refactor: reuse built-ins and shared helpers

crates/chanora_audio/src/ptt_backends/mod.rs

@@ -22,6 +22,7 @@
 use core::fmt;
 
 use crate::ptt::{AudioTransmitGate, PttBackendDescriptor};
+use thiserror::Error;
 
 mod focused;
 
@@ -108,34 +109,50 @@ impl fmt::Display for PttInputClass {
 }
 
 /// Errors raised by a desktop PTT backend.
-#[derive(Debug)]
+#[derive(Debug, Error)]
 pub enum PttBackendError {
     /// The OS rejected the backend initialisation (e.g. Raw Input
     /// registration failed, event tap creation failed).
+    #[error("init failed: {0}")]
     Init(String),
     /// The user-granted permission required for global capture is
     /// not granted (typically macOS Input Monitoring / Accessibility).
+    #[error("permission denied")]
     PermissionDenied,
     /// The display server or compositor does not expose the
     /// expected interface (typically a non-tested Linux compositor).
+    #[error("unsupported environment")]
     UnsupportedEnvironment,
     /// Caller submitted a binding whose `platform_key` cannot be
     /// parsed in the active OS.
+    #[error("invalid binding: {0}")]
     InvalidBinding(String),
 }
 
-impl fmt::Display for PttBackendError {
+#[cfg(test)]
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+mod tests {
-        match self {
+    use super::*;
-            Self::Init(s) => write!(f, "init failed: {s}"),
-            Self::PermissionDenied => f.write_str("permission denied"),
-            Self::UnsupportedEnvironment => f.write_str("unsupported environment"),
-            Self::InvalidBinding(s) => write!(f, "invalid binding: {s}"),
-        }
-    }
-}
 
-impl std::error::Error for PttBackendError {}
+    #[test]
+    fn ptt_backend_error_display_strings_stay_stable() {
+        assert_eq!(
+            PttBackendError::Init("rawinput".into()).to_string(),
+            "init failed: rawinput"
+        );
+        assert_eq!(
+            PttBackendError::PermissionDenied.to_string(),
+            "permission denied"
+        );
+        assert_eq!(
+            PttBackendError::UnsupportedEnvironment.to_string(),
+            "unsupported environment"
+        );
+        assert_eq!(
+            PttBackendError::InvalidBinding("bad key".into()).to_string(),
+            "invalid binding: bad key"
+        );
+    }
+}
 
 /// Cross-platform desktop PTT backend (SDD-081).
 ///

crates/chanora_audio/src/voice_render.rs

@@ -1,4 +1,5 @@
 /// Diagnostics returned by render downmix helpers.
+#[cfg(any(target_os = "ios", test))]
 #[derive(Debug, Clone, Copy, Default, PartialEq, Eq)]
 pub(crate) struct RenderDownmixStats {
     /// Peak absolute sample magnitude after i16 conversion.
@@ -7,47 +8,7 @@ pub(crate) struct RenderDownmixStats {
     pub clipped_samples: u64,
 }
 
-/// Downmix interleaved stereo f32 samples into mono i16 samples.
-///
-/// The helper is allocation-free and safe for realtime render callbacks.
-/// If the stereo source is shorter than expected, the remainder of `out`
-/// is filled with silence.
 #[cfg(any(target_os = "ios", test))]
-pub(crate) fn downmix_stereo_f32_to_mono_i16(
-    stereo: &[f32],
-    out: &mut [i16],
-    gain: f32,
-    muted: bool,
-) -> RenderDownmixStats {
-    if muted {
-        out.fill(0);
-        return RenderDownmixStats::default();
-    }
-
-    let available_frames = stereo.len() / 2;
-    if available_frames < out.len() {
-        out.fill(0);
-    }
-
-    let mut peak = 0_u16;
-    let mut clipped_samples = 0_u64;
-    for (dst, lr) in out.iter_mut().zip(stereo.chunks_exact(2)) {
-        let mono = (lr[0] + lr[1]) * 0.5 * gain;
-        let clamped = mono.clamp(-1.0, 1.0);
-        if (mono - clamped).abs() > f32::EPSILON {
-            clipped_samples = clipped_samples.saturating_add(1);
-        }
-        let sample = (clamped * i16::MAX as f32) as i16;
-        *dst = sample;
-        peak = peak.max(sample.unsigned_abs());
-    }
-
-    RenderDownmixStats {
-        peak_i16: peak.min(i16::MAX as u16) as i16,
-        clipped_samples,
-    }
-}
-
 pub(crate) fn downmix_stereo_f32_to_interleaved_i16(
     stereo: &[f32],
     out: &mut [i16],
@@ -122,10 +83,7 @@ pub(crate) fn limit_peak_inplace(samples: &mut [f32], threshold: f32) -> f32 {
     if threshold <= 0.0 || !threshold.is_finite() {
         return 1.0;
     }
-    let peak = samples
+    let peak = samples.iter().map(|s| s.abs()).fold(0.0_f32, f32::max);
-        .iter()
-        .map(|s| s.abs())
-        .fold(0.0_f32, f32::max);
     if peak <= threshold {
         return 1.0;
     }
@@ -145,7 +103,7 @@ mod tests {
         let stereo = [1.0_f32, 1.0, 0.25, -0.25, -2.0, -2.0];
         let mut out = [0_i16; 3];
 
