("https://rojo.space/docs")?;
+    Ok(())
+}

src/cli/init.rs

@@ -1,17 +1,229 @@
+use std::{
+    fs::{self, OpenOptions},
+    io::{self, Write},
+    path::Path,
+    process::{Command, Stdio},
+};
+
 use snafu::Snafu;
 
-use crate::cli::InitCommand;
+use crate::cli::{InitCommand, InitKind};
+
+static MODEL_PROJECT: &str =
+    include_str!("../../assets/default-model-project/default.project.json");
+static MODEL_README: &str = include_str!("../../assets/default-model-project/README.md");
+static MODEL_INIT: &str = include_str!("../../assets/default-model-project/src-init.lua");
+static MODEL_GIT_IGNORE: &str = include_str!("../../assets/default-model-project/gitignore.txt");
+
+static PLACE_PROJECT: &str =
+    include_str!("../../assets/default-place-project/default.project.json");
+static PLACE_README: &str = include_str!("../../assets/default-place-project/README.md");
+static PLACE_GIT_IGNORE: &str = include_str!("../../assets/default-place-project/gitignore.txt");
 
 #[derive(Debug, Snafu)]
 pub struct InitError(Error);
 
 #[derive(Debug, Snafu)]
-enum Error {}
+enum Error {
+    #[snafu(display("A project file named default.project.json already exists in this folder"))]
+    AlreadyExists,
+
+    #[snafu(display("git init failed"))]
+    GitInit,
+
+    #[snafu(display("I/O error"))]
+    Io { source: io::Error },
+}
+
+impl From<io::Error> for Error {
+    fn from(source: io::Error) -> Self {
+        Self::Io { source }
+    }
+}
 
 pub fn init(options: InitCommand) -> Result<(), InitError> {
     Ok(init_inner(options)?)
 }
 
-fn init_inner(_options: InitCommand) -> Result<(), Error> {
-    unimplemented!("init command");
+fn init_inner(options: InitCommand) -> Result<(), Error> {
+    let base_path = options.absolute_path();
+    fs::create_dir_all(&base_path)?;
+
+    let canonical = fs::canonicalize(&base_path)?;
+    let project_name = canonical
+        .file_name()
+        .and_then(|name| name.to_str())
+        .unwrap_or("new-project");
+
+    let project_params = ProjectParams {
+        name: project_name.to_owned(),
+    };
+
+    match options.kind {
+        InitKind::Place => init_place(&base_path, project_params),
+        InitKind::Model => init_model(&base_path, project_params),
+    }
+}
+
+fn init_place(base_path: &Path, project_params: ProjectParams) -> Result<(), Error> {
+    eprintln!("Creating new place project '{}'", project_params.name);
+
+    let project_file = project_params.render_template(PLACE_PROJECT);
+    try_create_project(base_path, &project_file)?;
+
+    let readme = project_params.render_template(PLACE_README);
+    write_if_not_exists(&base_path.join("README.md"), &readme)?;
+
+    let src = base_path.join("src");
+    fs::create_dir_all(&src)?;
+
+    let src_shared = src.join("shared");
+    fs::create_dir_all(src.join(&src_shared))?;
+
+    let src_server = src.join("server");
+    fs::create_dir_all(src.join(&src_server))?;
+
+    let src_client = src.join("client");
+    fs::create_dir_all(src.join(&src_client))?;
+
+    write_if_not_exists(
+        &src_shared.join("Hello.lua"),
+        "return function()\n\tprint(\"Hello, world!\")\nend",
+    )?;
+
+    write_if_not_exists(
+        &src_server.join("init.server.lua"),
+        "print(\"Hello world, from server!\")",
+    )?;
+
+    write_if_not_exists(
+        &src_client.join("init.client.lua"),
+        "print(\"Hello world, from client!\")",
+    )?;
+
+    let git_ignore = project_params.render_template(PLACE_GIT_IGNORE);
+    try_git_init(base_path, &git_ignore)?;
+
+    eprintln!("Created project successfully.");
+
+    Ok(())
+}
+
+fn init_model(base_path: &Path, project_params: ProjectParams) -> Result<(), Error> {
+    eprintln!("Creating new model project '{}'", project_params.name);
+
+    let project_file = project_params.render_template(MODEL_PROJECT);
+    try_create_project(base_path, &project_file)?;
+
+    let readme = project_params.render_template(MODEL_README);
+    write_if_not_exists(&base_path.join("README.md"), &readme)?;
+
+    let src = base_path.join("src");
+    fs::create_dir_all(&src)?;
+
+    let init = project_params.render_template(MODEL_INIT);
+    write_if_not_exists(&src.join("init.lua"), &init)?;
+
+    let git_ignore = project_params.render_template(MODEL_GIT_IGNORE);
+    try_git_init(base_path, &git_ignore)?;
+
+    eprintln!("Created project successfully.");
+
+    Ok(())
+}
+
+/// Contains parameters used in templates to create a project.
+struct ProjectParams {
+    name: String,
+}
+
+impl ProjectParams {
+    /// Render a template by replacing variables with project parameters.
+    fn render_template(&self, template: &str) -> String {
+        template
+            .replace("{project_name}", &self.name)
+            .replace("{rojo_version}", env!("CARGO_PKG_VERSION"))
+    }
+}
+
+/// Attempt to initialize a Git repository if necessary, and create .gitignore.
+fn try_git_init(path: &Path, git_ignore: &str) -> Result<(), Error> {
+    if should_git_init(path) {
+        log::debug!("Initializing Git repository...");
+
+        let status = Command::new("git").arg("init").current_dir(path).status()?;
+
+        if !status.success() {
+            return Err(Error::GitInit);
+        }
+    }
+
+    write_if_not_exists(&path.join(".gitignore"), git_ignore)?;
+
+    Ok(())
+}
+
+/// Tells whether we should initialize a Git repository inside the given path.
+///
+/// Will return false if the user doesn't have Git installed or if the path is
+/// already inside a Git repository.
+fn should_git_init(path: &Path) -> bool {
+    let result = Command::new("git")
+        .args(&["rev-parse", "--is-inside-work-tree"])
+        .stdout(Stdio::null())
+        .stderr(Stdio::null())
+        .current_dir(path)
+        .status();
+
+    match result {
+        // If the command ran, but returned a non-zero exit code, we are not in
+        // a Git repo and we should initialize one.
+        Ok(status) => !status.success(),
+
+        // If the command failed to run, we probably don't have Git installed.
+        Err(_) => false,
+    }
+}
+
+/// Write a file if it does not exist yet, otherwise, leave it alone.
+fn write_if_not_exists(path: &Path, contents: &str) -> Result<(), Error> {
+    let file_res = OpenOptions::new().write(true).create_new(true).open(path);
+
+    let mut file = match file_res {
+        Ok(file) => file,
+        Err(err) => {
+            return match err.kind() {
+                io::ErrorKind::AlreadyExists => return Ok(()),
+                _ => Err(err.into()),
+            }
+        }
+    };
+
+    file.write_all(contents.as_bytes())?;
+
+    Ok(())
+}
+
+/// Try to create a project file and fail if it already exists.
+fn try_create_project(base_path: &Path, contents: &str) -> Result<(), Error> {
+    let project_path = base_path.join("default.project.json");
+
+    let file_res = OpenOptions::new()
+        .write(true)
+        .create_new(true)
+        .open(project_path);
+
+    let mut file = match file_res {
+        Ok(file) => file,
+        Err(err) => {
+            return match err.kind() {
+                io::ErrorKind::AlreadyExists => Err(Error::AlreadyExists),
+                _ => Err(err.into()),
+            }
+        }
+    };
+
+    file.write_all(contents.as_bytes())?;
+
+    Ok(())
 }

src/cli/mod.rs

@@ -1,6 +1,7 @@
 //! Defines Rojo's CLI through structopt types.
 
 mod build;
+mod doc;
 mod init;
 mod serve;
 mod upload;
@@ -17,6 +18,7 @@ use std::{
 use structopt::StructOpt;
 
 pub use self::build::*;
+pub use self::doc::*;
 pub use self::init::*;
 pub use self::serve::*;
 pub use self::upload::*;
@@ -48,6 +50,9 @@ pub enum Subcommand {
 
     /// Generates a place or model file out of the project and uploads it to Roblox.
     Upload(UploadCommand),
+
+    /// Open Rojo's documentation in your browser.
+    Doc,
 }
 
 /// Initializes a new Rojo project.
@@ -140,6 +145,10 @@ pub struct BuildCommand {
     /// Where to output the result.
     #[structopt(long, short)]
     pub output: PathBuf,
+
+    /// Whether to automatically rebuild when any input files change.
+    #[structopt(long)]
+    pub watch: bool,
 }
 
 impl BuildCommand {

src/cli/serve.rs

@@ -3,15 +3,11 @@ use std::{
     sync::Arc,
 };
 
+use memofs::Vfs;
 use snafu::Snafu;
 use termcolor::{BufferWriter, Color, ColorChoice, ColorSpec, WriteColor};
 
-use crate::{
-    cli::ServeCommand,
-    serve_session::ServeSession,
-    vfs::{RealFetcher, Vfs, WatchMode},
-    web::LiveServer,
-};
+use crate::{cli::ServeCommand, serve_session::ServeSession, web::LiveServer};
 
 const DEFAULT_PORT: u16 = 34872;
 
@@ -26,7 +22,7 @@ pub fn serve(options: ServeCommand) -> Result<(), ServeError> {
 }
 
 fn serve_inner(options: ServeCommand) -> Result<(), Error> {
-    let vfs = Vfs::new(RealFetcher::new(WatchMode::Enabled));
+    let vfs = Vfs::new_default();
 
     let session = Arc::new(ServeSession::new(vfs, &options.absolute_project()));
 

src/cli/upload.rs

@@ -1,12 +1,8 @@
+use memofs::Vfs;
 use reqwest::header::{ACCEPT, CONTENT_TYPE, COOKIE, USER_AGENT};
 use snafu::{ResultExt, Snafu};
 
-use crate::{
-    auth_cookie::get_auth_cookie,
-    cli::UploadCommand,
-    common_setup,
-    vfs::{RealFetcher, Vfs, WatchMode},
-};
+use crate::{auth_cookie::get_auth_cookie, cli::UploadCommand, common_setup};
 
 #[derive(Debug, Snafu)]
 pub struct UploadError(Error);
@@ -40,7 +36,7 @@ fn upload_inner(options: UploadCommand) -> Result<(), Error> {
         .ok_or(Error::NeedAuthCookie)?;
 
     log::trace!("Constructing in-memory filesystem");
-    let vfs = Vfs::new(RealFetcher::new(WatchMode::Disabled));
+    let vfs = Vfs::new_default();
 
     let (_maybe_project, tree) = common_setup::start(&options.absolute_project(), &vfs);
 

src/common_setup.rs

@@ -3,6 +3,7 @@
 
 use std::path::Path;
 
+use memofs::Vfs;
 use rbx_dom_weak::RbxInstanceProperties;
 
 use crate::{
@@ -12,13 +13,9 @@ use crate::{
         PathIgnoreRule, RojoTree,
     },
     snapshot_middleware::snapshot_from_vfs,
-    vfs::{Vfs, VfsFetcher},
 };
 
-pub fn start<F: VfsFetcher>(
-    fuzzy_project_path: &Path,
-    vfs: &Vfs<F>,
-) -> (Option<Project>, RojoTree) {
+pub fn start(fuzzy_project_path: &Path, vfs: &Vfs) -> (Option<Project>, RojoTree) {
     log::trace!("Loading project file from {}", fuzzy_project_path.display());
     let maybe_project = Project::load_fuzzy(fuzzy_project_path).expect("TODO: Project load failed");
 
@@ -34,11 +31,6 @@ pub fn start<F: VfsFetcher>(
 
     let root_id = tree.get_root_id();
 
-    log::trace!("Reading project root");
-    let entry = vfs
-        .get(fuzzy_project_path)
-        .expect("could not get project path");
-
     let mut instance_context = InstanceContext::default();
 
     if let Some(project) = &maybe_project {
@@ -51,7 +43,7 @@ pub fn start<F: VfsFetcher>(
     }
 
     log::trace!("Generating snapshot of instances from VFS");
-    let snapshot = snapshot_from_vfs(&instance_context, vfs, &entry)
+    let snapshot = snapshot_from_vfs(&instance_context, vfs, &fuzzy_project_path)
         .expect("snapshot failed")
         .expect("snapshot did not return an instance");
 

src/error.rs

@@ -0,0 +1,18 @@
+use std::{error::Error, fmt};
+
+/// Wrapper type to print errors with source-chasing.
+pub struct ErrorDisplay<E>(pub E);
+
+impl<E: Error> fmt::Display for ErrorDisplay<E> {
+    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        writeln!(formatter, "{}", self.0)?;
+
+        let mut current_err: &dyn Error = &self.0;
+        while let Some(source) = current_err.source() {
+            writeln!(formatter, "  caused by {}", source)?;
+            current_err = &*source;
+        }
+
+        Ok(())
+    }
+}

src/lib.rs

@@ -10,17 +10,16 @@ mod tree_view;
 mod auth_cookie;
 mod change_processor;
 mod common_setup;
+mod error;
 mod glob;
 mod message_queue;
 mod multimap;
-mod path_map;
 mod path_serializer;
 mod project;
 mod serve_session;
 mod session_id;
 mod snapshot;
 mod snapshot_middleware;
-mod vfs;
 mod web;
 
 pub use project::*;

src/path_map.rs

@@ -1,282 +0,0 @@
-use std::{
-    collections::{BTreeSet, HashMap},
-    path::{Path, PathBuf},
-};
-
-use log::warn;
-use serde::Serialize;
-
-#[derive(Debug, Serialize)]
-struct PathMapNode<T> {
-    value: T,
-    children: BTreeSet<PathBuf>,
-}
-
-/// A map from paths to another type, like instance IDs, with a bit of
-/// additional data that enables removing a path and all of its child paths from
-/// the tree more quickly.
-#[derive(Debug, Serialize)]
-pub struct PathMap<T> {
-    nodes: HashMap<PathBuf, PathMapNode<T>>,
-
-    /// Contains the set of all paths whose parent either does not exist, or is
-    /// not present in the PathMap.
-    ///
-    /// Note that these paths may have other _ancestors_ in the tree, but if an
-    /// orphan's parent path is ever inserted, it will stop being an orphan. It
-    /// will be... adopted!
-    orphan_paths: BTreeSet<PathBuf>,
-}
-
-impl<T> Default for PathMap<T> {
-    fn default() -> Self {
-        Self::new()
-    }
-}
-
-impl<T> PathMap<T> {
-    pub fn new() -> PathMap<T> {
-        PathMap {
-            nodes: HashMap::new(),
-            orphan_paths: BTreeSet::new(),
-        }
-    }
-
-    pub fn get(&self, path: impl AsRef<Path>) -> Option<&T> {
-        self.nodes.get(path.as_ref()).map(|v| &v.value)
-    }
-
-    pub fn get_mut(&mut self, path: impl AsRef<Path>) -> Option<&mut T> {
-        self.nodes.get_mut(path.as_ref()).map(|v| &mut v.value)
-    }
-
-    pub fn children(&self, path: impl AsRef<Path>) -> Option<Vec<&Path>> {
-        self.nodes
-            .get(path.as_ref())
-            .map(|v| v.children.iter().map(AsRef::as_ref).collect())
-    }
-
-    pub fn contains_key(&self, path: impl AsRef<Path>) -> bool {
-        self.nodes.contains_key(path.as_ref())
-    }
-
-    pub fn insert(&mut self, path: impl Into<PathBuf>, value: T) {
-        let path = path.into();
-
-        self.add_to_parent(path.clone());
-
-        // Collect any children that are currently marked as orphaned paths, but
-        // are actually children of this new node.
-        let mut children = BTreeSet::new();
-        for orphan_path in &self.orphan_paths {
-            if orphan_path.parent() == Some(&path) {
-                children.insert(orphan_path.clone());
-            }
-        }
-
-        for child in &children {
-            self.orphan_paths.remove(child);
-        }
-
-        self.nodes.insert(path, PathMapNode { value, children });
-    }
-
-    /// Remove the given path and all of its linked descendants, returning all
-    /// values stored in the map.
-    pub fn remove(&mut self, root_path: impl AsRef<Path>) -> Vec<(PathBuf, T)> {
-        let root_path = root_path.as_ref();
-
-        self.remove_from_parent(root_path);
-
-        let (root_path, root_node) = match self.nodes.remove_entry(root_path) {
-            Some(node) => node,
-            None => return Vec::new(),
-        };
-
-        let mut removed_entries = vec![(root_path, root_node.value)];
-        let mut to_visit: Vec<PathBuf> = root_node.children.into_iter().collect();
-
-        while let Some(path) = to_visit.pop() {
-            match self.nodes.remove_entry(&path) {
-                Some((path, node)) => {
-                    removed_entries.push((path, node.value));
-
-                    for child in node.children.into_iter() {
-                        to_visit.push(child);
-                    }
-                }
-                None => {
-                    warn!(
-                        "Consistency issue; tried to remove {} but it was already removed",
-                        path.display()
-                    );
-                }
-            }
-        }
-
-        removed_entries
-    }
-
-    pub fn orphans(&self) -> impl Iterator<Item = &Path> {
-        self.orphan_paths.iter().map(|item| item.as_ref())
-    }
-
-    /// Adds the path to its parent if it's present in the tree, or the set of
-    /// orphaned paths if it is not.
-    fn add_to_parent(&mut self, path: PathBuf) {
-        if let Some(parent_path) = path.parent() {
-            if let Some(parent) = self.nodes.get_mut(parent_path) {
-                parent.children.insert(path);
-                return;
-            }
-        }
-
-        // In this branch, the path is orphaned because it either doesn't have a
-        // parent according to Path, or because its parent doesn't exist in the
-        // PathMap.
-        self.orphan_paths.insert(path);
-    }
-
-    /// Removes the path from its parent, or from the orphaned paths set if it
-    /// has no parent.
-    fn remove_from_parent(&mut self, path: &Path) {
-        if let Some(parent_path) = path.parent() {
-            if let Some(parent) = self.nodes.get_mut(parent_path) {
-                parent.children.remove(path);
-                return;
-            }
-        }
-
-        // In this branch, the path is orphaned because it either doesn't have a
-        // parent according to Path, or because its parent doesn't exist in the
-        // PathMap.
-        self.orphan_paths.remove(path);
-    }
-}
-
-#[cfg(test)]
-mod test {
-    use super::*;
-
-    use maplit::btreeset;
-
-    #[test]
-    fn smoke_test() {
-        let mut map = PathMap::new();
-
-        assert_eq!(map.get("/foo"), None);
-        map.insert("/foo", 5);
-        assert_eq!(map.get("/foo"), Some(&5));
-
-        map.insert("/foo/bar", 6);
-        assert_eq!(map.get("/foo"), Some(&5));
-        assert_eq!(map.get("/foo/bar"), Some(&6));
-        assert_eq!(map.children("/foo"), Some(vec![Path::new("/foo/bar")]));
-    }
-
-    #[test]
-    fn orphans() {
-        let mut map = PathMap::new();
-
-        map.insert("/foo/bar", 5);
-        assert_eq!(map.orphan_paths, btreeset!["/foo/bar".into()]);
-
-        map.insert("/foo", 6);
-        assert_eq!(map.orphan_paths, btreeset!["/foo".into()]);
-    }
-
-    #[test]
-    fn remove_one() {
-        let mut map = PathMap::new();
-
-        map.insert("/foo", 6);
-
-        assert_eq!(map.remove("/foo"), vec![(PathBuf::from("/foo"), 6),]);
-
-        assert_eq!(map.get("/foo"), None);
-    }
-
-    #[test]
-    fn remove_child() {
-        let mut map = PathMap::new();
-
-        map.insert("/foo", 6);
-        map.insert("/foo/bar", 12);
-
-        assert_eq!(
-            map.remove("/foo"),
-            vec![(PathBuf::from("/foo"), 6), (PathBuf::from("/foo/bar"), 12),]
-        );
-
-        assert_eq!(map.get("/foo"), None);
-        assert_eq!(map.get("/foo/bar"), None);
-    }
-
-    #[test]
-    fn remove_descendant() {
-        let mut map = PathMap::new();
-
-        map.insert("/foo", 6);
-        map.insert("/foo/bar", 12);
-        map.insert("/foo/bar/baz", 18);
-
-        assert_eq!(
-            map.remove("/foo"),
-            vec![
-                (PathBuf::from("/foo"), 6),
-                (PathBuf::from("/foo/bar"), 12),
-                (PathBuf::from("/foo/bar/baz"), 18),
-            ]
-        );
-
-        assert_eq!(map.get("/foo"), None);
-        assert_eq!(map.get("/foo/bar"), None);
-        assert_eq!(map.get("/foo/bar/baz"), None);
-    }
-
-    #[test]
-    fn remove_not_orphan_descendants() {
-        let mut map = PathMap::new();
-
-        map.insert("/foo", 6);
-        map.insert("/foo/bar/baz", 12);
-
-        assert_eq!(map.remove("/foo"), vec![(PathBuf::from("/foo"), 6),]);
-
-        assert_eq!(map.get("/foo"), None);
-        assert_eq!(map.get("/foo/bar/baz"), Some(&12));
-    }
-
-    // Makes sure that regardless of addition order, paths are always sorted
-    // when asking for children.
-    #[test]
-    fn add_order_sorted() {
-        let mut map = PathMap::new();
-
-        map.insert("/foo", 5);
-        map.insert("/foo/b", 2);
-        map.insert("/foo/d", 0);
-        map.insert("/foo/c", 3);
-
-        assert_eq!(
-            map.children("/foo"),
-            Some(vec![
-                Path::new("/foo/b"),
-                Path::new("/foo/c"),
-                Path::new("/foo/d"),
-            ])
-        );
-
-        map.insert("/foo/a", 1);
-
-        assert_eq!(
-            map.children("/foo"),
-            Some(vec![
-                Path::new("/foo/a"),
-                Path::new("/foo/b"),
-                Path::new("/foo/c"),
-                Path::new("/foo/d"),
-            ])
-        );
-    }
-}

src/serve_session.rs

@@ -6,6 +6,7 @@ use std::{
 };
 
 use crossbeam_channel::Sender;
+use memofs::Vfs;
 
 use crate::{
     change_processor::ChangeProcessor,
@@ -14,7 +15,6 @@ use crate::{
     project::Project,
     session_id::SessionId,
     snapshot::{AppliedPatchSet, PatchSet, RojoTree},
-    vfs::{Vfs, VfsFetcher},
 };
 
