From 2e83e3614668823c70039aeafe5f55e82d6bc073 Mon Sep 17 00:00:00 2001
From: Emil Ernerfeldt <emil.ernerfeldt@gmail.com>
Date: Tue, 28 Sep 2021 17:56:24 +0200
Subject: [PATCH] Use ahash for Id and other things that need hashing

---
 egui/src/id.rs     | 14 ++++----------
 epaint/src/util.rs |  2 +-
 2 files changed, 5 insertions(+), 11 deletions(-)

diff --git a/egui/src/id.rs b/egui/src/id.rs
index ce641fc6..5e4367bb 100644
--- a/egui/src/id.rs
+++ b/egui/src/id.rs
@@ -1,7 +1,5 @@
 // TODO: have separate types `PositionId` and `UniqueId`. ?
 
-use std::hash::Hash;
-
 /// egui tracks widgets frame-to-frame using `Id`s.
 ///
 /// For instance, if you start dragging a slider one frame, egui stores
@@ -37,21 +35,17 @@ impl Id {
     }
 
     /// Generate a new `Id` by hashing some source (e.g. a string or integer).
-    pub fn new(source: impl Hash) -> Id {
-        // NOTE: AHasher is NOT suitable for this!
-        use std::collections::hash_map::DefaultHasher;
+    pub fn new(source: impl std::hash::Hash) -> Id {
         use std::hash::Hasher;
-        let mut hasher = DefaultHasher::default();
+        let mut hasher = epaint::ahash::AHasher::new_with_keys(123, 456);
         source.hash(&mut hasher);
         Id(hasher.finish())
     }
 
     /// Generate a new `Id` by hashing the parent `Id` and the given argument.
-    pub fn with(self, child: impl Hash) -> Id {
-        // NOTE: AHasher is NOT suitable for this!
-        use std::collections::hash_map::DefaultHasher;
+    pub fn with(self, child: impl std::hash::Hash) -> Id {
         use std::hash::Hasher;
-        let mut hasher = DefaultHasher::default();
+        let mut hasher = epaint::ahash::AHasher::new_with_keys(123, 456);
         hasher.write_u64(self.0);
         child.hash(&mut hasher);
         Id(hasher.finish())
diff --git a/epaint/src/util.rs b/epaint/src/util.rs
index 22981841..0f47c1f9 100644
--- a/epaint/src/util.rs
+++ b/epaint/src/util.rs
@@ -1,7 +1,7 @@
 /// Hash the given value with a predictable hasher.
 #[inline]
 pub fn hash(value: impl std::hash::Hash) -> u64 {
-    hash_with(value, std::collections::hash_map::DefaultHasher::default())
+    hash_with(value, ahash::AHasher::new_with_keys(123, 456))
 }
 
 /// Hash the given value with the given hasher.