-        let stats = downmix_stereo_f32_to_mono_i16(&stereo, &mut out, 2.0, false);
+        let stats = downmix_stereo_f32_to_interleaved_i16(&stereo, &mut out, 1, 2.0, false);
 
         assert_eq!(out[0], i16::MAX);
         assert_eq!(out[1], 0);
@@ -159,7 +117,7 @@ mod tests {
         let stereo = [1.0_f32, 1.0, -1.0, -1.0];
         let mut out = [123_i16; 2];
 
-        let stats = downmix_stereo_f32_to_mono_i16(&stereo, &mut out, 1.0, true);
+        let stats = downmix_stereo_f32_to_interleaved_i16(&stereo, &mut out, 1, 1.0, true);
 
         assert_eq!(out, [0, 0]);
         assert_eq!(stats, RenderDownmixStats::default());
@@ -234,7 +192,7 @@ mod tests {
         let mut scratch = [1.0_f32, 1.0, -0.5, -0.5, 0.8, 0.8];
         limit_peak_inplace(&mut scratch, 0.95);
         let mut out = [0_i16; 3];
-        let stats = downmix_stereo_f32_to_mono_i16(&scratch, &mut out, 1.0, false);
+        let stats = downmix_stereo_f32_to_interleaved_i16(&scratch, &mut out, 1, 1.0, false);
         assert_eq!(stats.clipped_samples, 0);
         assert!(stats.peak_i16 < i16::MAX);
     }

crates/chanora_diagnostics/src/lib.rs

@@ -36,7 +36,7 @@
 #![forbid(unsafe_code)]
 #![warn(missing_docs)]
 
-use std::collections::HashSet;
+use std::collections::{HashSet, VecDeque};
 use std::sync::{Arc, Mutex};
 
 use thiserror::Error;
@@ -712,7 +712,7 @@ impl DiagnosticExport {
 /// diagnostic export and state-sync replay verification.
 #[derive(Debug, Clone)]
 pub struct ProtocolEventRecorder {
-    events: Vec<String>,
+    events: VecDeque<String>,
     capacity: usize,
 }
 
@@ -720,17 +720,20 @@ impl ProtocolEventRecorder {
     /// Create a recorder with the given ring-buffer capacity.
     pub fn new(capacity: usize) -> Self {
         Self {
-            events: Vec::with_capacity(capacity),
+            events: VecDeque::with_capacity(capacity),
             capacity,
         }
     }
 
     fn push(&mut self, ts: &str, kind: &str, detail: &str) {
+        if self.capacity == 0 {
+            return;
+        }
         let s = format!("[{ts}] {kind}: {detail}");
         if self.events.len() >= self.capacity {
-            self.events.remove(0);
+            self.events.pop_front();
         }
-        self.events.push(s);
+        self.events.push_back(s);
     }
 
     /// Record a successful connection.
@@ -777,12 +780,12 @@ impl ProtocolEventRecorder {
 
     /// Drain all recorded events and reset the buffer.
     pub fn drain(&mut self) -> Vec<String> {
-        std::mem::take(&mut self.events)
+        self.events.drain(..).collect()
     }
 
     /// Snapshot all recorded events without clearing the buffer.
     pub fn snapshot(&self) -> Vec<String> {
-        self.events.clone()
+        self.events.iter().cloned().collect()
     }
 }
 
@@ -1103,4 +1106,13 @@ mod tests {
         assert_eq!(first, second);
         assert_eq!(drained, first);
     }
+
+    #[test]
+    fn protocol_event_zero_capacity_drops_events() {
+        let mut recorder = ProtocolEventRecorder::new(0);
+        recorder.record_connected("Server");
+
+        assert!(recorder.snapshot().is_empty());
+        assert!(recorder.drain().is_empty());
+    }
 }