 /// Contains all of the state for a Rojo serve session.
@@ -24,7 +24,7 @@ use crate::{
 /// why Rojo couldn't expose an IPC or channels-based API for embedding in the
 /// future. `ServeSession` would be roughly the right interface to expose for
 /// those cases.
-pub struct ServeSession<F> {
+pub struct ServeSession {
     /// The object responsible for listening to changes from the in-memory
     /// filesystem, applying them, updating the Roblox instance tree, and
     /// routing messages through the session's message queue to any connected
@@ -68,7 +68,7 @@ pub struct ServeSession<F> {
     ///
     /// The main use for accessing it from the session is for debugging issues
     /// with Rojo's live-sync protocol.
-    vfs: Arc<Vfs<F>>,
+    vfs: Arc<Vfs>,
 
     /// A queue of changes that have been applied to `tree` that affect clients.
     ///
@@ -85,14 +85,14 @@ pub struct ServeSession<F> {
 /// Methods that need thread-safety bounds on VfsFetcher are limited to this
 /// block to prevent needing to spread Send + Sync + 'static into everything
 /// that handles ServeSession.
-impl<F: VfsFetcher + Send + Sync + 'static> ServeSession<F> {
+impl ServeSession {
     /// Start a new serve session from the given in-memory filesystem  and start
     /// path.
     ///
     /// The project file is expected to be loaded out-of-band since it's
     /// currently loaded from the filesystem directly instead of through the
     /// in-memory filesystem layer.
-    pub fn new<P: AsRef<Path>>(vfs: Vfs<F>, start_path: P) -> Self {
+    pub fn new<P: AsRef<Path>>(vfs: Vfs, start_path: P) -> Self {
         let start_path = start_path.as_ref();
 
         log::trace!("Starting new ServeSession at path {}", start_path.display(),);
@@ -131,7 +131,7 @@ impl<F: VfsFetcher + Send + Sync + 'static> ServeSession<F> {
     }
 }
 
-impl<F: VfsFetcher> ServeSession<F> {
+impl ServeSession {
     pub fn tree_handle(&self) -> Arc<Mutex<RojoTree>> {
         Arc::clone(&self.tree)
     }
@@ -144,7 +144,7 @@ impl<F: VfsFetcher> ServeSession<F> {
         self.tree_mutation_sender.clone()
     }
 
-    pub fn vfs(&self) -> &Vfs<F> {
+    pub fn vfs(&self) -> &Vfs {
         &self.vfs
     }
 
@@ -189,201 +189,201 @@ mod serve_session {
 
     use std::{path::PathBuf, time::Duration};
 
-    use insta::assert_yaml_snapshot;
     use maplit::hashmap;
+    use memofs::{InMemoryFs, VfsEvent, VfsSnapshot};
     use rojo_insta_ext::RedactionMap;
     use tokio::{runtime::Runtime, timer::Timeout};
 
-    use crate::{
-        tree_view::view_tree,
-        vfs::{NoopFetcher, TestFetcher, VfsDebug, VfsEvent, VfsSnapshot},
-    };
+    use crate::tree_view::view_tree;
 
     #[test]
     fn just_folder() {
-        let vfs = Vfs::new(NoopFetcher);
+        let mut imfs = InMemoryFs::new();
+        imfs.load_snapshot("/foo", VfsSnapshot::empty_dir())
+            .unwrap();
 
-        vfs.debug_load_snapshot("/foo", VfsSnapshot::empty_dir());
+        let vfs = Vfs::new(imfs);
 
         let session = ServeSession::new(vfs, "/foo");
 
         let mut rm = RedactionMap::new();
-        assert_yaml_snapshot!(view_tree(&session.tree(), &mut rm));
+        insta::assert_yaml_snapshot!(view_tree(&session.tree(), &mut rm));
     }
 
     #[test]
     fn project_with_folder() {
-        let vfs = Vfs::new(NoopFetcher);
-
-        vfs.debug_load_snapshot(
+        let mut imfs = InMemoryFs::new();
+        imfs.load_snapshot(
             "/foo",
             VfsSnapshot::dir(hashmap! {
                 "default.project.json" => VfsSnapshot::file(r#"
-                {
-                    "name": "HelloWorld",
-                    "tree": {
-                        "$path": "src"
+                    {
+                        "name": "HelloWorld",
+                        "tree": {
+                            "$path": "src"
+                        }
                     }
-                }
-            "#),
+                "#),
                 "src" => VfsSnapshot::dir(hashmap! {
                     "hello.txt" => VfsSnapshot::file("Hello, world!"),
                 }),
             }),
-        );
+        )
+        .unwrap();
+
+        let vfs = Vfs::new(imfs);
 
         let session = ServeSession::new(vfs, "/foo");
 
         let mut rm = RedactionMap::new();
-        assert_yaml_snapshot!(view_tree(&session.tree(), &mut rm));
+        insta::assert_yaml_snapshot!(view_tree(&session.tree(), &mut rm));
     }
 
     #[test]
     fn script_with_meta() {
-        let vfs = Vfs::new(NoopFetcher);
-
-        vfs.debug_load_snapshot(
+        let mut imfs = InMemoryFs::new();
+        imfs.load_snapshot(
             "/root",
             VfsSnapshot::dir(hashmap! {
                 "test.lua" => VfsSnapshot::file("This is a test."),
                 "test.meta.json" => VfsSnapshot::file(r#"{ "ignoreUnknownInstances": true }"#),
             }),
-        );
+        )
+        .unwrap();
+
+        let vfs = Vfs::new(imfs);
 
         let session = ServeSession::new(vfs, "/root");
 
         let mut rm = RedactionMap::new();
-        assert_yaml_snapshot!(view_tree(&session.tree(), &mut rm));
-    }
-
-    #[test]
-    fn change_script_meta() {
-        let (state, fetcher) = TestFetcher::new();
-
-        state.load_snapshot(
-            "/root",
-            VfsSnapshot::dir(hashmap! {
-                "test.lua" => VfsSnapshot::file("This is a test."),
-                "test.meta.json" => VfsSnapshot::file(r#"{ "ignoreUnknownInstances": true }"#),
-            }),
-        );
-
-        let vfs = Vfs::new(fetcher);
-        let session = ServeSession::new(vfs, "/root");
-
-        let mut redactions = RedactionMap::new();
-        assert_yaml_snapshot!(
-            "change_script_meta_before",
-            view_tree(&session.tree(), &mut redactions)
-        );
-
-        state.load_snapshot(
-            "/root/test.meta.json",
-            VfsSnapshot::file(r#"{ "ignoreUnknownInstances": false }"#),
-        );
-
-        let receiver = Timeout::new(
-            session.message_queue().subscribe_any(),
-            Duration::from_millis(200),
-        );
-        state.raise_event(VfsEvent::Modified(PathBuf::from("/root/test.meta.json")));
-
-        let mut rt = Runtime::new().unwrap();
-        let changes = rt.block_on(receiver).unwrap();
-
-        assert_yaml_snapshot!(
-            "change_script_meta_patch",
-            redactions.redacted_yaml(changes)
-        );
-        assert_yaml_snapshot!(
-            "change_script_meta_after",
-            view_tree(&session.tree(), &mut redactions)
-        );
+        insta::assert_yaml_snapshot!(view_tree(&session.tree(), &mut rm));
     }
 
     #[test]
     fn change_txt_file() {
-        let (state, fetcher) = TestFetcher::new();
+        let mut imfs = InMemoryFs::new();
+        imfs.load_snapshot("/foo.txt", VfsSnapshot::file("Hello!"))
+            .unwrap();
 
-        state.load_snapshot("/foo.txt", VfsSnapshot::file("Hello!"));
+        let vfs = Vfs::new(imfs.clone());
 
-        let vfs = Vfs::new(fetcher);
         let session = ServeSession::new(vfs, "/foo.txt");
 
-        let mut redactions = RedactionMap::new();
-        assert_yaml_snapshot!(
+        let mut rm = RedactionMap::new();
+        insta::assert_yaml_snapshot!(
             "change_txt_file_before",
-            view_tree(&session.tree(), &mut redactions)
+            view_tree(&session.tree(), &mut rm)
         );
 
-        state.load_snapshot("/foo.txt", VfsSnapshot::file("World!"));
+        imfs.load_snapshot("/foo.txt", VfsSnapshot::file("World!"))
+            .unwrap();
 
         let receiver = session.message_queue().subscribe_any();
 
-        state.raise_event(VfsEvent::Modified(PathBuf::from("/foo.txt")));
+        imfs.raise_event(VfsEvent::Write(PathBuf::from("/foo.txt")));
 
         let receiver = Timeout::new(receiver, Duration::from_millis(200));
 
         let mut rt = Runtime::new().unwrap();
         let result = rt.block_on(receiver).unwrap();
 
-        assert_yaml_snapshot!("change_txt_file_patch", redactions.redacted_yaml(result));
-        assert_yaml_snapshot!(
-            "change_txt_file_after",
-            view_tree(&session.tree(), &mut redactions)
+        insta::assert_yaml_snapshot!("change_txt_file_patch", rm.redacted_yaml(result));
+        insta::assert_yaml_snapshot!("change_txt_file_after", view_tree(&session.tree(), &mut rm));
+    }
+
+    #[test]
+    fn change_script_meta() {
+        let mut imfs = InMemoryFs::new();
+        imfs.load_snapshot(
+            "/root",
+            VfsSnapshot::dir(hashmap! {
+                "test.lua" => VfsSnapshot::file("This is a test."),
+                "test.meta.json" => VfsSnapshot::file(r#"{ "ignoreUnknownInstances": true }"#),
+            }),
+        )
+        .unwrap();
+
+        let vfs = Vfs::new(imfs.clone());
+
+        let session = ServeSession::new(vfs, "/root");
+
+        let mut rm = RedactionMap::new();
+        insta::assert_yaml_snapshot!(
+            "change_script_meta_before",
+            view_tree(&session.tree(), &mut rm)
+        );
+
+        imfs.load_snapshot(
+            "/root/test.meta.json",
+            VfsSnapshot::file(r#"{ "ignoreUnknownInstances": false }"#),
+        )
+        .unwrap();
+
+        let receiver = session.message_queue().subscribe_any();
+
+        imfs.raise_event(VfsEvent::Write(PathBuf::from("/root/test.meta.json")));
+
+        let receiver = Timeout::new(receiver, Duration::from_millis(200));
+
+        let mut rt = Runtime::new().unwrap();
+        let result = rt.block_on(receiver).unwrap();
+
+        insta::assert_yaml_snapshot!("change_script_meta_patch", rm.redacted_yaml(result));
+        insta::assert_yaml_snapshot!(
+            "change_script_meta_after",
+            view_tree(&session.tree(), &mut rm)
         );
     }
 
     #[test]
     fn change_file_in_project() {
-        let (state, fetcher) = TestFetcher::new();
-
-        state.load_snapshot(
+        let mut imfs = InMemoryFs::new();
+        imfs.load_snapshot(
             "/foo",
             VfsSnapshot::dir(hashmap! {
                 "default.project.json" => VfsSnapshot::file(r#"
-                {
-                    "name": "change_file_in_project",
-                    "tree": {
-                        "$className": "Folder",
+                    {
+                        "name": "change_file_in_project",
+                        "tree": {
+                            "$className": "Folder",
 
-                        "Child": {
-                            "$path": "file.txt"
+                            "Child": {
+                                "$path": "file.txt"
+                            }
                         }
                     }
-                }
-            "#),
+                "#),
                 "file.txt" => VfsSnapshot::file("initial content"),
             }),
-        );
+        )
+        .unwrap();
+
+        let vfs = Vfs::new(imfs.clone());
 
-        let vfs = Vfs::new(fetcher);
         let session = ServeSession::new(vfs, "/foo");
 
-        let mut redactions = RedactionMap::new();
-        assert_yaml_snapshot!(
+        let mut rm = RedactionMap::new();
+        insta::assert_yaml_snapshot!(
             "change_file_in_project_before",
-            view_tree(&session.tree(), &mut redactions)
+            view_tree(&session.tree(), &mut rm)
         );
 
-        state.load_snapshot("/foo/file.txt", VfsSnapshot::file("Changed!"));
+        imfs.load_snapshot("/foo/file.txt", VfsSnapshot::file("Changed!"))
+            .unwrap();
 
         let receiver = session.message_queue().subscribe_any();
 
-        state.raise_event(VfsEvent::Modified(PathBuf::from("/foo/file.txt")));
+        imfs.raise_event(VfsEvent::Write(PathBuf::from("/foo/file.txt")));
 
         let receiver = Timeout::new(receiver, Duration::from_millis(200));
 
         let mut rt = Runtime::new().unwrap();
         let result = rt.block_on(receiver).unwrap();
 
-        assert_yaml_snapshot!(
-            "change_file_in_project_patch",
-            redactions.redacted_yaml(result)
-        );
-        assert_yaml_snapshot!(
+        insta::assert_yaml_snapshot!("change_file_in_project_patch", rm.redacted_yaml(result));
+        insta::assert_yaml_snapshot!(
             "change_file_in_project_after",
-            view_tree(&session.tree(), &mut redactions)
+            view_tree(&session.tree(), &mut rm)
         );
     }
 }

src/snapshot_middleware/csv.rs

@@ -1,13 +1,11 @@
-use std::collections::BTreeMap;
+use std::{collections::BTreeMap, path::Path};
 
 use maplit::hashmap;
+use memofs::{IoResultExt, Vfs};
 use rbx_dom_weak::RbxValue;
 use serde::Serialize;
 
-use crate::{
-    snapshot::{InstanceContext, InstanceMetadata, InstanceSnapshot},
-    vfs::{FsResultExt, Vfs, VfsEntry, VfsFetcher},
-};
+use crate::snapshot::{InstanceContext, InstanceMetadata, InstanceSnapshot};
 
 use super::{
     meta_file::AdjacentMetadata,
@@ -18,25 +16,21 @@ use super::{
 pub struct SnapshotCsv;
 
 impl SnapshotMiddleware for SnapshotCsv {
-    fn from_vfs<F: VfsFetcher>(
-        _context: &InstanceContext,
-        vfs: &Vfs<F>,
-        entry: &VfsEntry,
-    ) -> SnapshotInstanceResult {
-        if entry.is_directory() {
+    fn from_vfs(_context: &InstanceContext, vfs: &Vfs, path: &Path) -> SnapshotInstanceResult {
+        let meta = vfs.metadata(path)?;
+
+        if meta.is_dir() {
             return Ok(None);
         }
 
-        let instance_name = match match_file_name(entry.path(), ".csv") {
+        let instance_name = match match_file_name(path, ".csv") {
             Some(name) => name,
             None => return Ok(None),
         };
 
-        let meta_path = entry
-            .path()
-            .with_file_name(format!("{}.meta.json", instance_name));
+        let meta_path = path.with_file_name(format!("{}.meta.json", instance_name));
 
-        let table_contents = convert_localization_csv(&entry.contents(vfs)?);
+        let table_contents = convert_localization_csv(&vfs.read(path)?);
 
         let mut snapshot = InstanceSnapshot::new()
             .name(instance_name)
@@ -48,13 +42,12 @@ impl SnapshotMiddleware for SnapshotCsv {
             })
             .metadata(
                 InstanceMetadata::new()
-                    .instigating_source(entry.path())
-                    .relevant_paths(vec![entry.path().to_path_buf(), meta_path.clone()]),
+                    .instigating_source(path)
+                    .relevant_paths(vec![path.to_path_buf(), meta_path.clone()]),
             );
 
-        if let Some(meta_entry) = vfs.get(meta_path).with_not_found()? {
-            let meta_contents = meta_entry.contents(vfs)?;
-            let mut metadata = AdjacentMetadata::from_slice(&meta_contents);
+        if let Some(meta_contents) = vfs.read(&meta_path).with_not_found()? {
+            let mut metadata = AdjacentMetadata::from_slice(&meta_contents, &meta_path)?;
             metadata.apply_all(&mut snapshot);
         }
 
@@ -142,48 +135,54 @@ fn convert_localization_csv(contents: &[u8]) -> String {
 mod test {
     use super::*;
 
-    use crate::vfs::{NoopFetcher, VfsDebug, VfsSnapshot};
-    use insta::assert_yaml_snapshot;
+    use memofs::{InMemoryFs, VfsSnapshot};
 
     #[test]
     fn csv_from_vfs() {
-        let mut vfs = Vfs::new(NoopFetcher);
-        let file = VfsSnapshot::file(
-            r#"
+        let mut imfs = InMemoryFs::new();
+        imfs.load_snapshot(
+            "/foo.csv",
+            VfsSnapshot::file(
+                r#"
 Key,Source,Context,Example,es
 Ack,Ack!,,An exclamation of despair,¡Ay!"#,
-        );
+            ),
+        )
+        .unwrap();
 
-        vfs.debug_load_snapshot("/foo.csv", file);
+        let mut vfs = Vfs::new(imfs);
 
-        let entry = vfs.get("/foo.csv").unwrap();
         let instance_snapshot =
-            SnapshotCsv::from_vfs(&InstanceContext::default(), &mut vfs, &entry)
+            SnapshotCsv::from_vfs(&InstanceContext::default(), &mut vfs, Path::new("/foo.csv"))
                 .unwrap()
                 .unwrap();
 
-        assert_yaml_snapshot!(instance_snapshot);
+        insta::assert_yaml_snapshot!(instance_snapshot);
     }
 
     #[test]
     fn csv_with_meta() {
-        let mut vfs = Vfs::new(NoopFetcher);
-        let file = VfsSnapshot::file(
-            r#"
+        let mut imfs = InMemoryFs::new();
+        imfs.load_snapshot(
+            "/foo.csv",
+            VfsSnapshot::file(
+                r#"
 Key,Source,Context,Example,es
 Ack,Ack!,,An exclamation of despair,¡Ay!"#,
-        );
-        let meta = VfsSnapshot::file(r#"{ "ignoreUnknownInstances": true }"#);
+            ),
+        )
+        .unwrap();
+        imfs.load_snapshot(
+            "/foo.meta.json",
+            VfsSnapshot::file(r#"{ "ignoreUnknownInstances": true }"#),
+        )
+        .unwrap();
 
-        vfs.debug_load_snapshot("/foo.csv", file);
-        vfs.debug_load_snapshot("/foo.meta.json", meta);
+        let mut vfs = Vfs::new(imfs);
 
-        let entry = vfs.get("/foo.csv").unwrap();
         let instance_snapshot =
-            SnapshotCsv::from_vfs(&InstanceContext::default(), &mut vfs, &entry)
+            SnapshotCsv::from_vfs(&InstanceContext::default(), &mut vfs, Path::new("/foo.csv"))
                 .unwrap()
                 .unwrap();
-
-        assert_yaml_snapshot!(instance_snapshot);
     }
 }

src/snapshot_middleware/dir.rs

@@ -1,32 +1,27 @@
-use std::collections::HashMap;
+use std::path::Path;
 
-use rbx_dom_weak::{RbxId, RbxTree};
+use memofs::{DirEntry, IoResultExt, Vfs};
 
