SmallString implementation

2022-05-27 02:54:33 -04:00
24 changed files with 208 additions and 318 deletions
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -690,19 +690,6 @@ dependencies = [
 "slab",
 ]
 [[package]]
 name = "generator"
 version = "0.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c1d9279ca822891c1a4dae06d185612cf8fc6acfe5dff37781b41297811b12ee"
 dependencies = [
 "cc",
 "libc",
 "log",
 "rustversion",
 "winapi 0.3.9",
 ]
 [[package]]
 name = "generic-array"
 version = "0.12.4"
@@ -1042,19 +1029,6 @@ dependencies = [
 "cfg-if 1.0.0",
 ]
 [[package]]
 name = "loom"
 version = "0.5.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ff50ecb28bb86013e935fb6683ab1f6d3a20016f123c76fd4c27470076ac30f5"
 dependencies = [
 "cfg-if 1.0.0",
 "generator",
 "scoped-tls",
 "tracing",
 "tracing-subscriber",
 ]
 [[package]]
 name = "lz4"
 version = "1.23.3"
@@ -1081,15 +1055,6 @@ version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3e2e65a1a2e43cfcb47a895c4c8b10d1f4a61097f9f254f183aee60cad9c651d"
 [[package]]
 name = "matchers"
 version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8263075bb86c5a1b1427b5ae862e8889656f126e9f77c484496e8b47cf5c5558"
 dependencies = [
 "regex-automata",
 ]
 [[package]]
 name = "matches"
 version = "0.1.9"
@@ -1534,7 +1499,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2f61dcf0b917cd75d4521d7343d1ffff3d1583054133c9b5cbea3375c703c40d"
 dependencies = [
 "profiling-procmacros",
- "tracy-client",
+ "superluminal-perf",
 ]
 [[package]]
@@ -1633,11 +1598,11 @@ dependencies = [
 [[package]]
 name = "rbx_binary"
 version = "0.6.4"
-source = "git+https://github.com/rojo-rbx/rbx-dom#4fa99b4190009f417ce63c86b2c6725e32c0090e"
+source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "68f424adb7a0a24ab4bd153be141035f1404ae40affed902fd2721b42cca7f86"
 dependencies = [
 "log",
 "lz4",
 "profiling",
 "rbx_dom_weak",
 "rbx_reflection",
 "rbx_reflection_database",
@@ -1647,7 +1612,8 @@ dependencies = [
 [[package]]
 name = "rbx_dom_weak"
 version = "2.3.0"
-source = "git+https://github.com/rojo-rbx/rbx-dom#4fa99b4190009f417ce63c86b2c6725e32c0090e"
+source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6f7f524fb18f30d7065c82c4e87f747705679329810207e96169c6d4ec922d1f"
 dependencies = [
 "rbx_types",
 "serde",
@@ -1656,7 +1622,8 @@ dependencies = [
 [[package]]
 name = "rbx_reflection"
 version = "4.2.0"
-source = "git+https://github.com/rojo-rbx/rbx-dom#4fa99b4190009f417ce63c86b2c6725e32c0090e"
+source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a8915748c8a3b2a92540e4e35e99ebd548df2d62b0a6cf38ae5d0081f0e611d5"
 dependencies = [
 "rbx_types",
 "serde",
@@ -1665,7 +1632,8 @@ dependencies = [
 [[package]]
 name = "rbx_reflection_database"
 version = "0.2.4+roblox-504"
-source = "git+https://github.com/rojo-rbx/rbx-dom#4fa99b4190009f417ce63c86b2c6725e32c0090e"
+source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b41e8da85aa697cd04cef48e6dd7d96992786d2e322bafe1d3cc93045f4de1e1"
 dependencies = [
 "lazy_static",
 "rbx_reflection",
@@ -1676,7 +1644,8 @@ dependencies = [
 [[package]]
 name = "rbx_types"
 version = "1.3.0"
-source = "git+https://github.com/rojo-rbx/rbx-dom#4fa99b4190009f417ce63c86b2c6725e32c0090e"
+source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d637383aa560cb675b7ea7a7778b945dab065ccc7c158f77b5455e27efadc6df"
 dependencies = [
 "base64 0.11.0",
 "bitflags",
@@ -1690,7 +1659,8 @@ dependencies = [
 [[package]]
 name = "rbx_xml"
 version = "0.12.3"
-source = "git+https://github.com/rojo-rbx/rbx-dom#4fa99b4190009f417ce63c86b2c6725e32c0090e"
+source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "67387cd246cdec9251dd2451672541499ae6ce0a47c768b3ea9ee0a1becda9dd"
 dependencies = [
 "base64 0.11.0",
 "log",
@@ -1736,9 +1706,6 @@ name = "regex-automata"
 version = "0.1.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6c230d73fb8d8c1b9c0b3135c5142a8acee3a0558fb8db5cf1cb65f8d7862132"
 dependencies = [
 "regex-syntax",
 ]
 [[package]]
 name = "regex-syntax"
@@ -1849,7 +1816,15 @@ dependencies = [
 ]
 [[package]]
-name = "rojo"
+name = "rojo-insta-ext"
 version = "0.1.0"
 dependencies = [
 "serde",
 "serde_yaml",
 ]
 [[package]]
 name = "rojo-smallstring"
 version = "7.1.1"
 dependencies = [
 "anyhow",
@@ -1888,24 +1863,16 @@ dependencies = [
 "serde",
 "serde_json",
