swap from HashMap to FxHashMap (#232)

Author: joshuadavidthomas

Cargo.lock

@@ -24,6 +24,7 @@ dashmap = "6.1"
 directories = "6.0"
 notify = "8.2"
 percent-encoding = "2.3"
+rustc-hash = "2.1"
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
 thiserror = "2.0"

Cargo.toml

@@ -7,6 +7,7 @@ edition = "2021"
 djls-workspace = { workspace = true }
 
 anyhow = { workspace = true }
+rustc-hash = { workspace = true }
 salsa = { workspace = true }
 serde = { workspace = true }
 serde_json = { workspace = true }

crates/djls-project/Cargo.toml

@@ -28,14 +28,15 @@ pub fn env_var(key: &str) -> Result<String, VarError> {
 #[cfg(test)]
 pub mod mock {
     use std::cell::RefCell;
-    use std::collections::HashMap;
     use std::thread_local;
 
+    use rustc_hash::FxHashMap;
+
     use super::*;
 
     thread_local! {
-        static MOCK_EXEC_RESULTS: RefCell<HashMap<String, Result<PathBuf, WhichError>>> = RefCell::new(HashMap::new());
-        static MOCK_ENV_RESULTS: RefCell<HashMap<String, Result<String, VarError>>> = RefCell::new(HashMap::new());
+        static MOCK_EXEC_RESULTS: RefCell<FxHashMap<String, Result<PathBuf, WhichError>>> = RefCell::new(FxHashMap::default());
+        static MOCK_ENV_RESULTS: RefCell<FxHashMap<String, Result<String, VarError>>> = RefCell::new(FxHashMap::default());
     }
 
     pub(super) fn find_executable_mocked(name: &str) -> Result<PathBuf, WhichError> {

crates/djls-project/src/system.rs

@@ -8,6 +8,7 @@ djls-conf = { workspace = true }
 djls-templates = { workspace = true }
 djls-workspace = { workspace = true }
 
+rustc-hash = { workspace = true }
 salsa = { workspace = true }
 serde = { workspace = true }
 thiserror = { workspace = true }

crates/djls-semantic/Cargo.toml

@@ -3,9 +3,10 @@
 //! This module defines all the standard Django template tags as compile-time
 //! constants, avoiding the need for runtime TOML parsing.
 
-use std::collections::HashMap;
 use std::sync::LazyLock;
 
+use rustc_hash::FxHashMap;
+
 use super::specs::EndTag;
 use super::specs::IntermediateTag;
 use super::specs::TagArg;
@@ -14,7 +15,7 @@ use super::specs::TagSpecs;
 
 // Static storage for built-in specs - built only once on first access
 static BUILTIN_SPECS: LazyLock<TagSpecs> = LazyLock::new(|| {
-    let mut specs = HashMap::new();
+    let mut specs = FxHashMap::default();
 
     // Define all Django built-in tags using direct struct construction
     let tags = vec![
@@ -380,7 +381,7 @@ static BUILTIN_SPECS: LazyLock<TagSpecs> = LazyLock::new(|| {
         },
     ];
 
-    // Insert all tags into the HashMap
+    // Insert all tags into the FxHashMap
     for tag in tags {
         if let Some(ref name) = tag.name {
             specs.insert(name.clone(), tag);

crates/djls-semantic/src/builtins.rs

@@ -1,4 +1,4 @@
-use std::collections::HashMap;
+use rustc_hash::FxHashMap;
 
 pub enum TagType {
     Opener,
@@ -23,11 +23,11 @@ impl TagType {
 }
 
 #[derive(Clone, Debug, Default)]
-pub struct TagSpecs(HashMap<String, TagSpec>);
+pub struct TagSpecs(FxHashMap<String, TagSpec>);
 
 impl TagSpecs {
     #[must_use]
-    pub fn new(specs: HashMap<String, TagSpec>) -> Self {
+    pub fn new(specs: FxHashMap<String, TagSpec>) -> Self {
         TagSpecs(specs)
     }
 
@@ -122,7 +122,7 @@ impl From<&djls_conf::Settings> for TagSpecs {
         let mut specs = crate::builtins::django_builtin_specs();
 
         // Convert and merge user-defined tagspecs
-        let mut user_specs = HashMap::new();
+        let mut user_specs = FxHashMap::default();
         for tagspec_def in settings.tagspecs() {
             // Clone because we're consuming the tagspec_def in the conversion
             let tagspec: TagSpec = tagspec_def.clone().into();
@@ -312,7 +312,7 @@ mod tests {
 
     // Helper function to create a small test TagSpecs
     fn create_test_specs() -> TagSpecs {
-        let mut specs = HashMap::new();
+        let mut specs = FxHashMap::default();
 
         // Add a simple single tag
         specs.insert(
@@ -567,7 +567,7 @@ mod tests {
         let mut specs1 = create_test_specs();
 
         // Create another TagSpecs with some overlapping and some new tags
-        let mut specs2_map = HashMap::new();
+        let mut specs2_map = FxHashMap::default();
 
         // Add a new tag
         specs2_map.insert(
@@ -626,7 +626,7 @@ mod tests {
         let original_count = specs.iter().count();
 
         // Merge with empty TagSpecs
-        specs.merge(TagSpecs::new(HashMap::new()));
+        specs.merge(TagSpecs::new(FxHashMap::default()));
 
         // Should remain unchanged
         assert_eq!(specs.iter().count(), original_count);

crates/djls-semantic/src/specs.rs

@@ -9,6 +9,7 @@ camino = { workspace = true }
 dashmap = { workspace = true }
 notify = { workspace = true }
 percent-encoding = { workspace = true }
+rustc-hash = { workspace = true }
 salsa = { workspace = true }
 tokio = { workspace = true }
 tower-lsp-server = { workspace = true }

crates/djls-workspace/Cargo.toml

@@ -3,12 +3,13 @@
 //! This module provides the [`FileSystem`] trait that abstracts file I/O operations.
 //! This allows the LSP to work with both real files and in-memory overlays.
 
-use std::collections::HashMap;
 use std::io;
 use std::path::Path;
 use std::path::PathBuf;
 use std::sync::Arc;
 
+use rustc_hash::FxHashMap;
+
 use crate::buffers::Buffers;
 use crate::paths;
 
@@ -18,14 +19,14 @@ pub trait FileSystem: Send + Sync {
 }
 
 pub struct InMemoryFileSystem {
-    files: HashMap<PathBuf, String>,
+    files: FxHashMap<PathBuf, String>,
 }
 
 impl InMemoryFileSystem {
     #[must_use]
     pub fn new() -> Self {
         Self {
-            files: HashMap::new(),
+            files: FxHashMap::default(),
         }
     }