optimizations

src/ui/app.rs

@@ -30,6 +30,8 @@ use std::{
 };
 
 const INITIAL_INTERVAL: u32 = 300;
+const MAIN_LAYOUT_WITH_SCROLLBAR: [Constraint; 2] = [Constraint::Min(1), Constraint::Length(1)];
+const MAIN_LAYOUT_WITHOUT_SCROLLBAR: [Constraint; 1] = [Constraint::Min(1)];
 
 enum FetchResult {
     Heartbeat(Result<HeartbeatResponse>),
@@ -134,12 +136,11 @@ impl App {
 
             render_header(frame, chunks[0], &self.state);
 
-            let mut main_constraint = Vec::with_capacity(2);
-            main_constraint.push(Constraint::Min(1));
-
-            if self.state.show_vertical_scrollbar(chunks[1].height) {
-                main_constraint.push(Constraint::Length(1));
-            }
+            let main_constraint = if self.state.show_vertical_scrollbar(chunks[1].height) {
+                &MAIN_LAYOUT_WITH_SCROLLBAR[..]
+            } else {
+                &MAIN_LAYOUT_WITHOUT_SCROLLBAR[..]
+            };
 
             let main_chunks = Layout::default()
                 .direction(Direction::Horizontal)

src/ui/components/monitor_list.rs

@@ -137,11 +137,10 @@ fn render_monitor_table(
 
     let header = Row::new(header_cells).style(title_style()).height(1);
 
-    let rows: Vec<Row> = monitors
-        .iter()
-        .take(items_to_show)
-        .map(|monitor| create_monitor_item(monitor))
-        .collect();
+    let mut rows: Vec<Row> = Vec::with_capacity(items_to_show);
+    for monitor in monitors.iter().take(items_to_show) {
+        rows.push(create_monitor_item(monitor));
+    }
 
     let widths = vec![
         Constraint::Length(3),
@@ -256,17 +255,20 @@ fn get_cached_status_line(status_history: &[MonitorStatus]) -> Line<'static> {
         }
     }
 
-    let spans: Vec<Span<'static>> = status_history
-        .iter()
-        .rev()
-        .take(STATUS_LINE_LENGTH)
-        .map(|status| get_status_span(status).clone())
-        .collect();
+    let mut spans: Vec<Span<'static>> = Vec::with_capacity(STATUS_LINE_LENGTH);
+    spans.extend(
+        status_history
+            .iter()
+            .rev()
+            .take(STATUS_LINE_LENGTH)
+            .map(|status| get_status_span(status).clone()),
+    );
 
     let new_line = Line::from(spans);
     let mut write = cache.write().unwrap();
     if write.len() > 1000 {
-        let keys_to_remove: Vec<_> = write.keys().take(250).copied().collect();
+        let mut keys_to_remove: Vec<u64> = Vec::with_capacity(250);
+        keys_to_remove.extend(write.keys().take(250).copied());
 
         for key in keys_to_remove {
             write.remove(&key);

src/ui/dashboard/model.rs

@@ -95,16 +95,12 @@ impl DashboardViewState {
 }
 
 fn get_status_history(heartbeats: &[HeartbeatEntry]) -> Vec<MonitorStatus> {
-    let mut history = heartbeats
-        .iter()
-        .rev()
-        .take(100)
-        .map(|h| match h.status {
-            0 => MonitorStatus::Down,
-            1 => MonitorStatus::Up,
-            _ => MonitorStatus::Unknown,
-        })
-        .collect::<Vec<_>>();
+    let mut history: Vec<_> = Vec::with_capacity(heartbeats.len());
+    history.extend(heartbeats.iter().rev().take(100).map(|h| match h.status {
+        0 => MonitorStatus::Down,
+        1 => MonitorStatus::Up,
+        _ => MonitorStatus::Unknown,
+    }));
 
     while history.len() < 100 {
         history.push(MonitorStatus::Unknown);
@@ -142,7 +138,7 @@ fn add_monitor_view_state(group: UnifiedGroupData) -> Vec<MonitorViewState> {
 
             let name: Cow<'static, str> = match monitor.name {
                 Cow::Borrowed(borrowed) => Cow::Owned(borrowed.to_string()),
-                Cow::Owned(owned) => Cow::Owned(owned)
+                Cow::Owned(owned) => Cow::Owned(owned),
             };
 
             MonitorViewState {