 "serde_yaml",
 "smol_str",
 "tempfile",
 "termcolor",
 "thiserror",
 "tokio",
 "tracy-client",
 "uuid",
 "walkdir",
 "winreg 0.10.1",
 ]
 [[package]]
 name = "rojo-insta-ext"
 version = "0.1.0"
 dependencies = [
 "serde",
 "serde_yaml",
 ]
 [[package]]
 name = "rustc-demangle"
 version = "0.1.21"
@@ -1921,12 +1888,6 @@ dependencies = [
 "semver",
 ]
 [[package]]
 name = "rustversion"
 version = "1.0.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f2cc38e8fa666e2de3c4aba7edeb5ffc5246c1c2ed0e3d17e560aeeba736b23f"
 [[package]]
 name = "ryu"
 version = "1.0.10"
@@ -1952,12 +1913,6 @@ dependencies = [
 "windows-sys",
 ]
 [[package]]
 name = "scoped-tls"
 version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ea6a9290e3c9cf0f18145ef7ffa62d68ee0bf5fcd651017e586dc7fd5da448c2"
 [[package]]
 name = "scopeguard"
 version = "1.1.0"
@@ -2070,15 +2025,6 @@ dependencies = [
 "opaque-debug",
 ]
 [[package]]
 name = "sharded-slab"
 version = "0.1.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "900fba806f70c630b0a382d0d825e17a0f19fcd059a2ade1ff237bcddf446b31"
 dependencies = [
 "lazy_static",
 ]
 [[package]]
 name = "similar"
 version = "2.1.0"
@@ -2092,10 +2038,13 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "eb703cfe953bccee95685111adeedb76fabe4e97549a58d16f03ea7b9367bb32"
 [[package]]
-name = "smallvec"
+name = "smol_str"
-version = "1.8.0"
+version = "0.1.23"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f2dd574626839106c320a323308629dcb1acfc96e32a8cba364ddc61ac23ee83"
+checksum = "7475118a28b7e3a2e157ce0131ba8c5526ea96e90ee601d9f6bb2e286a35ab44"
 dependencies = [
 "serde",
 ]
 [[package]]
 name = "snax"
@@ -2128,6 +2077,21 @@ version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2d67a5a62ba6e01cb2192ff309324cb4875d0c451d55fe2319433abe7a05a8ee"
 [[package]]
 name = "superluminal-perf"
 version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "80ed8ddf5d2a4a849fa7dc75b3e0be740adb882fe7fee87e79584402ac9b1e60"
 dependencies = [
 "superluminal-perf-sys",
 ]
 [[package]]
 name = "superluminal-perf-sys"
 version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0342a02bcc62538822a46f54294130677f026666c2e19d078fc213b7bc07ff16"
 [[package]]
 name = "syn"
 version = "1.0.95"
@@ -2207,15 +2171,6 @@ dependencies = [
 "syn",
 ]
 [[package]]
 name = "thread_local"
 version = "1.1.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5516c27b78311c50bf42c071425c560ac799b11c30b31f87e3081965fe5e0180"
 dependencies = [
 "once_cell",
 ]
 [[package]]
 name = "tinytemplate"
 version = "1.2.1"
@@ -2327,56 +2282,6 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f54c8ca710e81886d498c2fd3331b56c93aa248d49de2222ad2742247c60072f"
 dependencies = [
 "lazy_static",
 "valuable",
 ]
 [[package]]
 name = "tracing-log"
 version = "0.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "78ddad33d2d10b1ed7eb9d1f518a5674713876e97e5bb9b7345a7984fbb4f922"
 dependencies = [
 "lazy_static",
 "log",
 "tracing-core",
 ]
 [[package]]
 name = "tracing-subscriber"
 version = "0.3.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4bc28f93baff38037f64e6f43d34cfa1605f27a49c34e8a04c5e78b0babf2596"
 dependencies = [
 "ansi_term",
 "lazy_static",
 "matchers",
 "regex",
 "sharded-slab",
 "smallvec",
 "thread_local",
 "tracing",
 "tracing-core",
 "tracing-log",
 ]
 [[package]]
 name = "tracy-client"
 version = "0.13.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "42ebfe7a24c18b5ba86d8920c124b41b942352f863fbe0c84d3d63428fa1860f"
 dependencies = [
 "loom",
 "once_cell",
 "tracy-client-sys",
 ]
 [[package]]
 name = "tracy-client-sys"
 version = "0.17.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9012b9dfeccaff16e93f5a8b02336125113a80a769902e679d334cbdd4d83f3b"
 dependencies = [
 "cc",
 ]
 [[package]]
@@ -2452,12 +2357,6 @@ dependencies = [
 "serde",
 ]
 [[package]]
 name = "valuable"
 version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "830b7e5d4d90034032940e4ace0d9a9a057e7a45cd94e6c007832e39edb82f6d"
 [[package]]
 name = "vcpkg"
 version = "0.2.15"
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,5 +1,5 @@
 [package]
-name = "rojo"
+name = "rojo-smallstring"
 version = "7.1.1"
 authors = ["Lucien Greathouse <me@lpghatguy.com>"]
 description = "Enables professional-grade development tools for Roblox developers"
@@ -27,8 +27,6 @@ default = []