-use crate::{
-    snapshot::{InstanceContext, InstanceMetadata, InstanceSnapshot},
-    vfs::{DirectorySnapshot, FsResultExt, Vfs, VfsEntry, VfsFetcher, VfsSnapshot},
-};
+use crate::snapshot::{InstanceContext, InstanceMetadata, InstanceSnapshot};
 
 use super::{
     error::SnapshotError,
     meta_file::DirectoryMetadata,
-    middleware::{SnapshotFileResult, SnapshotInstanceResult, SnapshotMiddleware},
-    snapshot_from_instance, snapshot_from_vfs,
+    middleware::{SnapshotInstanceResult, SnapshotMiddleware},
+    snapshot_from_vfs,
 };
 
 pub struct SnapshotDir;
 
 impl SnapshotMiddleware for SnapshotDir {
-    fn from_vfs<F: VfsFetcher>(
-        context: &InstanceContext,
-        vfs: &Vfs<F>,
-        entry: &VfsEntry,
-    ) -> SnapshotInstanceResult {
-        if entry.is_file() {
+    fn from_vfs(context: &InstanceContext, vfs: &Vfs, path: &Path) -> SnapshotInstanceResult {
+        let meta = vfs.metadata(path)?;
+
+        if meta.is_file() {
             return Ok(None);
         }
 
-        let passes_filter_rules = |child: &VfsEntry| {
+        let passes_filter_rules = |child: &DirEntry| {
             context
                 .path_ignore_rules
                 .iter()
@@ -35,31 +30,36 @@ impl SnapshotMiddleware for SnapshotDir {
 
         let mut snapshot_children = Vec::new();
 
-        for child in entry.children(vfs)?.into_iter().filter(passes_filter_rules) {
-            if let Some(child_snapshot) = snapshot_from_vfs(context, vfs, &child)? {
+        for entry in vfs.read_dir(path)? {
+            let entry = entry?;
+
+            if !passes_filter_rules(&entry) {
+                continue;
+            }
+
+            if let Some(child_snapshot) = snapshot_from_vfs(context, vfs, entry.path())? {
                 snapshot_children.push(child_snapshot);
             }
         }
 
-        let instance_name = entry
-            .path()
+        let instance_name = path
             .file_name()
             .expect("Could not extract file name")
             .to_str()
-            .ok_or_else(|| SnapshotError::file_name_bad_unicode(entry.path()))?
+            .ok_or_else(|| SnapshotError::file_name_bad_unicode(path))?
             .to_string();
 
-        let meta_path = entry.path().join("init.meta.json");
+        let meta_path = path.join("init.meta.json");
 
         let relevant_paths = vec![
-            entry.path().to_path_buf(),
+            path.to_path_buf(),
             meta_path.clone(),
             // TODO: We shouldn't need to know about Lua existing in this
             // middleware. Should we figure out a way for that function to add
             // relevant paths to this middleware?
-            entry.path().join("init.lua"),
-            entry.path().join("init.server.lua"),
-            entry.path().join("init.client.lua"),
+            path.join("init.lua"),
+            path.join("init.server.lua"),
+            path.join("init.client.lua"),
         ];
 
         let mut snapshot = InstanceSnapshot::new()
@@ -68,81 +68,61 @@ impl SnapshotMiddleware for SnapshotDir {
             .children(snapshot_children)
             .metadata(
                 InstanceMetadata::new()
-                    .instigating_source(entry.path())
+                    .instigating_source(path)
                     .relevant_paths(relevant_paths)
                     .context(context),
             );
 
-        if let Some(meta_entry) = vfs.get(meta_path).with_not_found()? {
-            let meta_contents = meta_entry.contents(vfs)?;
-            let mut metadata = DirectoryMetadata::from_slice(&meta_contents);
+        if let Some(meta_contents) = vfs.read(&meta_path).with_not_found()? {
+            let mut metadata = DirectoryMetadata::from_slice(&meta_contents, &meta_path)?;
             metadata.apply_all(&mut snapshot);
         }
 
         Ok(Some(snapshot))
     }
-
-    fn from_instance(tree: &RbxTree, id: RbxId) -> SnapshotFileResult {
-        let instance = tree.get_instance(id).unwrap();
-
-        if instance.class_name != "Folder" {
-            return None;
-        }
-
-        let mut children = HashMap::new();
-
-        for child_id in instance.get_children_ids() {
-            if let Some((name, child)) = snapshot_from_instance(tree, *child_id) {
-                children.insert(name, child);
-            }
-        }
-
-        let snapshot = VfsSnapshot::Directory(DirectorySnapshot { children });
-
-        Some((instance.name.clone(), snapshot))
-    }
 }
 
 #[cfg(test)]
 mod test {
     use super::*;
 
-    use insta::assert_yaml_snapshot;
     use maplit::hashmap;
-
-    use crate::vfs::{NoopFetcher, VfsDebug};
+    use memofs::{InMemoryFs, VfsSnapshot};
 
     #[test]
     fn empty_folder() {
-        let mut vfs = Vfs::new(NoopFetcher);
-        let dir = VfsSnapshot::dir::<String>(HashMap::new());
+        let mut imfs = InMemoryFs::new();
+        imfs.load_snapshot("/foo", VfsSnapshot::empty_dir())
+            .unwrap();
 
-        vfs.debug_load_snapshot("/foo", dir);
+        let mut vfs = Vfs::new(imfs);
 
-        let entry = vfs.get("/foo").unwrap();
         let instance_snapshot =
-            SnapshotDir::from_vfs(&InstanceContext::default(), &mut vfs, &entry)
+            SnapshotDir::from_vfs(&InstanceContext::default(), &mut vfs, Path::new("/foo"))
                 .unwrap()
                 .unwrap();
 
-        assert_yaml_snapshot!(instance_snapshot);
+        insta::assert_yaml_snapshot!(instance_snapshot);
     }
 
     #[test]
     fn folder_in_folder() {
-        let mut vfs = Vfs::new(NoopFetcher);
-        let dir = VfsSnapshot::dir(hashmap! {
-            "Child" => VfsSnapshot::dir::<String>(HashMap::new()),
-        });
+        let mut imfs = InMemoryFs::new();
+        imfs.load_snapshot(
+            "/foo",
+            VfsSnapshot::dir(hashmap! {
+                "Child" => VfsSnapshot::empty_dir(),
+            }),
+        )
+        .unwrap();
 
-        vfs.debug_load_snapshot("/foo", dir);
+        let mut vfs = Vfs::new(imfs);
 
-        let entry = vfs.get("/foo").unwrap();
         let instance_snapshot =
-            SnapshotDir::from_vfs(&InstanceContext::default(), &mut vfs, &entry)
+            SnapshotDir::from_vfs(&InstanceContext::default(), &mut vfs, Path::new("/foo"))
                 .unwrap()
                 .unwrap();
 
-        assert_yaml_snapshot!(instance_snapshot);
+        insta::assert_yaml_snapshot!(instance_snapshot);
     }
 }

src/snapshot_middleware/error.rs

@@ -1,6 +1,6 @@
 use std::{error::Error, fmt, io, path::PathBuf};
 
-use crate::vfs::FsError;
+use snafu::Snafu;
 
 #[derive(Debug)]
 pub struct SnapshotError {
@@ -10,49 +10,63 @@ pub struct SnapshotError {
 
 impl SnapshotError {
     pub fn new(detail: SnapshotErrorDetail, path: Option<impl Into<PathBuf>>) -> Self {
-        SnapshotError {
+        Self {
             detail,
             path: path.map(Into::into),
         }
     }
 
-    pub(crate) fn wrap(inner: impl Into<SnapshotErrorDetail>, path: impl Into<PathBuf>) -> Self {
-        SnapshotError {
-            detail: inner.into(),
+    pub(crate) fn wrap(source: impl Into<SnapshotErrorDetail>, path: impl Into<PathBuf>) -> Self {
+        Self {
+            detail: source.into(),
             path: Some(path.into()),
         }
     }
 
-    pub(crate) fn file_did_not_exist(path: impl Into<PathBuf>) -> SnapshotError {
-        SnapshotError {
+    pub(crate) fn file_did_not_exist(path: impl Into<PathBuf>) -> Self {
+        Self {
             detail: SnapshotErrorDetail::FileDidNotExist,
             path: Some(path.into()),
         }
     }
 
-    pub(crate) fn file_name_bad_unicode(path: impl Into<PathBuf>) -> SnapshotError {
-        SnapshotError {
+    pub(crate) fn file_name_bad_unicode(path: impl Into<PathBuf>) -> Self {
+        Self {
             detail: SnapshotErrorDetail::FileNameBadUnicode,
             path: Some(path.into()),
         }
     }
 
     pub(crate) fn file_contents_bad_unicode(
-        inner: std::str::Utf8Error,
+        source: std::str::Utf8Error,
         path: impl Into<PathBuf>,
-    ) -> SnapshotError {
-        SnapshotError {
-            detail: SnapshotErrorDetail::FileContentsBadUnicode { inner },
+    ) -> Self {
+        Self {
+            detail: SnapshotErrorDetail::FileContentsBadUnicode { source },
             path: Some(path.into()),
         }
     }
 
-    pub(crate) fn malformed_project(
-        inner: serde_json::Error,
+    pub(crate) fn malformed_project(source: serde_json::Error, path: impl Into<PathBuf>) -> Self {
+        Self {
+            detail: SnapshotErrorDetail::MalformedProject { source },
+            path: Some(path.into()),
+        }
+    }
+
+    pub(crate) fn malformed_model_json(
+        source: serde_json::Error,
         path: impl Into<PathBuf>,
-    ) -> SnapshotError {
-        SnapshotError {
-            detail: SnapshotErrorDetail::MalformedProject { inner },
+    ) -> Self {
+        Self {
+            detail: SnapshotErrorDetail::MalformedModelJson { source },
+            path: Some(path.into()),
+        }
+    }
+
+    pub(crate) fn malformed_meta_json(source: serde_json::Error, path: impl Into<PathBuf>) -> Self {
+        Self {
+            detail: SnapshotErrorDetail::MalformedMetaJson { source },
             path: Some(path.into()),
         }
     }
@@ -73,11 +87,9 @@ impl fmt::Display for SnapshotError {
     }
 }
 
-impl From<FsError> for SnapshotError {
-    fn from(error: FsError) -> Self {
-        let (inner, path) = error.into_raw();
-
-        Self::new(inner.into(), Some(path))
+impl From<io::Error> for SnapshotError {
+    fn from(inner: io::Error) -> Self {
+        Self::new(inner.into(), Option::<PathBuf>::None)
     }
 }
 
@@ -87,55 +99,41 @@ impl From<rlua::Error> for SnapshotError {
     }
 }
 
-#[derive(Debug)]
+#[derive(Debug, Snafu)]
 pub enum SnapshotErrorDetail {
-    IoError { inner: io::Error },
-    Lua { inner: rlua::Error },
+    #[snafu(display("I/O error"))]
+    IoError { source: io::Error },
+
+    #[snafu(display("Lua error"))]
+    Lua { source: rlua::Error },
+
+    #[snafu(display("file did not exist"))]
     FileDidNotExist,
+
+    #[snafu(display("file name had malformed Unicode"))]
     FileNameBadUnicode,
-    FileContentsBadUnicode { inner: std::str::Utf8Error },
-    MalformedProject { inner: serde_json::Error },
+
+    #[snafu(display("file had malformed Unicode contents"))]
+    FileContentsBadUnicode { source: std::str::Utf8Error },
+
+    #[snafu(display("malformed project file"))]
+    MalformedProject { source: serde_json::Error },
+
+    #[snafu(display("malformed .model.json file"))]
+    MalformedModelJson { source: serde_json::Error },
+
+    #[snafu(display("malformed .meta.json file"))]
+    MalformedMetaJson { source: serde_json::Error },
 }
 
 impl From<io::Error> for SnapshotErrorDetail {
-    fn from(inner: io::Error) -> Self {
-        SnapshotErrorDetail::IoError { inner }
+    fn from(source: io::Error) -> Self {
+        SnapshotErrorDetail::IoError { source }
     }
 }
 
 impl From<rlua::Error> for SnapshotErrorDetail {
-    fn from(inner: rlua::Error) -> Self {
-        SnapshotErrorDetail::Lua { inner }
-    }
-}
-
-impl SnapshotErrorDetail {
-    fn source(&self) -> Option<&(dyn Error + 'static)> {
-        use self::SnapshotErrorDetail::*;
-
-        match self {
-            IoError { inner } => Some(inner),
-            Lua { inner } => Some(inner),
-            FileContentsBadUnicode { inner } => Some(inner),
-            MalformedProject { inner } => Some(inner),
-            _ => None,
-        }
-    }
-}
-
-impl fmt::Display for SnapshotErrorDetail {
-    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
-        use self::SnapshotErrorDetail::*;
-
-        match self {
-            IoError { inner } => write!(formatter, "I/O error: {}", inner),
-            Lua { inner } => write!(formatter, "{}", inner),
-            FileDidNotExist => write!(formatter, "file did not exist"),
-            FileNameBadUnicode => write!(formatter, "file name had malformed Unicode"),
-            FileContentsBadUnicode { inner } => {
-                write!(formatter, "file had malformed unicode: {}", inner)
-            }
-            MalformedProject { inner } => write!(formatter, "{}", inner),
-        }
+    fn from(source: rlua::Error) -> Self {
+        SnapshotErrorDetail::Lua { source }
     }
 }

src/snapshot_middleware/json_model.rs

@@ -1,15 +1,14 @@
-use std::{borrow::Cow, collections::HashMap};
+use std::{borrow::Cow, collections::HashMap, path::Path};
 
+use memofs::Vfs;
 use rbx_dom_weak::UnresolvedRbxValue;
 use rbx_reflection::try_resolve_value;
 use serde::Deserialize;
 
-use crate::{
-    snapshot::{InstanceContext, InstanceSnapshot},
-    vfs::{Vfs, VfsEntry, VfsFetcher},
-};
+use crate::snapshot::{InstanceContext, InstanceSnapshot};
 
 use super::{
+    error::SnapshotError,
     middleware::{SnapshotInstanceResult, SnapshotMiddleware},
     util::match_file_name,
 };
@@ -17,28 +16,27 @@ use super::{
 pub struct SnapshotJsonModel;
 
 impl SnapshotMiddleware for SnapshotJsonModel {
-    fn from_vfs<F: VfsFetcher>(
-        context: &InstanceContext,
-        vfs: &Vfs<F>,
-        entry: &VfsEntry,
-    ) -> SnapshotInstanceResult {
-        if entry.is_directory() {
+    fn from_vfs(context: &InstanceContext, vfs: &Vfs, path: &Path) -> SnapshotInstanceResult {
+        let meta = vfs.metadata(path)?;
+
+        if meta.is_dir() {
             return Ok(None);
         }
 
-        let instance_name = match match_file_name(entry.path(), ".model.json") {
+        let instance_name = match match_file_name(path, ".model.json") {
             Some(name) => name,
             None => return Ok(None),
         };
 
-        let instance: JsonModel =
-            serde_json::from_slice(&entry.contents(vfs)?).expect("TODO: Handle serde_json errors");
+        let contents = vfs.read(path)?;
+        let instance: JsonModel = serde_json::from_slice(&contents)
+            .map_err(|source| SnapshotError::malformed_model_json(source, path))?;
 
         if let Some(json_name) = &instance.name {
             if json_name != instance_name {
                 log::warn!(
                     "Name from JSON model did not match its file name: {}",
-                    entry.path().display()
+                    path.display()
                 );
                 log::warn!(
                     "In Rojo <  alpha 14, this model is named \"{}\" (from its 'Name' property)",
@@ -56,8 +54,8 @@ impl SnapshotMiddleware for SnapshotJsonModel {
 
         snapshot.metadata = snapshot
             .metadata
-            .instigating_source(entry.path())
-            .relevant_paths(vec![entry.path().to_path_buf()])
+            .instigating_source(path)
+            .relevant_paths(vec![path.to_path_buf()])
             .context(context);
 
         Ok(Some(snapshot))
@@ -137,39 +135,43 @@ impl JsonModelCore {
 mod test {
     use super::*;
 
-    use insta::assert_yaml_snapshot;
-
-    use crate::vfs::{NoopFetcher, VfsDebug, VfsSnapshot};
+    use memofs::{InMemoryFs, VfsSnapshot};
 
     #[test]
     fn model_from_vfs() {
-        let mut vfs = Vfs::new(NoopFetcher);
-        let file = VfsSnapshot::file(
-            r#"
-            {
-              "Name": "children",
-              "ClassName": "IntValue",
-              "Properties": {
-                "Value": 5
-              },
-              "Children": [
-                {
-                  "Name": "The Child",
-                  "ClassName": "StringValue"
-                }
-              ]
-            }
-        "#,
-        );
+        let mut imfs = InMemoryFs::new();
+        imfs.load_snapshot(
+            "/foo.model.json",
+            VfsSnapshot::file(
+                r#"
+                    {
+                      "Name": "children",
+                      "ClassName": "IntValue",
+                      "Properties": {
+                        "Value": 5
+                      },
+                      "Children": [
+                        {
+                          "Name": "The Child",
+                          "ClassName": "StringValue"
+                        }
+                      ]
+                    }
+                "#,
+            ),
+        )
+        .unwrap();
 
-        vfs.debug_load_snapshot("/foo.model.json", file);
+        let mut vfs = Vfs::new(imfs);
 
-        let entry = vfs.get("/foo.model.json").unwrap();
-        let instance_snapshot =
-            SnapshotJsonModel::from_vfs(&InstanceContext::default(), &mut vfs, &entry)
-                .unwrap()
-                .unwrap();
+        let instance_snapshot = SnapshotJsonModel::from_vfs(
+            &InstanceContext::default(),
+            &mut vfs,
+            Path::new("/foo.model.json"),
+        )
+        .unwrap()
+        .unwrap();
 
-        assert_yaml_snapshot!(instance_snapshot);
+        insta::assert_yaml_snapshot!(instance_snapshot);
     }
 }

src/snapshot_middleware/lua.rs

@@ -1,12 +1,10 @@
-use std::str;
+use std::{path::Path, str};
 
 use maplit::hashmap;
+use memofs::{IoResultExt, Vfs};
 use rbx_dom_weak::RbxValue;
 
-use crate::{
-    snapshot::{InstanceContext, InstanceMetadata, InstanceSnapshot},
-    vfs::{FsResultExt, Vfs, VfsEntry, VfsFetcher},
-};
+use crate::snapshot::{InstanceContext, InstanceMetadata, InstanceSnapshot};
 
 use super::{
     dir::SnapshotDir,
@@ -18,12 +16,8 @@ use super::{
 pub struct SnapshotLua;
 
 impl SnapshotMiddleware for SnapshotLua {
-    fn from_vfs<F: VfsFetcher>(
-        context: &InstanceContext,
-        vfs: &Vfs<F>,
-        entry: &VfsEntry,
-    ) -> SnapshotInstanceResult {
-        let file_name = entry.path().file_name().unwrap().to_string_lossy();
+    fn from_vfs(context: &InstanceContext, vfs: &Vfs, path: &Path) -> SnapshotInstanceResult {
+        let file_name = path.file_name().unwrap().to_string_lossy();
 
         // These paths alter their parent instance, so we don't need to turn
         // them into a script instance here.
@@ -32,18 +26,20 @@ impl SnapshotMiddleware for SnapshotLua {
             _ => {}
         }
 
-        if entry.is_file() {
-            snapshot_lua_file(context, vfs, entry)
+        let meta = vfs.metadata(path)?;
+
+        if meta.is_file() {
+            snapshot_lua_file(context, vfs, path)
         } else {
             // At this point, our entry is definitely a directory!
 
