Vec::drain with VecDeque::pop_front for O(1) log pruning across all apps

apps/mofa-asr/src/screen/log_panel.rs

@@ -215,11 +215,10 @@ impl MoFaASRScreen {
 
     /// Add a log entry (throttled)
     pub(super) fn add_log(&mut self, cx: &mut Cx, entry: &str) {
-        self.log_entries.push(entry.to_string());
+        self.log_entries.push_back(entry.to_string());
 
-        if self.log_entries.len() > MAX_LOG_ENTRIES {
-            let excess = self.log_entries.len() - MAX_LOG_ENTRIES;
-            self.log_entries.drain(0..excess);
+        while self.log_entries.len() > MAX_LOG_ENTRIES {
+            self.log_entries.pop_front();
         }
 
         self.mark_log_dirty(cx);
@@ -233,12 +232,11 @@ impl MoFaASRScreen {
         }
 
         for log_msg in logs {
-            self.log_entries.push(log_msg.format());
+            self.log_entries.push_back(log_msg.format());
         }
 
-        if self.log_entries.len() > MAX_LOG_ENTRIES {
-            let excess = self.log_entries.len() - MAX_LOG_ENTRIES;
-            self.log_entries.drain(0..excess);
+        while self.log_entries.len() > MAX_LOG_ENTRIES {
+            self.log_entries.pop_front();
         }
 
         self.mark_log_dirty(cx);

apps/mofa-asr/src/screen/mod.rs

@@ -13,6 +13,7 @@ use mofa_ui::{LedMeterWidgetExt, MicButtonWidgetExt, AecButtonWidgetExt};
 use mofa_settings::data::Preferences;
 use crate::dora_integration::{AsrEngineId, DoraIntegration, DoraEvent};
 use std::collections::HashMap;
+use std::collections::VecDeque;
 use std::path::PathBuf;
 use std::sync::{Arc, Mutex};
 use moly_kit::prelude::*;
@@ -139,7 +140,7 @@ pub struct MoFaASRScreen {
     #[rust]
     log_node_filter: usize,
     #[rust]
-    log_entries: Vec<String>,
+    log_entries: VecDeque<String>,
     #[rust]
     log_display_dirty: bool,
     #[rust]

apps/mofa-debate/src/screen/audio_controls.rs

@@ -121,10 +121,10 @@ impl MoFaDebateScreen {
     /// Initialize log entries with a startup message
     pub(super) fn init_demo_logs(&mut self, cx: &mut Cx) {
         // Start with empty logs - real logs will come from log_bridge
-        self.log_entries = vec![
+        self.log_entries = std::collections::VecDeque::from(vec![
             "[INFO] [App] MoFA FM initialized".to_string(),
             "[INFO] [App] System log ready - Rust logs will appear here".to_string(),
-        ];
+        ]);
 
         // Update the log display
         self.update_log_display(cx);

apps/mofa-debate/src/screen/log_panel.rs

@@ -7,6 +7,8 @@ use makepad_widgets::*;
 
 use super::MoFaDebateScreen;
 
+const MAX_LOG_ENTRIES: usize = 5000;
+
 impl MoFaDebateScreen {
     /// Toggle log panel visibility
     pub(super) fn toggle_log_panel(&mut self, cx: &mut Cx) {
@@ -221,7 +223,12 @@ impl MoFaDebateScreen {
 
     /// Add a log entry
     pub(super) fn add_log(&mut self, cx: &mut Cx, entry: &str) {
-        self.log_entries.push(entry.to_string());
+        self.log_entries.push_back(entry.to_string());
+
+        while self.log_entries.len() > MAX_LOG_ENTRIES {
+            self.log_entries.pop_front();
+        }
+
         self.update_log_display(cx);
     }
 
@@ -233,7 +240,11 @@ impl MoFaDebateScreen {
         }
 
         for log_msg in logs {
-            self.log_entries.push(log_msg.format());
+            self.log_entries.push_back(log_msg.format());
+        }
+
+        while self.log_entries.len() > MAX_LOG_ENTRIES {
+            self.log_entries.pop_front();
         }
 