 # Enable this feature to live-reload assets from the web UI.
 dev_live_assets = []
 profile-with-tracy = ["profiling/profile-with-tracy", "tracy-client"]
 [workspace]
 members = ["crates/*"]
@@ -50,17 +48,11 @@ memofs = { version = "0.2.0", path = "crates/memofs" }
 # rbx_reflection_database = { path = "../rbx-dom/rbx_reflection_database" }
 # rbx_xml = { path = "../rbx-dom/rbx_xml" }
-rbx_binary = { git = "https://github.com/rojo-rbx/rbx-dom" }
+rbx_binary = "0.6.4"
-rbx_dom_weak = { git = "https://github.com/rojo-rbx/rbx-dom" }
+rbx_dom_weak = "2.3.0"
-rbx_reflection = { git = "https://github.com/rojo-rbx/rbx-dom" }
+rbx_reflection = "4.2.0"
-rbx_reflection_database = { git = "https://github.com/rojo-rbx/rbx-dom" }
+rbx_reflection_database = "0.2.2"
-rbx_xml = { git = "https://github.com/rojo-rbx/rbx-dom" }
+rbx_xml = "0.12.3"
 # rbx_binary = "0.6.4"
 # rbx_dom_weak = "2.3.0"
 # rbx_reflection = "4.2.0"
 # rbx_reflection_database = "0.2.2"
 # rbx_xml = "0.12.3"
 anyhow = "1.0.44"
 backtrace = "0.3.61"
@@ -88,8 +80,8 @@ thiserror = "1.0.30"
 tokio = { version = "1.12.0", features = ["rt", "rt-multi-thread"] }
 uuid = { version = "1.0.0", features = ["v4", "serde"] }
 clap = { version = "3.1.18", features = ["derive"] }
-profiling = "1.0.6"
+smol_str = "0.1.23"
-tracy-client = { version = "0.13.2", optional = true }
+profiling = { version = "1.0.6", features = ["profile-with-superluminal"] }
 [target.'cfg(windows)'.dependencies]
 winreg = "0.10.1"
--- a/src/change_processor.rs
+++ b/src/change_processor.rs
@@ -46,6 +46,7 @@ pub struct ChangeProcessor {
 impl ChangeProcessor {
    /// Spin up the ChangeProcessor, connecting it to the given tree, VFS, and
    /// outbound message queue.
    #[profiling::function]
    pub fn start(
        tree: Arc<Mutex<RojoTree>>,
        vfs: Arc<Vfs>,
@@ -291,7 +292,7 @@ fn compute_and_apply_changes(tree: &mut RojoTree, vfs: &Vfs, id: Ref) -> Option<
                    }
                };
-                let patch_set = compute_patch_set(snapshot, &tree, id);
+                let patch_set = compute_patch_set(snapshot.as_ref(), &tree, id);
                apply_patch_set(tree, patch_set)
            }
            Ok(None) => {
@@ -334,7 +335,7 @@ fn compute_and_apply_changes(tree: &mut RojoTree, vfs: &Vfs, id: Ref) -> Option<
                }
            };
-            let patch_set = compute_patch_set(snapshot, &tree, id);
+            let patch_set = compute_patch_set(snapshot.as_ref(), &tree, id);
            apply_patch_set(tree, patch_set)
        }
    };
--- a/src/cli/build.rs
+++ b/src/cli/build.rs
@@ -1,6 +1,5 @@
 use std::{
    io::{BufWriter, Write},
    mem::ManuallyDrop,
    path::{Path, PathBuf},
 };
@@ -62,14 +61,6 @@ impl BuildCommand {
            }
        }
        // Never drop ServeSession, because it's VERY expensive to drop and
        // we're about to exit anyways.
        //
        // This is kind of evil; if this function is ever called outside of the
        // context of a CLI, this will leak a large object forever. However, the
        // performance benefits of leaking it outweigh the cost at this time.
        let _session = ManuallyDrop::new(session);
        Ok(())
    }
 }
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -18,6 +18,7 @@ mod project;
 mod resolution;
 mod serve_session;
 mod session_id;
 mod small_string;
 mod snapshot;
 mod snapshot_middleware;
 mod web;
--- a/src/main.rs
+++ b/src/main.rs
@@ -6,8 +6,7 @@ use clap::Parser;
 use librojo::cli::Options;
 fn main() {
-    #[cfg(feature = "profile-with-tracy")]
+    profiling::register_thread!("Main Thread");
    tracy_client::Client::start();
    panic::set_hook(Box::new(|panic_info| {
        // PanicInfo's payload is usually a &'static str or String.
--- a/src/serve_session.rs
+++ b/src/serve_session.rs
@@ -96,6 +96,7 @@ impl ServeSession {
    /// 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.
    #[profiling::function]
    pub fn new<P: AsRef<Path>>(vfs: Vfs, start_path: P) -> Result<Self, ServeSessionError> {
        let start_path = start_path.as_ref();
        let start_time = Instant::now();
@@ -130,7 +131,7 @@ impl ServeSession {
        let snapshot = snapshot_from_vfs(&instance_context, &vfs, &start_path)?;
        log::trace!("Computing initial patch set");
-        let patch_set = compute_patch_set(snapshot, &tree, root_id);
+        let patch_set = compute_patch_set(snapshot.as_ref(), &tree, root_id);
        log::trace!("Applying initial patch set");
        apply_patch_set(&mut tree, patch_set);
--- a/src/small_string.rs
+++ b/src/small_string.rs
@@ -0,0 +1 @@
 pub use smol_str::SmolStr as SmallString;
--- a/src/snapshot/instance_snapshot.rs
+++ b/src/snapshot/instance_snapshot.rs
@@ -1,13 +1,15 @@
 //! Defines the structure of an instance snapshot.
-use std::{borrow::Cow, collections::HashMap};
+use std::collections::HashMap;
 use rbx_dom_weak::{
    types::{Ref, Variant},
-    Instance, WeakDom,
+    WeakDom,
 };
 use serde::{Deserialize, Serialize};
 use crate::small_string::SmallString;
 use super::InstanceMetadata;
 /// A lightweight description of what an instance should look like.
@@ -25,13 +27,13 @@ pub struct InstanceSnapshot {
    pub metadata: InstanceMetadata,
    /// Correpsonds to the Name property of the instance.
-    pub name: Cow<'static, str>,
+    pub name: SmallString,
    /// Corresponds to the ClassName property of the instance.