-            if let Some(snapshot) = snapshot_init(context, vfs, entry, "init.lua")? {
+            if let Some(snapshot) = snapshot_init(context, vfs, path, "init.lua")? {
                 // An `init.lua` file turns its parent into a ModuleScript
                 Ok(Some(snapshot))
-            } else if let Some(snapshot) = snapshot_init(context, vfs, entry, "init.server.lua")? {
+            } else if let Some(snapshot) = snapshot_init(context, vfs, path, "init.server.lua")? {
                 // An `init.server.lua` file turns its parent into a Script
                 Ok(Some(snapshot))
-            } else if let Some(snapshot) = snapshot_init(context, vfs, entry, "init.client.lua")? {
+            } else if let Some(snapshot) = snapshot_init(context, vfs, path, "init.client.lua")? {
                 // An `init.client.lua` file turns its parent into a LocalScript
                 Ok(Some(snapshot))
             } else {
@@ -54,12 +50,8 @@ impl SnapshotMiddleware for SnapshotLua {
 }
 
 /// Core routine for turning Lua files into snapshots.
-fn snapshot_lua_file<F: VfsFetcher>(
-    context: &InstanceContext,
-    vfs: &Vfs<F>,
-    entry: &VfsEntry,
-) -> SnapshotInstanceResult {
-    let file_name = entry.path().file_name().unwrap().to_string_lossy();
+fn snapshot_lua_file(context: &InstanceContext, vfs: &Vfs, path: &Path) -> SnapshotInstanceResult {
+    let file_name = path.file_name().unwrap().to_string_lossy();
 
     let (class_name, instance_name) = if let Some(name) = match_trailing(&file_name, ".server.lua")
     {
@@ -72,15 +64,13 @@ fn snapshot_lua_file<F: VfsFetcher>(
         return Ok(None);
     };
 
-    let contents = entry.contents(vfs)?;
+    let contents = vfs.read(path)?;
     let contents_str = str::from_utf8(&contents)
         // TODO: Turn into error type
         .expect("File content was not valid UTF-8")
         .to_string();
 
-    let meta_path = entry
-        .path()
-        .with_file_name(format!("{}.meta.json", instance_name));
+    let meta_path = path.with_file_name(format!("{}.meta.json", instance_name));
 
     let mut snapshot = InstanceSnapshot::new()
         .name(instance_name)
@@ -92,14 +82,13 @@ fn snapshot_lua_file<F: VfsFetcher>(
         })
         .metadata(
             InstanceMetadata::new()
-                .instigating_source(entry.path())
-                .relevant_paths(vec![entry.path().to_path_buf(), meta_path.clone()])
+                .instigating_source(path)
+                .relevant_paths(vec![path.to_path_buf(), meta_path.clone()])
                 .context(context),
         );
 
-    if let Some(meta_entry) = vfs.get(meta_path).with_not_found()? {
-        let meta_contents = meta_entry.contents(vfs)?;
-        let mut metadata = AdjacentMetadata::from_slice(&meta_contents);
+    if let Some(meta_contents) = vfs.read(&meta_path).with_not_found()? {
+        let mut metadata = AdjacentMetadata::from_slice(&meta_contents, &meta_path)?;
         metadata.apply_all(&mut snapshot);
     }
 
@@ -111,17 +100,17 @@ fn snapshot_lua_file<F: VfsFetcher>(
 ///
 /// Scripts named `init.lua`, `init.server.lua`, or `init.client.lua` usurp
 /// their parents, which acts similarly to `__init__.py` from the Python world.
-fn snapshot_init<F: VfsFetcher>(
+fn snapshot_init(
     context: &InstanceContext,
-    vfs: &Vfs<F>,
-    folder_entry: &VfsEntry,
+    vfs: &Vfs,
+    folder_path: &Path,
     init_name: &str,
 ) -> SnapshotInstanceResult {
-    let init_path = folder_entry.path().join(init_name);
+    let init_path = folder_path.join(init_name);
 
-    if let Some(init_entry) = vfs.get(init_path).with_not_found()? {
-        if let Some(dir_snapshot) = SnapshotDir::from_vfs(context, vfs, folder_entry)? {
-            if let Some(mut init_snapshot) = snapshot_lua_file(context, vfs, &init_entry)? {
+    if vfs.metadata(&init_path).with_not_found()?.is_some() {
+        if let Some(dir_snapshot) = SnapshotDir::from_vfs(context, vfs, folder_path)? {
+            if let Some(mut init_snapshot) = snapshot_lua_file(context, vfs, &init_path)? {
                 if dir_snapshot.class_name != "Folder" {
                     panic!(
                         "init.lua, init.server.lua, and init.client.lua can \
@@ -146,149 +135,171 @@ fn snapshot_init<F: VfsFetcher>(
 mod test {
     use super::*;
 
-    use insta::{assert_yaml_snapshot, with_settings};
-
-    use crate::vfs::{NoopFetcher, VfsDebug, VfsSnapshot};
+    use memofs::{InMemoryFs, VfsSnapshot};
 
     #[test]
     fn module_from_vfs() {
-        let mut vfs = Vfs::new(NoopFetcher);
-        let file = VfsSnapshot::file("Hello there!");
+        let mut imfs = InMemoryFs::new();
+        imfs.load_snapshot("/foo.lua", VfsSnapshot::file("Hello there!"))
+            .unwrap();
 
-        vfs.debug_load_snapshot("/foo.lua", file);
+        let mut vfs = Vfs::new(imfs);
 
-        let entry = vfs.get("/foo.lua").unwrap();
         let instance_snapshot =
-            SnapshotLua::from_vfs(&InstanceContext::default(), &mut vfs, &entry)
+            SnapshotLua::from_vfs(&InstanceContext::default(), &mut vfs, Path::new("/foo.lua"))
                 .unwrap()
                 .unwrap();
 
-        assert_yaml_snapshot!(instance_snapshot);
+        insta::assert_yaml_snapshot!(instance_snapshot);
     }
 
     #[test]
     fn server_from_vfs() {
-        let mut vfs = Vfs::new(NoopFetcher);
-        let file = VfsSnapshot::file("Hello there!");
+        let mut imfs = InMemoryFs::new();
+        imfs.load_snapshot("/foo.server.lua", VfsSnapshot::file("Hello there!"))
+            .unwrap();
 
-        vfs.debug_load_snapshot("/foo.server.lua", file);
+        let mut vfs = Vfs::new(imfs);
 
-        let entry = vfs.get("/foo.server.lua").unwrap();
-        let instance_snapshot =
-            SnapshotLua::from_vfs(&InstanceContext::default(), &mut vfs, &entry)
-                .unwrap()
-                .unwrap();
+        let instance_snapshot = SnapshotLua::from_vfs(
+            &InstanceContext::default(),
+            &mut vfs,
+            Path::new("/foo.server.lua"),
+        )
+        .unwrap()
+        .unwrap();
 
-        assert_yaml_snapshot!(instance_snapshot);
+        insta::assert_yaml_snapshot!(instance_snapshot);
     }
 
     #[test]
     fn client_from_vfs() {
-        let mut vfs = Vfs::new(NoopFetcher);
-        let file = VfsSnapshot::file("Hello there!");
+        let mut imfs = InMemoryFs::new();
+        imfs.load_snapshot("/foo.client.lua", VfsSnapshot::file("Hello there!"))
+            .unwrap();
 
-        vfs.debug_load_snapshot("/foo.client.lua", file);
+        let mut vfs = Vfs::new(imfs);
 
-        let entry = vfs.get("/foo.client.lua").unwrap();
-        let instance_snapshot =
-            SnapshotLua::from_vfs(&InstanceContext::default(), &mut vfs, &entry)
-                .unwrap()
-                .unwrap();
+        let instance_snapshot = SnapshotLua::from_vfs(
+            &InstanceContext::default(),
+            &mut vfs,
+            Path::new("/foo.client.lua"),
+        )
+        .unwrap()
+        .unwrap();
 
-        assert_yaml_snapshot!(instance_snapshot);
+        insta::assert_yaml_snapshot!(instance_snapshot);
     }
 
     #[test]
     fn init_module_from_vfs() {
-        let mut vfs = Vfs::new(NoopFetcher);
-        let dir = VfsSnapshot::dir(hashmap! {
-            "init.lua" => VfsSnapshot::file("Hello!"),
-        });
+        let mut imfs = InMemoryFs::new();
+        imfs.load_snapshot(
+            "/root",
+            VfsSnapshot::dir(hashmap! {
+                "init.lua" => VfsSnapshot::file("Hello!"),
+            }),
+        )
+        .unwrap();
 
-        vfs.debug_load_snapshot("/root", dir);
+        let mut vfs = Vfs::new(imfs);
 
-        let entry = vfs.get("/root").unwrap();
         let instance_snapshot =
-            SnapshotLua::from_vfs(&InstanceContext::default(), &mut vfs, &entry)
+            SnapshotLua::from_vfs(&InstanceContext::default(), &mut vfs, Path::new("/root"))
                 .unwrap()
                 .unwrap();
 
-        assert_yaml_snapshot!(instance_snapshot);
+        insta::assert_yaml_snapshot!(instance_snapshot);
     }
 
     #[test]
     fn module_with_meta() {
-        let mut vfs = Vfs::new(NoopFetcher);
-        let file = VfsSnapshot::file("Hello there!");
-        let meta = VfsSnapshot::file(
-            r#"
-            {
-                "ignoreUnknownInstances": true
-            }
-        "#,
-        );
+        let mut imfs = InMemoryFs::new();
+        imfs.load_snapshot("/foo.lua", VfsSnapshot::file("Hello there!"))
+            .unwrap();
+        imfs.load_snapshot(
+            "/foo.meta.json",
+            VfsSnapshot::file(
+                r#"
+                    {
+                        "ignoreUnknownInstances": true
+                    }
+                "#,
+            ),
+        )
+        .unwrap();
 
-        vfs.debug_load_snapshot("/foo.lua", file);
-        vfs.debug_load_snapshot("/foo.meta.json", meta);
+        let mut vfs = Vfs::new(imfs);
 
-        let entry = vfs.get("/foo.lua").unwrap();
         let instance_snapshot =
-            SnapshotLua::from_vfs(&InstanceContext::default(), &mut vfs, &entry)
+            SnapshotLua::from_vfs(&InstanceContext::default(), &mut vfs, Path::new("/foo.lua"))
                 .unwrap()
                 .unwrap();
 
-        assert_yaml_snapshot!(instance_snapshot);
+        insta::assert_yaml_snapshot!(instance_snapshot);
     }
 
     #[test]
     fn script_with_meta() {
-        let mut vfs = Vfs::new(NoopFetcher);
-        let file = VfsSnapshot::file("Hello there!");
-        let meta = VfsSnapshot::file(
-            r#"
-            {
-                "ignoreUnknownInstances": true
-            }
-        "#,
-        );
+        let mut imfs = InMemoryFs::new();
+        imfs.load_snapshot("/foo.server.lua", VfsSnapshot::file("Hello there!"))
+            .unwrap();
+        imfs.load_snapshot(
+            "/foo.meta.json",
+            VfsSnapshot::file(
+                r#"
+                    {
+                        "ignoreUnknownInstances": true
+                    }
+                "#,
+            ),
+        )
+        .unwrap();
 
-        vfs.debug_load_snapshot("/foo.server.lua", file);
-        vfs.debug_load_snapshot("/foo.meta.json", meta);
+        let mut vfs = Vfs::new(imfs);
 
-        let entry = vfs.get("/foo.server.lua").unwrap();
-        let instance_snapshot =
-            SnapshotLua::from_vfs(&InstanceContext::default(), &mut vfs, &entry)
-                .unwrap()
-                .unwrap();
+        let instance_snapshot = SnapshotLua::from_vfs(
+            &InstanceContext::default(),
+            &mut vfs,
+            Path::new("/foo.server.lua"),
+        )
+        .unwrap()
+        .unwrap();
 
-        assert_yaml_snapshot!(instance_snapshot);
+        insta::assert_yaml_snapshot!(instance_snapshot);
     }
 
     #[test]
     fn script_disabled() {
-        let mut vfs = Vfs::new(NoopFetcher);
-        let file = VfsSnapshot::file("Hello there!");
-        let meta = VfsSnapshot::file(
-            r#"
-            {
-                "properties": {
-                    "Disabled": true
-                }
-            }
-            "#,
-        );
+        let mut imfs = InMemoryFs::new();
+        imfs.load_snapshot("/bar.server.lua", VfsSnapshot::file("Hello there!"))
+            .unwrap();
+        imfs.load_snapshot(
+            "/bar.meta.json",
+            VfsSnapshot::file(
+                r#"
+                    {
+                        "properties": {
+                            "Disabled": true
+                        }
+                    }
+                "#,
+            ),
+        )
+        .unwrap();
 
-        vfs.debug_load_snapshot("/bar.server.lua", file);
-        vfs.debug_load_snapshot("/bar.meta.json", meta);
+        let mut vfs = Vfs::new(imfs);
 
-        let entry = vfs.get("/bar.server.lua").unwrap();
-        let instance_snapshot =
-            SnapshotLua::from_vfs(&InstanceContext::default(), &mut vfs, &entry)
-                .unwrap()
-                .unwrap();
+        let instance_snapshot = SnapshotLua::from_vfs(
+            &InstanceContext::default(),
+            &mut vfs,
+            Path::new("/bar.server.lua"),
+        )
+        .unwrap()
+        .unwrap();
 
-        with_settings!({ sort_maps => true }, {
-            assert_yaml_snapshot!(instance_snapshot);
+        insta::with_settings!({ sort_maps => true }, {
+            insta::assert_yaml_snapshot!(instance_snapshot);
         });
     }
 }

src/snapshot_middleware/meta_file.rs

@@ -1,4 +1,4 @@
-use std::{borrow::Cow, collections::HashMap};
+use std::{borrow::Cow, collections::HashMap, path::Path};
 
 use rbx_dom_weak::UnresolvedRbxValue;
 use rbx_reflection::try_resolve_value;
@@ -6,6 +6,8 @@ use serde::{Deserialize, Serialize};
 
 use crate::snapshot::InstanceSnapshot;
 
+use super::error::SnapshotError;
+
 /// Represents metadata in a sibling file with the same basename.
 ///
 /// As an example, hello.meta.json next to hello.lua would allow assigning
@@ -21,10 +23,9 @@ pub struct AdjacentMetadata {
 }
 
 impl AdjacentMetadata {
-    pub fn from_slice(slice: &[u8]) -> Self {
+    pub fn from_slice(slice: &[u8], path: &Path) -> Result<Self, SnapshotError> {
         serde_json::from_slice(slice)
-            // TODO: Turn into error type
-            .expect(".meta.json file was malformed")
+            .map_err(|source| SnapshotError::malformed_meta_json(source, path))
     }
 
     pub fn apply_ignore_unknown_instances(&mut self, snapshot: &mut InstanceSnapshot) {
@@ -74,10 +75,9 @@ pub struct DirectoryMetadata {
 }
 
 impl DirectoryMetadata {
-    pub fn from_slice(slice: &[u8]) -> Self {
+    pub fn from_slice(slice: &[u8], path: &Path) -> Result<Self, SnapshotError> {
         serde_json::from_slice(slice)
-            // TODO: Turn into error type
-            .expect("init.meta.json file was malformed")
+            .map_err(|source| SnapshotError::malformed_meta_json(source, path))
     }
 
     pub fn apply_all(&mut self, snapshot: &mut InstanceSnapshot) {

src/snapshot_middleware/middleware.rs

@@ -1,23 +1,13 @@
-use rbx_dom_weak::{RbxId, RbxTree};
+use std::path::Path;
 
-use crate::{
-    snapshot::{InstanceContext, InstanceSnapshot},
-    vfs::{Vfs, VfsEntry, VfsFetcher, VfsSnapshot},
-};
+use memofs::Vfs;
+
+use crate::snapshot::{InstanceContext, InstanceSnapshot};
 
 use super::error::SnapshotError;
 
 pub type SnapshotInstanceResult = Result<Option<InstanceSnapshot>, SnapshotError>;
-pub type SnapshotFileResult = Option<(String, VfsSnapshot)>;
 
 pub trait SnapshotMiddleware {
-    fn from_vfs<F: VfsFetcher>(
-        context: &InstanceContext,
-        vfs: &Vfs<F>,
-        entry: &VfsEntry,
-    ) -> SnapshotInstanceResult;
-
-    fn from_instance(_tree: &RbxTree, _id: RbxId) -> SnapshotFileResult {
-        None
-    }
+    fn from_vfs(context: &InstanceContext, vfs: &Vfs, path: &Path) -> SnapshotInstanceResult;
 }

src/snapshot_middleware/mod.rs

@@ -15,46 +15,37 @@ mod rbxlx;
 mod rbxm;
 mod rbxmx;
 mod txt;
-mod user_plugins;
 mod util;
 
 pub use self::error::*;
 
-use rbx_dom_weak::{RbxId, RbxTree};
+use std::path::Path;
 
+use memofs::Vfs;
+
+use self::middleware::{SnapshotInstanceResult, SnapshotMiddleware};
 use self::{
-    csv::SnapshotCsv,
-    dir::SnapshotDir,
-    json_model::SnapshotJsonModel,
-    lua::SnapshotLua,
-    middleware::{SnapshotFileResult, SnapshotInstanceResult, SnapshotMiddleware},
-    project::SnapshotProject,
-    rbxlx::SnapshotRbxlx,
-    rbxm::SnapshotRbxm,
-    rbxmx::SnapshotRbxmx,
+    csv::SnapshotCsv, dir::SnapshotDir, json_model::SnapshotJsonModel, lua::SnapshotLua,
+    project::SnapshotProject, rbxlx::SnapshotRbxlx, rbxm::SnapshotRbxm, rbxmx::SnapshotRbxmx,
     txt::SnapshotTxt,
-    user_plugins::SnapshotUserPlugins,
-};
-use crate::{
-    snapshot::InstanceContext,
-    vfs::{Vfs, VfsEntry, VfsFetcher},
 };
+use crate::snapshot::InstanceContext;
 
 pub use self::project::snapshot_project_node;
 
 macro_rules! middlewares {
     ( $($middleware: ident,)* ) => {
-        /// Generates a snapshot of instances from the given VfsEntry.
-        pub fn snapshot_from_vfs<F: VfsFetcher>(
+        /// Generates a snapshot of instances from the given path.
+        pub fn snapshot_from_vfs(
             context: &InstanceContext,
-            vfs: &Vfs<F>,
-            entry: &VfsEntry,
+            vfs: &Vfs,
+            path: &Path,
         ) -> SnapshotInstanceResult {
             $(
-                log::trace!("trying middleware {} on {}", stringify!($middleware), entry.path().display());
+                log::trace!("trying middleware {} on {}", stringify!($middleware), path.display());
 
-                if let Some(snapshot) = $middleware::from_vfs(context, vfs, entry)? {
-                    log::trace!("middleware {} success on {}", stringify!($middleware), entry.path().display());
+                if let Some(snapshot) = $middleware::from_vfs(context, vfs, path)? {
+                    log::trace!("middleware {} success on {}", stringify!($middleware), path.display());
                     return Ok(Some(snapshot));
                 }
             )*
@@ -62,24 +53,11 @@ macro_rules! middlewares {
             log::trace!("no middleware returned Ok(Some)");
             Ok(None)
         }
-
-        /// Generates an in-memory filesystem snapshot of the given Roblox
-        /// instance.
-        pub fn snapshot_from_instance(tree: &RbxTree, id: RbxId) -> SnapshotFileResult {
-            $(
-                if let Some(result) = $middleware::from_instance(tree, id) {
-                    return Some(result);
-                }
-            )*
-
-            None
-        }
     };
 }
 
 middlewares! {
     SnapshotProject,
-    SnapshotUserPlugins,
     SnapshotJsonModel,
     SnapshotRbxlx,
     SnapshotRbxmx,

src/snapshot_middleware/project.rs

@@ -1,5 +1,6 @@
 use std::{borrow::Cow, collections::HashMap, path::Path};
 
+use memofs::{IoResultExt, Vfs};
 use rbx_reflection::try_resolve_value;
 
 use crate::{
@@ -7,7 +8,6 @@ use crate::{
     snapshot::{
         InstanceContext, InstanceMetadata, InstanceSnapshot, InstigatingSource, PathIgnoreRule,
     },
-    vfs::{FsResultExt, Vfs, VfsEntry, VfsFetcher},
 };
 
 use super::{
@@ -22,30 +22,28 @@ use super::{
 pub struct SnapshotProject;
 
 impl SnapshotMiddleware for SnapshotProject {
-    fn from_vfs<F: VfsFetcher>(
-        context: &InstanceContext,
-        vfs: &Vfs<F>,
-        entry: &VfsEntry,
-    ) -> SnapshotInstanceResult {
-        if entry.is_directory() {
-            let project_path = entry.path().join("default.project.json");
+    fn from_vfs(context: &InstanceContext, vfs: &Vfs, path: &Path) -> SnapshotInstanceResult {
+        let meta = vfs.metadata(path)?;
 
-            match vfs.get(project_path).with_not_found()? {
+        if meta.is_dir() {
+            let project_path = path.join("default.project.json");
+
+            match vfs.metadata(&project_path).with_not_found()? {
                 // TODO: Do we need to muck with the relevant paths if we're a
                 // project file within a folder? Should the folder path be the
                 // relevant path instead of the project file path?
-                Some(entry) => return SnapshotProject::from_vfs(context, vfs, &entry),
+                Some(_meta) => return SnapshotProject::from_vfs(context, vfs, &project_path),
                 None => return Ok(None),
             }
         }
 
-        if !entry.path().to_string_lossy().ends_with(".project.json") {
+        if !path.to_string_lossy().ends_with(".project.json") {
             // This isn't a project file, so it's not our job.
             return Ok(None);
         }
 
-        let project = Project::load_from_slice(&entry.contents(vfs)?, entry.path())
-            .map_err(|err| SnapshotError::malformed_project(err, entry.path()))?;
+        let project = Project::load_from_slice(&vfs.read(path)?, path)
+            .map_err(|err| SnapshotError::malformed_project(err, path))?;
 
         let mut context = context.clone();
 