         // Only update display if we got new logs

apps/mofa-debate/src/screen/mod.rs

@@ -25,6 +25,7 @@ use mofa_ui::{
 };
 use mofa_widgets::participant_panel::ParticipantPanelWidgetExt;
 use mofa_widgets::{StateChangeListener, TimerControl};
+use std::collections::VecDeque;
 use std::path::PathBuf;
 
 /// Register live design for this module
@@ -82,7 +83,7 @@ pub struct MoFaDebateScreen {
     #[rust]
     log_node_filter: usize, // 0=ALL, 1=ASR, 2=TTS, 3=LLM, 4=Bridge, 5=Monitor, 6=App
     #[rust]
-    log_entries: Vec<String>, // Raw log entries for filtering
+    log_entries: VecDeque<String>,
 
     // Dropdown width caching for popup menu sync
     #[rust]

apps/mofa-fm/src/screen/audio_controls.rs

@@ -109,10 +109,10 @@ impl MoFaFMScreen {
     /// Initialize log entries with a startup message
     pub(super) fn init_demo_logs(&mut self, cx: &mut Cx) {
         // Start with empty logs - real logs will come from log_bridge
-        self.log_entries = vec![
+        self.log_entries = std::collections::VecDeque::from(vec![
             "[INFO] [App] MoFA FM initialized".to_string(),
             "[INFO] [App] System log ready - Rust logs will appear here".to_string(),
-        ];
+        ]);
 
         // Update the log display
         self.update_log_display(cx);

apps/mofa-fm/src/screen/log_panel.rs

@@ -254,12 +254,10 @@ impl MoFaFMScreen {
 
     /// Add a log entry (throttled - doesn't immediately update display)
     pub(super) fn add_log(&mut self, cx: &mut Cx, entry: &str) {
-        self.log_entries.push(entry.to_string());
+        self.log_entries.push_back(entry.to_string());
 
-        // Prune oldest entries if over limit
-        if self.log_entries.len() > MAX_LOG_ENTRIES {
-            let excess = self.log_entries.len() - MAX_LOG_ENTRIES;
-            self.log_entries.drain(0..excess);
+        while self.log_entries.len() > MAX_LOG_ENTRIES {
+            self.log_entries.pop_front();
         }
 
         // Mark dirty for throttled update (don't update immediately)
@@ -274,13 +272,11 @@ impl MoFaFMScreen {
         }
 
         for log_msg in logs {
-            self.log_entries.push(log_msg.format());
+            self.log_entries.push_back(log_msg.format());
         }
 
-        // Prune oldest entries if over limit
-        if self.log_entries.len() > MAX_LOG_ENTRIES {
-            let excess = self.log_entries.len() - MAX_LOG_ENTRIES;
-            self.log_entries.drain(0..excess);
+        while self.log_entries.len() > MAX_LOG_ENTRIES {
+            self.log_entries.pop_front();
         }
 