-    pub class_name: Cow<'static, str>,
+    pub class_name: SmallString,
    /// All other properties of the instance, weakly-typed.
-    pub properties: HashMap<String, Variant>,
+    pub properties: HashMap<SmallString, Variant>,
    /// The children of the instance represented as more snapshots.
    ///
@@ -44,37 +46,37 @@ impl InstanceSnapshot {
        Self {
            snapshot_id: None,
            metadata: InstanceMetadata::default(),
-            name: Cow::Borrowed("DEFAULT"),
+            name: "DEFAULT".into(),
-            class_name: Cow::Borrowed("DEFAULT"),
+            class_name: "DEFAULT".into(),
            properties: HashMap::new(),
            children: Vec::new(),
        }
    }
-    pub fn name(self, name: impl Into<String>) -> Self {
+    pub fn name(self, name: impl Into<SmallString>) -> Self {
        Self {
-            name: Cow::Owned(name.into()),
+            name: name.into(),
            ..self
        }
    }
-    pub fn class_name(self, class_name: impl Into<String>) -> Self {
+    pub fn class_name(self, class_name: impl Into<SmallString>) -> Self {
        Self {
-            class_name: Cow::Owned(class_name.into()),
+            class_name: class_name.into(),
            ..self
        }
    }
    pub fn property<K, V>(mut self, key: K, value: V) -> Self
    where
-        K: Into<String>,
+        K: Into<SmallString>,
        V: Into<Variant>,
    {
        self.properties.insert(key.into(), value.into());
        self
    }
-    pub fn properties(self, properties: impl Into<HashMap<String, Variant>>) -> Self {
+    pub fn properties(self, properties: impl Into<HashMap<SmallString, Variant>>) -> Self {
        Self {
            properties: properties.into(),
            ..self
@@ -102,29 +104,28 @@ impl InstanceSnapshot {
        }
    }
-    #[profiling::function]
+    pub fn from_tree(tree: &WeakDom, id: Ref) -> Self {
-    pub fn from_tree(tree: WeakDom, id: Ref) -> Self {
+        let instance = tree.get_by_ref(id).expect("instance did not exist in tree");
        let (_, mut raw_tree) = tree.into_raw();
        Self::from_raw_tree(&mut raw_tree, id)
    }
    fn from_raw_tree(raw_tree: &mut HashMap<Ref, Instance>, id: Ref) -> Self {
        let instance = raw_tree
            .remove(&id)
            .expect("instance did not exist in tree");
        let children = instance
            .children()
            .iter()
-            .map(|&id| Self::from_raw_tree(raw_tree, id))
+            .copied()
            .map(|id| Self::from_tree(tree, id))
            .collect();
        let properties = instance
            .properties
            .iter()
            .map(|(key, value)| (key.into(), value.clone()))
            .collect();
        Self {
            snapshot_id: Some(id),
            metadata: InstanceMetadata::default(),
-            name: Cow::Owned(instance.name),
+            name: SmallString::from(&instance.name),
-            class_name: Cow::Owned(instance.class),
+            class_name: SmallString::from(&instance.class),
-            properties: instance.properties,
+            properties,
            children,
        }
    }
--- a/src/snapshot/patch.rs
+++ b/src/snapshot/patch.rs
@@ -5,6 +5,8 @@ use std::collections::HashMap;
 use rbx_dom_weak::types::{Ref, Variant};
 use serde::{Deserialize, Serialize};
 use crate::small_string::SmallString;
 use super::{InstanceMetadata, InstanceSnapshot};
 /// A set of different kinds of patches that can be applied to an WeakDom.
@@ -40,12 +42,12 @@ pub struct PatchAdd {
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 pub struct PatchUpdate {
    pub id: Ref,
-    pub changed_name: Option<String>,
+    pub changed_name: Option<SmallString>,
-    pub changed_class_name: Option<String>,
+    pub changed_class_name: Option<SmallString>,
    /// Contains all changed properties. If a property is assigned to `None`,
    /// then that property has been removed.
-    pub changed_properties: HashMap<String, Option<Variant>>,
+    pub changed_properties: HashMap<SmallString, Option<Variant>>,
    /// Changed Rojo-specific metadata, if any of it changed.
    pub changed_metadata: Option<InstanceMetadata>,
@@ -83,9 +85,9 @@ pub struct AppliedPatchUpdate {
    pub id: Ref,
    // TODO: Store previous values in order to detect application conflicts
-    pub changed_name: Option<String>,
+    pub changed_name: Option<SmallString>,
-    pub changed_class_name: Option<String>,
+    pub changed_class_name: Option<SmallString>,
-    pub changed_properties: HashMap<String, Option<Variant>>,
+    pub changed_properties: HashMap<SmallString, Option<Variant>>,
    pub changed_metadata: Option<InstanceMetadata>,
 }
--- a/src/snapshot/patch_apply.rs
+++ b/src/snapshot/patch_apply.rs
@@ -1,12 +1,11 @@
 //! Defines the algorithm for applying generated patches.
-use std::{
+use std::collections::HashMap;
    collections::{HashMap, HashSet},
    mem::take,
 };
 use rbx_dom_weak::types::{Ref, Variant};
 use crate::small_string::SmallString;
 use super::{
    patch::{AppliedPatchSet, AppliedPatchUpdate, PatchSet, PatchUpdate},
    InstanceSnapshot, RojoTree,
@@ -19,27 +18,18 @@ use super::{
 pub fn apply_patch_set(tree: &mut RojoTree, patch_set: PatchSet) -> AppliedPatchSet {
    let mut context = PatchApplyContext::default();
-    {
+    for removed_id in patch_set.removed_instances {
-        profiling::scope!("removals");
+        apply_remove_instance(&mut context, tree, removed_id);
        for removed_id in patch_set.removed_instances {
            apply_remove_instance(&mut context, tree, removed_id);
        }
    }
-    {
+    for add_patch in patch_set.added_instances {
-        profiling::scope!("additions");
+        apply_add_child(&mut context, tree, add_patch.parent_id, add_patch.instance);
        for add_patch in patch_set.added_instances {
            apply_add_child(&mut context, tree, add_patch.parent_id, add_patch.instance);
        }
    }
-    {
+    // Updates need to be applied after additions, which reduces the complexity
-        profiling::scope!("updates");
+    // of updates significantly.