@@ -75,7 +73,7 @@ impl SnapshotMiddleware for SnapshotProject {
         // relevant path -> snapshot path mapping per instance, we pick the more
         // conservative approach of snapshotting the project file if any
         // relevant paths changed.
-        snapshot.metadata.instigating_source = Some(entry.path().to_path_buf().into());
+        snapshot.metadata.instigating_source = Some(path.to_path_buf().into());
 
         // Mark this snapshot (the root node of the project file) as being
         // related to the project file.
@@ -83,21 +81,18 @@ impl SnapshotMiddleware for SnapshotProject {
         // We SHOULD NOT mark the project file as a relevant path for any
         // nodes that aren't roots. They'll be updated as part of the project
         // file being updated.
-        snapshot
-            .metadata
-            .relevant_paths
-            .push(entry.path().to_path_buf());
+        snapshot.metadata.relevant_paths.push(path.to_path_buf());
 
         Ok(Some(snapshot))
     }
 }
 
-pub fn snapshot_project_node<F: VfsFetcher>(
+pub fn snapshot_project_node(
     context: &InstanceContext,
     project_folder: &Path,
     instance_name: &str,
     node: &ProjectNode,
-    vfs: &Vfs<F>,
+    vfs: &Vfs,
 ) -> SnapshotInstanceResult {
     let name = Cow::Owned(instance_name.to_owned());
     let mut class_name = node
@@ -117,9 +112,7 @@ pub fn snapshot_project_node<F: VfsFetcher>(
             Cow::Borrowed(path)
         };
 
-        let entry = vfs.get(path.as_path())?;
-
-        if let Some(snapshot) = snapshot_from_vfs(context, vfs, &entry)? {
+        if let Some(snapshot) = snapshot_from_vfs(context, vfs, &path)? {
             // If a class name was already specified, then it'll override the
             // class name of this snapshot ONLY if it's a Folder.
             //
@@ -217,259 +210,284 @@ pub fn snapshot_project_node<F: VfsFetcher>(
 mod test {
     use super::*;
 
-    use insta::assert_yaml_snapshot;
     use maplit::hashmap;
-
-    use crate::vfs::{NoopFetcher, VfsDebug, VfsSnapshot};
+    use memofs::{InMemoryFs, VfsSnapshot};
 
     #[test]
     fn project_from_folder() {
         let _ = env_logger::try_init();
 
-        let mut vfs = Vfs::new(NoopFetcher);
-        let dir = VfsSnapshot::dir(hashmap! {
-            "default.project.json" => VfsSnapshot::file(r#"
-                {
-                    "name": "indirect-project",
-                    "tree": {
-                        "$className": "Folder"
+        let mut imfs = InMemoryFs::new();
+        imfs.load_snapshot(
+            "/foo",
+            VfsSnapshot::dir(hashmap! {
+                "default.project.json" => VfsSnapshot::file(r#"
+                    {
+                        "name": "indirect-project",
+                        "tree": {
+                            "$className": "Folder"
+                        }
                     }
-                }
-            "#),
-        });
+                "#),
+            }),
+        )
+        .unwrap();
 
-        vfs.debug_load_snapshot("/foo", dir);
+        let mut vfs = Vfs::new(imfs);
 
-        let entry = vfs.get("/foo").unwrap();
         let instance_snapshot =
-            SnapshotProject::from_vfs(&InstanceContext::default(), &mut vfs, &entry)
+            SnapshotProject::from_vfs(&InstanceContext::default(), &mut vfs, Path::new("/foo"))
                 .expect("snapshot error")
                 .expect("snapshot returned no instances");
 
-        assert_yaml_snapshot!(instance_snapshot);
+        insta::assert_yaml_snapshot!(instance_snapshot);
     }
 
     #[test]
     fn project_from_direct_file() {
         let _ = env_logger::try_init();
 
-        let mut vfs = Vfs::new(NoopFetcher);
-        let dir = VfsSnapshot::dir(hashmap! {
-            "hello.project.json" => VfsSnapshot::file(r#"
-                {
-                    "name": "direct-project",
-                    "tree": {
-                        "$className": "Model"
+        let mut imfs = InMemoryFs::new();
+        imfs.load_snapshot(
+            "/foo",
+            VfsSnapshot::dir(hashmap! {
+                "hello.project.json" => VfsSnapshot::file(r#"
+                    {
+                        "name": "direct-project",
+                        "tree": {
+                            "$className": "Model"
+                        }
                     }
-                }
-            "#),
-        });
+                "#),
+            }),
+        )
+        .unwrap();
 
-        vfs.debug_load_snapshot("/foo", dir);
+        let mut vfs = Vfs::new(imfs);
 
-        let entry = vfs.get("/foo/hello.project.json").unwrap();
-        let instance_snapshot =
-            SnapshotProject::from_vfs(&InstanceContext::default(), &mut vfs, &entry)
-                .expect("snapshot error")
-                .expect("snapshot returned no instances");
+        let instance_snapshot = SnapshotProject::from_vfs(
+            &InstanceContext::default(),
+            &mut vfs,
+            Path::new("/foo/hello.project.json"),
+        )
+        .expect("snapshot error")
+        .expect("snapshot returned no instances");
 
-        assert_yaml_snapshot!(instance_snapshot);
+        insta::assert_yaml_snapshot!(instance_snapshot);
     }
 
     #[test]
     fn project_with_resolved_properties() {
         let _ = env_logger::try_init();
 
-        let mut vfs = Vfs::new(NoopFetcher);
-        let dir = VfsSnapshot::dir(hashmap! {
-            "default.project.json" => VfsSnapshot::file(r#"
-                {
-                    "name": "resolved-properties",
-                    "tree": {
-                        "$className": "StringValue",
-                        "$properties": {
-                            "Value": {
-                                "Type": "String",
-                                "Value": "Hello, world!"
+        let mut imfs = InMemoryFs::new();
+        imfs.load_snapshot(
+            "/foo",
+            VfsSnapshot::dir(hashmap! {
+                "default.project.json" => VfsSnapshot::file(r#"
+                    {
+                        "name": "resolved-properties",
+                        "tree": {
+                            "$className": "StringValue",
+                            "$properties": {
+                                "Value": {
+                                    "Type": "String",
+                                    "Value": "Hello, world!"
+                                }
                             }
                         }
                     }
-                }
-            "#),
-        });
+                "#),
+            }),
+        )
+        .unwrap();
 
-        vfs.debug_load_snapshot("/foo", dir);
+        let mut vfs = Vfs::new(imfs);
 
-        let entry = vfs.get("/foo").unwrap();
         let instance_snapshot =
-            SnapshotProject::from_vfs(&InstanceContext::default(), &mut vfs, &entry)
+            SnapshotProject::from_vfs(&InstanceContext::default(), &mut vfs, Path::new("/foo"))
                 .expect("snapshot error")
                 .expect("snapshot returned no instances");
 
-        assert_yaml_snapshot!(instance_snapshot);
+        insta::assert_yaml_snapshot!(instance_snapshot);
     }
 
     #[test]
     fn project_with_unresolved_properties() {
         let _ = env_logger::try_init();
 
-        let mut vfs = Vfs::new(NoopFetcher);
-        let dir = VfsSnapshot::dir(hashmap! {
-            "default.project.json" => VfsSnapshot::file(r#"
-                {
-                    "name": "unresolved-properties",
-                    "tree": {
-                        "$className": "StringValue",
-                        "$properties": {
-                            "Value": "Hi!"
+        let mut imfs = InMemoryFs::new();
+        imfs.load_snapshot(
+            "/foo",
+            VfsSnapshot::dir(hashmap! {
+                "default.project.json" => VfsSnapshot::file(r#"
+                    {
+                        "name": "unresolved-properties",
+                        "tree": {
+                            "$className": "StringValue",
+                            "$properties": {
+                                "Value": "Hi!"
+                            }
                         }
                     }
-                }
-            "#),
-        });
+                "#),
+            }),
+        )
+        .unwrap();
 
-        vfs.debug_load_snapshot("/foo", dir);
+        let mut vfs = Vfs::new(imfs);
 
-        let entry = vfs.get("/foo").unwrap();
         let instance_snapshot =
-            SnapshotProject::from_vfs(&InstanceContext::default(), &mut vfs, &entry)
+            SnapshotProject::from_vfs(&InstanceContext::default(), &mut vfs, Path::new("/foo"))
                 .expect("snapshot error")
                 .expect("snapshot returned no instances");
 
-        assert_yaml_snapshot!(instance_snapshot);
+        insta::assert_yaml_snapshot!(instance_snapshot);
     }
 
     #[test]
     fn project_with_children() {
         let _ = env_logger::try_init();
 
-        let mut vfs = Vfs::new(NoopFetcher);
-        let dir = VfsSnapshot::dir(hashmap! {
-            "default.project.json" => VfsSnapshot::file(r#"
-                {
-                    "name": "children",
-                    "tree": {
-                        "$className": "Folder",
+        let mut imfs = InMemoryFs::new();
+        imfs.load_snapshot(
+            "/foo",
+            VfsSnapshot::dir(hashmap! {
+                "default.project.json" => VfsSnapshot::file(r#"
+                    {
+                        "name": "children",
+                        "tree": {
+                            "$className": "Folder",
 
-                        "Child": {
-                            "$className": "Model"
+                            "Child": {
+                                "$className": "Model"
+                            }
                         }
                     }
-                }
-            "#),
-        });
+                "#),
+            }),
+        )
+        .unwrap();
 
-        vfs.debug_load_snapshot("/foo", dir);
+        let mut vfs = Vfs::new(imfs);
 
-        let entry = vfs.get("/foo").unwrap();
         let instance_snapshot =
-            SnapshotProject::from_vfs(&InstanceContext::default(), &mut vfs, &entry)
+            SnapshotProject::from_vfs(&InstanceContext::default(), &mut vfs, Path::new("/foo"))
                 .expect("snapshot error")
                 .expect("snapshot returned no instances");
 
-        assert_yaml_snapshot!(instance_snapshot);
+        insta::assert_yaml_snapshot!(instance_snapshot);
     }
 
     #[test]
     fn project_with_path_to_txt() {
         let _ = env_logger::try_init();
 
-        let mut vfs = Vfs::new(NoopFetcher);
-        let dir = VfsSnapshot::dir(hashmap! {
-            "default.project.json" => VfsSnapshot::file(r#"
-                {
-                    "name": "path-project",
-                    "tree": {
-                        "$path": "other.txt"
+        let mut imfs = InMemoryFs::new();
+        imfs.load_snapshot(
+            "/foo",
+            VfsSnapshot::dir(hashmap! {
+                "default.project.json" => VfsSnapshot::file(r#"
+                    {
+                        "name": "path-project",
+                        "tree": {
+                            "$path": "other.txt"
+                        }
                     }
-                }
-            "#),
-            "other.txt" => VfsSnapshot::file("Hello, world!"),
-        });
+                "#),
+                "other.txt" => VfsSnapshot::file("Hello, world!"),
+            }),
+        )
+        .unwrap();
 
-        vfs.debug_load_snapshot("/foo", dir);
+        let mut vfs = Vfs::new(imfs);
 
-        let entry = vfs.get("/foo").unwrap();
         let instance_snapshot =
-            SnapshotProject::from_vfs(&InstanceContext::default(), &mut vfs, &entry)
+            SnapshotProject::from_vfs(&InstanceContext::default(), &mut vfs, Path::new("/foo"))
                 .expect("snapshot error")
                 .expect("snapshot returned no instances");
 
-        assert_yaml_snapshot!(instance_snapshot);
+        insta::assert_yaml_snapshot!(instance_snapshot);
     }
 
     #[test]
     fn project_with_path_to_project() {
         let _ = env_logger::try_init();
 
-        let mut vfs = Vfs::new(NoopFetcher);
-        let dir = VfsSnapshot::dir(hashmap! {
-            "default.project.json" => VfsSnapshot::file(r#"
-                {
-                    "name": "path-project",
-                    "tree": {
-                        "$path": "other.project.json"
+        let mut imfs = InMemoryFs::new();
+        imfs.load_snapshot(
+            "/foo",
+            VfsSnapshot::dir(hashmap! {
+                "default.project.json" => VfsSnapshot::file(r#"
+                    {
+                        "name": "path-project",
+                        "tree": {
+                            "$path": "other.project.json"
+                        }
                     }
-                }
-            "#),
-            "other.project.json" => VfsSnapshot::file(r#"
-                {
-                    "name": "other-project",
-                    "tree": {
-                        "$className": "Model"
+                "#),
+                "other.project.json" => VfsSnapshot::file(r#"
+                    {
+                        "name": "other-project",
+                        "tree": {
+                            "$className": "Model"
+                        }
                     }
-                }
-            "#),
-        });
+                "#),
+            }),
+        )
+        .unwrap();
 
-        vfs.debug_load_snapshot("/foo", dir);
+        let mut vfs = Vfs::new(imfs);
 
-        let entry = vfs.get("/foo").unwrap();
         let instance_snapshot =
-            SnapshotProject::from_vfs(&InstanceContext::default(), &mut vfs, &entry)
+            SnapshotProject::from_vfs(&InstanceContext::default(), &mut vfs, Path::new("/foo"))
                 .expect("snapshot error")
                 .expect("snapshot returned no instances");
 
-        assert_yaml_snapshot!(instance_snapshot);
+        insta::assert_yaml_snapshot!(instance_snapshot);
     }
 
     #[test]
     fn project_with_path_to_project_with_children() {
         let _ = env_logger::try_init();
 
-        let mut vfs = Vfs::new(NoopFetcher);
-        let dir = VfsSnapshot::dir(hashmap! {
-            "default.project.json" => VfsSnapshot::file(r#"
-                {
-                    "name": "path-child-project",
-                    "tree": {
-                        "$path": "other.project.json"
-                    }
-                }
-            "#),
-            "other.project.json" => VfsSnapshot::file(r#"
-                {
-                    "name": "other-project",
-                    "tree": {
-                        "$className": "Folder",
-
-                        "SomeChild": {
-                            "$className": "Model"
+        let mut imfs = InMemoryFs::new();
+        imfs.load_snapshot(
+            "/foo",
+            VfsSnapshot::dir(hashmap! {
+                "default.project.json" => VfsSnapshot::file(r#"
+                    {
+                        "name": "path-child-project",
+                        "tree": {
+                            "$path": "other.project.json"
                         }
                     }
-                }
-            "#),
-        });
+                "#),
+                "other.project.json" => VfsSnapshot::file(r#"
+                    {
+                        "name": "other-project",
+                        "tree": {
+                            "$className": "Folder",
 
-        vfs.debug_load_snapshot("/foo", dir);
+                            "SomeChild": {
+                                "$className": "Model"
+                            }
+                        }
+                    }
+                "#),
+            }),
+        )
+        .unwrap();
+
+        let mut vfs = Vfs::new(imfs);
 
-        let entry = vfs.get("/foo").unwrap();
         let instance_snapshot =
-            SnapshotProject::from_vfs(&InstanceContext::default(), &mut vfs, &entry)
+            SnapshotProject::from_vfs(&InstanceContext::default(), &mut vfs, Path::new("/foo"))
                 .expect("snapshot error")
                 .expect("snapshot returned no instances");
 
-        assert_yaml_snapshot!(instance_snapshot);
+        insta::assert_yaml_snapshot!(instance_snapshot);
     }
 
     /// Ensures that if a property is defined both in the resulting instance
@@ -479,40 +497,43 @@ mod test {
     fn project_path_property_overrides() {
         let _ = env_logger::try_init();
 
-        let mut vfs = Vfs::new(NoopFetcher);
-        let dir = VfsSnapshot::dir(hashmap! {
-            "default.project.json" => VfsSnapshot::file(r#"
-                {
-                    "name": "path-property-override",
-                    "tree": {
-                        "$path": "other.project.json",
-                        "$properties": {
-                            "Value": "Changed"
+        let mut imfs = InMemoryFs::new();
+        imfs.load_snapshot(
+            "/foo",
+            VfsSnapshot::dir(hashmap! {
+                "default.project.json" => VfsSnapshot::file(r#"
+                    {
+                        "name": "path-property-override",
+                        "tree": {
+                            "$path": "other.project.json",
+                            "$properties": {
+                                "Value": "Changed"
+                            }
                         }
                     }
-                }
-            "#),
-            "other.project.json" => VfsSnapshot::file(r#"
-                {
-                    "name": "other-project",
-                    "tree": {
-                        "$className": "StringValue",
-                        "$properties": {
-                            "Value": "Original"
+                "#),
+                "other.project.json" => VfsSnapshot::file(r#"
+                    {
+                        "name": "other-project",
+                        "tree": {
+                            "$className": "StringValue",
+                            "$properties": {
+                                "Value": "Original"
+                            }
                         }
                     }
-                }
-            "#),
-        });
+                "#),
+            }),
+        )
+        .unwrap();
 
-        vfs.debug_load_snapshot("/foo", dir);
+        let mut vfs = Vfs::new(imfs);
 
-        let entry = vfs.get("/foo").unwrap();
         let instance_snapshot =
-            SnapshotProject::from_vfs(&InstanceContext::default(), &mut vfs, &entry)
+            SnapshotProject::from_vfs(&InstanceContext::default(), &mut vfs, Path::new("/foo"))
                 .expect("snapshot error")
                 .expect("snapshot returned no instances");
 
-        assert_yaml_snapshot!(instance_snapshot);
+        insta::assert_yaml_snapshot!(instance_snapshot);
     }
 }

src/snapshot_middleware/rbxlx.rs

@@ -1,7 +1,8 @@
-use crate::{
-    snapshot::{InstanceContext, InstanceMetadata, InstanceSnapshot},
-    vfs::{Vfs, VfsEntry, VfsFetcher},
-};
+use std::path::Path;
+
+use memofs::Vfs;
+
+use crate::snapshot::{InstanceContext, InstanceMetadata, InstanceSnapshot};
 
 use super::{
     middleware::{SnapshotInstanceResult, SnapshotMiddleware},
@@ -11,16 +12,14 @@ use super::{
 pub struct SnapshotRbxlx;
 
 impl SnapshotMiddleware for SnapshotRbxlx {
-    fn from_vfs<F: VfsFetcher>(
-        context: &InstanceContext,
-        vfs: &Vfs<F>,
-        entry: &VfsEntry,
-    ) -> SnapshotInstanceResult {
-        if entry.is_directory() {
+    fn from_vfs(context: &InstanceContext, vfs: &Vfs, path: &Path) -> SnapshotInstanceResult {
+        let meta = vfs.metadata(path)?;
+
+        if meta.is_dir() {
             return Ok(None);
         }
 
-        let instance_name = match match_file_name(entry.path(), ".rbxlx") {
+        let instance_name = match match_file_name(path, ".rbxlx") {
             Some(name) => name,
             None => return Ok(None),
         };
@@ -28,7 +27,7 @@ impl SnapshotMiddleware for SnapshotRbxlx {
         let options = rbx_xml::DecodeOptions::new()
             .property_behavior(rbx_xml::DecodePropertyBehavior::ReadUnknown);
 
-        let temp_tree = rbx_xml::from_reader(entry.contents(vfs)?.as_slice(), options)
+        let temp_tree = rbx_xml::from_reader(vfs.read(path)?.as_slice(), options)
             .expect("TODO: Handle rbx_xml errors");
 
         let root_id = temp_tree.get_root_id();
@@ -37,8 +36,8 @@ impl SnapshotMiddleware for SnapshotRbxlx {
             .name(instance_name)
             .metadata(
                 InstanceMetadata::new()
-                    .instigating_source(entry.path())
-                    .relevant_paths(vec![entry.path().to_path_buf()])
+                    .instigating_source(path)
+                    .relevant_paths(vec![path.to_path_buf()])
                     .context(context),
             );
 

src/snapshot_middleware/rbxm.rs

@@ -1,11 +1,9 @@
-use std::collections::HashMap;
+use std::{collections::HashMap, path::Path};
 
+use memofs::Vfs;
 use rbx_dom_weak::{RbxInstanceProperties, RbxTree};
 
-use crate::{
-    snapshot::{InstanceContext, InstanceMetadata, InstanceSnapshot},
-    vfs::{Vfs, VfsEntry, VfsFetcher},
-};
+use crate::snapshot::{InstanceContext, InstanceMetadata, InstanceSnapshot};
 
 use super::{
     middleware::{SnapshotInstanceResult, SnapshotMiddleware},
@@ -15,16 +13,14 @@ use super::{
 pub struct SnapshotRbxm;
 
 impl SnapshotMiddleware for SnapshotRbxm {
-    fn from_vfs<F: VfsFetcher>(
-        context: &InstanceContext,
-        vfs: &Vfs<F>,
-        entry: &VfsEntry,
-    ) -> SnapshotInstanceResult {
-        if entry.is_directory() {
+    fn from_vfs(context: &InstanceContext, vfs: &Vfs, path: &Path) -> SnapshotInstanceResult {
+        let meta = vfs.metadata(path)?;
+
+        if meta.is_dir() {
             return Ok(None);
         }
 
