[optimize] switch to ahash for ids and most maps and sets

emigui/Cargo.toml

@@ -7,13 +7,14 @@ edition = "2018"
 [lib]
 
 [dependencies]
+ahash = "0.3"
 parking_lot = "0.10"
 rusttype = "0.9"
 serde = "1"
 serde_derive = "1"
 
 [dev-dependencies]
-criterion = "0.3"
+criterion = { version = "0.3", default-features = false }
 
 [[bench]]
 name = "benchmark"

emigui/src/context.rs

@@ -1,6 +1,6 @@
-use std::{collections::HashMap, sync::Arc};
+use std::sync::Arc;
 
-use parking_lot::Mutex;
+use {ahash::AHashMap, parking_lot::Mutex};
 
 use crate::{layout::align_rect, paint::*, *};
 
@@ -31,7 +31,7 @@ pub struct Context {
     graphics: Mutex<GraphicLayers>,
     output: Mutex<Output>,
     /// Used to debug name clashes of e.g. windows
-    used_ids: Mutex<HashMap<Id, Pos2>>,
+    used_ids: Mutex<AHashMap<Id, Pos2>>,
 
     paint_stats: Mutex<PaintStats>,
 }

emigui/src/id.rs

@@ -27,7 +27,7 @@
 //! So we have two type of Ids: `PositionId` and `UniqueId`.
 //! TODO: have separate types for `PositionId` and `UniqueId`.
 
-use std::{collections::hash_map::DefaultHasher, hash::Hash};
+use std::hash::Hash;
 
 use crate::math::Pos2;
 
@@ -47,14 +47,14 @@ impl Id {
 
     pub fn new(source: impl Hash) -> Id {
         use std::hash::Hasher;
-        let mut hasher = DefaultHasher::new();
+        let mut hasher = ahash::AHasher::default();
         source.hash(&mut hasher);
         Id(hasher.finish())
     }
 
     pub fn with(self, child: impl Hash) -> Id {
         use std::hash::Hasher;
-        let mut hasher = DefaultHasher::new();
+        let mut hasher = ahash::AHasher::default();
         hasher.write_u64(self.0);
         child.hash(&mut hasher);
         Id(hasher.finish())

emigui/src/layers.rs

@@ -1,5 +1,4 @@
-use std::collections::HashMap;
-
+use ahash::AHashMap;
 use serde_derive::{Deserialize, Serialize};
 
 use crate::{math::Rect, paint::PaintCmd, Id};
@@ -39,7 +38,7 @@ type PaintList = Vec<(Rect, PaintCmd)>;
 
 /// TODO: improve this
 #[derive(Clone, Default)]
-pub struct GraphicLayers(HashMap<Layer, PaintList>);
+pub struct GraphicLayers(AHashMap<Layer, PaintList>);
 
 impl GraphicLayers {
     pub fn layer(&mut self, layer: Layer) -> &mut PaintList {

emigui/src/paint/font.rs

@@ -1,7 +1,10 @@
-use std::{collections::HashMap, sync::Arc};
+use std::sync::Arc;
 
-use parking_lot::Mutex;
-use rusttype::{point, Scale};
+use {
+    ahash::AHashMap,
+    parking_lot::Mutex,
+    rusttype::{point, Scale},
+};
 
 use crate::math::{vec2, Vec2};
 
@@ -179,7 +182,7 @@ pub struct Font {
     /// Maximum character height
     scale_in_pixels: f32,
     pixels_per_point: f32,
-    glyph_infos: HashMap<char, GlyphInfo>, // TODO: optimize these lookups, e.g. with binary search or a fast hashmap
+    glyph_infos: AHashMap<char, GlyphInfo>, // TODO: see if we can optimize if we switch to a binary search
     atlas: Arc<Mutex<TextureAtlas>>,
 }
 

emigui/src/paint/fonts.rs

@@ -1,5 +1,5 @@
 use std::{
-    collections::{hash_map::DefaultHasher, BTreeMap},
+    collections::BTreeMap,
     hash::{Hash, Hasher},
     sync::Arc,
 };
@@ -107,7 +107,7 @@ impl Fonts {
             .collect();
         self.texture = atlas.lock().texture().clone();
 
-        let mut hasher = DefaultHasher::new();
+        let mut hasher = ahash::AHasher::default();
         self.texture.pixels.hash(&mut hasher);
         self.texture.id = hasher.finish();
     }