-        // Updates need to be applied after additions, which reduces the complexity
+    for update_patch in patch_set.updated_instances {
-        // of updates significantly.
+        apply_update_child(&mut context, tree, update_patch);
        for update_patch in patch_set.updated_instances {
            apply_update_child(&mut context, tree, update_patch);
        }
    }
    finalize_patch_application(context, tree)
@@ -68,9 +58,20 @@ struct PatchApplyContext {
    /// eachother.
    snapshot_id_to_instance_id: HashMap<Ref, Ref>,
-    /// Tracks all of the instances added by this patch that have refs that need
+    /// The properties of instances added by the current `PatchSet`.
-    /// to be rewritten.
+    ///
-    has_refs_to_rewrite: HashSet<Ref>,
+    /// Instances added to the tree can refer to eachother via Ref properties,
    /// but we need to make sure they're correctly transformed from snapshot
    /// space into tree space (via `snapshot_id_to_instance_id`).
    ///
    /// It's not possible to do that transformation for refs that refer to added
    /// instances until all the instances have actually been inserted into the
    /// tree. For simplicity, we defer application of _all_ properties on added
    /// instances instead of just Refs.
    ///
    /// This doesn't affect updated instances, since they're always applied
    /// after we've added all the instances from the patch.
    added_instance_properties: HashMap<Ref, HashMap<SmallString, Variant>>,
    /// The current applied patch result, describing changes made to the tree.
    applied_patch_set: AppliedPatchSet,
@@ -86,22 +87,25 @@ struct PatchApplyContext {
 /// The remaining Ref properties need to be handled during patch application,
 /// where we build up a map of snapshot IDs to instance IDs as they're created,
 /// then apply properties all at once at the end.
 #[profiling::function]
 fn finalize_patch_application(context: PatchApplyContext, tree: &mut RojoTree) -> AppliedPatchSet {
-    for id in context.has_refs_to_rewrite {
+    for (id, properties) in context.added_instance_properties {
        // This should always succeed since instances marked as added in our
        // patch should be added without fail.
        let mut instance = tree
            .get_instance_mut(id)
            .expect("Invalid instance ID in deferred property map");
-        for value in instance.properties_mut().values_mut() {
+        for (key, mut property_value) in properties {
-            if let Variant::Ref(referent) = value {
+            if let Variant::Ref(referent) = property_value {
                if let Some(&instance_referent) = context.snapshot_id_to_instance_id.get(&referent)
                {
-                    *value = Variant::Ref(instance_referent);
+                    property_value = Variant::Ref(instance_referent);
                }
            }
            instance
                .properties_mut()
                .insert(key.to_string(), property_value);
        }
    }
@@ -117,24 +121,24 @@ fn apply_add_child(
    context: &mut PatchApplyContext,
    tree: &mut RojoTree,
    parent_id: Ref,
-    mut snapshot: InstanceSnapshot,
+    snapshot: InstanceSnapshot,
 ) {
    let snapshot_id = snapshot.snapshot_id;
-    let children = take(&mut snapshot.children);
+    let properties = snapshot.properties;
    let children = snapshot.children;
-    // If an object we're adding has a non-null referent, we'll note this
+    // Property application is deferred until after all children
-    // instance down as needing to be revisited later.
+    // are constructed. This helps apply referents correctly.
-    let has_refs = snapshot.properties.values().any(|value| match value {
+    let remaining_snapshot = InstanceSnapshot::new()
-        Variant::Ref(value) => value.is_some(),
+        .name(snapshot.name)
-        _ => false,
+        .class_name(snapshot.class_name)
-    });
+        .metadata(snapshot.metadata)
        .snapshot_id(snapshot.snapshot_id);
-    let id = tree.insert_instance(parent_id, snapshot);
+    let id = tree.insert_instance(parent_id, remaining_snapshot);
    context.applied_patch_set.added.push(id);
-    if has_refs {
+    context.added_instance_properties.insert(id, properties);
        context.has_refs_to_rewrite.insert(id);
    }
    if let Some(snapshot_id) = snapshot_id {
        context.snapshot_id_to_instance_id.insert(snapshot_id, id);
@@ -165,13 +169,13 @@ fn apply_update_child(context: &mut PatchApplyContext, tree: &mut RojoTree, patc
    };
    if let Some(name) = patch.changed_name {
-        *instance.name_mut() = name.clone();
+        *instance.name_mut() = name.to_string();
-        applied_patch.changed_name = Some(name);
+        applied_patch.changed_name = Some(name.into());
    }
    if let Some(class_name) = patch.changed_class_name {
-        *instance.class_name_mut() = class_name.clone();
+        *instance.class_name_mut() = class_name.to_string();
-        applied_patch.changed_class_name = Some(class_name);
+        applied_patch.changed_class_name = Some(class_name.into());
    }
    for (key, property_entry) in patch.changed_properties {
@@ -196,13 +200,15 @@ fn apply_update_child(context: &mut PatchApplyContext, tree: &mut RojoTree, patc
                instance
                    .properties_mut()
-                    .insert(key.clone(), Variant::Ref(new_referent));
+                    .insert(key.to_string(), Variant::Ref(new_referent));
            }
            Some(ref value) => {
-                instance.properties_mut().insert(key.clone(), value.clone());
+                instance
                    .properties_mut()
                    .insert(key.to_string(), value.clone());
            }
            None => {
-                instance.properties_mut().remove(&key);
+                instance.properties_mut().remove(key.as_str());
            }
        }
--- a/src/snapshot/patch_compute.rs
+++ b/src/snapshot/patch_compute.rs
@@ -1,10 +1,7 @@
 //! Defines the algorithm for computing a roughly-minimal patch set given an
 //! existing instance tree and an instance snapshot.