         // Mark dirty for throttled update (don't update immediately)
@@ -295,3 +291,97 @@ impl MoFaFMScreen {
         self.update_log_display_now(cx);
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use std::collections::VecDeque;
+
+    const MAX_LOG_ENTRIES: usize = super::MAX_LOG_ENTRIES;
+
+    fn push_and_prune(buf: &mut VecDeque<String>, entry: String) {
+        buf.push_back(entry);
+        while buf.len() > MAX_LOG_ENTRIES {
+            buf.pop_front();
+        }
+    }
+
+    #[test]
+    fn stays_within_capacity() {
+        let mut buf = VecDeque::new();
+        for i in 0..(MAX_LOG_ENTRIES + 500) {
+            push_and_prune(&mut buf, format!("log {i}"));
+        }
+        assert_eq!(buf.len(), MAX_LOG_ENTRIES);
+    }
+
+    #[test]
+    fn oldest_entries_evicted_first() {
+        let mut buf = VecDeque::new();
+        for i in 0..(MAX_LOG_ENTRIES + 3) {
+            push_and_prune(&mut buf, format!("log {i}"));
+        }
+        // first 3 entries should be evicted
+        assert_eq!(buf.front().unwrap(), "log 3");
+        assert_eq!(buf.back().unwrap(), &format!("log {}", MAX_LOG_ENTRIES + 2));
+    }
+
+    #[test]
+    fn below_cap_no_eviction() {
+        let mut buf = VecDeque::new();
+        for i in 0..100 {
+            push_and_prune(&mut buf, format!("log {i}"));
+        }
+        assert_eq!(buf.len(), 100);
+        assert_eq!(buf.front().unwrap(), "log 0");
+        assert_eq!(buf.back().unwrap(), "log 99");
+    }
+
+    #[test]
+    fn exactly_at_cap() {
+        let mut buf = VecDeque::new();
+        for i in 0..MAX_LOG_ENTRIES {
+            push_and_prune(&mut buf, format!("log {i}"));
+        }
+        assert_eq!(buf.len(), MAX_LOG_ENTRIES);
+        assert_eq!(buf.front().unwrap(), "log 0");
+        // One more triggers first eviction
+        push_and_prune(&mut buf, "overflow".to_string());
+        assert_eq!(buf.len(), MAX_LOG_ENTRIES);
+        assert_eq!(buf.front().unwrap(), "log 1");
+        assert_eq!(buf.back().unwrap(), "overflow");
+    }
+
+    #[test]
+    fn clear_resets_buffer() {
+        let mut buf = VecDeque::new();
+        for i in 0..100 {
+            push_and_prune(&mut buf, format!("log {i}"));
+        }
+        buf.clear();
+        assert_eq!(buf.len(), 0);
+        assert!(buf.is_empty());
+        // Can continue adding after clear
+        push_and_prune(&mut buf, "after clear".to_string());
+        assert_eq!(buf.len(), 1);
+        assert_eq!(buf.front().unwrap(), "after clear");
+    }
+
+    #[test]
+    fn batch_insert_pruning() {
+        // poll_rust_logs
+        let mut buf = VecDeque::new();
+        for i in 0..MAX_LOG_ENTRIES {
+            buf.push_back(format!("log {i}"));
+        }
+        // Batch of 10
+        for i in 0..10 {
+            buf.push_back(format!("batch {i}"));
+        }
+        while buf.len() > MAX_LOG_ENTRIES {
+            buf.pop_front();
+        }
+        assert_eq!(buf.len(), MAX_LOG_ENTRIES);
+        assert_eq!(buf.front().unwrap(), "log 10");
+        assert_eq!(buf.back().unwrap(), "batch 9");
+    }
+}

apps/mofa-fm/src/screen/mod.rs

@@ -23,6 +23,7 @@ use crate::dora_integration::{DoraIntegration, DoraCommand};
 use mofa_widgets::participant_panel::ParticipantPanelWidgetExt;
 use mofa_widgets::{StateChangeListener, TimerControl};
 use mofa_ui::{LedMeterWidgetExt, MicButtonWidgetExt, AecButtonWidgetExt};
+use std::collections::VecDeque;
 use std::path::PathBuf;
 use std::sync::{Arc, Mutex};
 use std::sync::atomic::{AtomicBool, AtomicU32, Ordering};
@@ -92,7 +93,7 @@ pub struct MoFaFMScreen {
     #[rust]
     log_node_filter: usize,   // 0=ALL, 1=ASR, 2=TTS, 3=LLM, 4=Bridge, 5=Monitor, 6=App
     #[rust]
-    log_entries: Vec<String>,  // Raw log entries for filtering
+    log_entries: VecDeque<String>,
     #[rust]
     log_display_dirty: bool,   // Flag to track if log display needs update
     #[rust]