-        let instance_name = match match_file_name(entry.path(), ".rbxm") {
+        let instance_name = match match_file_name(path, ".rbxm") {
             Some(name) => name,
             None => return Ok(None),
         };
@@ -36,7 +32,7 @@ impl SnapshotMiddleware for SnapshotRbxm {
         });
 
         let root_id = temp_tree.get_root_id();
-        rbx_binary::decode(&mut temp_tree, root_id, entry.contents(vfs)?.as_slice())
+        rbx_binary::decode(&mut temp_tree, root_id, vfs.read(path)?.as_slice())
             .expect("TODO: Handle rbx_binary errors");
 
         let root_instance = temp_tree.get_instance(root_id).unwrap();
@@ -47,8 +43,8 @@ impl SnapshotMiddleware for SnapshotRbxm {
                 .name(instance_name)
                 .metadata(
                     InstanceMetadata::new()
-                        .instigating_source(entry.path())
-                        .relevant_paths(vec![entry.path().to_path_buf()])
+                        .instigating_source(path)
+                        .relevant_paths(vec![path.to_path_buf()])
                         .context(context),
                 );
 
@@ -63,20 +59,26 @@ impl SnapshotMiddleware for SnapshotRbxm {
 mod test {
     use super::*;
 
-    use crate::vfs::{NoopFetcher, VfsDebug, VfsSnapshot};
+    use memofs::{InMemoryFs, VfsSnapshot};
 
     #[test]
     fn model_from_vfs() {
-        let mut vfs = Vfs::new(NoopFetcher);
-        let file = VfsSnapshot::file(include_bytes!("../../assets/test-folder.rbxm").to_vec());
+        let mut imfs = InMemoryFs::new();
+        imfs.load_snapshot(
+            "/foo.rbxm",
+            VfsSnapshot::file(include_bytes!("../../assets/test-folder.rbxm").to_vec()),
+        )
+        .unwrap();
 
-        vfs.debug_load_snapshot("/foo.rbxm", file);
+        let mut vfs = Vfs::new(imfs);
 
-        let entry = vfs.get("/foo.rbxm").unwrap();
-        let instance_snapshot =
-            SnapshotRbxm::from_vfs(&InstanceContext::default(), &mut vfs, &entry)
-                .unwrap()
-                .unwrap();
+        let instance_snapshot = SnapshotRbxm::from_vfs(
+            &InstanceContext::default(),
+            &mut vfs,
+            Path::new("/foo.rbxm"),
+        )
+        .unwrap()
+        .unwrap();
 
         assert_eq!(instance_snapshot.name, "foo");
         assert_eq!(instance_snapshot.class_name, "Folder");

src/snapshot_middleware/rbxmx.rs

@@ -1,7 +1,8 @@
-use crate::{
-    snapshot::{InstanceContext, InstanceMetadata, InstanceSnapshot},
-    vfs::{Vfs, VfsEntry, VfsFetcher},
-};
+use std::path::Path;
+
+use memofs::Vfs;
+
+use crate::snapshot::{InstanceContext, InstanceMetadata, InstanceSnapshot};
 
 use super::{
     middleware::{SnapshotInstanceResult, SnapshotMiddleware},
@@ -11,16 +12,14 @@ use super::{
 pub struct SnapshotRbxmx;
 
 impl SnapshotMiddleware for SnapshotRbxmx {
-    fn from_vfs<F: VfsFetcher>(
-        context: &InstanceContext,
-        vfs: &Vfs<F>,
-        entry: &VfsEntry,
-    ) -> SnapshotInstanceResult {
-        if entry.is_directory() {
+    fn from_vfs(context: &InstanceContext, vfs: &Vfs, path: &Path) -> SnapshotInstanceResult {
+        let meta = vfs.metadata(path)?;
+
+        if meta.is_dir() {
             return Ok(None);
         }
 
-        let instance_name = match match_file_name(entry.path(), ".rbxmx") {
+        let instance_name = match match_file_name(path, ".rbxmx") {
             Some(name) => name,
             None => return Ok(None),
         };
@@ -28,7 +27,7 @@ impl SnapshotMiddleware for SnapshotRbxmx {
         let options = rbx_xml::DecodeOptions::new()
             .property_behavior(rbx_xml::DecodePropertyBehavior::ReadUnknown);
 
-        let temp_tree = rbx_xml::from_reader(entry.contents(vfs)?.as_slice(), options)
+        let temp_tree = rbx_xml::from_reader(vfs.read(path)?.as_slice(), options)
             .expect("TODO: Handle rbx_xml errors");
 
         let root_instance = temp_tree.get_instance(temp_tree.get_root_id()).unwrap();
@@ -39,8 +38,8 @@ impl SnapshotMiddleware for SnapshotRbxmx {
                 .name(instance_name)
                 .metadata(
                     InstanceMetadata::new()
-                        .instigating_source(entry.path())
-                        .relevant_paths(vec![entry.path().to_path_buf()])
+                        .instigating_source(path)
+                        .relevant_paths(vec![path.to_path_buf()])
                         .context(context),
                 );
 
@@ -55,36 +54,40 @@ impl SnapshotMiddleware for SnapshotRbxmx {
 mod test {
     use super::*;
 
-    use std::collections::HashMap;
-
-    use crate::vfs::{NoopFetcher, VfsDebug, VfsSnapshot};
+    use memofs::{InMemoryFs, VfsSnapshot};
 
     #[test]
-    fn model_from_vfs() {
-        let mut vfs = Vfs::new(NoopFetcher);
-        let file = VfsSnapshot::file(
-            r#"
-            <roblox version="4">
-                <Item class="Folder" referent="0">
-                    <Properties>
-                        <string name="Name">THIS NAME IS IGNORED</string>
-                    </Properties>
-                </Item>
-            </roblox>
-        "#,
-        );
+    fn plain_folder() {
+        let mut imfs = InMemoryFs::new();
+        imfs.load_snapshot(
+            "/foo.rbxmx",
+            VfsSnapshot::file(
+                r#"
+                    <roblox version="4">
+                        <Item class="Folder" referent="0">
+                            <Properties>
+                                <string name="Name">THIS NAME IS IGNORED</string>
+                            </Properties>
+                        </Item>
+                    </roblox>
+                "#,
+            ),
+        )
+        .unwrap();
 
-        vfs.debug_load_snapshot("/foo.rbxmx", file);
+        let mut vfs = Vfs::new(imfs);
 
-        let entry = vfs.get("/foo.rbxmx").unwrap();
-        let instance_snapshot =
-            SnapshotRbxmx::from_vfs(&InstanceContext::default(), &mut vfs, &entry)
-                .unwrap()
-                .unwrap();
+        let instance_snapshot = SnapshotRbxmx::from_vfs(
+            &InstanceContext::default(),
+            &mut vfs,
+            Path::new("/foo.rbxmx"),
+        )
+        .unwrap()
+        .unwrap();
 
         assert_eq!(instance_snapshot.name, "foo");
         assert_eq!(instance_snapshot.class_name, "Folder");
-        assert_eq!(instance_snapshot.properties, HashMap::new());
+        assert_eq!(instance_snapshot.properties, Default::default());
         assert_eq!(instance_snapshot.children, Vec::new());
     }
 }

src/snapshot_middleware/txt.rs

@@ -1,40 +1,36 @@
-use std::str;
+use std::{path::Path, str};
 
 use maplit::hashmap;
-use rbx_dom_weak::{RbxId, RbxTree, RbxValue};
+use memofs::{IoResultExt, Vfs};
+use rbx_dom_weak::RbxValue;
 
-use crate::{
-    snapshot::{InstanceContext, InstanceMetadata, InstanceSnapshot},
-    vfs::{FileSnapshot, FsResultExt, Vfs, VfsEntry, VfsFetcher, VfsSnapshot},
-};
+use crate::snapshot::{InstanceContext, InstanceMetadata, InstanceSnapshot};
 
 use super::{
     error::SnapshotError,
     meta_file::AdjacentMetadata,
-    middleware::{SnapshotFileResult, SnapshotInstanceResult, SnapshotMiddleware},
+    middleware::{SnapshotInstanceResult, SnapshotMiddleware},
     util::match_file_name,
 };
 
 pub struct SnapshotTxt;
 
 impl SnapshotMiddleware for SnapshotTxt {
-    fn from_vfs<F: VfsFetcher>(
-        context: &InstanceContext,
-        vfs: &Vfs<F>,
-        entry: &VfsEntry,
-    ) -> SnapshotInstanceResult {
-        if entry.is_directory() {
+    fn from_vfs(context: &InstanceContext, vfs: &Vfs, path: &Path) -> SnapshotInstanceResult {
+        let meta = vfs.metadata(path)?;
+
+        if meta.is_dir() {
             return Ok(None);
         }
 
-        let instance_name = match match_file_name(entry.path(), ".txt") {
+        let instance_name = match match_file_name(path, ".txt") {
             Some(name) => name,
             None => return Ok(None),
         };
 
-        let contents = entry.contents(vfs)?;
+        let contents = vfs.read(path)?;
         let contents_str = str::from_utf8(&contents)
-            .map_err(|err| SnapshotError::file_contents_bad_unicode(err, entry.path()))?
+            .map_err(|err| SnapshotError::file_contents_bad_unicode(err, path))?
             .to_string();
 
         let properties = hashmap! {
@@ -43,9 +39,7 @@ impl SnapshotMiddleware for SnapshotTxt {
             },
         };
 
-        let meta_path = entry
-            .path()
-            .with_file_name(format!("{}.meta.json", instance_name));
+        let meta_path = path.with_file_name(format!("{}.meta.json", instance_name));
 
         let mut snapshot = InstanceSnapshot::new()
             .name(instance_name)
@@ -53,99 +47,39 @@ impl SnapshotMiddleware for SnapshotTxt {
             .properties(properties)
             .metadata(
                 InstanceMetadata::new()
-                    .instigating_source(entry.path())
-                    .relevant_paths(vec![entry.path().to_path_buf(), meta_path.clone()])
+                    .instigating_source(path)
+                    .relevant_paths(vec![path.to_path_buf(), meta_path.clone()])
                     .context(context),
             );
 
-        if let Some(meta_entry) = vfs.get(meta_path).with_not_found()? {
-            let meta_contents = meta_entry.contents(vfs)?;
-            let mut metadata = AdjacentMetadata::from_slice(&meta_contents);
+        if let Some(meta_contents) = vfs.read(&meta_path).with_not_found()? {
+            let mut metadata = AdjacentMetadata::from_slice(&meta_contents, &meta_path)?;
             metadata.apply_all(&mut snapshot);
         }
 
         Ok(Some(snapshot))
     }
-
-    fn from_instance(tree: &RbxTree, id: RbxId) -> SnapshotFileResult {
-        let instance = tree.get_instance(id).unwrap();
-
-        if instance.class_name != "StringValue" {
-            return None;
-        }
-
-        if !instance.get_children_ids().is_empty() {
-            return None;
-        }
-
-        let value = match instance.properties.get("Value") {
-            Some(RbxValue::String { value }) => value.clone(),
-            Some(_) => panic!("wrong type ahh"),
-            None => String::new(),
-        };
-
-        let snapshot = VfsSnapshot::File(FileSnapshot {
-            contents: value.into_bytes(),
-        });
-
-        let mut file_name = instance.name.clone();
-        file_name.push_str(".txt");
-
-        Some((file_name, snapshot))
-    }
 }
 
 #[cfg(test)]
 mod test {
     use super::*;
 
-    use insta::assert_yaml_snapshot;
-    use maplit::hashmap;
-    use rbx_dom_weak::RbxInstanceProperties;
-
-    use crate::vfs::{NoopFetcher, VfsDebug};
+    use memofs::{InMemoryFs, VfsSnapshot};
 
     #[test]
     fn instance_from_vfs() {
-        let mut vfs = Vfs::new(NoopFetcher);
-        let file = VfsSnapshot::file("Hello there!");
+        let mut imfs = InMemoryFs::new();
+        imfs.load_snapshot("/foo.txt", VfsSnapshot::file("Hello there!"))
+            .unwrap();
 
-        vfs.debug_load_snapshot("/foo.txt", file);
+        let mut vfs = Vfs::new(imfs.clone());
 
-        let entry = vfs.get("/foo.txt").unwrap();
         let instance_snapshot =
-            SnapshotTxt::from_vfs(&InstanceContext::default(), &mut vfs, &entry)
+            SnapshotTxt::from_vfs(&InstanceContext::default(), &mut vfs, Path::new("/foo.txt"))
                 .unwrap()
                 .unwrap();
 
-        assert_yaml_snapshot!(instance_snapshot);
-    }
-
-    #[test]
-    fn vfs_from_instance() {
-        let tree = RbxTree::new(string_value("Root", "Hello, world!"));
-        let root_id = tree.get_root_id();
-
-        let (_file_name, _file) = SnapshotTxt::from_instance(&tree, root_id).unwrap();
-    }
-
-    fn folder(name: impl Into<String>) -> RbxInstanceProperties {
-        RbxInstanceProperties {
-            name: name.into(),
-            class_name: "Folder".to_owned(),
-            properties: Default::default(),
-        }
-    }
-
-    fn string_value(name: impl Into<String>, value: impl Into<String>) -> RbxInstanceProperties {
-        RbxInstanceProperties {
-            name: name.into(),
-            class_name: "StringValue".to_owned(),
-            properties: hashmap! {
-                "Value".to_owned() => RbxValue::String {
-                    value: value.into(),
-                },
-            },
-        }
+        insta::assert_yaml_snapshot!(instance_snapshot);
     }
 }

src/vfs/error.rs

@@ -1,55 +0,0 @@
-use std::{error::Error, fmt, io, path::PathBuf};
-
-pub type FsResult<T> = Result<T, FsError>;
-pub use io::ErrorKind as FsErrorKind;
-
-pub trait FsResultExt<T> {
-    fn with_not_found(self) -> Result<Option<T>, FsError>;
-}
-
-impl<T> FsResultExt<T> for Result<T, FsError> {
-    fn with_not_found(self) -> Result<Option<T>, FsError> {
-        match self {
-            Ok(value) => Ok(Some(value)),
-            Err(ref err) if err.kind() == FsErrorKind::NotFound => Ok(None),
-            Err(err) => Err(err),
-        }
-    }
-}
-
-/// A wrapper around io::Error that also attaches the path associated with the
-/// error.
-#[derive(Debug)]
-pub struct FsError {
-    source: io::Error,
-    path: PathBuf,
-}
-
-impl FsError {
-    pub fn new<P: Into<PathBuf>>(source: io::Error, path: P) -> FsError {
-        FsError {
-            source,
-            path: path.into(),
-        }
-    }
-
-    pub fn kind(&self) -> FsErrorKind {
-        self.source.kind()
-    }
-
-    pub fn into_raw(self) -> (io::Error, PathBuf) {
-        (self.source, self.path)
-    }
-}
-
-impl Error for FsError {
-    fn source(&self) -> Option<&(dyn Error + 'static)> {
-        Some(&self.source)
-    }
-}
-
-impl fmt::Display for FsError {
-    fn fmt(&self, output: &mut fmt::Formatter) -> fmt::Result {
-        write!(output, "{}: {}", self.path.display(), self.source)
-    }
-}

src/vfs/event.rs

@@ -1,8 +0,0 @@
-use std::path::PathBuf;
-
-#[derive(Debug)]
-pub enum VfsEvent {
-    Modified(PathBuf),
-    Created(PathBuf),
-    Removed(PathBuf),
-}

src/vfs/fetcher.rs

@@ -1,37 +0,0 @@
-use std::{
-    io,
-    path::{Path, PathBuf},
-};
-
-use crossbeam_channel::Receiver;
-
-use super::event::VfsEvent;
-
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub enum FileType {
-    File,
-    Directory,
-}
-
-/// The generic interface that `Vfs` 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 VfsFetcher {
-    fn file_type(&self, path: &Path) -> io::Result<FileType>;
-    fn read_children(&self, path: &Path) -> io::Result<Vec<PathBuf>>;
-    fn read_contents(&self, path: &Path) -> io::Result<Vec<u8>>;
-
-    fn create_directory(&self, path: &Path) -> io::Result<()>;
-    fn write_file(&self, path: &Path, contents: &[u8]) -> io::Result<()>;
-    fn remove(&self, path: &Path) -> io::Result<()>;
-
-    fn receiver(&self) -> Receiver<VfsEvent>;
-
-    fn watch(&self, _path: &Path) {}
-    fn unwatch(&self, _path: &Path) {}
-
-    /// A method intended for debugging what paths the fetcher is watching.
-    fn watched_paths(&self) -> Vec<PathBuf> {
-        Vec::new()
-    }
-}

src/vfs/mod.rs

@@ -1,24 +0,0 @@
-mod error;
-mod event;
-mod fetcher;
-mod noop_fetcher;
-mod real_fetcher;
-mod snapshot;
-
-// I don't think module inception is a real problem?
-#[allow(clippy::module_inception)]
-mod vfs;
-
-pub use error::*;
-pub use event::*;
-pub use fetcher::*;
-pub use noop_fetcher::*;
-pub use real_fetcher::*;
-pub use snapshot::*;
-pub use vfs::*;
-
-#[cfg(test)]
-mod test_fetcher;
-
-#[cfg(test)]
-pub use test_fetcher::*;

src/vfs/noop_fetcher.rs

@@ -1,62 +0,0 @@
-//! Implements the VFS fetcher interface for a fake filesystem using Rust's
-//! std::fs interface.
-
-// This interface is only used for testing, so it's okay if it isn't used.
-#![allow(unused)]
-
-use std::{
-    io,
-    path::{Path, PathBuf},
-};
-
-use crossbeam_channel::Receiver;
-
-use super::{
-    event::VfsEvent,
-    fetcher::{FileType, VfsFetcher},
-};
-
-pub struct NoopFetcher;
-
-impl VfsFetcher for NoopFetcher {
-    fn file_type(&self, _path: &Path) -> io::Result<FileType> {
-        Err(io::Error::new(
-            io::ErrorKind::NotFound,
-            "NoopFetcher always returns NotFound",
-        ))
-    }
-
-    fn read_children(&self, _path: &Path) -> io::Result<Vec<PathBuf>> {
-        Err(io::Error::new(
-            io::ErrorKind::NotFound,
-            "NoopFetcher always returns NotFound",
-        ))
-    }
-
-    fn read_contents(&self, _path: &Path) -> io::Result<Vec<u8>> {
-        Err(io::Error::new(
-            io::ErrorKind::NotFound,
-            "NoopFetcher always returns NotFound",
-        ))
-    }
-
-    fn create_directory(&self, _path: &Path) -> io::Result<()> {
-        Ok(())
-    }
-
-    fn write_file(&self, _path: &Path, _contents: &[u8]) -> io::Result<()> {
-        Ok(())
-    }
-
-    fn remove(&self, _path: &Path) -> io::Result<()> {
-        Ok(())
-    }
-
-    fn watch(&self, _path: &Path) {}
-
-    fn unwatch(&self, _path: &Path) {}
-
-    fn receiver(&self) -> Receiver<VfsEvent> {
-        crossbeam_channel::never()
-    }
-}