-use std::{
+use std::collections::{HashMap, HashSet};
    collections::{HashMap, HashSet},
    mem::take,
 };
 use rbx_dom_weak::types::{Ref, Variant};
@@ -14,7 +11,11 @@ use super::{
 };
 #[profiling::function]
-pub fn compute_patch_set(snapshot: Option<InstanceSnapshot>, tree: &RojoTree, id: Ref) -> PatchSet {
+pub fn compute_patch_set(
    snapshot: Option<&InstanceSnapshot>,
    tree: &RojoTree,
    id: Ref,
 ) -> PatchSet {
    let mut patch_set = PatchSet::new();
    if let Some(snapshot) = snapshot {
@@ -74,7 +75,7 @@ fn rewrite_refs_in_snapshot(context: &ComputePatchContext, snapshot: &mut Instan
 fn compute_patch_set_internal(
    context: &mut ComputePatchContext,
-    mut snapshot: InstanceSnapshot,
+    snapshot: &InstanceSnapshot,
    tree: &RojoTree,
    id: Ref,
    patch_set: &mut PatchSet,
@@ -87,12 +88,12 @@ fn compute_patch_set_internal(
        .get_instance(id)
        .expect("Instance did not exist in tree");
-    compute_property_patches(&mut snapshot, &instance, patch_set);
+    compute_property_patches(snapshot, &instance, patch_set);
-    compute_children_patches(context, &mut snapshot, tree, id, patch_set);
+    compute_children_patches(context, snapshot, tree, id, patch_set);
 }
 fn compute_property_patches(
-    snapshot: &mut InstanceSnapshot,
+    snapshot: &InstanceSnapshot,
    instance: &InstanceWithMeta,
    patch_set: &mut PatchSet,
 ) {
@@ -102,32 +103,32 @@ fn compute_property_patches(
    let changed_name = if snapshot.name == instance.name() {
        None
    } else {
-        Some(take(&mut snapshot.name).into_owned())
+        Some(snapshot.name.clone())
    };
    let changed_class_name = if snapshot.class_name == instance.class_name() {
        None
    } else {
-        Some(take(&mut snapshot.class_name).into_owned())
+        Some(snapshot.class_name.clone())
    };
    let changed_metadata = if &snapshot.metadata == instance.metadata() {
        None
    } else {
-        Some(take(&mut snapshot.metadata))
+        Some(snapshot.metadata.clone())
    };
-    for (name, snapshot_value) in take(&mut snapshot.properties) {
+    for (name, snapshot_value) in &snapshot.properties {
-        visited_properties.insert(name.clone());
+        visited_properties.insert(name.as_str());
-        match instance.properties().get(&name) {
+        match instance.properties().get(name.as_str()) {
            Some(instance_value) => {
-                if &snapshot_value != instance_value {
+                if snapshot_value != instance_value {
-                    changed_properties.insert(name, Some(snapshot_value));
+                    changed_properties.insert(name.clone(), Some(snapshot_value.clone()));
                }
            }
            None => {
-                changed_properties.insert(name, Some(snapshot_value));
+                changed_properties.insert(name.clone(), Some(snapshot_value.clone()));
            }
        }
    }
@@ -137,7 +138,7 @@ fn compute_property_patches(
            continue;
        }
-        changed_properties.insert(name.clone(), None);
+        changed_properties.insert(name.into(), None);
    }
    if changed_properties.is_empty()
@@ -159,7 +160,7 @@ fn compute_property_patches(
 fn compute_children_patches(
    context: &mut ComputePatchContext,
-    snapshot: &mut InstanceSnapshot,
+    snapshot: &InstanceSnapshot,
    tree: &RojoTree,
    id: Ref,
    patch_set: &mut PatchSet,
@@ -172,7 +173,7 @@ fn compute_children_patches(
    let mut paired_instances = vec![false; instance_children.len()];
-    for snapshot_child in take(&mut snapshot.children) {
+    for snapshot_child in snapshot.children.iter() {
        let matching_instance =
            instance_children
                .iter()
@@ -209,7 +210,7 @@ fn compute_children_patches(
            None => {
                patch_set.added_instances.push(PatchAdd {
                    parent_id: id,
-                    instance: snapshot_child,
+                    instance: snapshot_child.clone(),
                });
            }
        }
@@ -257,7 +258,7 @@ mod test {
            children: Vec::new(),
        };
-        let patch_set = compute_patch_set(Some(snapshot), &tree, root_id);
+        let patch_set = compute_patch_set(Some(&snapshot), &tree, root_id);
        let expected_patch_set = PatchSet {
            updated_instances: vec![PatchUpdate {
@@ -307,7 +308,7 @@ mod test {
            class_name: Cow::Borrowed("foo"),
        };
-        let patch_set = compute_patch_set(Some(snapshot), &tree, root_id);
+        let patch_set = compute_patch_set(Some(&snapshot), &tree, root_id);
        let expected_patch_set = PatchSet {
            added_instances: vec![PatchAdd {
--- a/src/snapshot/tests/compute.rs
+++ b/src/snapshot/tests/compute.rs
@@ -23,7 +23,7 @@ fn set_name_and_class_name() {
        children: Vec::new(),
    };
-    let patch_set = compute_patch_set(Some(snapshot), &tree, tree.get_root_id());
+    let patch_set = compute_patch_set(Some(&snapshot), &tree, tree.get_root_id());
