Feat: background head-preload for sample libraries

src/init.rs

@@ -121,6 +121,10 @@ pub fn init(args: InitArgs) -> Init {
         app.audio.config.sample_count += index.len();
         initial_samples.extend(index);
     }
+    let preload_entries: Vec<(String, std::path::PathBuf)> = initial_samples
+        .iter()
+        .map(|e| (e.name.clone(), e.path.clone()))
+        .collect();
 
     #[cfg(feature = "desktop")]
     let mouse_x = Arc::new(AtomicU32::new(0.5_f32.to_bits()));
@@ -168,11 +172,23 @@ pub fn init(args: InitArgs) -> Init {
         initial_samples,
         Arc::clone(&audio_sample_pos),
     ) {
-        Ok((s, info, analysis)) => {
+        Ok((s, info, analysis, registry)) => {
             app.audio.config.sample_rate = info.sample_rate;
             app.audio.config.host_name = info.host_name;
             app.audio.config.channels = info.channels;
             sample_rate_shared.store(info.sample_rate as u32, Ordering::Relaxed);
+            app.audio.sample_registry = Some(Arc::clone(&registry));
+
+            if !preload_entries.is_empty() {
+                let sr = info.sample_rate;
+                std::thread::Builder::new()
+                    .name("sample-preload".into())
+                    .spawn(move || {
+                        preload_sample_heads(preload_entries, sr, &registry);
+                    })
+                    .expect("failed to spawn preload thread");
+            }
+
             (Some(s), Some(analysis))
         }
         Err(e) => {
@@ -208,3 +224,20 @@ pub fn init(args: InitArgs) -> Init {
         mouse_down,
     }
 }
+
+pub fn preload_sample_heads(
+    entries: Vec<(String, std::path::PathBuf)>,
+    target_sr: f32,
+    registry: &doux::SampleRegistry,
+) {
+    let mut batch = Vec::with_capacity(entries.len());
+    for (name, path) in &entries {
+        match doux::sampling::decode_sample_head(path, target_sr) {
+            Ok(data) => batch.push((name.clone(), Arc::new(data))),
+            Err(e) => eprintln!("preload {name}: {e}"),
+        }
+    }
+    if !batch.is_empty() {
+        registry.insert_batch(batch);
+    }
+}