From 22a3a75eb5b20f66651a9040ec9bbc6d1771dfcd Mon Sep 17 00:00:00 2001
From: Emil Ernerfeldt <emil.ernerfeldt@gmail.com>
Date: Sat, 9 Oct 2021 14:15:45 +0200
Subject: [PATCH] Optimization: replace HashSet uses with AHashSet

---
 Cargo.lock                      |  1 +
 egui/src/memory.rs              | 10 +++++-----
 egui/src/widgets/plot/legend.rs | 11 +++++------
 egui/src/widgets/plot/mod.rs    |  7 +++----
 epaint/Cargo.toml               |  8 ++++----
 epaint/src/mutex.rs             |  2 +-
 6 files changed, 19 insertions(+), 20 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 92fa74b54..adbfcf98a 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -47,6 +47,7 @@ checksum = "43bb833f0bf979d8475d38fbf09ed3b8a55e1885fe93ad3f93239fc6a4f17b98"
 dependencies = [
  "getrandom",
  "once_cell",
+ "serde",
  "version_check",
 ]
 
diff --git a/egui/src/memory.rs b/egui/src/memory.rs
index a646e631c..df7228886 100644
--- a/egui/src/memory.rs
+++ b/egui/src/memory.rs
@@ -1,4 +1,4 @@
-use std::collections::HashSet;
+use epaint::ahash::AHashSet;
 
 use crate::{any, area, window, Id, IdMap, InputState, LayerId, Pos2, Rect, Style};
 
@@ -464,15 +464,15 @@ pub struct Areas {
     areas: IdMap<area::State>,
     /// Back-to-front. Top is last.
     order: Vec<LayerId>,
-    visible_last_frame: HashSet<LayerId>,
-    visible_current_frame: HashSet<LayerId>,
+    visible_last_frame: AHashSet<LayerId>,
+    visible_current_frame: AHashSet<LayerId>,
 
     /// When an area want to be on top, it is put in here.
     /// At the end of the frame, this is used to reorder the layers.
     /// This means if several layers want to be on top, they will keep their relative order.
     /// So if you close three windows and then reopen them all in one frame,
     /// they will all be sent to the top, but keep their previous internal order.
-    wants_to_be_on_top: HashSet<LayerId>,
+    wants_to_be_on_top: AHashSet<LayerId>,
 }
 
 impl Areas {
@@ -524,7 +524,7 @@ impl Areas {
         self.visible_last_frame.contains(layer_id) || self.visible_current_frame.contains(layer_id)
     }
 
-    pub fn visible_layer_ids(&self) -> HashSet<LayerId> {
+    pub fn visible_layer_ids(&self) -> AHashSet<LayerId> {
         self.visible_last_frame
             .iter()
             .cloned()
diff --git a/egui/src/widgets/plot/legend.rs b/egui/src/widgets/plot/legend.rs
index f461f6225..676480494 100644
--- a/egui/src/widgets/plot/legend.rs
+++ b/egui/src/widgets/plot/legend.rs
@@ -1,7 +1,6 @@
-use std::{
-    collections::{BTreeMap, HashSet},
-    string::String,
-};
+use std::{collections::BTreeMap, string::String};
+
+use epaint::ahash::AHashSet;
 
 use crate::*;
 
@@ -167,7 +166,7 @@ impl LegendWidget {
         rect: Rect,
         config: Legend,
         items: &[Box<dyn PlotItem>],
-        hidden_items: &HashSet<String>,
+        hidden_items: &AHashSet<String>,
     ) -> Option<Self> {
         // Collect the legend entries. If multiple items have the same name, they share a
         // checkbox. If their colors don't match, we pick a neutral color for the checkbox.
@@ -198,7 +197,7 @@ impl LegendWidget {
     }
 
     // Get the names of the hidden items.
-    pub fn get_hidden_items(&self) -> HashSet<String> {
+    pub fn get_hidden_items(&self) -> AHashSet<String> {
         self.entries
             .iter()
             .filter(|(_, entry)| !entry.checked)
diff --git a/egui/src/widgets/plot/mod.rs b/egui/src/widgets/plot/mod.rs
index 74b873e08..1576093b1 100644
--- a/egui/src/widgets/plot/mod.rs
+++ b/egui/src/widgets/plot/mod.rs
@@ -4,8 +4,6 @@ mod items;
 mod legend;
 mod transform;
 
-use std::collections::HashSet;
-
 use items::PlotItem;
 pub use items::{
     Arrows, HLine, Line, LineStyle, MarkerShape, PlotImage, Points, Polygon, Text, VLine, Value,
@@ -17,6 +15,7 @@ use transform::{Bounds, ScreenTransform};
 
 use crate::*;
 use color::Hsva;
+use epaint::ahash::AHashSet;
 
 // ----------------------------------------------------------------------------
 
@@ -27,7 +26,7 @@ struct PlotMemory {
     bounds: Bounds,
     auto_bounds: bool,
     hovered_entry: Option<String>,
-    hidden_items: HashSet<String>,
+    hidden_items: AHashSet<String>,
     min_auto_bounds: Bounds,
 }
 
@@ -350,7 +349,7 @@ impl Widget for Plot {
                 bounds: min_auto_bounds,
                 auto_bounds: !min_auto_bounds.is_valid(),
                 hovered_entry: None,
-                hidden_items: HashSet::new(),
+                hidden_items: Default::default(),
                 min_auto_bounds,
             })
             .clone();
diff --git a/epaint/Cargo.toml b/epaint/Cargo.toml
index 7b0a4bb33..60cc7a8f4 100644
--- a/epaint/Cargo.toml
+++ b/epaint/Cargo.toml
@@ -39,6 +39,9 @@ bytemuck = { version = "1.7.2", features = ["derive"], optional = true }
 [features]
 default = ["default_fonts", "multi_threaded"]
 
+# implement bytemuck on most types.
+convert_bytemuck = ["bytemuck", "emath/bytemuck"]
+
 # If set, epaint will use `include_bytes!` to bundle some fonts.
 # If you plan on specifying your own fonts you may disable this feature.
 default_fonts = []
@@ -52,10 +55,7 @@ extra_asserts = ["emath/extra_asserts"]
 mint = ["emath/mint"]
 
 # implement serde on most types.
-serialize = ["serde", "emath/serde"]
-
-# implement bytemuck on most types.
-convert_bytemuck = ["bytemuck", "emath/bytemuck"]
+serialize = ["serde", "ahash/serde", "emath/serde"]
 
 single_threaded = ["atomic_refcell"]
 
diff --git a/epaint/src/mutex.rs b/epaint/src/mutex.rs
index dec4d86b8..e0163ddb2 100644
--- a/epaint/src/mutex.rs
+++ b/epaint/src/mutex.rs
@@ -24,7 +24,7 @@ pub struct Mutex<T>(parking_lot::Mutex<T>);
 
 #[cfg(debug_assertions)]
 thread_local! {
-    static HELD_LOCKS_TLS: std::cell::RefCell<std::collections::HashSet<*const ()>> = std::cell::RefCell::new(std::collections::HashSet::new());
+    static HELD_LOCKS_TLS: std::cell::RefCell<ahash::AHashSet<*const ()>> = std::cell::RefCell::new(ahash::AHashSet::new());
 }
 
 #[cfg(feature = "multi_threaded")]