    let patch_value = redactions.redacted_yaml(patch_set);
    assert_yaml_snapshot!(patch_value);
@@ -47,7 +47,7 @@ fn set_property() {
        children: Vec::new(),
    };
-    let patch_set = compute_patch_set(Some(snapshot), &tree, tree.get_root_id());
+    let patch_set = compute_patch_set(Some(&snapshot), &tree, tree.get_root_id());
    let patch_value = redactions.redacted_yaml(patch_set);
    assert_yaml_snapshot!(patch_value);
@@ -78,7 +78,7 @@ fn remove_property() {
        children: Vec::new(),
    };
-    let patch_set = compute_patch_set(Some(snapshot), &tree, tree.get_root_id());
+    let patch_set = compute_patch_set(Some(&snapshot), &tree, tree.get_root_id());
    let patch_value = redactions.redacted_yaml(patch_set);
    assert_yaml_snapshot!(patch_value);
@@ -107,7 +107,7 @@ fn add_child() {
        }],
    };
-    let patch_set = compute_patch_set(Some(snapshot), &tree, tree.get_root_id());
+    let patch_set = compute_patch_set(Some(&snapshot), &tree, tree.get_root_id());
    let patch_value = redactions.redacted_yaml(patch_set);
    assert_yaml_snapshot!(patch_value);
@@ -139,7 +139,7 @@ fn remove_child() {
        children: Vec::new(),
    };
-    let patch_set = compute_patch_set(Some(snapshot), &tree, tree.get_root_id());
+    let patch_set = compute_patch_set(Some(&snapshot), &tree, tree.get_root_id());
    let patch_value = redactions.redacted_yaml(patch_set);
    assert_yaml_snapshot!(patch_value);
--- a/src/snapshot/tree.rs
+++ b/src/snapshot/tree.rs
@@ -87,9 +87,8 @@ impl RojoTree {
    }
    pub fn insert_instance(&mut self, parent_ref: Ref, snapshot: InstanceSnapshot) -> Ref {
-        let builder = InstanceBuilder::empty()
+        let builder = InstanceBuilder::new(snapshot.class_name.to_owned())
-            .with_class(snapshot.class_name.into_owned())
+            .with_name(snapshot.name.to_owned())
            .with_name(snapshot.name.into_owned())
            .with_properties(snapshot.properties);
        let referent = self.inner.insert(parent_ref, builder);
--- a/src/snapshot_middleware/csv.rs
+++ b/src/snapshot_middleware/csv.rs
@@ -30,7 +30,7 @@ pub fn snapshot_csv(
        .name(name)
        .class_name("LocalizationTable")
        .properties(hashmap! {
-            "Contents".to_owned() => table_contents.into(),
+            "Contents".into() => table_contents.into(),
        })
        .metadata(
            InstanceMetadata::new()
--- a/src/snapshot_middleware/json.rs
+++ b/src/snapshot_middleware/json.rs
@@ -25,7 +25,7 @@ pub fn snapshot_json(
    let as_lua = json_to_lua(value).to_string();
    let properties = hashmap! {
-        "Source".to_owned() => as_lua.into(),
+        "Source".into() => as_lua.into(),
    };
    let meta_path = path.with_file_name(format!("{}.meta.json", name));
--- a/src/snapshot_middleware/json_model.rs
+++ b/src/snapshot_middleware/json_model.rs
@@ -1,4 +1,4 @@
-use std::{borrow::Cow, collections::HashMap, path::Path, str};
+use std::{collections::HashMap, path::Path, str};
 use anyhow::Context;
 use memofs::Vfs;
@@ -85,14 +85,14 @@ impl JsonModelCore {
        let mut properties = HashMap::with_capacity(self.properties.len());
        for (key, unresolved) in self.properties {
            let value = unresolved.resolve(&class_name, &key)?;
-            properties.insert(key, value);
+            properties.insert(key.into(), value);
        }
        Ok(InstanceSnapshot {
            snapshot_id: None,
            metadata: Default::default(),
-            name: Cow::Owned(name),
+            name: name.into(),
-            class_name: Cow::Owned(class_name),
+            class_name: class_name.into(),
            properties,
            children,
        })
--- a/src/snapshot_middleware/lua.rs
+++ b/src/snapshot_middleware/lua.rs
@@ -38,7 +38,7 @@ pub fn snapshot_lua(
        .name(instance_name)
        .class_name(class_name)
        .properties(hashmap! {
-            "Source".to_owned() => contents_str.into(),
+            "Source".into() => contents_str.into(),
        })
        .metadata(
            InstanceMetadata::new()
--- a/src/snapshot_middleware/meta_file.rs
+++ b/src/snapshot_middleware/meta_file.rs
@@ -1,4 +1,4 @@
-use std::{borrow::Cow, collections::HashMap, path::PathBuf};
+use std::{collections::HashMap, path::PathBuf};
 use anyhow::{format_err, Context};
 use serde::{Deserialize, Serialize};
@@ -49,7 +49,7 @@ impl AdjacentMetadata {
                .resolve(&snapshot.class_name, &key)
                .with_context(|| format!("error applying meta file {}", path.display()))?;
-            snapshot.properties.insert(key, value);
+            snapshot.properties.insert(key.into(), value);
        }
        Ok(())
@@ -116,7 +116,7 @@ impl DirectoryMetadata {
                ));
            }
-            snapshot.class_name = Cow::Owned(class_name);
+            snapshot.class_name = class_name.into();
        }
        Ok(())
@@ -136,7 +136,7 @@ impl DirectoryMetadata {
