ei: make handling of touchscreen events stricter

src/ei/ei_ifs/ei_device.rs

@@ -11,7 +11,7 @@ use {
         leaks::Tracker,
         rect::Rect,
         scale::Scale,
-        utils::syncqueue::SyncQueue,
+        utils::{copyhashmap::CopyHashMap, syncqueue::SyncQueue},
         wire_ei::{
             ei_device::{
                 ClientFrame, ClientStartEmulating, ClientStopEmulating, Destroyed, DeviceType,
@@ -37,7 +37,7 @@ pub struct EiDevice {
     pub seat: Rc<EiSeat>,
 
     pub button_changes: SyncQueue<(u32, KeyState)>,
-    pub touch_changes: SyncQueue<(u32, TouchChange)>,
+    pub touch_changes: CopyHashMap<u32, TouchChange>,
     pub scroll_px: [Cell<Option<f32>>; 2],
     pub scroll_v120: [Cell<Option<i32>>; 2],
     pub scroll_stop: [Cell<Option<bool>>; 2],
@@ -219,7 +219,7 @@ impl EiDeviceRequestHandler for EiDevice {
             }
         }
         if self.touch_changes.is_not_empty() {
-            while let Some((touch_id, change)) = self.touch_changes.pop() {
+            for (touch_id, change) in self.touch_changes.lock().drain() {
                 let id = touch_id as i32;
                 match change {
                     TouchChange::Down(x, y) => {

src/ei/ei_ifs/ei_touchscreen.rs

@@ -7,6 +7,7 @@ use {
         },
         fixed::Fixed,
         leaks::Tracker,
+        utils::clonecell::UnsafeCellCloneSafe,
         wire_ei::{
             ei_touchscreen::{
                 ClientDown, ClientMotion, ClientUp, EiTouchscreenRequestHandler, Release,
@@ -15,7 +16,7 @@ use {
             EiTouchscreenId,
         },
     },
-    std::rc::Rc,
+    std::{collections::hash_map::Entry, rc::Rc},
     thiserror::Error,
 };
 
@@ -34,6 +35,8 @@ pub enum TouchChange {
     Up,
 }
 
+unsafe impl UnsafeCellCloneSafe for TouchChange {}
+
 ei_device_interface!(EiTouchscreen, ei_touchscreen, touchscreen);
 
 impl EiTouchscreen {
@@ -61,6 +64,25 @@ impl EiTouchscreen {
             touchid,
         });
     }
+
+    fn set_client_event(&self, touchid: u32, event: TouchChange) -> Result<(), EiTouchscreenError> {
+        match self.device.touch_changes.lock().entry(touchid) {
+            Entry::Occupied(mut o) => {
+                use TouchChange::*;
+                match (o.get(), event) {
+                    (Motion(_, _), Motion(_, _)) | (Down(_, _), Down(_, _)) | (Up, Up) => {
+                        o.insert(event);
+                        Ok(())
+                    }
+                    _ => Err(EiTouchscreenError::InvalidEventCombination),
+                }
+            }
+            Entry::Vacant(v) => {
+                v.insert(event);
+                Ok(())
+            }
+        }
+    }
 }
 
 impl EiTouchscreenRequestHandler for EiTouchscreen {
@@ -72,24 +94,15 @@ impl EiTouchscreenRequestHandler for EiTouchscreen {
     }
 
     fn client_down(&self, req: ClientDown, _slf: &Rc<Self>) -> Result<(), Self::Error> {
-        self.device
-            .touch_changes
-            .push((req.touchid, TouchChange::Down(req.x, req.y)));
-        Ok(())
+        self.set_client_event(req.touchid, TouchChange::Down(req.x, req.y))
     }
 
     fn client_motion(&self, req: ClientMotion, _slf: &Rc<Self>) -> Result<(), Self::Error> {
-        self.device
-            .touch_changes
-            .push((req.touchid, TouchChange::Motion(req.x, req.y)));
-        Ok(())
+        self.set_client_event(req.touchid, TouchChange::Motion(req.x, req.y))
     }
 
     fn client_up(&self, req: ClientUp, _slf: &Rc<Self>) -> Result<(), Self::Error> {
-        self.device
-            .touch_changes
-            .push((req.touchid, TouchChange::Up));
-        Ok(())
+        self.set_client_event(req.touchid, TouchChange::Up)
     }
 }
 
@@ -104,5 +117,7 @@ impl EiObject for EiTouchscreen {}
 pub enum EiTouchscreenError {
     #[error(transparent)]
     EiClientError(Box<EiClientError>),
+    #[error("Touch frame contains an invalid combination of events")]
+    InvalidEventCombination,
 }
 efrom!(EiTouchscreenError, EiClientError);

src/utils/syncqueue.rs

@@ -37,6 +37,7 @@ impl<T> SyncQueue<T> {
         unsafe { self.el.get().deref_mut().is_empty() }
     }
 
+    #[expect(dead_code)]
     pub fn is_not_empty(&self) -> bool {
         !self.is_empty()
     }