refactor: resync with qbqt baseline and restore genre browser

rust/src/player/output.rs

@@ -3,7 +3,7 @@ use cpal::{
     traits::{DeviceTrait, HostTrait, StreamTrait},
     StreamConfig,
 };
-use rb::{RbConsumer, RbProducer, SpscRb, RB};
+use rb::{RbConsumer, RbInspector, RbProducer, SpscRb, RB};
 use std::sync::{
     atomic::{AtomicBool, Ordering},
     Arc,
@@ -13,6 +13,7 @@ use symphonia::core::audio::AudioBufferRef;
 const RING_BUFFER_SIZE: usize = 32 * 1024;
 
 pub struct AudioOutput {
+    _ring: SpscRb<f32>,
     ring_buf_producer: rb::Producer<f32>,
     _stream: cpal::Stream,
     pub sample_rate: u32,
@@ -50,6 +51,7 @@ impl AudioOutput {
         stream.play()?;
 
         Ok(Self {
+            _ring: ring,
             ring_buf_producer: producer,
             _stream: stream,
             sample_rate,
@@ -87,4 +89,13 @@ impl AudioOutput {
         }
         Ok(())
     }
+
+    pub fn flush(&self) {
+        // Wait until the ring buffer is fully emptied by cpal
+        while !self._ring.is_empty() {
+            std::thread::sleep(std::time::Duration::from_millis(10));
+        }
+        // Give the physical DAC an extra 100ms to output the last samples
+        std::thread::sleep(std::time::Duration::from_millis(100));
+    }
 }