handle_messages impls: do not expect cx.last_child().is_some()

kas-gui · Dec 18, 2023 · 6791f6e · 6791f6e
1 parent f2030b8
commit 6791f6e
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Showing 4 changed files with 30 additions and 27 deletions.
diff --git a/crates/kas-widgets/src/grid.rs b/crates/kas-widgets/src/grid.rs
@@ -125,14 +125,15 @@ impl_scope! {
             if self.message_handlers.is_empty() {
                 return;
             }
-            let mut update = false;
-            let mut cx = AdaptEventCx::new(cx, self.id());
-            let index = cx.last_child().expect("message not sent from self");
-            for handler in self.message_handlers.iter() {
-                update |= handler(&mut cx, data, index);
-            }
-            if update {
-                cx.update(self.as_node(data));
+            if let Some(index) = cx.last_child() {
+                let mut update = false;
+                let mut cx = AdaptEventCx::new(cx, self.id());
+                for handler in self.message_handlers.iter() {
+                    update |= handler(&mut cx, data, index);
+                }
+                if update {
+                    cx.update(self.as_node(data));
+                }
             }
         }
     }

diff --git a/crates/kas-widgets/src/list.rs b/crates/kas-widgets/src/list.rs
@@ -143,14 +143,15 @@ impl_scope! {
             if self.message_handlers.is_empty() {
                 return;
             }
-            let mut update = false;
-            let mut cx = AdaptEventCx::new(cx, self.id());
-            let index = cx.last_child().expect("message not sent from self");
-            for handler in self.message_handlers.iter() {
-                update |= handler(&mut cx, data, index);
-            }
-            if update {
-                cx.update(self.as_node(data));
+            if let Some(index) = cx.last_child() {
+                let mut update = false;
+                let mut cx = AdaptEventCx::new(cx, self.id());
+                for handler in self.message_handlers.iter() {
+                    update |= handler(&mut cx, data, index);
+                }
+                if update {
+                    cx.update(self.as_node(data));
+                }
             }
         }
     }

diff --git a/crates/kas-widgets/src/scroll_bar.rs b/crates/kas-widgets/src/scroll_bar.rs
@@ -559,13 +559,13 @@ impl_scope! {
 
     impl Events for Self {
         fn handle_messages(&mut self, cx: &mut EventCx, _: &Self::Data) {
-            let index = cx.last_child().expect("message not sent from self");
-            if index == widget_index![self.horiz_bar] {
+            let index = cx.last_child();
+            if index == Some(widget_index![self.horiz_bar]) {
                 if let Some(ScrollMsg(x)) = cx.try_pop() {
                     let offset = Offset(x, self.inner.scroll_offset().1);
                     self.inner.set_scroll_offset(cx, offset);
                 }
-            } else if index == widget_index![self.vert_bar] {
+            } else if index == Some(widget_index![self.vert_bar]) {
                 if let Some(ScrollMsg(y)) = cx.try_pop() {
                     let offset = Offset(self.inner.scroll_offset().0, y);
                     self.inner.set_scroll_offset(cx, offset);

diff --git a/crates/kas-widgets/src/splitter.rs b/crates/kas-widgets/src/splitter.rs
@@ -254,14 +254,15 @@ impl_scope! {
         }
 
         fn handle_messages(&mut self, cx: &mut EventCx, _: &Self::Data) {
-            let index = cx.last_child().expect("message not sent from self");
-            if (index & 1) == 1 {
-                if let Some(GripMsg::PressMove(offset)) = cx.try_pop() {
-                    let n = index >> 1;
-                    assert!(n < self.handles.len());
-                    let action = self.handles[n].set_offset(offset).1;
-                    cx.action(&self, action);
-                    self.adjust_size(&mut cx.config_cx(), n);
+            if let Some(index) = cx.last_child() {
+                if (index & 1) == 1 {
+                    if let Some(GripMsg::PressMove(offset)) = cx.try_pop() {
+                        let n = index >> 1;
+                        assert!(n < self.handles.len());
+                        let action = self.handles[n].set_offset(offset).1;
+                        cx.action(&self, action);
+                        self.adjust_size(&mut cx.config_cx(), n);
+                    }
                 }
             }
         }