                .resolve(&snapshot.class_name, &key)
                .with_context(|| format!("error applying meta file {}", path.display()))?;
-            snapshot.properties.insert(key, value);
+            snapshot.properties.insert(key.into(), value);
        }
        Ok(())
--- a/src/snapshot_middleware/project.rs
+++ b/src/snapshot_middleware/project.rs
@@ -6,6 +6,7 @@ use rbx_reflection::ClassTag;
 use crate::{
    project::{PathNode, Project, ProjectNode},
    small_string::SmallString,
    snapshot::{
        InstanceContext, InstanceMetadata, InstanceSnapshot, InstigatingSource, PathIgnoreRule,
    },
@@ -67,13 +68,10 @@ pub fn snapshot_project_node(
 ) -> anyhow::Result<Option<InstanceSnapshot>> {
    let project_folder = project_path.parent().unwrap();
-    let class_name_from_project = node
+    let class_name_from_project = node.class_name.as_ref().map(|name| SmallString::from(name));
        .class_name
        .as_ref()
        .map(|name| Cow::Owned(name.clone()));
    let mut class_name_from_path = None;
-    let name = Cow::Owned(instance_name.to_owned());
+    let name = SmallString::from(instance_name);
    let mut properties = HashMap::new();
    let mut children = Vec::new();
    let mut metadata = InstanceMetadata::default();
@@ -228,7 +226,7 @@ pub fn snapshot_project_node(
            _ => {}
        }
-        properties.insert(key.clone(), value);
+        properties.insert(key.into(), value);
    }
    // If the user specified $ignoreUnknownInstances, overwrite the existing
@@ -262,7 +260,7 @@ pub fn snapshot_project_node(
    }))
 }
-fn infer_class_name(name: &str, parent_class: Option<&str>) -> Option<Cow<'static, str>> {
+fn infer_class_name(name: &str, parent_class: Option<&str>) -> Option<SmallString> {
    // If className wasn't defined from another source, we may be able
    // to infer one.
@@ -275,13 +273,13 @@ fn infer_class_name(name: &str, parent_class: Option<&str>) -> Option<Cow<'stati
        let descriptor = rbx_reflection_database::get().classes.get(name)?;
        if descriptor.tags.contains(&ClassTag::Service) {
-            return Some(Cow::Owned(name.to_owned()));
+            return Some(name.into());
        }
    } else if parent_class == "StarterPlayer" {
        // StarterPlayer has two special members with their own classes.
        if name == "StarterPlayerScripts" || name == "StarterCharacterScripts" {
-            return Some(Cow::Owned(name.to_owned()));
+            return Some(name.into());
        }
    }
--- a/src/snapshot_middleware/rbxm.rs
+++ b/src/snapshot_middleware/rbxm.rs
@@ -7,7 +7,6 @@ use crate::snapshot::{InstanceContext, InstanceMetadata, InstanceSnapshot};
 use super::util::PathExt;
 #[profiling::function]
 pub fn snapshot_rbxm(
    context: &InstanceContext,
    vfs: &Vfs,
@@ -22,8 +21,7 @@ pub fn snapshot_rbxm(
    let children = root_instance.children();
    if children.len() == 1 {
-        let child = children[0];
+        let snapshot = InstanceSnapshot::from_tree(&temp_tree, children[0])
        let snapshot = InstanceSnapshot::from_tree(temp_tree, child)
            .name(name)
            .metadata(
                InstanceMetadata::new()
--- a/src/snapshot_middleware/rbxmx.rs
+++ b/src/snapshot_middleware/rbxmx.rs
@@ -24,8 +24,7 @@ pub fn snapshot_rbxmx(
    let children = root_instance.children();
    if children.len() == 1 {
-        let child = children[0];
+        let snapshot = InstanceSnapshot::from_tree(&temp_tree, children[0])
        let snapshot = InstanceSnapshot::from_tree(temp_tree, child)
            .name(name)
            .metadata(
                InstanceMetadata::new()
--- a/src/snapshot_middleware/txt.rs
+++ b/src/snapshot_middleware/txt.rs
@@ -21,7 +21,7 @@ pub fn snapshot_txt(
        .to_owned();
    let properties = hashmap! {
-        "Value".to_owned() => contents_str.into(),
+        "Value".into() => contents_str.into(),
    };
    let meta_path = path.with_file_name(format!("{}.meta.json", name));
--- a/src/web/interface.rs
+++ b/src/web/interface.rs
@@ -12,6 +12,7 @@ use serde::{Deserialize, Serialize};
 use crate::{
    session_id::SessionId,
    small_string::SmallString,
    snapshot::{
        AppliedPatchSet, InstanceMetadata as RojoInstanceMetadata, InstanceWithMeta, RojoTree,
    },
@@ -83,13 +84,13 @@ impl<'a> SubscribeMessage<'a> {
 #[serde(rename_all = "camelCase")]
 pub struct InstanceUpdate {
    pub id: Ref,
-    pub changed_name: Option<String>,
+    pub changed_name: Option<SmallString>,
-    pub changed_class_name: Option<String>,
+    pub changed_class_name: Option<SmallString>,
-    // TODO: Transform from HashMap<String, Option<_>> to something else, since
+    // TODO: Transform from HashMap<_, Option<_>> to something else, since
    // null will get lost when decoding from JSON in some languages.
    #[serde(default)]
-    pub changed_properties: HashMap<String, Option<Variant>>,
+    pub changed_properties: HashMap<SmallString, Option<Variant>>,
    pub changed_metadata: Option<InstanceMetadata>,
 }