src/vfs/real_fetcher.rs

@@ -1,225 +0,0 @@
-//! Implements the VFS fetcher interface for the real filesystem using Rust's
-//! std::fs interface and notify as the file watcher.
-
-use std::{
-    collections::HashSet,
-    fs, io,
-    path::{Path, PathBuf},
-    sync::{mpsc, Mutex},
-    time::Duration,
-};
-
-use crossbeam_channel::{unbounded, Receiver, Sender};
-use jod_thread::JoinHandle;
-use notify::{DebouncedEvent, RecommendedWatcher, RecursiveMode, Watcher};
-
-use super::{
-    event::VfsEvent,
-    fetcher::{FileType, VfsFetcher},
-};
-
-/// Workaround to disable the file watcher for processes that don't need it,
-/// since notify appears hang on to mpsc Sender objects too long, causing Rojo
-/// to deadlock on drop.
-///
-/// We can make constructing the watcher optional in order to hotfix rojo build.
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub enum WatchMode {
-    Enabled,
-    Disabled,
-}
-
-pub struct RealFetcher {
-    // Drop order is relevant here!
-    //
-    // `watcher` must be dropped before `_converter_thread` or else joining the
-    // thread will cause a deadlock.
-    watcher: Option<Mutex<RecommendedWatcher>>,
-
-    /// Thread handle to convert notify's mpsc channel messages into
-    /// crossbeam_channel messages.
-    _converter_thread: JoinHandle<()>,
-
-    /// The crossbeam receiver filled with events from the converter thread.
-    receiver: Receiver<VfsEvent>,
-
-    /// All of the paths that the fetcher is watching, tracked here because
-    /// notify does not expose this information.
-    watched_paths: Mutex<HashSet<PathBuf>>,
-}
-
-impl RealFetcher {
-    pub fn new(watch_mode: WatchMode) -> RealFetcher {
-        log::trace!("Starting RealFetcher with watch mode {:?}", watch_mode);
-
-        let (notify_sender, notify_receiver) = mpsc::channel();
-        let (sender, receiver) = unbounded();
-
-        let handle = jod_thread::Builder::new()
-            .name("notify message converter".to_owned())
-            .spawn(move || {
-                log::trace!("RealFetcher converter thread started");
-                converter_thread(notify_receiver, sender);
-                log::trace!("RealFetcher converter thread stopped");
-            })
-            .expect("Could not start message converter thread");
-
-        // TODO: Investigate why notify hangs onto notify_sender too long,
-        // causing our program to deadlock. Once this is fixed, watcher no
-        // longer needs to be optional, but is still maybe useful?
-        let watcher = match watch_mode {
-            WatchMode::Enabled => {
-                let watcher = notify::watcher(notify_sender, Duration::from_millis(300))
-                    .expect("Couldn't start 'notify' file watcher");
-
-                Some(Mutex::new(watcher))
-            }
-            WatchMode::Disabled => None,
-        };
-
-        RealFetcher {
-            watcher,
-            _converter_thread: handle,
-            receiver,
-            watched_paths: Mutex::new(HashSet::new()),
-        }
-    }
-}
-
-fn converter_thread(notify_receiver: mpsc::Receiver<DebouncedEvent>, sender: Sender<VfsEvent>) {
-    use DebouncedEvent::*;
-
-    for event in notify_receiver {
-        log::trace!("Notify event: {:?}", event);
-
-        match event {
-            Create(path) => sender.send(VfsEvent::Created(path)).unwrap(),
-            Write(path) => sender.send(VfsEvent::Modified(path)).unwrap(),
-            Remove(path) => sender.send(VfsEvent::Removed(path)).unwrap(),
-            Rename(from_path, to_path) => {
-                sender.send(VfsEvent::Created(from_path)).unwrap();
-                sender.send(VfsEvent::Removed(to_path)).unwrap();
-            }
-            Rescan => {
-                log::warn!("Unhandled filesystem rescan event.");
-                log::warn!(
-                    "Please file an issue! Rojo may need to handle this case, but does not yet."
-                );
-            }
-            Error(err, maybe_path) => {
-                log::warn!("Unhandled filesystem error: {}", err);
-
-                match maybe_path {
-                    Some(path) => log::warn!("On path {}", path.display()),
-                    None => log::warn!("No path was associated with this error."),
-                }
-
-                log::warn!(
-                    "Rojo may need to handle this. If this happens again, please file an issue!"
-                );
-            }
-            NoticeWrite(_) | NoticeRemove(_) | Chmod(_) => {}
-        }
-    }
-}
-
-impl VfsFetcher for RealFetcher {
-    fn file_type(&self, path: &Path) -> io::Result<FileType> {
-        let metadata = fs::metadata(path)?;
-
-        if metadata.is_file() {
-            Ok(FileType::File)
-        } else {
-            Ok(FileType::Directory)
-        }
-    }
-
-    fn read_children(&self, path: &Path) -> io::Result<Vec<PathBuf>> {
-        log::trace!("Reading directory {}", path.display());
-
-        let mut result = Vec::new();
-
-        let iter = fs::read_dir(path)?;
-
-        for entry in iter {
-            result.push(entry?.path());
-        }
-
-        Ok(result)
-    }
-
-    fn read_contents(&self, path: &Path) -> io::Result<Vec<u8>> {
-        log::trace!("Reading file {}", path.display());
-
-        fs::read(path)
-    }
-
-    fn create_directory(&self, path: &Path) -> io::Result<()> {
-        log::trace!("Creating directory {}", path.display());
-
-        fs::create_dir(path)
-    }
-
-    fn write_file(&self, path: &Path, contents: &[u8]) -> io::Result<()> {
-        log::trace!("Writing path {}", path.display());
-
-        fs::write(path, contents)
-    }
-
-    fn remove(&self, path: &Path) -> io::Result<()> {
-        log::trace!("Removing path {}", path.display());
-
-        let metadata = fs::metadata(path)?;
-
-        if metadata.is_file() {
-            fs::remove_file(path)
-        } else {
-            fs::remove_dir_all(path)
-        }
-    }
-
-    fn watch(&self, path: &Path) {
-        log::trace!("Watching path {}", path.display());
-
-        if let Some(watcher_handle) = &self.watcher {
-            let mut watcher = watcher_handle.lock().unwrap();
-
-            match watcher.watch(path, RecursiveMode::NonRecursive) {
-                Ok(_) => {
-                    let mut watched_paths = self.watched_paths.lock().unwrap();
-                    watched_paths.insert(path.to_path_buf());
-                }
-                Err(err) => {
-                    log::warn!("Couldn't watch path {}: {:?}", path.display(), err);
-                }
-            }
-        }
-    }
-
-    fn unwatch(&self, path: &Path) {
-        log::trace!("Stopped watching path {}", path.display());
-
-        if let Some(watcher_handle) = &self.watcher {
-            let mut watcher = watcher_handle.lock().unwrap();
-
-            // Remove the path from our watched paths regardless of the outcome
-            // of notify's unwatch to ensure we drop old paths in the event of a
-            // rename.
-            let mut watched_paths = self.watched_paths.lock().unwrap();
-            watched_paths.remove(path);
-
-            if let Err(err) = watcher.unwatch(path) {
-                log::warn!("Couldn't unwatch path {}: {:?}", path.display(), err);
-            }
-        }
-    }
-
-    fn receiver(&self) -> Receiver<VfsEvent> {
-        self.receiver.clone()
-    }
-
-    fn watched_paths(&self) -> Vec<PathBuf> {
-        let watched_paths = self.watched_paths.lock().unwrap();
-        watched_paths.iter().cloned().collect()
-    }
-}

src/vfs/snapshot.rs

@@ -1,42 +0,0 @@
-// This file is non-critical and used for testing, so it's okay if it's unused.
-#![allow(unused)]
-
-use std::collections::HashMap;
-
-#[derive(Debug, Clone)]
-pub enum VfsSnapshot {
-    File(FileSnapshot),
-    Directory(DirectorySnapshot),
-}
-
-impl VfsSnapshot {
-    /// Create a new file VfsSnapshot with the given contents.
-    pub fn file(contents: impl Into<Vec<u8>>) -> VfsSnapshot {
-        VfsSnapshot::File(FileSnapshot {
-            contents: contents.into(),
-        })
-    }
-
-    /// Create a new directory VfsSnapshot with the given children.
-    pub fn dir<S: Into<String>>(children: HashMap<S, VfsSnapshot>) -> VfsSnapshot {
-        let children = children.into_iter().map(|(k, v)| (k.into(), v)).collect();
-
-        VfsSnapshot::Directory(DirectorySnapshot { children })
-    }
-
-    pub fn empty_dir() -> VfsSnapshot {
-        VfsSnapshot::Directory(DirectorySnapshot {
-            children: Default::default(),
-        })
-    }
-}
-
-#[derive(Debug, Clone)]
-pub struct FileSnapshot {
-    pub contents: Vec<u8>,
-}
-
-#[derive(Debug, Clone)]
-pub struct DirectorySnapshot {
-    pub children: HashMap<String, VfsSnapshot>,
-}

src/vfs/test_fetcher.rs

@@ -1,171 +0,0 @@
-//! Implements the VFS fetcher interface for a fake filesystem that can be
-//! mutated and have changes signaled through it.
-//!
-//! This is useful for testing how things using Vfs react to changed events
-//! without relying on the real filesystem implementation, which is very
-//! platform-specific.
-
-// This interface is only used for testing, so it's okay if it isn't used.
-#![allow(unused)]
-
-use std::{
-    io,
-    path::{self, Path, PathBuf},
-    sync::{Arc, Mutex},
-};
-
-use crossbeam_channel::{unbounded, Receiver, Sender};
-
-use crate::path_map::PathMap;
-
-use super::{
-    event::VfsEvent,
-    fetcher::{FileType, VfsFetcher},
-    snapshot::VfsSnapshot,
-};
-
-#[derive(Clone)]
-pub struct TestFetcherState {
-    inner: Arc<Mutex<TestFetcherStateInner>>,
-}
-
-impl TestFetcherState {
-    pub fn load_snapshot<P: AsRef<Path>>(&self, path: P, snapshot: VfsSnapshot) {
-        let mut inner = self.inner.lock().unwrap();
-        inner.load_snapshot(path.as_ref().to_path_buf(), snapshot);
-    }
-
-    pub fn remove<P: AsRef<Path>>(&self, path: P) {
-        let mut inner = self.inner.lock().unwrap();
-        inner.remove(path.as_ref());
-    }
-
-    pub fn raise_event(&self, event: VfsEvent) {
-        let mut inner = self.inner.lock().unwrap();
-        inner.raise_event(event);
-    }
-}
-
-pub enum TestFetcherEntry {
-    File(Vec<u8>),
-    Dir,
-}
-
-struct TestFetcherStateInner {
-    entries: PathMap<TestFetcherEntry>,
-    sender: Sender<VfsEvent>,
-}
-
-impl TestFetcherStateInner {
-    fn new(sender: Sender<VfsEvent>) -> Self {
-        let mut entries = PathMap::new();
-        entries.insert(Path::new("/"), TestFetcherEntry::Dir);
-
-        Self { sender, entries }
-    }
-
-    fn load_snapshot(&mut self, path: PathBuf, snapshot: VfsSnapshot) {
-        match snapshot {
-            VfsSnapshot::File(file) => {
-                self.entries
-                    .insert(path, TestFetcherEntry::File(file.contents));
-            }
-            VfsSnapshot::Directory(directory) => {
-                self.entries.insert(path.clone(), TestFetcherEntry::Dir);
-
-                for (child_name, child) in directory.children.into_iter() {
-                    self.load_snapshot(path.join(child_name), child);
-                }
-            }
-        }
-    }
-
-    fn remove(&mut self, path: &Path) {
-        self.entries.remove(path);
-    }
-
-    fn raise_event(&mut self, event: VfsEvent) {
-        self.sender.send(event).unwrap();
-    }
-}
-
-pub struct TestFetcher {
-    state: TestFetcherState,
-    receiver: Receiver<VfsEvent>,
-}
-
-impl TestFetcher {
-    pub fn new() -> (TestFetcherState, Self) {
-        let (sender, receiver) = unbounded();
-
-        let state = TestFetcherState {
-            inner: Arc::new(Mutex::new(TestFetcherStateInner::new(sender))),
-        };
-
-        (state.clone(), Self { receiver, state })
-    }
-}
-
-impl VfsFetcher for TestFetcher {
-    fn file_type(&self, path: &Path) -> io::Result<FileType> {
-        let inner = self.state.inner.lock().unwrap();
-
-        match inner.entries.get(path) {
-            Some(TestFetcherEntry::File(_)) => Ok(FileType::File),
-            Some(TestFetcherEntry::Dir) => Ok(FileType::Directory),
-            None => Err(io::Error::new(io::ErrorKind::NotFound, "Path not found")),
-        }
-    }
-
-    fn read_children(&self, path: &Path) -> io::Result<Vec<PathBuf>> {
-        let inner = self.state.inner.lock().unwrap();
-
-        Ok(inner
-            .entries
-            .children(path)
-            .ok_or_else(|| io::Error::new(io::ErrorKind::NotFound, "Path not found"))?
-            .into_iter()
-            .map(|path| path.to_path_buf())
-            .collect())
-    }
-
-    fn read_contents(&self, path: &Path) -> io::Result<Vec<u8>> {
-        let inner = self.state.inner.lock().unwrap();
-
-        let node = inner.entries.get(path);
-
-        match node {
-            Some(TestFetcherEntry::File(contents)) => Ok(contents.clone()),
-            Some(TestFetcherEntry::Dir) => Err(io::Error::new(
-                io::ErrorKind::Other,
-                "Cannot read contents of a directory",
-            )),
-            None => Err(io::Error::new(io::ErrorKind::NotFound, "Path not found")),
-        }
-    }
-
-    fn create_directory(&self, _path: &Path) -> io::Result<()> {
-        Err(io::Error::new(
-            io::ErrorKind::Other,
-            "TestFetcher is not mutable yet",
-        ))
-    }
-
-    fn write_file(&self, _path: &Path, _contents: &[u8]) -> io::Result<()> {
-        Err(io::Error::new(
-            io::ErrorKind::Other,
-            "TestFetcher is not mutable yet",
-        ))
-    }
-
-    fn remove(&self, _path: &Path) -> io::Result<()> {
-        Err(io::Error::new(
-            io::ErrorKind::Other,
-            "TestFetcher is not mutable yet",
-        ))
-    }
-
-    fn receiver(&self) -> Receiver<VfsEvent> {
-        self.receiver.clone()
-    }
-}

