From 6bea5a072c3c1ef4c3d0dbbc62533a3714cdc006 Mon Sep 17 00:00:00 2001
From: Julian Orth <ju.orth@gmail.com>
Date: Sun, 7 Sep 2025 12:28:57 +0200
Subject: [PATCH] kbvm: identify keymaps by their hash

---
 Cargo.lock  | 20 ++++++++++++++++++++
 Cargo.toml  |  1 +
 src/kbvm.rs | 11 ++++-------
 3 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index ca363744..fd6c166c 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -173,6 +173,19 @@ version = "2.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8f68f53c83ab957f72c32642f3868eec03eb974d1fb82e453128456482613d36"
 
+[[package]]
+name = "blake3"
+version = "1.8.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3888aaa89e4b2a40fca9848e400f6a658a5a3978de7be858e209cafa8be9a4a0"
+dependencies = [
+ "arrayref",
+ "arrayvec",
+ "cc",
+ "cfg-if",
+ "constant_time_eq",
+]
+
 [[package]]
 name = "bstr"
 version = "1.11.3"
@@ -295,6 +308,12 @@ version = "1.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5b63caa9aa9397e2d9480a9b13673856c78d8ac123288526c37d7839f2a86990"
 
+[[package]]
+name = "constant_time_eq"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7c74b8349d32d297c9134b8c88677813a227df8f779daa29bfc29c183fe3dca6"
+
 [[package]]
 name = "core-foundation-sys"
 version = "0.8.7"
@@ -587,6 +606,7 @@ dependencies = [
  "ash",
  "backtrace",
  "bincode",
+ "blake3",
  "bstr",
  "byteorder",
  "cc",
diff --git a/Cargo.toml b/Cargo.toml
index 5a0d9519..0898817d 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -67,6 +67,7 @@ regex = "1.11.1"
 cfg-if = "1.0.0"
 opera = "1.0.1"
 with_builtin_macros = "0.1.0"
+blake3 = "1.8.2"
 
 [build-dependencies]
 repc = "0.1.1"
diff --git a/src/kbvm.rs b/src/kbvm.rs
index 992cf8a7..85c38689 100644
--- a/src/kbvm.rs
+++ b/src/kbvm.rs
@@ -33,21 +33,18 @@ pub enum KbvmError {
 
 pub struct KbvmContext {
     pub ctx: xkb::Context,
-    pub ids: KbvmMapIds,
 }
 
 impl Default for KbvmContext {
     fn default() -> Self {
         let mut ctx = xkb::Context::builder();
         ctx.enable_environment(true);
-        Self {
-            ctx: ctx.build(),
-            ids: Default::default(),
-        }
+        Self { ctx: ctx.build() }
     }
 }
 
-linear_ids!(KbvmMapIds, KbvmMapId, u64);
+#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
+pub struct KbvmMapId([u8; 32]);
 
 pub struct KbvmMap {
     pub id: KbvmMapId,
@@ -90,7 +87,7 @@ impl KbvmContext {
             .map_err(KbvmError::CouldNotParseKeymap)?;
         let builder = map.to_builder();
         Ok(Rc::new(KbvmMap {
-            id: self.ids.next(),
+            id: KbvmMapId(*blake3::hash(keymap).as_bytes()),
             state_machine: builder.build_state_machine(),
             map: create_keymap_memfd(&map, false).map_err(KbvmError::KeymapMemfd)?,
             xwayland_map: create_keymap_memfd(&map, true).map_err(KbvmError::KeymapMemfd)?,