src/vfs/vfs.rs

@@ -1,614 +0,0 @@
-use std::{
-    io,
-    path::{Path, PathBuf},
-    sync::{Arc, Mutex},
-};
-
-use crossbeam_channel::Receiver;
-
-use crate::path_map::PathMap;
-
-use super::{
-    error::{FsError, FsResult},
-    event::VfsEvent,
-    fetcher::{FileType, VfsFetcher},
-    snapshot::VfsSnapshot,
-};
-
-/// An in-memory filesystem that can be incrementally populated and updated as
-/// filesystem modification events occur.
-///
-/// All operations on the `Vfs` are lazy and do I/O as late as they can to
-/// avoid reading extraneous files or directories from the disk. This means that
-/// they all take `self` mutably, and means that it isn't possible to hold
-/// references to the internal state of the Vfs while traversing it!
-///
-/// Most operations return `VfsEntry` objects to work around this, which is
-/// effectively a index into the `Vfs`.
-pub struct Vfs<F> {
-    /// A hierarchical map from paths to items that have been read or partially
-    /// read into memory by the Vfs.
-    data: Mutex<PathMap<VfsItem>>,
-
-    /// This Vfs's fetcher, which is used for all actual interactions with the
-    /// filesystem. It's referred to by the type parameter `F` all over, and is
-    /// generic in order to make it feasible to mock.
-    fetcher: F,
-}
-
-impl<F: VfsFetcher> Vfs<F> {
-    pub fn new(fetcher: F) -> Self {
-        Self {
-            data: Mutex::new(PathMap::new()),
-            fetcher,
-        }
-    }
-
-    pub fn change_receiver(&self) -> Receiver<VfsEvent> {
-        self.fetcher.receiver()
-    }
-
-    pub fn commit_change(&self, event: &VfsEvent) -> FsResult<()> {
-        use VfsEvent::*;
-
-        log::trace!("Committing Vfs change {:?}", event);
-
-        let mut data = self.data.lock().unwrap();
-
-        match event {
-            Created(path) | Modified(path) => {
-                Self::raise_file_changed(&mut data, &self.fetcher, path)?;
-            }
-            Removed(path) => {
-                Self::raise_file_removed(&mut data, &self.fetcher, path)?;
-            }
-        }
-
-        Ok(())
-    }
-
-    pub fn get(&self, path: impl AsRef<Path>) -> FsResult<VfsEntry> {
-        let mut data = self.data.lock().unwrap();
-        Self::get_internal(&mut data, &self.fetcher, path)
-    }
-
-    pub fn get_contents(&self, path: impl AsRef<Path>) -> FsResult<Arc<Vec<u8>>> {
-        let path = path.as_ref();
-
-        let mut data = self.data.lock().unwrap();
-        Self::read_if_not_exists(&mut data, &self.fetcher, path)?;
-
-        match data.get_mut(path).unwrap() {
-            VfsItem::File(file) => {
-                if file.contents.is_none() {
-                    file.contents = Some(
-                        self.fetcher
-                            .read_contents(path)
-                            .map(Arc::new)
-                            .map_err(|err| FsError::new(err, path.to_path_buf()))?,
-                    );
-                }
-
-                Ok(file.contents.clone().unwrap())
-            }
-            VfsItem::Directory(_) => Err(FsError::new(
-                io::Error::new(io::ErrorKind::Other, "Can't read a directory"),
-                path.to_path_buf(),
-            )),
-        }
-    }
-
-    pub fn get_children(&self, path: impl AsRef<Path>) -> FsResult<Vec<VfsEntry>> {
-        let path = path.as_ref();
-
-        let mut data = self.data.lock().unwrap();
-        Self::read_if_not_exists(&mut data, &self.fetcher, path)?;
-
-        match data.get_mut(path).unwrap() {
-            VfsItem::Directory(dir) => {
-                self.fetcher.watch(path);
-
-                // If the directory hasn't been marked as enumerated yet, find
-                // all of its children and insert them into the VFS.
-                if !dir.children_enumerated {
-                    dir.children_enumerated = true;
-
-                    let children = self
-                        .fetcher
-                        .read_children(path)
-                        .map_err(|err| FsError::new(err, path.to_path_buf()))?;
-
-                    for path in children {
-                        Self::get_internal(&mut data, &self.fetcher, path)?;
-                    }
-                }
-
-                data.children(path)
-                    .unwrap() // TODO: Handle None here, which means the PathMap entry did not exist.
-                    .into_iter()
-                    .map(PathBuf::from) // Convert paths from &Path to PathBuf
-                    .collect::<Vec<PathBuf>>() // Collect all PathBufs, since self.get needs to borrow self mutably.
-                    .into_iter()
-                    .map(|path| Self::get_internal(&mut data, &self.fetcher, path))
-                    .collect::<FsResult<Vec<VfsEntry>>>()
-            }
-            VfsItem::File(_) => Err(FsError::new(
-                io::Error::new(io::ErrorKind::Other, "Can't read a directory"),
-                path.to_path_buf(),
-            )),
-        }
-    }
-
-    fn get_internal(
-        data: &mut PathMap<VfsItem>,
-        fetcher: &F,
-        path: impl AsRef<Path>,
-    ) -> FsResult<VfsEntry> {
-        let path = path.as_ref();
-
-        Self::read_if_not_exists(data, fetcher, path)?;
-
-        let item = data.get(path).unwrap();
-
-        let is_file = match item {
-            VfsItem::File(_) => true,
-            VfsItem::Directory(_) => false,
-        };
-
-        Ok(VfsEntry {
-            path: item.path().to_path_buf(),
-            is_file,
-        })
-    }
-
-    fn raise_file_changed(
-        data: &mut PathMap<VfsItem>,
-        fetcher: &F,
-        path: impl AsRef<Path>,
-    ) -> FsResult<()> {
-        let path = path.as_ref();
-
-        if !Self::would_be_resident(&data, path) {
-            log::trace!(
-                "Path would not be resident, skipping change: {}",
-                path.display()
-            );
-
-            return Ok(());
-        }
-
-        let new_type = fetcher
-            .file_type(path)
-            .map_err(|err| FsError::new(err, path.to_path_buf()))?;
-
-        match data.get_mut(path) {
-            Some(existing_item) => {
-                match (existing_item, &new_type) {
-                    (VfsItem::File(existing_file), FileType::File) => {
-                        // Invalidate the existing file contents.
-                        // We can probably be smarter about this by reading the changed file.
-                        existing_file.contents = None;
-                    }
-                    (VfsItem::Directory(_), FileType::Directory) => {
-                        // No changes required, a directory updating doesn't mean anything to us.
-                        fetcher.watch(path);
-                    }
-                    (VfsItem::File(_), FileType::Directory) => {
-                        data.remove(path);
-                        data.insert(
-                            path.to_path_buf(),
-                            VfsItem::new_from_type(FileType::Directory, path),
-                        );
-                        fetcher.watch(path);
-                    }
-                    (VfsItem::Directory(_), FileType::File) => {
-                        data.remove(path);
-                        data.insert(
-                            path.to_path_buf(),
-                            VfsItem::new_from_type(FileType::File, path),
-                        );
-                        fetcher.unwatch(path);
-                    }
-                }
-            }
-            None => {
-                log::trace!("Inserting new path {}", path.display());
-                data.insert(path.to_path_buf(), VfsItem::new_from_type(new_type, path));
-            }
-        }
-
-        Ok(())
-    }
-
-    fn raise_file_removed(
-        data: &mut PathMap<VfsItem>,
-        fetcher: &F,
-        path: impl AsRef<Path>,
-    ) -> FsResult<()> {
-        let path = path.as_ref();
-
-        if !Self::would_be_resident(data, path) {
-            return Ok(());
-        }
-
-        data.remove(path);
-        fetcher.unwatch(path);
-        Ok(())
-    }
-
-    /// Attempts to read the path into the `Vfs` if it doesn't exist.
-    ///
-    /// This does not necessitate that file contents or directory children will
-    /// be read. Depending on the `VfsFetcher` implementation that the `Vfs`
-    /// is using, this call may read exactly only the given path and no more.
-    fn read_if_not_exists(data: &mut PathMap<VfsItem>, fetcher: &F, path: &Path) -> FsResult<()> {
-        if !data.contains_key(path) {
-            let kind = fetcher
-                .file_type(path)
-                .map_err(|err| FsError::new(err, path.to_path_buf()))?;
-
-            if kind == FileType::Directory {
-                fetcher.watch(path);
-            }
-
-            data.insert(path.to_path_buf(), VfsItem::new_from_type(kind, path));
-        }
-
-        Ok(())
-    }
-
-    /// Tells whether the given path, if it were loaded, would be loaded if it
-    /// existed.
-    ///
-    /// Returns true if the path is loaded or if its parent is loaded, is a
-    /// directory, and is marked as having been enumerated before.
-    ///
-    /// This idea corresponds to whether a file change event should result in
-    /// tangible changes to the in-memory filesystem. If a path would be
-    /// resident, we need to read it, and if its contents were known before, we
-    /// need to update them.
-    fn would_be_resident(data: &PathMap<VfsItem>, path: &Path) -> bool {
-        if data.contains_key(path) {
-            return true;
-        }
-
-        if let Some(parent) = path.parent() {
-            if let Some(VfsItem::Directory(dir)) = data.get(parent) {
-                return dir.children_enumerated;
-            }
-        }
-
-        false
-    }
-}
-
-/// Contains extra methods that should only be used for debugging. They're
-/// broken out into a separate trait to make it more explicit to depend on them.
-pub trait VfsDebug {
-    fn debug_load_snapshot<P: AsRef<Path>>(&self, path: P, snapshot: VfsSnapshot);
-    fn debug_is_file(&self, path: &Path) -> bool;
-    fn debug_contents(&self, path: &Path) -> Option<Arc<Vec<u8>>>;
-    fn debug_children(&self, path: &Path) -> Option<(bool, Vec<PathBuf>)>;
-    fn debug_orphans(&self) -> Vec<PathBuf>;
-    fn debug_watched_paths(&self) -> Vec<PathBuf>;
-}
-
-impl<F: VfsFetcher> VfsDebug for Vfs<F> {
-    fn debug_load_snapshot<P: AsRef<Path>>(&self, path: P, snapshot: VfsSnapshot) {
-        fn load_snapshot<P: AsRef<Path>>(
-            data: &mut PathMap<VfsItem>,
-            path: P,
-            snapshot: VfsSnapshot,
-        ) {
-            let path = path.as_ref();
-
-            match snapshot {
-                VfsSnapshot::File(file) => {
-                    data.insert(
-                        path.to_path_buf(),
-                        VfsItem::File(VfsFile {
-                            path: path.to_path_buf(),
-                            contents: Some(Arc::new(file.contents)),
-                        }),
-                    );
-                }
-                VfsSnapshot::Directory(directory) => {
-                    data.insert(
-                        path.to_path_buf(),
-                        VfsItem::Directory(VfsDirectory {
-                            path: path.to_path_buf(),
-                            children_enumerated: true,
-                        }),
-                    );
-
-                    for (child_name, child) in directory.children.into_iter() {
-                        load_snapshot(data, path.join(child_name), child);
-                    }
-                }
-            }
-        }
-
-        let mut data = self.data.lock().unwrap();
-        load_snapshot(&mut data, path, snapshot)
-    }
-
-    fn debug_is_file(&self, path: &Path) -> bool {
-        let data = self.data.lock().unwrap();
-        match data.get(path) {
-            Some(VfsItem::File(_)) => true,
-            _ => false,
-        }
-    }
-
-    fn debug_contents(&self, path: &Path) -> Option<Arc<Vec<u8>>> {
-        let data = self.data.lock().unwrap();
-        match data.get(path) {
-            Some(VfsItem::File(file)) => file.contents.clone(),
-            _ => None,
-        }
-    }
-
-    fn debug_children(&self, path: &Path) -> Option<(bool, Vec<PathBuf>)> {
-        let data = self.data.lock().unwrap();
-        match data.get(path) {
-            Some(VfsItem::Directory(dir)) => Some((
-                dir.children_enumerated,
-                data.children(path)
-                    .unwrap()
-                    .iter()
-                    .map(|path| path.to_path_buf())
-                    .collect(),
-            )),
-            _ => None,
-        }
-    }
-
-    fn debug_orphans(&self) -> Vec<PathBuf> {
-        let data = self.data.lock().unwrap();
-        data.orphans().map(|path| path.to_path_buf()).collect()
-    }
-
-    fn debug_watched_paths(&self) -> Vec<PathBuf> {
-        self.fetcher.watched_paths()
-    }
-}
-
-/// A reference to file or folder in an `Vfs`. Can only be produced by the
-/// entry existing in the Vfs, but can later point to nothing if something
-/// would invalidate that path.
-///
-/// This struct does not borrow from the Vfs since every operation has the
-/// possibility to mutate the underlying data structure and move memory around.
-pub struct VfsEntry {
-    path: PathBuf,
-    is_file: bool,
-}
-
-impl VfsEntry {
-    pub fn path(&self) -> &Path {
-        &self.path
-    }
-
-    pub fn contents(&self, vfs: &Vfs<impl VfsFetcher>) -> FsResult<Arc<Vec<u8>>> {
-        vfs.get_contents(&self.path)
-    }
-
-    pub fn children(&self, vfs: &Vfs<impl VfsFetcher>) -> FsResult<Vec<VfsEntry>> {
-        vfs.get_children(&self.path)
-    }
-
-    pub fn is_file(&self) -> bool {
-        self.is_file
-    }
-
-    pub fn is_directory(&self) -> bool {
-        !self.is_file
-    }
-}
-
-/// Internal structure describing potentially partially-resident files and
-/// folders in the `Vfs`.
-#[derive(Debug)]
-pub enum VfsItem {
-    File(VfsFile),
-    Directory(VfsDirectory),
-}
-
-impl VfsItem {
-    fn path(&self) -> &Path {
-        match self {
-            VfsItem::File(file) => &file.path,
-            VfsItem::Directory(dir) => &dir.path,
-        }
-    }
-
-    fn new_from_type(kind: FileType, path: impl Into<PathBuf>) -> VfsItem {
-        match kind {
-            FileType::Directory => VfsItem::Directory(VfsDirectory {
-                path: path.into(),
-                children_enumerated: false,
-            }),
-            FileType::File => VfsItem::File(VfsFile {
-                path: path.into(),
-                contents: None,
-            }),
-        }
-    }
-}
-
-#[derive(Debug)]
-pub struct VfsFile {
-    pub(super) path: PathBuf,
-    pub(super) contents: Option<Arc<Vec<u8>>>,
-}
-
-#[derive(Debug)]
-pub struct VfsDirectory {
-    pub(super) path: PathBuf,
-    pub(super) children_enumerated: bool,
-}
-
-#[cfg(test)]
-mod test {
-    use super::*;
-
-    use std::{cell::RefCell, rc::Rc};
-
-    use crossbeam_channel::Receiver;
-    use maplit::hashmap;
-
-    use super::super::{error::FsErrorKind, event::VfsEvent, noop_fetcher::NoopFetcher};
-
-    #[test]
-    fn from_snapshot_file() {
-        let vfs = Vfs::new(NoopFetcher);
-        let file = VfsSnapshot::file("hello, world!");
-
-        vfs.debug_load_snapshot("/hello.txt", file);
-
-        let contents = vfs.get_contents("/hello.txt").unwrap();
-        assert_eq!(contents.as_slice(), b"hello, world!");
-    }
-
-    #[test]
-    fn from_snapshot_dir() {
-        let vfs = Vfs::new(NoopFetcher);
-        let dir = VfsSnapshot::dir(hashmap! {
-            "a.txt" => VfsSnapshot::file("contents of a.txt"),
-            "b.lua" => VfsSnapshot::file("contents of b.lua"),
-        });
-
-        vfs.debug_load_snapshot("/dir", dir);
-
-        let children = vfs.get_children("/dir").unwrap();
-
-        let mut has_a = false;
-        let mut has_b = false;
-
-        for child in children.into_iter() {
-            if child.path() == Path::new("/dir/a.txt") {
-                has_a = true;
-            } else if child.path() == Path::new("/dir/b.lua") {
-                has_b = true;
-            } else {
-                panic!("Unexpected child in /dir");
-            }
-        }
-
-        assert!(has_a, "/dir/a.txt was missing");
-        assert!(has_b, "/dir/b.lua was missing");
-
-        let a_contents = vfs.get_contents("/dir/a.txt").unwrap();
-        assert_eq!(a_contents.as_slice(), b"contents of a.txt");
-
-        let b_contents = vfs.get_contents("/dir/b.lua").unwrap();
-        assert_eq!(b_contents.as_slice(), b"contents of b.lua");
-    }
-
-    #[test]
-    fn changed_event() {
-        #[derive(Default)]
-        struct MockState {
-            a_contents: &'static str,
-        }
-
-        struct MockFetcher {
-            inner: Rc<RefCell<MockState>>,
-        }
-
-        impl VfsFetcher for MockFetcher {
-            fn file_type(&self, path: &Path) -> io::Result<FileType> {
-                if path == Path::new("/dir/a.txt") {
-                    return Ok(FileType::File);
-                }
-
-                unimplemented!();
-            }
-
-            fn read_contents(&self, path: &Path) -> io::Result<Vec<u8>> {
-                if path == Path::new("/dir/a.txt") {
-                    let inner = self.inner.borrow();
-
-                    return Ok(Vec::from(inner.a_contents));
-                }
-
-                unimplemented!();
-            }
-
-            fn read_children(&self, _path: &Path) -> io::Result<Vec<PathBuf>> {
-                unimplemented!();
-            }
-
-            fn create_directory(&self, _path: &Path) -> io::Result<()> {
-                unimplemented!();
-            }
-
-            fn write_file(&self, _path: &Path, _contents: &[u8]) -> io::Result<()> {
-                unimplemented!();
-            }
-
-            fn remove(&self, _path: &Path) -> io::Result<()> {
-                unimplemented!();
-            }
-
-            fn receiver(&self) -> Receiver<VfsEvent> {
-                crossbeam_channel::never()
-            }
-        }
-
-        let mock_state = Rc::new(RefCell::new(MockState {
-            a_contents: "Initial contents",
-        }));
-
-        let mut vfs = Vfs::new(MockFetcher {
-            inner: mock_state.clone(),
-        });
-
-        let a = vfs.get("/dir/a.txt").expect("mock file did not exist");
-
-        let contents = a.contents(&mut vfs).expect("mock file contents error");
-
-        assert_eq!(contents.as_slice(), b"Initial contents");
-
-        {
-            let mut mock_state = mock_state.borrow_mut();
-            mock_state.a_contents = "Changed contents";
-        }
-
-        vfs.commit_change(&VfsEvent::Modified(PathBuf::from("/dir/a.txt")))
-            .expect("error processing file change");
-
-        let contents = a.contents(&mut vfs).expect("mock file contents error");
-
-        assert_eq!(contents.as_slice(), b"Changed contents");
-    }
-
-    #[test]
-    fn removed_event_existing() {
-        let mut vfs = Vfs::new(NoopFetcher);
-
-        let file = VfsSnapshot::file("hello, world!");
-        vfs.debug_load_snapshot("/hello.txt", file);
-
-        let hello = vfs.get("/hello.txt").expect("couldn't get hello.txt");
-
-        let contents = hello
-            .contents(&mut vfs)
-            .expect("couldn't get hello.txt contents");
-
-        assert_eq!(contents.as_slice(), b"hello, world!");
-
-        vfs.commit_change(&VfsEvent::Removed(PathBuf::from("/hello.txt")))
-            .expect("error processing file removal");
-
-        match vfs.get("hello.txt") {
-            Err(ref err) if err.kind() == FsErrorKind::NotFound => {}
-            Ok(_) => {
-                panic!("hello.txt was not removed from Vfs");
-            }
-            Err(err) => {
-                panic!("Unexpected error: {:?}", err);
-            }
-        }
-    }
-}

src/web/api.rs

@@ -11,7 +11,6 @@ use rbx_dom_weak::RbxId;
 use crate::{
     serve_session::ServeSession,
     snapshot::{PatchSet, PatchUpdate},
-    vfs::VfsFetcher,
     web::{
         interface::{
             ErrorResponse, Instance, InstanceMetadata as WebInstanceMetadata, InstanceUpdate,
@@ -22,11 +21,11 @@ use crate::{
     },
 };
 
-pub struct ApiService<F> {
-    serve_session: Arc<ServeSession<F>>,
+pub struct ApiService {
+    serve_session: Arc<ServeSession>,
 }
 
-impl<F: VfsFetcher> Service for ApiService<F> {
+impl Service for ApiService {
     type ReqBody = Body;
     type ResBody = Body;
     type Error = hyper::Error;
@@ -53,8 +52,8 @@ impl<F: VfsFetcher> Service for ApiService<F> {
     }
 }
 
-impl<F: VfsFetcher> ApiService<F> {
-    pub fn new(serve_session: Arc<ServeSession<F>>) -> Self {
+impl ApiService {
+    pub fn new(serve_session: Arc<ServeSession>) -> Self {
         ApiService { serve_session }
     }
 

src/web/mod.rs

@@ -13,16 +13,16 @@ use futures::{
 use hyper::{service::Service, Body, Request, Response, Server};
 use log::trace;
 
-use crate::{serve_session::ServeSession, vfs::VfsFetcher};
+use crate::serve_session::ServeSession;
 
 use self::{api::ApiService, ui::UiService};
 
-pub struct RootService<F> {
-    api: ApiService<F>,
-    ui: UiService<F>,
+pub struct RootService {
+    api: ApiService,
+    ui: UiService,
 }
 
-impl<F: VfsFetcher> Service for RootService<F> {
+impl Service for RootService {
     type ReqBody = Body;
     type ResBody = Body;
     type Error = hyper::Error;
@@ -39,8 +39,8 @@ impl<F: VfsFetcher> Service for RootService<F> {
     }
 }
 
-impl<F: VfsFetcher> RootService<F> {
-    pub fn new(serve_session: Arc<ServeSession<F>>) -> Self {
+impl RootService {
+    pub fn new(serve_session: Arc<ServeSession>) -> Self {
         RootService {
             api: ApiService::new(Arc::clone(&serve_session)),
             ui: UiService::new(Arc::clone(&serve_session)),
@@ -48,12 +48,12 @@ impl<F: VfsFetcher> RootService<F> {
     }
 }
 
-pub struct LiveServer<F> {
-    serve_session: Arc<ServeSession<F>>,
+pub struct LiveServer {
+    serve_session: Arc<ServeSession>,
 }
 
-impl<F: VfsFetcher + Send + Sync + 'static> LiveServer<F> {
-    pub fn new(serve_session: Arc<ServeSession<F>>) -> Self {
+impl LiveServer {
+    pub fn new(serve_session: Arc<ServeSession>) -> Self {
         LiveServer { serve_session }
     }
 

src/web/ui.rs

@@ -1,6 +1,6 @@
 //! Defines the HTTP-based UI. These endpoints generally return HTML and SVG.
 
-use std::{borrow::Cow, path::Path, sync::Arc, time::Duration};
+use std::{borrow::Cow, sync::Arc, time::Duration};
 
 use futures::{future, Future};
 use hyper::{header, service::Service, Body, Method, Request, Response, StatusCode};
@@ -11,7 +11,6 @@ use ritz::{html, Fragment, HtmlContent, HtmlSelfClosingTag};
 use crate::{
     serve_session::ServeSession,
     snapshot::RojoTree,
-    vfs::{Vfs, VfsDebug, VfsFetcher},
     web::{
         assets,
         interface::{ErrorResponse, SERVER_VERSION},
@@ -19,11 +18,11 @@ use crate::{
     },
 };
 
-pub struct UiService<F> {
-    serve_session: Arc<ServeSession<F>>,
+pub struct UiService {
+    serve_session: Arc<ServeSession>,
 }
 
-impl<F: VfsFetcher> Service for UiService<F> {
+impl Service for UiService {
     type ReqBody = Body;
     type ResBody = Body;
     type Error = hyper::Error;
@@ -35,7 +34,6 @@ impl<F: VfsFetcher> Service for UiService<F> {
             (&Method::GET, "/logo.png") => self.handle_logo(),
             (&Method::GET, "/icon.png") => self.handle_icon(),
             (&Method::GET, "/show-instances") => self.handle_show_instances(),
-            (&Method::GET, "/show-vfs") => self.handle_show_vfs(),
             (_method, path) => {
                 return json(
                     ErrorResponse::not_found(format!("Route not found: {}", path)),
@@ -48,8 +46,8 @@ impl<F: VfsFetcher> Service for UiService<F> {
     }
 }
 
-impl<F: VfsFetcher> UiService<F> {
-    pub fn new(serve_session: Arc<ServeSession<F>>) -> Self {
+impl UiService {
+    pub fn new(serve_session: Arc<ServeSession>) -> Self {
         UiService { serve_session }
     }
 
@@ -71,7 +69,6 @@ impl<F: VfsFetcher> UiService<F> {
         let page = self.normal_page(html! {
             <div class="button-list">
                 { Self::button("Rojo Documentation", "https://rojo.space/docs") }
-                { Self::button("View virtual filesystem state", "/show-vfs") }
                 { Self::button("View instance tree state", "/show-instances") }
             </div>
         });
@@ -96,100 +93,6 @@ impl<F: VfsFetcher> UiService<F> {
             .unwrap()
     }
 
-    fn handle_show_vfs(&self) -> Response<Body> {
-        let vfs = self.serve_session.vfs();
-
-        let orphans: Vec<_> = vfs
-            .debug_orphans()
-            .into_iter()
-            .map(|path| Self::render_vfs_path(&vfs, &path, true))
-            .collect();
-
-        let watched_list: Vec<_> = vfs
-            .debug_watched_paths()
-            .into_iter()
-            .map(|path| {
-                html! {
-                    <li>{ format!("{}", path.display()) }</li>
-                }
-            })
-            .collect();
-
-        let page = self.normal_page(html! {
-            <>
-                <section class="main-section">
-                    <h1 class="section-title">"Known FS Items"</h1>
-                    <div>{ Fragment::new(orphans) }</div>
-                </section>
-
-                <section class="main-section">
-                    <h1 class="section-title">"Watched Paths"</h1>
-                    <ul class="path-list">{ Fragment::new(watched_list) }</ul>
-                </section>
-            </>
-        });
-
-        Response::builder()
-            .header(header::CONTENT_TYPE, "text/html")
-            .body(Body::from(format!("<!DOCTYPE html>{}", page)))
-            .unwrap()
-    }
-
-    fn render_vfs_path(vfs: &Vfs<F>, path: &Path, is_root: bool) -> HtmlContent<'static> {
-        let is_file = vfs.debug_is_file(path);
-
-        let (note, children) = if is_file {
-            (HtmlContent::None, Vec::new())
-        } else {
-            let (is_exhaustive, mut children) = vfs.debug_children(path).unwrap();
-
-            // Sort files above directories, then sort how Path does after that.
-            children.sort_unstable_by(|a, b| {
-                let a_is_file = vfs.debug_is_file(a);
-                let b_is_file = vfs.debug_is_file(b);
-
-                b_is_file.cmp(&a_is_file).then_with(|| a.cmp(b))
-            });
-
-            let children: Vec<_> = children
-                .into_iter()
-                .map(|child| Self::render_vfs_path(vfs, &child, false))
-                .collect();
-
-            let note = if is_exhaustive {
-                HtmlContent::None
-            } else {
-                html!({ " (not enumerated)" })
-            };
-
-            (note, children)
-        };
-
-        // For root entries, we want the full path to contextualize the path.
-        let mut name = if is_root {
-            path.to_str().unwrap().to_owned()
-        } else {
-            path.file_name().unwrap().to_str().unwrap().to_owned()
-        };
-
-        // Directories should end with `/` in the UI to mark them.
-        if !is_file && !name.ends_with('/') && !name.ends_with('\\') {
-            name.push('/');
-        }
-
-        html! {
-            <div class="vfs-entry">
-                <div>
-                    <span class="vfs-entry-name">{ name }</span>
-                    <span class="vfs-entry-note">{ note }</span>
-                </div>
-                <div class="vfs-entry-children">
-                    { Fragment::new(children) }
-                </div>
-            </div>
-        }
-    }
-
     fn instance(tree: &RojoTree, id: RbxId) -> HtmlContent<'_> {
         let instance = tree.get_instance(id).unwrap();
         let children_list: Vec<_> = instance

vfs/README.md

@@ -1,5 +0,0 @@
-# [vfs]
-Name pending. Implementation of a virtual filesystem with a configurable backend and file watching.
-
-## License
-[vfs] is available under the terms of the MIT license. See [LICENSE.txt](LICENSE.txt) or <https://opensource.org/licenses/MIT> for more details.